Terpenes based hydrophobic deep eutectic solvents for dispersive liquid-liquid microextraction of aliphatic aldehydes in drinking water and alcoholic beverages

Aliphatic aldehydes are a class of organic compounds containing aldehyde groups, which are widespread, and closely related to people's daily life and health. In this work, a series of terpenes based hydrophobic deep eutectic solvents were designed and synthesized using hexafluoroisopropanol as hydrogen bond donor and menthol/thymol as hydrogen bond acceptor. Then they are used as extraction solvent in dispersive liquid-liquid microextraction for extracting and determining seven aliphatic aldehydes from drinking water and alcoholic beverage combined with high performance liquid chromatography-ultraviolet. Due to the fact that these hydrophobic deep eutectic solvents are liquid at the room temperature, a density greater than that of water, a lower viscosity (≤26.10 mPa s, 25 °C), after extraction and centrifugation, the microvolume DES-rich phase in the bottom is convenient for collection and direct analysis without further dissolution or dilution with organic solvents. Some factors affecting the extraction recovery were optimized by one-variable-at-a-time and response surface methodology. Under the optimal conditions, the enrichment factors for the seven aliphatic aldehydes were 48-56. The method had good performance: linear ranges of 1.0-200, 0.5-200, 0.2-200, 0.4-400, 1.0-400, 0.4-400 and 0.4-400 μg L-1 for seven aliphatic aldehydes (r2 ≥ 0.9949), limits of detection of 0.1-0.5 μg L-1, intra-day and inter-day precisions <4.9%. The recoveries of seven aliphatic aldehydes ranged from 76.0 to 119.0%. The proposed dispersive liquid-liquid microextraction method is simple, rapid, highly efficient, and green, which effectively reduces the amount of toxic chemical reagents used and their impact on the environment. Rapid and efficient detection of aliphatic aldehydes helps ensure a healthy diet and has great application prospects in food safety analysis.

Detection of trace components in Xiangdan injection of Dalbergia odorifera based on microextraction and back-extraction along with bar-form-diagram strategy

Xiangdan Injection are commonly used traditional Chinese medicine formulations for the clinical treatment of cardiovascular diseases. However, the trace components of Dalbergia odorifera in Xiangdan Injection pose a challenge for evaluating its quality due to the difficulty of detection. This study proposes a technology combining dispersive liquid-liquid microextraction and back-extraction (DLLME-BE) along with Bar-Form-Diagram (BFD) to address this issue. The proposed combination method involves vortex-mixing tetradecane, which has a lower density than water, with the sample solution to facilitate the transfer of the target components. Subsequently, a new vortex-assisted liquid-liquid extraction step is performed to enrich the components of Dalbergia odorifera in acetonitrile. The sample analysis was performed on HPLC-DAD, and a clear overview of the chemical composition was obtained by integrating spectral and chromatographic information using BFD. The combination of BFD and CRITIC-TOPSIS strategies was used to optimize the process parameters of DLLME-BE. The determined optimal sample pre-treatment process parameters were as follows: 200 μL extraction solvent, 60 s extraction time, 50 μL back-extraction solvent, and 90 s back-extraction time. Based on the above strategy, a total of 29 trace components, including trans-nerolidol, were detected in the Xiangdan Injection. This combination technology provides valuable guidance for the enrichment analysis of trace components in traditional Chinese medicines.

Dispersive liquid-liquid microextraction followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry for determination of six breast cancer drugs in human plasma

Herein, we have developed a novel method of aqueous-sample dispersive liquid-liquid microextraction (AqS-DLLME) followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry (MEKC-MS/MS) for simultaneous determination of breast cancer drugs letrozole, anastrozole, palbociclib, ribociclib, abemaciclib, and fulvestrant in human plasma. Coupling of MEKC to MS was possible due to the use of ammonium perfluorooctanoate (APFO) as a volatile surfactant. The MEKC and MS conditions were optimized to achieve a fast, sensitive, selective, and green analysis enabling full separation of the analytes within 16 min. Electrophoretic buffer was 125 mM APFO at apparent pH 10.5 in 32 % MeOH, while sheath liquid was 70 % MeOH with 0.2 % formic acid, delivered at 10 µL/min. Excellent extraction recoveries from plasma ranging from 89.4 to 104.9 % were obtained with a combination of protein precipitation and DLLME. The developed method was validated according to the ICH guidelines. Remarkable selectivity, accuracy (bias < 6.7 %), precision (RSD < 15.8 %), and stability (bias < 10.4 %) with insignificant matrix effect (RSD < 14.0 %) and no carry-over were obtained over a wide range of concentrations. Linearity with inter-day slope RSD lower than 8.7 % was demonstrated. With this method, very low concentrations could be detected after the injection of only 68.7 nL of the sample. The method was applied to plasma samples from six women currently receiving breast cancer treatment. Determined concentrations of the drugs of interest agreed with concentrations found in clinical studies, thus proving the suitability of the developed method for therapeutic drug monitoring as a superior alternative to published LC-MS methods.

Molecularly imprinted solid-phase extraction combined with non-ionic hydrophobic deep eutectic solvents dispersed liquid-liquid microextraction for efficient enrichment and determination of the estrogens in serum samples

Hormonal drugs in biological samples are usually in low concentration and highly intrusive. It is of great significance to enhance the sensitivity and specificity of the detection process of hormone drugs in biological samples by utilizing appropriate sample pretreatment methods for the detection of hormone drugs. In this study, a sample pretreatment method was developed to effectively enrich estrogens in serum samples by combining molecularly imprinted solid-phase extraction, which has high specificity, and non-ionic hydrophobic deep eutectic solvent-dispersive liquid-liquid microextraction, which has a high enrichment ability. The theoretical basis for the effective enrichment of estrogens by non-ionic hydrophobic deep eutectic solvent was also computed by simulation. The results showed that the combination of molecularly imprinted solid-phase extraction and deep eutectic solvent-dispersive liquid-liquid microextraction could improve the sensitivity of HPLC by 33∼125 folds, and at the same time effectively reduce the interference. In addition, the non-ionic hydrophobic deep eutectic solvent has a relatively low solvation energy for estrogen and possesses a surface charge similar to that of estrogen, and thus can effectively enrich estrogen. The study provides ideas and methods for the extraction and determination of low-concentration drugs in biological samples and also provides a theoretical basis for the application of non-ionic hydrophobic deep eutectic solvent extraction.

Efficiency comparison of extraction methods for the determination of 11 of the 16 USEPA priority polycyclic aromatic hydrocarbons in water matrices: Sources of origin and ecological risk assessment

As a result of their toxicity, ease of analysis, and environmental occurrence, 16 polycyclic aromatic hydrocarbons (PAHs) were chosen as priority pollutants by the USEPA. Few studies have been conducted to assess the levels of PAHs in South Africa, especially KwaZulu Natal province, and no work has been done in the selected study area. Therefore, this study aimed to evaluate the levels of such PAHs in river water and wastewater samples and evaluate their source and ecological risk. The status of these PAHs in the South African environment has not been investigated fully, which is a gap this study intended to fill. The PAHs were determined using solid-phase extraction (SPE) and dispersive liquid-liquid microextraction (DLLME) methods. The optimization and validation of these methods indicated that both methods can be used for the extraction of PAHs in liquid samples. This is because of the acceptable %recovery of 72.1%-118% for SPE and 70.7%-88.4% for DLLME with a %RSD less than 10% (indicating high precision) that was obtained. The limit of detection and limit of quantification ranged from 5.0 to 18 ng/L and 6.0-20 ng/L for SPE and from 10 to 44 ng/L and 11 to 63 ng/L for DLLME. These results demonstrated that SPE is more accurate and sensitive than DLLME, which was also confirmed by statistical analysis. The PAH concentration levels ranged from not detected (nd) to 1046 ng/L in river water and nd to 778 ng/L in wastewater samples with naphthalene demonstrating dominance over all other PAHs in both water matrices. The PAHs were found to be of petrogenic origin and posed low ecological risk on average. Integr Environ Assess Manag 2024;00:1-13. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A surfactant-based quasi-hydrophobic deep eutectic solvent for dispersive liquid-liquid microextraction of gliflozins from environmental water samples using UHPLC/fluorescence detection

Despite the anticipated exceptional properties of deep eutectic solvents (DES) in microextraction techniques, their self-aggregation behaviour has only been sporadically studied in the previous literature. In the presented study, a novel surfactant-based quasi-hydrophobic deep eutectic solvent (DES) is synthesized and utilized in dispersive liquid-liquid microextraction (DLLME) of three gliflozins in environmental water samples as a proof-of-concept examples. The synthesized DES is composed of benzalkonium chloride (BZKCl) as a hydrogen bond acceptor and octanol (Oct) as a hydrogen bond donor. A full optimization of the extraction conditions was carried out including molar ratio and composition of DES, volume of DES, volume of water samples, extraction time and type of diluting solvent. Moreover, the extraction mechanism was thoroughly investigated, and it was established that the extraction of the target analytes is attributed to the analytes' incorporation into the micelles' cores that facilitates mass transfer from the aqueous layer into DES layer. Furthermore, micelles formed by surfactant-based DES will provide adequate dispersion of extractant phase within water samples, which consequently improves the extraction efficiency. Micelles formation was confirmed by transmission electron microscopy (TEM). Furthermore, 1H NMR spectra verifies that the synthesized DES keeps its integrity even after extraction, which excludes any decomposition of DES after DLLME procedure. The extraction recovery is in an excellent agreement with the hydrophobicity of the investigated drugs, being the highest for the most hydrophobic one. The extracted analytes were separated by UHPLC coupled with fluorescence detection. Under the optimized experimental conditions, the method exhibits excellent linearity and a high detection sensitivity with a limit of detection of 0.5, 2.0 and 0.1 ng mL-1 for EMP (empagliflozin), DAP (dapagliflozin) and CAN (canagliflozin), respectively. The greenness of the developed microextraction approach was assessed by different greenness metrics such as Complex GAPI and AGREE tools. The developed method shows excellent greenness of synthetic procedure for preparation of DES, the environmentally benign nature of DLLME procedure as well as the greenness of the developed UHPLC approach.

A reverse micelle-mediated dispersive liquid-liquid microextraction coupled to high-performance liquid chromatography for the simultaneous determination of agomelatine and venlafaxine in pharmaceuticals and human plasma

An eco-friendly dispersive liquid-liquid microextraction mediated with a reverse micelle and coupled to an HPLC-DAD was developed for the simultaneous determination of venlafaxine and agomelatine in dosage forms and human plasma. All the parameters affecting the extraction efficiencies of both drugs were investigated and optimized. Under the optimal conditions, an effective analytes' preconcentration with enrichment factors (EFs) up to 72 was achieved. The linearity of the method was established over the concentration range of 0.50-70.0 and 3.0-100.0 ng/mL for venlafaxine and agomelatine, respectively with good correlation coefficients > 0.998. The method exhibited low detection limits in the range of 0.15-0.89 ng/mL and excellent precisions expressed in %RSD < 3% with average recoveries between 95.0 to 101.0%. The proposed method was employed to analyze the targeted analytes in dosage forms and human plasma samples with favorable characteristics like excellent enrichment, high sensitivity, great accuracy, and high precision. Finally, the greenness of the developed method was assessed using three distinct metric tools, confirming the greenness of the proposed method. The findings of this research could have more general implications for the extraction of other analytes from various matrices.

A green deep eutectic solvent based dispersive liquid-liquid microextraction for the quantitative analysis of 21 polychlorinated biphenyl metabolites in food of animal origin using injector port silylation-gas chromatography-tandem mass spectrometry

An analytical method was developed for the quantitative determination of 21 polychlorinated biphenyls (PCBs) metabolites (17 were -OH, 1 -MeO, and 3 were MeSO2) in foods of animal origin using deep eutectic solvent (DES) based dispersive liquid-liquid microextraction followed by injector port silylation-gas chromatography-tandem mass spectrometry. The type of DES (thymol: camphor, 1:1 molar ratio) and optimum volume of DES (300 µL), pH (7.0), and disperser solvent (acetonitrile) were optimized to attain the maximum extraction efficiency. The limit of detection, limit of quantification, and percent recovery were found to be in the range of 0.12-0.23 ng/mL, 0.40-0.76 ng/mL, and 80.1-111.4%, respectively. The expanded uncertainty was observed to be in the range of 7.2-22.8% for the targeted analytes. The proposed method was applied to real food samples (milk, meat, fish, and egg) and the levels were found to be in the range of 0.64-32.14 ng/g. This is first of its kind method using green solvent based method for the analysis of PCB metabolites (-OH, MeO, and MeSO2) and will find extensive application in routine testing for foods of animal origin.

Deep eutectic solvent-based modified quick, easy, cheap, effective, rugged, and safe extraction combined with solidification of floating organic droplet-dispersive liquid-liquid microextraction of some pesticides from canola oil followed by gas chromatography analysis

Herein, a modified quick, easy, cheap, effective, rugged, and safe extraction was developed based on deep eutectic solvent for the extraction of several pesticides from canola oil samples. In this work, first, different sorbents were selected to remove the sample interferences, and the composition of the sorbents was optimized by simplex centroid design. The extracted analytes were more concentrated by solidification of floating deep eutectic solvent droplet-dispersive liquid-liquid microextraction. Low limits of detection (0.15-0.23 ng/g) and quantification (0.49-0.76 ng/g), high extraction recoveries (74-87%) and enrichment factors (224-263), and good repeatability (relative standard deviation equal to or less than 5.1 and 4.7% for intra- and interday precisions, respectively) were achieved using the proposed method. The suggested approach was used for the quantification of the analytes in different canola oil samples. Additionally, the effects of microwave irradiations exposure and sonication in decontamination of the samples were evaluated. In this method, there was no need for centrifugation and toxic solvents. Also, effective extraction of the analytes and minimizing interferences were achieved through the use of various sorbents.

Rapid determination of ampyra in urine samples using dispersive liquid-liquid microextraction coupled with ion mobility spectrometry

Ampyra (AMP, 4-Aminopyridine) is a potassium channel blocker that attracts growing research interest due to its adverse effects at high doses. The fast analysis of AMP is challenging because it typically requires complex analytical techniques. In this research, we developed and validated a novel method to assess the fast and quantitative analysis of AMP from real samples. This method combines the strength of ion mobility spectrometry (IMS) for rapid detection and the dispersive liquid-liquid microextraction as a fast and effective preconcentration method for the preconcentration/extraction of AMP. In this method, Ag nanoparticles were used as modifier agents. Moreover, the proposed mechanism for interaction of AMP with AgNPs was investigated based on the quantum theory of atoms in molecules (QTAIM) analysis. Also, the sensitivity of the proposed method was improved through the application of a delay on the carrier gas flow after sample injection. Under the optimum conditions, the developed method detected AMP in the linear range of 0.4-16 μmol L^-1 with a detection limit of 0.12 µmol L^-1. Finally, the developed method was successfully employed to quantify AMP in urine samples. Method validation was performed by comparing our results with those obtained by HPLC-UV/Vis, confirming the applicability of the proposed method for the AMP analysis in real samples. The proposed method will open up a new door toward developing simple, fast, and effective analytical methods.

Aromatic hydrocarbons extracted by headspace and microextraction methods in water-soluble fractions from crude oil, fuels and lubricants

Two extraction protocols were developed for the determination of mono- and poly-aromatic hydrocarbons in water-soluble fractions from gasoline, diesel, crude, mineral insulating, and lubricant oils. Development of the procedures was based on clean miniaturized strategies, such as headspace extraction and vortex-assisted dispersive liquid micro-extraction, together with quantification by gas chromatography-mass spectrometry. The mono-aromatic hydrocarbons were extracted using the headspace extraction method. The linear range obtained was 10-500 µg L^-1, with r² > 0.99. Based on the parameters of the analytical curves, detection and quantification limits of 2.56-3.20 and 7.76-9.71 µg L^-1 were estimated. In addition, the method showed adequate recoveries of 69.4-83.5%, with a satisfactory precision of 4.7-17.1% (n = 5). Micro-extraction was applied for the poly-aromatics and the most favorable variables were sample volume (5.00 mL) in sodium chloride medium (1%, w/v), trichloromethane as extractor solvent (75 µL), acetone as disperser (925 µL) and vortexing for 1 min. Under these conditions, analytical curves of 0.15-4.00 µg L^-1 were obtained and limits of determination and quantification were 0.03-0.15 and 0.09-0.46 µg L^-1, respectively. Recovery values of 87.6-124.5% and a maximum relative standard deviation of 18.9% (n = 5) verify satisfactory accuracy and precision. This led to the achievement of enrichment factors for poly-aromatic hydrocarbons of 41-89 times. Finally, the methods were employed in samples of water-soluble fractions for the determination of analytes. The values followed the order: gasoline > diesel > crude > lubricant > mineral insulating oil. These results indicate an increase in lighter fractions, followed by poly-aromatics in more refined products.

Effervescent powder-assisted floating organic solvent-based dispersive liquid-liquid microextraction for determination of organochlorine pesticides in water by GC-MS

An effervescent powder-assisted floating organic solvent-based dispersive liquid-liquid microextraction was introduced for determination of 13 organochlorine pesticides in water samples. In this method, a less toxic low-density organic solvent was used as extraction solvent. The extraction solvent was dispersed in to the aqueous sample via CO₂ bubbles, in-situ generated up on addition of water to a falcon tube containing the mixture of effervescent powder precursors as well as the extraction solvent. Various experimental parameters such as effervescent and its weight fractions, extraction solvent type and its volume, the total mass of effervescent precursors, and the effect of salt were investigated and the optimal conditions were established. Under the optimum conditions, the proposed method exhibited good linearity for all target pesticides with the coefficient of determinations varying from 0.9981 to 0.9997. The limits of detection and quantification were within the range of 0.03-0.24 and 0.26-0.75 μg/L, respectively. The intra- and inter-day precisions which were expressed in terms of the relative standard deviation ranged from 0.33 to 4.47 and 0.51-5.52%, respectively. The enrichment factors and recoveries ranged from 24 to 293 and 76-116%, respectively. The proposed method could be used simple, cheap, fast, and environmentally friendly alternative for analysis of organochlorine pesticides from environmental water and other similar matrices.

Analysis of alkylphenols, bisphenols and alkylphenol ethoxylates in microbial-fermented functional beverages and bottled water: Optimization of a dispersive liquid-liquid microextraction protocol based on natural hydrophobic deep eutectic solvents

In this work, the analysis of alkylphenols, bisphenols and alkylphenol ethoxylates in bottled waters, kombuchas and water kefir was performed through a vortex-assisted dispersive liquid-liquid microextraction method based on a natural hydrophobic eutectic solvent. For this purpose, mixtures of monoterpenes and fatty acids were employed. Different factors affecting extraction were optimized and the method was validated in terms of matrix effect, linearity, limits of detection and recovery. Recovery values varied between 70.0 and 124.3% (except for 4-tert-butylphenol: 67.0% and 4-n-nonylphenol: 60.8% in water kefir) and limits of detection were in the range 0.10 ng/L - 2.99 µg/L. Finally, 8 bottled waters, 8 kombuchas and 4 water kefirs were analyzed and 4-tert-octylphenol monoethoxylate was detected in water (20.28 ± 0.99 - 62.08 ± 3.63 µg/L). This is the first application analyzing xenobiotic contaminants in kombucha and water kefir and the first time in which the three types of compounds are simultaneously extracted by dispersive liquid-liquid microextraction.

Reversed-phase dispersive liquid-liquid microextraction based on decomposition of deep eutectic solvent for the determination of lead and cadmium in vegetable oil

In this work, a reversed-phase dispersive liquid-liquid microextraction procedure based on the decomposition of deep eutectic solvent was suggested for the first time. The procedure was utilized for fast and simple separation of lead and cadmium from vegetable oil samples. The procedure assumed mixing of oil sample and DES based on menthol, formic acid and water. Water as component of DES promoted its decomposition in sample matrix resulting menthol dissolution in the sample phase and dispersion of aqueous formic acid solution. In this procedure menthol acted as a dispersive solvent during DES decomposition for dispersion of aqueous formic acid solution. The metals were determined by the square-wave anodic stripping voltammetry. The limits of detection, were 0.01 µg kg^-1 for lead and 0.006 µg kg^-1 for cadmium. The RSD was less then 6% for both analytes. The enrichment factor was 36 and 39 for lead and cadmium, respectively.

Artificial networks for spectral resolution of antibiotic residues in bovine milk; solidification of floating organic droplet in dispersive liquid-liquid microextraction for sample treatment

The intensive use of antibiotics in livestock practice has a negative impact on human health and increases the antibiotic resistance. In this study feasible data interpretation algorithm along with efficient extraction protocol were combined for selective analysis of three antibiotics in milk samples. Trimethoprim, sulphamethoxazole and oxytetracycline are widely used antibiotics in veterinary pharmaceuticals. The studied antibiotics were efficiently extracted from milk samples with solidification of floating organic droplet in dispersive liquid-liquid microextraction. This extraction protocol was optimized not only to maximize extraction recoveries but also to approach the lower residue limits specified by European Union. Artificial neural networks succeeded in resolving spectral overlap between the studied drugs. The network architecture was optimized and validated for accurate and precise analysis. The proposed method outweighs the reported chromatographic methods for being simple and inexpensive and compared favorable to official methods.

In-syringe dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction (DLLME) has recently been widely used in the separation and preconcentration of various chemical species. Among the various approaches using DLLME are systems that use a syringe as an extraction environment. In this review, details of some methods that use this approach are presented. The ways to promote dispersion, analytical characteristics, and the advantages and disadvantages of the methods, among other aspects, are discussed critically. Finally, some trends in the use of in-syringe microextraction systems are described.

New low viscous hydrophobic deep eutectic solvents for the ultrasound-assisted dispersive liquid-liquid microextraction of endocrine-disrupting phenols in water, milk and beverage

In the present work, several new hydrophobic deep eutectic solvents (HDESs) were prepared with quaternary ammonium salts as hydrogen bond acceptors (HBAs) and salicylate esters as hydrogen bond donors (HBDs). Then, the obtained HDESs were used as extraction solvents to establish an ultrasound-assisted dispersive liquid-liquid microextraction method combined with high-performance liquid chromatography-ultraviolet detection technique for the determination of four endocrine-disrupting phenols (EDPs) compounds. One of the obtained HDESs composed of tetrabutylammonium chloride (N₄₄₄₄Cl) and methyl salicylate possessed a viscosity of 89.28 mPa•s lower than most reported ionic HDESs (>200 mPa•s), and the low viscous HDES was selected as the optimal extraction solvent. Several key parameters affecting the extraction efficiency were investigated, including the type and volume of HDES, ultrasound time, sample solution pH and salt addition. Under the optimized experimental conditions, the proposed method had good coefficients of determination (R² > 0.9976) in the linear range of 0.5-400 µg•L^-1, the limits of quantification and limits of detection respectively were 0.5-2.5 µg•L^-1 and 0.25-1 µg•L^-1, and the recoveries were in the range of 81.79-109.82%. Finally, the method was used for the preconcentration and determination of EDPs in different samples, including bottled water, tea beverage and milk.

Strategies of dispersive liquid-liquid microextraction for coastal zone environmental pollutant determination

Coastal zone means the interface of land and sea, and therefore, environmental pollutants steaming from land-based activities (like manufactories) and sea-based activities (like shipping) are all existing in coastal zone. These pollutants usually have characteristics of low residues, complicated matrices, easy accumulation and so on, causing difficulty to detect coastal pollutants quickly and sensitively. It is imperative to perform effective sample preparation prior to instrumental analysis. Dispersive liquid-liquid microextraction (DLLME) has attracted significant research interest for sample preparation, owing to its high enrichment ability, low reagent/sample consumption, and wide analyte/matrix applicability, as well as robustness, simplicity, rapidity and inexpensiveness. Herein, we comprehensively review the recent advancements of DLLME technology and its analytical parameters including enrichment principles, extraction modes, and practical application; the emphasis is on novel mode-construction and representative coastal-environmental pollutants extraction. Construction strategies are highlighted by classifying DLLME into five major modes, according to extractant's types, including normal ones, low density solvents, ionic liquids, deep eutectic solvents and others. The coupling of DLLME with other extraction techniques like solid-phase extraction is also briefly introduced. The strengths and weaknesses of each strategy and its rationality are also elaborated. In addition, some typical applications of the different DLLME modes for the determination of organic compounds and heavy metals in coastal water, sediment, soil, and biota are summarized. The increasingly concerned green aspects and instrumentation of DLLME are presented, and finally, the challenges and perspectives of the DLLME for environmental analysis are proposed.

Dispersive liquid-liquid microextraction based on deep eutectic solvent for elemental impurities determination in oral and parenteral drugs by inductively coupled plasma optical emission spectrometry

A simple, fast, sensitive and green pretreatment method for determination of Cd, Co, Hg, Ni, Pb and V in oral and parenteral drug samples using inductively coupled plasma optical emission spectrometry (ICP OES) has been developed. According to United States Pharmacopoeia (USP), those metals must be reported in all pharmaceutical products for quality control evaluation (i.e., elemental impurities from classes 1 and 2A of USP Chapter 232). To improve the analytical capabilities of ICP OES, a dispersive liquid-liquid microextraction (DLLME) has performed using a safe, cheap and biodegradable deep eutectic solvent (DES) as extractant solvent (a mixture of 2:1 M ratio of DL-menthol and decanoic acid). Seven parameters affecting the microextraction efficiency have carefully optimized by multivariate analysis. Under optimized conditions, the DES-based DLLME-ICP OES procedure improved limit of quantitation (LOQ) values on range from 12 to 85-fold and afforded an enrichment factor on average 60-times higher than those obtained to direct ICP OES analysis. Consequently, LOQ values for Cd, Co, Hg, Ni, Pb and V have been on average 10-times lower than target limits recommended for drugs from parenteral route of administration. Trueness has evaluated by addition and recovery experiments following USP recommendations for three oral drug samples in liquid dosage form and three parenteral drugs. Recovery and RSD values have been within the range of 90-109% and 1-6%, respectively. All analytes were below the respectives LOQ values, hence, lower than the limits proposed by USP Chapter 232.

Simultaneous determination of mitotane, its metabolite, and five steroid hormones in urine samples by capillary electrophoresis using β-CD2 SDS1 complexes as hydrophobic compounds solubilizers

Mitotane is a cytotoxic drug used in the treatment of inoperable adrenocortical carcinoma, it inhibits steroidogenesis as well, and therefore monitoring the level of steroid hormones in patients treated with mitotane is a crucial point of therapy. Hence, we have developed a simple, fast, and efficient electrophoretic method combined with reverse polarity sweeping as online preconcentration technique and dispersive liquid-liquid microextraction for the simultaneous determination of mitotane, its main metabolite DDA, and five steroid hormones (progesterone, testosterone, epitestosterone, cortisol, and corticosterone) in urine samples. In addition, a new sample matrix consisting of β-CD₂ SDS₁ complexes for a high hydrophobic compounds solubilization was developed. Approach based on the application of β-cyclodextrin and SDS complex of a ratio 2:1 allowed for hydrodynamic injection into the capillary of a solution containing both mitotane and other analytes. The detection limits of the analytes for the reverse polarity sweeping-dispersive liquid-liquid microextraction method were found to be in the range of 1.5-3 ng/mL, which were approximately 1000 times lower than in the conventional hydrodynamic injection (5 s, 0.5 psi) without any preconcentration procedure. All analytes were completely resolved in less than 13 min by uncoated silica capillary with an inner diameter of 75 μm (ID) × 60 cm. Electrophoretic separation was performed in reverse polarity with a voltage of -25 kV with a background electrolyte (BGE) consisting of 100 mM SDS, 25% ACN, 25 mM phosphate buffer (pH 2.5), and 7 mM β-cyclodextrin.

Determination of morphine and norlaudanosoline in murine brain regions by dispersive liquid-liquid micro-extraction and liquid chromatograpy-electrochemical detection

Morphine can be synthesized endogenously by mammals from dopamine via the intermediate norlaudanosoline. Previously, both compounds have been detected separately in whole brains of mice and brain regions of rats, and in urine of humans. Here, we report a novel method for the analysis of both compounds in single murine brain regions. Initially, a variant of dispersive liquid-liquid microextraction was established by using methanol as an extractant, cyclohexane as solvent, and tributylphosphate as disperser. The extraction method was applied to murine brain regions homogenized with perchloric acid while the subsequent detection was carried out by HPLC with electrochemical detection. In the thalamus of C57Bl/6J mice (n = 3, male, age 4-8 months), morphine and norlaudanosoline could be detected at levels of 19 ± 3.9 and 7.2 ± 2.3 pg/mg, respectively. Overall, we provide a novel method for the simultaneous extraction and detection of both morphine and norlaudanosoline in single murine brain regions.

Determination of imidacloprid and acetamiprid in bottled juice by a new DLLME-HPLC

A new kind of surfactant-emulsified vortex-assisted dispersive liquid-liquid microextraction method (SE-VA-DLLME) using benzyldimethyldodecylammonium chloride (BDDAC) as emulsifier and disperser has been developed for the determination of imidacloprid and acetamiprid in bottled grenadine and black currant juice samples prior to high-performance liquid chromatography-diode array detection. For grenadine juice and black currant juice, LODs were 0.78 and 0.45 μg/L and 0.81 and 0.83 μg/L and LOQs were 2.8 and 1.7 μg/L and 3.2 and 2.8 μg/L for imidacloprid and acetamiprid, respectively. The linear ranges were wider than 10-3000 μg/L with a correlation coefficient higher than 0.9913, the extraction recoveries were in the range of 61.6-84.2%, the enrichment factors were in the range of 27.0-43.3, and the recoveries and relative standard deviations of the studied neonicotinoids were in the range of 91.94-99.63% and 2.8-6.7%, respectively. The proposed method is presented as a simple, cheap, precise, accurate, and sensitive alternative for the determination of imidacloprid and acetamiprid in bottled grenadine juice and black currant juice samples.

Development of a magnetic dispersive solid phase extraction method by employing folic acid magnetic nanoparticles as an effective, green, and reliable sorbent followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of seven pesticides from fruit juices

Folic acid magnetic nanoparticles have been prepared and utilized as an effective and reliable sorbent in magnetic dispersive solid phase extraction combined with dispersive liquid-liquid microextraction for the extraction of seven pesticides from different juices before their determination by gas chromatography-flame ionization detector. The sorbent is prepared through ball milling process using a proper mixture of folic acid and magnetic iron oxide. Characterization of the sorbent was done with X-ray diffraction pattern, scanning electron microscopy, and vibrating sample magnetometry. In the current study, limits of detection were in the range 0.12-0.33 μg L^-1. Relative standard deviations at a concentration of 40 μg L^-1 of each analyte were in the ranges of 2.15-5.14% for intra-day (n = 6) and 3.78-6.91% for inter-day (n = 4) precisions. Extraction recoveries and enrichment factors were obtained in the ranges of 70-88 % and 566-708, respectively. The performance of the method was evaluated by determination the selected pesticides in different samples. Graphical Abstract.

Determination of bisphenol a migration from food packaging by dispersive liquid-liquid microextraction

In the current work, a rapid and simple dispersive liquid-liquid microextraction method (DLLME) was used to determine Bisphenol A (BPA). High performance liquid chromatography with the photodiode-array detector (HPLC-DAD) coupled DLLME method was employed to analyze BPA in food samples packaged including cans, paper boxes, and glass jars. The calibration curve was obtained to be in the linear range 0.009-25 ngg^-1 with a correlation coefficient of R2 = 0.9981. The mean relative standard deviations (RSDs) was of 5.2% (n = 3). The limit of detection (LOD) and the limit of quantification (LOQ) of the method were obtained to be 0.001 ngg^-1 and 0.08 ng.g^-1, respectively. In sum, this method presents:•A rapid, simple and efficient modified DLLME method was used to measure BPA in packaged foods.•The advantages of this method were low detection limit, fast preparation, and high BPA recovery.•The DLLME-HPLC method consists of low detection limit and high recoveries to determine BPA in samples.•The results indicated that DLLME -HPLC-DAD was an applied method to measure BPA in food samples.

Determination of Six Tetracyclines in Eggs and Chicken by Dispersive Liquid-Liquid Microextraction Combined with High-Performance Liquid Chromatography

BACKGROUND

The wide livestock usage of tetracyclines may result in drug residues in foods. Therefore, it is necessary to develop reliable methods for the determination of tetracyclines in foods.

OBJECTIVE

A dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC) method was developed for the analysis of six tetracyclines in eggs and chicken.

METHODS

After deproteinization, tetracyclines in acidic solutions were concentrated by vortex-assisted DLLME. Followed by the addition of NaCl (35% for eggs and 20% for chicken), a mixture of ionic liquid [Bmim]PF6 and ethyl acetate (300 μL-50 μL for eggs and 200 μL-60 μL for chicken) was used as the extractant. After centrifugation, the extract was collected for HPLC analysis.

RESULTS

The developed method showed good linear relationship (10.0-500 μg/kg), low method detection limits (0.219-1.42 μg/kg) and quantification limits (0.731-4.72 μg/kg), satisfactory relative recoveries (87.1-104%) with intra-day and inter-day RSDs in the ranges of 0.853-8.62% and 1.65-11.8%, respectively. The established method was successfully applied for the determination of six tetracyclines in eggs and chicken of different parts. The contents of tetracyclines in all samples were lower than their maximum residue limits.

CONCLUSIONS

A DLLME-HPLC method has been developed for the analysis of six tetracyclines in animal derived foods using ionic liquid and ethyl acetate as the extractant.

HIGHLIGHTS

The developed method is simple, sensitive, cost-effective and has strong anti-interference ability. This method has been successfully applied to the analysis of six tetracyclines in eggs and chicken.

Preparation of new hydrophobic deep eutectic solvents and their application in dispersive liquid-liquid microextraction of Sudan dyes from food samples

In this work, a new generation of hydrophobic deep eutectic solvents (DESs) was prepared using eugenol (as hydrogen bond donor) and benzyltriethylammonium bromide, benzyltributylammonium bromide, benzyltriethylammonium chloride and benzyltributylammonium chloride (as hydrogen bond acceptor) in different molar ratios. These DESs were applied to vortex-assisted dispersive liquid-liquid microextraction of Sudan dyes from food samples, followed by high-performance liquid chromatographic determination. The influencing parameters, including the type of DES, amount of DES, extraction time, solution pH and salt addition, were investigated and optimized. Under the optimized conditions, a linear range of 2-1000 ng mL^-1 with determination coefficients of <0.999 was obtained. Limits of detection and limits of quantification were in the range of 0.5 to 1 ng mL^-1 and 2 to 3 ng mL^-1, respectively. The proposed method was successfully used in the determination of Sudan dyes in chili sauce, chili powder and ketchup, and satisfactory recoveries of between 89.9 and 119.3% were obtained, with relative standard deviations in the range of 0.1-6.8%. The proposed method is simple, green and efficient, and can be applied to determine Sudan dyes in complex matrices.

Sensitive determination of methotrexate in plasma of children with acute leukemia using double-solvent supramolecular systemas a novel extractant for dispersive liquid-liquid microextraction

Methotrexate, as a folate antagonist, is one of the first anti-neoplasm drugs offered and is still used as an effective drug in the treatment of various malignancies. Methotrexate has a narrow treatment index and is associated with numerous side effects.In thisresearch, for the first time a double-solvent supramolecular system (DSS) was developed as an extractant without disperser solvent for dispersive liquid-liquid microextraction (DLLME). DSS - DLLME was applied to the extraction of methotrexate in plasma of children with acute leukemiaprior to itsdetermination by high-performance liquid chromatography-ultraviolet detection (HPLC - UV). In the present method, two long normal chain alcohols are mixed in a particular ratio, and then it is injected into the sample solution, which is on the magnetic stirrer. In this case, the mixture of the two alcohol changes to new supramolecular aggregate. This new supermolecule is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 0.1-150 µg L^-1 with detection limit of 0.03 µg L^-1. Relative standard deviations (RSDs) including intra-day and inter-day of method based on7 replicate determinations of 100.0 µg L^-1of methotrexate were 2.6% and 4.8%,respectively. The results proved that DSS - DLLME is a sensitive, very simple, inexpensive, environmental friendly, rapid and efficient method for the preconcentration of trace amount of drugs in biological samples.

Essential oil-based dispersive liquid-liquid microextraction for the determination of N,N-dimethyltryptamine and β-carbolines in human plasma: A novel solvent-free alternative

The present study describes the development of a novel solvent-free vortex-assisted dispersive liquid-liquid microextraction alternative based on a natural essential oil as extracting solvent (VA-EO-DLLME) for the determination of N,N-dimethyltryptamine (DMT), harmine (HRM), harmaline (HRL) and tetrahydroarmine (THH) (compounds found in the ayahuasca tea, a psychedelic plant preparation) in human plasma. After optimization through full factorial and Box-Behnken experimental designs, this VA-EO-DLLME followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was completely validated and applied to authentic plasma specimens. Sample preparation consisted in the addition of 60 mg of NaCl, 100 μL of borate buffer and 100 μL of Eucalyptus globulus essential oil to a 200 μL aliquot of human plasma. After 30 s of vortex agitation followed by 5 min of centrifugation (10,000 rpm), 80 μL of the oil supernatant was dried and resuspended in mobile phase prior to injection into the UHPLC-MS/MS system. Once optimized, the validated method yielded LoDs ≤1.0 ng mL^-1 for all analytes. LoQ was 1.0 ng mL^-1 for DMT, HRL and HRM and 2.0 ng mL^-1 for THH. The method has shown to be linear over the range of LoQ up to 150 ng mL^-1 (r² ≥ 0.9926). Intra/inter-day precision and accuracy met the acceptance criteria at three quality control (QC) levels. An additional intermediate precision study demonstrated that, except for THH and HRL at low and medium QCs, the overall method performance was similar for the three different oil sources. Matrix effect evaluation showed predominant ion suppression, ranging from 56% to 83%. Recovery varied from 33 up to 101% with an average of 50 ± 15.8%. Selectivity studies showed no interferences. Analysis of 13 authentic samples proved method feasibility. Finally, we believe that our novel VA-EO-DLLME approach offers a very simple, fast, cost-effective and eco-friendly alternative based on the use of an easily accessible and entirely green material as an extracting solvent. This may represent an incentive for researchers to investigate novel and creative alternatives, such as essential oils, as substitutes of organic solvents for microextraction methods in forensic and clinical contexts.

Determination of teicoplanin in human plasma by reverse micelle mediated dispersive liquid-liquid microextraction with high performance liquid chromatography

A reverse micelle mediated dispersive liquid-liquid microextraction (RM-DLLME) combined with high performance liquid chromatography-ultraviolet detector (HPLC-UV) was developed for extraction and determination of 5 A₂ components of teicoplanin (TA_2-1, TA_2-2, TA_2-3, TA_2-4, TA_2-5) in human plasma, and the mechanism of RM-DLLME was analysed and explored. In this method, 80 µL of the reverse micelle solution of cetylpyridinium chloride/n-hexanol (15 mmol/L) was used as the extraction solvent for the separation, extraction and enrichment of the teicoplanin in plasma sample. All factors affecting the extraction efficiencies of the target analytes, such as the amounts of acetonitrile and chloroform, the type and volume of reverse micelle solution, pH and volume of sample phase, dispersant, salt addition, extraction mode and time, centrifugation rate and time, were investigated and optimized. Under the optimum conditions, the 5 A₂ components of teicoplanin achieved effective enrichment with the enrichment factors of 228-347 and obtained good linearity in the range of 0.8375-100.5 µg/mL with correlation coefficients higher than 0.9960. The limits of detection were ranged between 0.5025-3.015 µg/mL. Relative standard deviation values of the method precisions were lower than 10.6% and the average recoveries were in the range of 82.7-111.3%. The determination results of the method were demonstrated with favorable characteristics, such as high enrichment, good selectivity and sensitivity, satisfactory precision and accuracy, and this method could be employed to analysis of the teicoplanin in human plasma samples.

Dispersive liquid-liquid microextraction using a low transition temperature mixture and liquid chromatography-mass spectrometry analysis of pesticides in urine samples

Biomonitoring is a potent tool to control the health risk of people occupationally and non-occupationally exposed. The latest trend in bioanalytical chemistry is to develop quick, cheap, easy, safe and reliable green analytical procedures to analyse a large number of chemicals in easily accessible biomatrices such as urine. In this paper, a new dispersive liquid-liquid microextraction (DLLME) procedure, conceived to treat urine samples and based on the use of a low transition temperature mixture (LTTM), was developed and validated to analyse twenty pesticides commonly used in farm practises. The LTTM was composed of choline chloride and sesamol in molar ratio 1:3 (ChCl:Ses 1:3); its characterization via differential scanning calorimetry identified it as an LTTM and not as a deep eutectic solvent due to the occurrence of a glass transition at -71 °C. The prepared mixture was used as the extraction solvent in the DLLME procedure, while ethyl acetate as the dispersing solvent. The salting out effect (50 mg mL^-1 of NaCl in a diluted urine sample) improved the separation phase and the analyte transfer to the extractant. Due to the high ionic strength and despite the density of ChCl:Ses 1:3 (1.25 g mL^-1), the LTTM layer floated on the top of the sample solution after centrifugation. All extracts were analysed by high-performance liquid chromatography coupled to mass spectrometry. After optimization and validation of the whole method, lower limits of quantitation were in the range of 0.02 - 0.76 µg  L^-1. Extraction recoveries spanned from 50 to 101 % depending on the spike level and analytes. Precision and accuracy ranges were 3-18% and 5-20%, respectively. The extraction procedure was also compared with other methods, showing to be advantageous for rapidity, simplicity, efficiency, and low cost. Finally, urine samples from ten volunteers were effectively analysed using the developed method.

Microscale extraction versus conventional approaches for handling gastrointestinal extracts in oral bioaccessibility assays of endocrine disrupting compounds from microplastic contaminated beach sand

The unified bioaccessibility method (UBM) was harnessed to assess in vitro oral bioaccessibility pools of dialkyl phthalate congeners (with methyl, -ethyl, -butylbenzyl, -n-butyl, -2-ethylhexyl, and -n-octyl moieties) and bisphenol A at the 17 μg g^-1 level in beach sand contaminated with polyethylene microplastics. A variety of sample preparation approaches prior to the analysis of the UBM gastrointestinal extracts, including traditional methods (protein precipitation, liquid-liquid extraction, and solid-phase extraction) and dispersive liquid-liquid microextraction (DLLME) were comprehensively evaluated for clean-up and analyte enrichment. DLLME was chosen among all tested approaches on account of the high extraction efficiency (73-95%, excluding bis(2-ethylhexyl)phthalate and di-n-octyl phthalate), high sample throughput (∼7 min per set of samples), and environmental friendliness as demonstrated by the analytical eco-scale score of 83, and the green analytical procedure index pictogram with green/yellow labeling. The release of the less hydrophobic plastic-laden compounds (dimethyl phthalate, diethyl phthalate and bisphenol A) from the contaminated sample into the body fluids was significant, with bioaccessibility values ranging from 30 to 70%, and from 43 to 74% in gastric and gastrointestinal fluids, respectively, and with relative standard deviation < 17% in all cases. The majority of the compounds were leached during gastric digestion, likely as the combined action of the low pH and the gastric enzymes. The risk exposure analysis revealed that accumulation/concentration in the body fluids is potentially relevant for dimethyl phthalate, diethyl phthalate and bisphenol A, with relative accumulation ratios ranging from 1.1 ± 0.1 to 2.6 ± 0.4. The average daily intake values for the suite of compounds, corrected with the bioaccessibility fraction, ranged from 60 to 430 ng kg of body weight^-1·day^-1, in all cases, far below the tolerable daily intakes, thus indicating the lack of children health risk by ingestion of microplastic-laden sand with elevated concentrations of plasticizers.

Determination of arsenic species using functionalized ionic liquid by in situ dispersive liquid-liquid microextraction followed by atomic absorption spectrometry

Synthesis and application of a task-specific ionic liquids (TSILs) as extracting solvents or chelating agents in dispersive liquid-liquid micro-extraction (DLLME) was evaluated. The developed method was based on the use of an ammonium pyrrolidine dithiocarbamate (APDC) bonded ionic liquid for chelation with As(III), followed by conversion of the As(III) chelated TSIL to a hydrophobic ionic liquid using KPF₆ as an anion-exchange reagent. As(V) was reduced to As(III), using a 2/1 w/w blend of KI and Na₂S₂O₃ and then the total amount of As was measured through ETAAS analysis. Under optimal conditions, linear dynamic ranges of 0.2-15 ng mL^-1 and 0.2-20 ng mL^-1 were observed in the determination of As(III) and total As respectively. The relative standard deviations (RSD%, n = 5) for the determination of As(III) (10 ng mL^-1) was 3.2% and the limits of detection and quantitation were determined to be 0.01 ng mL^-1 and 0.0.034 ng mL^-1; respectively.

Analysis of Zinc and Chromium in Grain Samples Using Ionic Liquid-Based Ultrasound-Assisted Microextraction Followed by Flame-AAS After Microwave Digestion

A simple, rapid and eco-friendly microextraction method was developed for the determination and preconcentration of zinc (Zn) and chromium (Cr) from grain products by ultrasonic-assisted ionic liquid dispersive liquid-liquid microextraction (UA-IL-DLLME) combined with flame atomic absorption spectrometry (FAAS). Quercetin (2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one dihydrate) was used for the complexation of Zn(II) and Cr(III) ions at different pHs. The 1-hexyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl]imide ([Hmim][NTf2] and acetonitrile were used as extraction solvent and dispersive solvent, respectively. To provide quantitative extraction of analytes, important experimental variables such as pH of sample solution, temperature, ultrasonic time, amount of chelating agent, amount of ionic liquid, type and amount of dispersive solvent, and interference effect were extensively studied and optimized. The detection limits and operating ranges for Zn(II) and Cr(III) using the optimized conditions were 7.5, 25-450 and 2.4, 8-300 μg L^-1, respectively. For the validation of the proposed method, the certified reference material was tested using the standard addition method. After microwave digestion analysis of grain products, relative standard deviations (RSDs%) and recoveries were ranged from 1.2 to 2.3% and from 91.2 to 103.7%, respectively. The UA-IL-DLLME method has been successfully applied for the determination of Zn and Cr in grain samples (chickpea, broad bean, pea, beans, and wheat).

Dispersive liquid-liquid microextraction, an effective tool for the determination of synthetic cannabinoids in oral fluid by liquid chromatography-tandem mass spectrometry

In the present work, dispersive liquid-liquid microextraction (DLLME) was used to extract six synthetic cannabinoids (JWH-018, JWH-019, JWH-073, JWH-200, or WIN 55,225, JWH-250, and AM-694) from oral fluids. A rapid baseline separation of the analytes was achieved on a bidentate octadecyl silica hydride phase (Cogent Bidentate C₁₈; 4.6 mm × 250 mm, 4 μm) maintained at 37 °C, by eluting in isocratic conditions (water:acetonitrile (25:75, V/V)). Detection was performed using positive electrospray ionization-tandem mass spectrometry. The parameters affecting DLLME (pH and ionic strength of the aqueous phase, type and volume of the extractant and dispersive solvent, vortex and centrifugation time) were optimized for maximizing yields. In particular, using 0.5 mL of oral fluid, acetonitrile (1 mL), was identified as the best option, both as a solvent to precipitate proteins and as a dispersing solvent in the DLLME procedure. To select an extraction solvent, a low transition temperature mixture (LTTM; composed of sesamol and chlorine chloride with a molar ratio of 1:3) and dichloromethane were compared; the latter (100 μL) was proved to be a better extractant, with recoveries ranging from 73% to 101 % by vortexing for 2 min. The method was validated according to the guidelines of Food and Drug Administration bioanalytical methods: intra-day and inter-day precisions ranged between 4 % and 18 % depending on the spike level and analyte; limits of detection spanned from 2 to 18 ng/mL; matrix-matched calibration curves were characterized by determination coefficients greater than 0.9914. Finally, the extraction procedure was compared with previous methods and with innovative techniques, presenting superior reliability, rapidity, simplicity, inexpensiveness, and efficiency.

[Determination of metabolites of styrene in urine by dispersive liquid-liquid microextraction coupled with high performance liquid chromatography]

Objective: To establish a method for the determination of mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography. Methods: N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis. Results: The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 μg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 μg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%. Conclusion: The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.

Sensitive determination of deferasirox in blood of patients with thalassemia using dispersive liquid-liquid microextraction based on solidification of floating organic drop followed by HPLC-UV

Deferasirox is an oral iron chelator that has been on the market since 2005 and has been a suitable replacement for injectable chelators. It is important to check the amount of this drug in the blood of patients due to side effects. In this study, a new dispersive liquid-liquid microextraction based on solidification of floating drganic drop (DLLME - SFO) was applied to the extraction of deferasirox in the blood of patients with thalassemia prior to its analysis by high-performance liquid chromatography-ultraviolet detection (HPLC - UV). In this method, two long alcohols of the normal chain are mixed in a particular ratio, and then it is injected into the sample solution, which is on the magnetic stirrer. In this case, the mixture of the two alcohol changes to new double-solvent aggregate. This new double-solvent system is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 0.2-200 μg L^-1 with detection limit of 0.06 μg L^-1. Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 100.0 μg L^-1of deferasirox were 3.8 % and 5.7 %, respectively. The results showed that DLLME - SFO is a very simple, inexpensive, environmental friendly, sensitive and efficient analytical method for the determination of trace amount of drugs in biological samples and suitable results were obtained.

Dispersive liquid-liquid microextraction (DLLME) and external real matrix calibration for the determination of the UV absorber 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328) and its metabolites in human blood

2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328; CAS: 25973-55-1) is a benzotriazole ultraviolet light (BUV) absorber which is applied to plastics and other organic substances to prevent discoloration and enhance product stability. Therefore, UV 328 is frequently used as a plastic additive and may lead to an exposure of consumers. For a reliable assessment of UV 328 metabolism, an analytical method applying dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography tandem mass spectrometry and advanced electron ionization was developed which allows the determination of UV 328 and six of its metabolites in human whole blood. Sample preparation was optimized with respect to DLLME parameters. A critical aspect of the procedure was the application of spiked human blood for calibration, which proved to be essential for achieving accurate results. Validation of the method resulted in limits of detection of 0.1 μg/L for all analytes. Variation coefficients ranged from 2 to 9% for intraday precision and from 3 to 11% for interday precision. Furthermore, relative recovery rates between 80 and 100% were calculated. Afterwards, the procedure was successfully applied to blood samples collected from a volunteer orally exposed to a single dose of UV 328. The method proved to be highly sensitive, repeatable and robust for all compounds and may further be used for studies to elucidate the human metabolism and kinetics of UV 328 and for biomonitoring of specific, environmental and occupational exposure to this UV stabilizer.

Salting-out strategy for speciation of selenium in aqueous samples using centrifuge-less dispersive liquid-liquid microextraction

The centrifuge-less dispersive liquid-liquid microextraction (DLLME) technique was used to separate selenium species in aqueous samples. According to the salting-out effect, a simple approach was used to eliminate the centrifugation step. The optimization of the independent variables was performed using chemometric methods. Under optimal conditions, this methodology was statistically validated. The linearity was between 20 and 300 μg L^-1. The limit of detection and quantification were calculated 3.4 μg L^-1 and 10.4 μg L^-1, respectively. The values of reproducibility and repeatability were determined ≤ 9.5% and ≤ 6.4, respectively. The possibility of the method was successfully assessed by analyzing the analytes in real samples clarified satisfactory recoveries (98.1-101.4% for Se (IV) and 98.4-101.5% for Se (VI)).

HPLC-MS/MS method for the determination of perfluoroalkyl substances in breast milk by combining salt-assisted and dispersive liquid-liquid microextraction

The widespread use of perfluoroalkyl substances has resulted in the universal exposure of humans to these endocrine-disrupting chemicals, including the exposure of neonates through breastfeeding. The objective of this study was to develop a method to determine 10 perfluoroalkyl substances in breast milk (1-mL aliquot) by combining salt-assisted liquid-liquid extraction with dispersive liquid-liquid microextraction and using high-performance liquid chromatography-tandem mass spectrometry. Chemometric strategies were applied to optimize experimental parameters. The limit of quantification was 20 pg mL^-1 for all analytes, and inter-day variability (evaluated as relative standard deviation) ranged from 8.2 to 13.8%. The method was validated by a recovery assay with spiked samples. Percentage recoveries ranged from 85.9 to 110.8%. The method was satisfactorily applied to assess target compounds in 20 breast milk samples from donors. Perfluorooctanoic acid, perfluorooctane sulfonate, and perfluorohexanoic acid were the most frequently detected analytes. This analytical procedure can provide useful information on newborn's exposure to these xenobiotics.

Assessment of perfluoroalkyl substances in placenta by coupling salt assisted liquid-liquid extraction with dispersive liquid-liquid microextraction prior to liquid chromatography-tandem mass spectrometry

The widespread use of perfluoroalkyl substances (PFAS) is resulting in a broad human exposure to these endocrine disrupting chemicals (EDCs), prompting biomonitoring research to evaluate its magnitude and impact, especially during critical windows of exposure such as fetal and perinatal periods. This study was focused on developing a method to determine 10 PFAS in placental tissue by combining salt-assisted liquid-liquid extraction with dispersive liquid-liquid microextraction and using liquid chromatography-tandem mass spectrometry. Chemometric strategies were applied to optimize the experimental parameters. The limit of quantification was 0.02 ng g^-1 for all analytes, and the inter-day variability (as relative standard deviation) ranged from 7.9% to 13.8%. Recoveries ranged from 88.2% to 113.9%. The suitableness of the procedure was demonstrated by assessing the targeted compounds in 20 placenta samples. The highest concentrations were recorded for perfluorooctanoic acid and perfluorooctane sulfonate, with maximum concentrations of 0.62 and 1.02 ng g^-1 and median concentrations of 0.13 and 0.53 ng g^-1, respectively. Median concentrations of the other PFAS ranged from detected values to 0.08 ng g^-1. This analytical procedure yields useful data on fetal exposure to PFAS.

[Determination of manganese in human urine by dispersive ionic liquid-liquid microextraction-graphite furnace atomic absorption spectrometry]

Objective: To establish a method for the determination of manganese in urine with graphite furnace atomic absorption spectrometry (GFAAS) by using ionic liquid microextraction. Methods: The ethanol, 8-hydroxyquinoline and ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, chelating agent and extraction solvent respectively, for the preconcentration of manganese. After the optimal extraction conditions were optimized by single factor rotations, evaluate the performance indicators such as methodological precision, accuracy, and detection limit. Results: The linear range of urine manganese was 0.0-1.6 μg/L, and the correlation coefficient of standard curve line was 0.992, the detection limit was 0.03 μg/L, the recovery of sample spiked was 84.90%-96.50%, and the relative standard deviation was 0.36%-1.84%. Conclusion: The method has the advantages of low detection limit, high recovery rate and high sensitivity. It is suitable for the determination of manganese in urine samples from occupational exposure populations and the general population.

Green, fast and simple dispersive liquid-liquid microextraction method by using hydrophobic deep eutectic solvent for analysis of folic acid in fortified flour samples before liquid chromatography determination

A fast, simple, sensitive, and efficient vortex-assisted dispersive liquid-liquid microextraction method (VA-DES-DLME) was developed based on hydrophobic deep eutectic solvent for extraction of folic acid from flour samples followed by HPLC determination. Hydrophobic DES was prepared by mixing amylalcohol as a hydrogen bond donor and methyltriocthylammonium chloride as a hydrogen bond acceptor. Factors affecting DLLME were considered and optimized. In optimal conditions, the calibration curve was linear in the range 5.0-500 ng g^-1 with a correlation coefficient higher than 0.99. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.0 and 3.0 ng g^-1, respectively. The intra-day and inter-day precision at concentrations of 10 and 100 ng g^-1 were less than 8%. Finally, application of the proposed procedure was investigated by folic acid analysis in flour samples and the relative recoveries obtained were acceptable (Recovery ≥ 90%).

Application of an agitation-assisted dispersed solvent microextraction for analysis of naphthalene and its derivatives from aqueous matrices

Agitation-assisted dispersive liquid-liquid extraction without a dispersing solvent is lately receiving considerable attention owing to the low to no solvent loss relative to its predecessor, which suffers severe extracting solvent loss. Herein, we report the application of a simple agitation-assisted dispersive liquid-liquid microextraction method, without a disperser solvent, for the extraction of naphthalene and its derivatives from aqueous solutions. Under the optimised conditions, namely, 25 μL 3:1 mixture of dichloroethane and ethylacetate with 20 s agitation, in 2-mL aqueous solutions containing 10% NaCl, the method demonstrated acceptable figures of merit: linearity-R² ≥ 0.9914 in the concentration range 0.5-50 ng/mL, repeatability (%RSD ≤ 12.9 for n = 15) and limits of detection (0.034-0.081 ng/mL). The recoveries obtained from the spiked dam water sample were also satisfactory (94-103%). These parameters are comparable with those reported in literature, especially for dispersive liquid-liquid microextraction techniques albeit for different analytes. Despite only naphthol being detected in one of the three sampled sites, the method shows considerable promise for routine monitoring of river and dam water quality subject to accuracy validation using certified reference materials.

Landing microextraction sediment phase onto surface enhanced Raman scattering to enhance sensitivity and selectivity for chromium speciation in food and environmental samples

The current study explores the first full mode liquid microextraction technique coupled with surface-enhanced Raman spectroscopy (SERS), and has been successfully applied for chromium speciation in food and environmental matrices. Herein, chromium as chlorochromate anion [CrO3Cl]- and the cationic rhodamine 6G [RG]+ dye has been extracted in organic phase as a complex ion associate [RG+.CrO3Cl-.nS]org at pH ≤ 1.0. Afterwards, the extracted phase was deposited on the surface of the nano-flower shaped silver nanoparticles substrate and the SERS response was monitored against the reagent blank at 1505 cm-1. Substrate characterizations, reaction mechanism assignment, stoichiometry, speciation, analytical applications, selectivity and validation were performed. The analytical procedure exhibits a detection limit of 0.03 µg L-1 under the optimized experimental conditions. The accuracy of the proposed strategy was validated by inductively coupled plasma optical emission spectrometry method using student's t- and F tests at 95% confidence.

Analysis of multiclass organic pollutant in municipal landfill leachate by dispersive liquid-liquid microextraction and comprehensive two-dimensional gas chromatography coupled with mass spectrometry

We propose a simple, fast, and inexpensive method for the analyses of 72 organic compounds in municipal landfill leachate, based on dispersive liquid-liquid microextraction and comprehensive two-dimensional gas chromatography coupled with mass spectrometry. Forty-one organic compounds belonging to several classes including hydrocarbons, mono- and polyaromatic hydrocarbons, carbonyl compounds, terpenes, terpenoids, phenols, amines, and phthalates, covering a wide range of physicochemical properties and linked to municipal landfill leachate, were quantitatively determined. Another 31 organic compounds such as indoles, pyrroles, glycols, organophosphate flame retardants, aromatic amines and amides, pharmaceuticals, and bisphenol A have been identified based on their mass spectra. The developed method provides good performances in terms of extraction recovery (63.8-127%), intra-day and inter-day precisions (< 7.7 and < 13.9 respectively), linearity (R² between 0.9669 and 0.9999), detection limit (1.01-69.30 μg L^-1), quantification limit (1.87-138.6 μg L^-1), and enrichment factor (69.6-138.5). Detailed information on the organic pollutants contained in municipal landfill leachate could be obtained with this method during a 40-min analysis of a 4-mL leachate sample, using only 75 μL of extraction solvent.

A screen-printed electrode modified with silver nanoparticles and carbon nanofibers in a nafion matrix for ionic liquid-based dispersive liquid-liquid microextraction and voltammetric assay of heterocyclic amine 8-MeIQx in food

An electrochemical method is described for the determination of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx) which is a heterocyclic aromatic amine formed in cooked food samples. The method uses a screen-printed carbon nanofiber electrode that is modified with silver nanoparticles (AgNPs) in a Nafion matrix. The surface of the modified electrode was characterized by UV-vis spectrometry, dynamic light scattering, scanning electron microscopy and Raman spectroscopy. The average size of the AgNPs is 14 nm. The modified electrode exhibits good properties in terms of reversibility, fast kinetics of electron transfer, and large electroactive area toward the reduction of 8-MeIQx. Differential pulse voltammetry is the most suitable electrochemical technique for quantification of 8-MeIQx, best at a voltage of -0.21 V (versus Ag reference electrode). The first derivative serves as the analytical signal that increases linearly in the 0.015-40 mg L^-1 8-MeIQx concentration range, with a 5 μg L^-1 detection limit. A dispersive liquid-liquid microextraction procedure assisted via ionic liquid was developed to isolate the analyte from real samples. The whole extraction-preconcentration and voltammetric method allows to determine 30 and 70 μg L^-1 in (spiked) bouillon cube, meat broth, beer and wine, with recoveries in the 93.6-110.4% range. Graphical abstractSchematic presentation for the analysis of aromatic amine 8-MeIQx, resultant compound from cooking meat. Extracted sample solution was placed onto modified electrode surface thus obtaining voltammetric analytical signal. So, quantification atrelevant levels can be performed.

Validation and Optimization of Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction as a Preparation Method for Detection of Methadone in Saliva with Gas Chromatography-Mass Spectrometry Technique

Purpose: We investigated validation and optimization of ultrasound-assisted dispersive liquidliquid microextraction (UADLLME) as a preparation method for detection of methadone in saliva samples.

Methods: We used blank and methadone-containing saliva samples and also standard methadone solution. Sodium hydroxide and chloroform were added to samples and they were held in ultrasonic bath. Then preparations were centrifuged and extracted analyte was analyzed by gas chromatography-mass spectrometry (GC-MS). Accuracy was measured by Intra and between-day mean relative errors (RE). Precision was assessed by coefficient of variation (CV). Recovery, specificity, linearity and limits of detection and quantification were also determined. Optimization was conducted for ultrasound duration, pH and extraction phase volume. Efficiency of dispersive liquid-liquid microextraction (DLLME) and UADLLME were compared.

Results: Intra and between-day accuracies (2.3 -7.5%), recovery (89.4-115.5%) and precision (5.2-11.3%) were all acceptable. Calibration curve was linear in the concentration range of 150 ng/mL-10 µL/mL with R² >0.9995 and equation of y=86.901x-5342.5. Limits of detection and quantification were 50 and 150 ng/mL, respectively. Specificity was measured by comparing retention times of saliva samples (containing methadone metabolites and other commonly used drugs) during UADLLME/GC-MS analysis and no interference was observed. Recovery of UADLLME was 1.4 of DLLME. Solvent and sample volumes required for UADLLME were 1/200 and 1/20 of DLLME. The greatest efficiency obtained at pH of 10, with ultrasound treatment duration of 5 minutes and extraction phase volume of 1000 µL.

Conclusion: Study found that UADLLME/GC-MS is a valid and efficient method for detection of methadone in oral fluid.

Dispersive liquid-liquid microextraction with high-performance liquid chromatography for the analysis of 1,4-benzodioxane-6-aldehyde in eliglustat tartrate active pharmaceutical ingredient

Potential genotoxic impurities (PGIs) are a series of compounds that could potentially damage DNA. Therefore, a sensitive method is needed for detection and quantification. The present work described and validated a method for the quantification of one PGI (namely 1,4-benzodioxane-6-aldehyde) in Eliglustat tartrate (EGT) active pharmaceutical ingredient (API) substances using dispersive liquid-liquid microextraction (DLLME) as sample preparation to remove matrix effect and detected by HPLC-UV. Parameters influencing the microextraction efficiency were systematically investigated. The combined application of DLLME and HPLC-UV provided the sensitivity of the method. The achieved limit of detection (LOD) and the limit of quantification (LOQ) were adequate for the specific purpose and found to be 1.29 μg g^-1 and 2.58 μg g^-1, respectively. This simple and effective methodology offers a key advantage in the ease of removing matrix effect and improves sensitivity obviously. In addition, no costly instrumentation and skilled personnel are needed when using this method, which is available and can be successfully implemented in routine factory drug quality control analysis.

A new and feasible analytical method using reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) for further determination of Nickel in hydrogenated vegetable fat

A new and simple method for Ni determination in hydrogenated vegetable fat (HVF) has been developed using a RP-DLLME sample preparation procedure for further determination by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrophotometry (GFAAS). The RP-DLLME procedure includes simultaneous microextraction and preconcentration of Ni in HVF, using 5.0 g of HVF preheated (75 °C) and diluted in 5.0 mL of xylene, with the addition of a dispersant/extractant mixture (n-propanol/dilute HNO₃). The sample was manually stirred and centrifuged and the aqueous phase was collected for further Ni determination by FAAS and GFAAS. RP-DLLME was carried out using only 700 μL of n-propanol and 300 μL of 2.0 mol L^-1 HNO₃. The recovery varied from 93.3% to 101.5% for HVF. The LODs and LOQs were 40 and 90 ng g^-1 for FAAS, and ^0.41 and ^1.36 ng g^-1 for GFAAS. The proposed analytical method is viable and this is the first application of RP-DLLME to solid fat samples, with Ni determination as an example of application. This method consumes small amounts of reagents, with lower toxicity as compared to microwave decomposition. Furthermore, the key features of the RP-DLLME method include simplicity of operation, high sample mass, reduced reagent consumption, and use of diluted HNO₃ as an extractant.

Combination of solid-phase extraction with microextraction techniques followed by HPLC for simultaneous determination of 2-methylimidazole and 4-methylimidazole in beverages

A sensitive analytical method for the monitoring 2-methylimidazole and 4-methylimidazole (2-MI and 4-MI) is desirable due to their carcinogenic property. Here, we propose a highly sensitive method basing on the combination of solid-phase extraction and dispersive liquid-liquid microextraction techniques followed by high-performance liquid chromatography to simultaneously determine 2-MI and 4-MI in beverages. Dansyl chloride was used as a derivatizing reagent. Microextraction parameters were optimized by Plackett-Burman design and response surface methodology. Results show that derivatization led to significant improvements in chromatographic behavior for 2-MI and 4-MI due to increased hydrophobicity. The method shows good linearity (R² ≥ 0.9985), satisfactory precision (%RSD ≤ 8.3%) and low limit of quantification (20 ng/mL), and was successfully applied to determine 2-MI and 4-MI in carbonated drinks, beers and energy drinks, achieving satisfactory recoveries (85-101%). This method provides a potential for routine analysis of 2-MI and 4-MI at the nanogram per milliliter level in beverages.