Solvent-Assisted dispersive solid phase extraction of diclofenac from human serum and pharmaceutical tablets quantified by high-performance liquid chromatography

Lab-in-syringe automated dispersive solid-phase microextraction of alkylphenols coupled online to liquid chromatography using iron (III) thenoyltrifluoroacetonate as dissolvable sorbent

BACKGROUND

Alkylphenols are water contaminants of strong endocrine disruptive potential. Sample preparation is generally imperative to improve sensitivity and minimize matrix effects. Dispersive solid phase extraction is a powerful alternative to cartridge-based sorbent extraction omitting backpressure problems and reducing procedural time. Herein, solvent-dissolvable sorbents offer the advantages of easy and cost-efficient production, efficiency, and full analyte recovery, while eluates can be directly submitted to instrumental determination. Despite the potential to reduce environmental impact and enhance reproducibility, there is a lack of automation attempts.

RESULTS

A fully automated solvent-assisted dispersive solid phase extraction method was developed for selected alkylphenols based on the technique Lab-In-Syringe. The void of automatic bidirectional syringe pump was used as mixing and extraction vessel. The iron(III) thenoyltrifluoroacetonate complex was used as novel dissolvable sorbent. 40 μL complex solution was dispersed in the sample, leading to the precipitation of 0.4 mg sorbent. Extraction occurred within 40 s and was accelerated by in-syringe magnetic stirring. The sorbent was retained on a melamine foam packing in the syringe inlet, dissolved in a methanolic solution of ascorbic acid, and injected into online-coupled HPLC. Linear working ranges were achieved from 1 to 1000 μg/L with sub-ppb detection limits and accuracies ranging from 98.3 to 110 %.

SIGNIFICANCE

In this work, we explored for the first time automated in-syringe automated dispersive SPE based on a dissolvable sorbent. Parallel operation of sample pretreatment and separation enabled throughputs of 4.5/h with typically <5 % RSD and preconcentrations of 16.4-21.2. AGREE greenness evaluation yielded a score of 0.59.

Hierarchically porous covalent organic framework doped monolithic column for on-line chip-based array microextraction of nonsteroidal anti-inflammatory drugs in microlitre volume of blood

BACKGROUND

Traditional blood drug analysis involves large blood consumption and complicated operations and a further reduction in blood consumption is urgently needed. Chip-based monolithic column microextraction is a good strategy for the pretreatment of small-volume samples, and new monolithic materials is the critical factor. Covalent organic frameworks (COFs) are good adsorbents due to large specific surface area and rich conjugated structure. However, the poor dispersion ability of COFs in prepolymer solution severely hinders the preparation of COFs doped monolithic columns. Herein, high internal phase emulsion with viscoelastic properties was adopted to fixed COF particles.

RESULTS

The COFs doped monolith exhibited a hierarchical porous structure and improved extraction efficiency for interest nonsteroidal anti-inflammatory drugs (NSAIDs) (68.2-77.3 vs 28.4-57.7 %). A chip-based monolithic column array was fabricated and coupled with high-performance liquid chromatography (HPLC)-ultraviolet detection for online determination of five NSAIDs in microlitre volume of blood. The throughput of the developed method was approximately 3 h-1, mainly determined by the separation time (22 min) of target NSAIDs in HPLC. Under the optimal conditions (200 μL sample solution, pH = 3 at a sampling folw rate of 5 μL min-1 and 20 μL of acetonitrile/10 mmol L-1 NaOH (9/1, v/v) as desorbent), the detection limit of 4.39-15.5 μg L-1 was obtained for target NSAIDs in blood with RSD of 7.8-15.3 % and R2 of 0.9943-0.9978. The method was applied to the analysis of human serum (20 μL) and dried blood spot, with recovery of 82.0-118 % for target NSAIDs.

SIGNIFICANCE

A method was proposed for the preparation of COF doped monolithic columns by emulsion polymerization, avoiding uneven distribution of COFs caused by their easy sedimentation in traditional free radical preparation of monolithic columns. Then a chip-based monolithic column array coupled with on-line HPLC-UV detection was established for the quantification of five NSAIDs in microlitre-blood samples. The developed method merits high automation and good anti-interference ability, with extremely low sample/reagents consumption.

Improved preconcentration workflow for organic explosive traces in aqueous samples using solvent-assisted dispersive solid-phase extraction

The present study deals with the development of a solvent-assisted dispersive solid phase extraction method for the extraction of HMX, RDX, and TNT from aqueous samples. Benzophenone and methanol were selected as explosives sorbent and dispersive solvent respectively. Extraction parameters like pH, extraction time, amount of sorbent, volume and type of the disperser solvent and centrifuge time were optimized. Dispersion of 0.5 mL dispersive solution (4% (w/v) benzophenone in methanol) was performed by injection into the 5 mL aqueous sample (pH=7) using a 1.0 mL syringe. After centrifuge, the extracted explosives were analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-Uv). The results indicated that the linear ranges with the correlation coefficients of 0.99 ≤ R2 were 1.6-204.6 μg L-1, 1.4-213.7 μg L-1 and 1.3-225.9 μg L-1 for HMX, RDX and TNT respectively. The limit of detection and limit of quantification obtained for each explosive were: 0.3 μg L-1 and 0.8 μg L-1 for HMX, 0.3 μg L-1 and 0.9 μg L-1 for RDX and 0.2 μg L-1 and 0.7 μg L-1 for TNT. Finally, the practical applicability of the developed method was evaluated for the extraction of some organic explosives in water samples followed their determination by HPLC-Uv.

Temperature-induced dispersive solid-phase extraction as a new approach for preconcentration of Sudan dyes in water and food samples prior to the determination by high-performance liquid chromatography

This study introduced a new microextraction method named temperature-induced dispersive solid-phase extraction. The performance of the method was demonstrated with the determination of Sudan dyes in food and natural water samples. In this method, a low quantity of sorbent was added to the aqueous solution and the mixture was shaken manually for about one minute. Then, the solution was heated in an ultrasonic water bath, and the sorbent was dissolved. Subsequently, the solution was cooled down with ice water, and consequently, the solubility of the sorbent was reduced in the sample solution and became cloudy. The phase separation was accelerated by centrifugation. The upper liquid phase was picked up using a syringe, and the remainder was solved in methanol and introduced into the HPLC for analysis. Various parameters affecting the extraction yield were evaluated. Analytical parameters, including limits of detection (0.011-0.016 μg/L) and quantification (0.038-0.055 μg/L), relative standard deviations (2.3%-3.1%), and preconcentration factor (40) proved the high efficiency of the developed method for the analysis of Sudan dyes. The proposed method was used to measure Sudan dyes in water and food samples and showed good extraction recoveries (95.0%-103.5%).

Solvent-assisted dispersive micro-solid phase extraction of bisphenols using iron(III) thenoyltrifluoroacetonate complex (Fe(TTA)3) as a new nanostructured sorbent: a proof of concept

In this work, we describe for the first time the use of iron(III) thenoyltrifluoroacetonate complex (Fe(TTA)₃) as a novel sorbent for solvent-assisted dispersive micro-solid phase extraction (SA-dμSPE) of bisphenols from water samples. The extraction procedure is based on the formation of nanoparticles in situ following the rapid injection of a methanolic solution of Fe(TTA)₃ into the stirred aqueous sample. Herein, the synthesis of Fe(TTA)₃ and study of the essential parameters of the preparative procedure are described. The optimized procedure allowed for efficient enrichment of bisphenols from various water samples, chosen as model contaminants and matrix, within 2.5 min. The sorbent was collected by centrifugation, dissolved in methanol, and injected to perform HPLC with spectrophotometric detection. The limits of detection and quantification obtained ranged from 1.0-3.1 and 3.1-7.5 μg L^-1, respectively. Intraday and interday precisions of <7% relative standard deviation (RSD) and <8% RSD with analyte recoveries ranging between 70-117% (103.8% on average) were obtained for the analysis of river water, wastewater treatment plant effluent, and bottled water.

Magnetic nanofluid based on hydrophobic deep eutectic solvent for efficient and rapid enrichment and subsequent determination of cinnamic acid in juice samples: Vortex-assisted liquid-phase microextraction

A quick, environmentally friendly and easy approach for the determination of cinnamic acid in juice samples based on the creation and usage of a novel magnetic nanofluid (mixture of hydrophobic deep eutectic solvent and magnetic nanoparticles) has been reported. Response surface methodology was applied to justify the contribution of the efficient factors including pH, nanofluid volume, ionic strength and vortex time. Cinnamic acid concentrations were monitored and quantified based on their HPLC peak representing linear correlations under the best operational circumstances showing linearity between 3 and 550 ng mL^-1. The LOD, LOQ, and enrichment factor for cinnamic acid were 0.8 ng mL^-1, 2.7 ng mL^-1 and 57.2, respectively. The proposed method was used for enrichment and subsequent determination of cinnamic acid from juice samples which suggests a potential alternative approach for cinnamic acid analysis in complicated food samples.

Development of a 3D disposable device for the electrochemical determination of diclofenac in different matrices

In this work, the development of a disposable electrochemical device (US$ 0.02 per electrode) using a 3D printed support (3Ds) of acrylonitrile butadiene styrene (ABS) insulating filament with a composite material (CM) based on graphite and nail polish, immobilized on the support surface, was described for the electrochemical determination of diclofenac (DCF). The device was compared to the commercial glassy carbon electrode (GCE) and showed superior electroanalytical performance with approximately 1.8-fold higher current density. Additionally, an amperometric method for DCF determination in tap water, synthetic urine, and pharmaceutical formulation samples with the proposed electrode, using a flow injection analysis (FIA-AD) system, was developed. The optimized method presented excellent detectability (LOD = 0.47 µmol L^-1), with excellent precision and accuracy (relative standard deviation < 5.6%) and percent recovery from spiked samples ranging from 89 to 106%. In addition, the sensor showed optimal analytical frequency with approximately 108 injections per hour, which demonstrates the potential of this system using the proposed disposable electrode for implementation in routine analysis and quality control with good selectivity and sensitivity.

Screen-Printed Graphite Electrode Modified with Graphene-Co3O4 Nanocomposite: Voltammetric Assay of Morphine in the Presence of Diclofenac in Pharmaceutical and Biological Samples

This work focuses on the development of a novel electrochemical sensor for the determination of morphine in the presence of diclofenac. The facile synthesis of graphene-Co₃O₄ nanocomposite was performed. The prepared material (graphene-Co₃O₄ nanocomposite) was analyzed by diverse microscopic and spectroscopic approaches for its crystallinity, composition, and morphology. Concerning the electrochemical determinations, after drop-casting the as-fabricated graphene-Co₃O₄ nanocomposite on the surface of a screen-printed graphite electrode (SPGE), their electrochemical performance was scrutinized towards the morphine detection. It was also found that an SPGE modified by a graphene-Co₃O₄ nanocomposite exhibited better electrocatalytic activity for morphine oxidation than unmodified electrode. Under optimal conditions, the differential pulse voltammetry (DPV) was employed to explore the present sensor (graphene-Co₃O₄/SPGE), the findings of which revealed a linear dynamic range as broad as 0.02-575.0 µM and a limit of detection (LOD) as narrow as 0.007 μM. The sensitivity was estimated to be 0.4 µM/(µA cm²). Furthermore, the graphene-Co₃O₄/SPGE sensor demonstrated good analytical efficiency for sensing morphine in the presence of diclofenac in well-spaced anodic peaks. According to the DPV results, this sensor displayed two distinct peaks for the oxidation of morphine and diclofenac with 350 mV potential difference. In addition, the graphene-Co₃O₄/SPGE was explored for voltammetric determination of diclofenac and morphine in pharmaceutical and biological specimens of morphine ampoule, diclofenac tablet, and urine, where recovery rates close to 100% were recorded for all of the samples.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

Facile fabrication of magnetic covalent organic frameworks for magnetic solid-phase extraction of diclofenac sodium in milk

A robust magnetic solid-phase extraction (MSPE) method based on magnetic covalent organic framework (MCOF) coupled with high-performance liquid chromatography (HPLC)-ultraviolet (UV)/mass spectrometry (MS) was proposed for the determination of trace diclofenac sodium (DS) in milk. The prepared MCOF exhibited high extraction efficiency, which can be attributed to its high specific surface area as well as strong π-π and hydrophobic interactions between MCOF and DS. In addition, the potential influencing factors, including sample volume, adsorbent dosage, extraction time, and elution parameters, were fully estimated. The experimental results demonstrated that the established method was sensitive for the quantification of DS with high accuracy. Remarkably, the detection limit of DS was found to be 10 ng/kg under the optimal conditions. More impressively, the developed method was successfully applied to monitor trace DS in milk, demonstrating its outstanding durability and practical potential as an appealing method to regular monitor trace pharmaceutical contaminants in real food samples.

Extraction of Cyproheptadine as Potent Appetizing Stimulant in Herbal Supplements by Efficient Carbon Nitride Nanosheets as Dispersive Solid Phase Extraction Adsorbent

Background: Application of natural-based herbal medicine is on a growing trend in some countries and people prefer to use plant-originated drugs rather than chemical-based ones. The present study describes an interesting sample preparation method for extraction and determination of cyproheptadine in herbal supplements as appetizing stimulant by using carbon nitride nanosheets as dispersive solid phase extraction method coupled with HPLCUV. Methods: Various techniques used for characterization of adsorbent such as: Infrared spectroscopy (IR), scanning electron microscopy (SEM), Zeta potential analysis and powder X-ray diffraction (XRD). Optimization of the important extraction parameters were conducted by one parameter-at-a time method. Next, method validation was carried out. Results: The optimized cyproheptadine extraction parameters were introduced and under optimized conditions the method presented a good linearity in the concentration range of 300-2000 ng/g. The limit of detection (LOD) was 100 ng/g for the introduced method. Conclusion: Quantitative analysis of fifteen real samples (Tablets or capsules) by proposed method confirmed the illegal presence of cyproheptadine in herbal appetizing stimulants supplements of the markets.