Microwave-assisted extraction of emerging pollutants in environmental and biological samples before chromatographic determination

Microwave-assisted extraction in closed vessel in food analysis

Microwave-assisted extraction (MAE) is an important technique in analytical chemistry. It offers several advantages over traditional extraction methods, such as improved extraction efficiency, shorter extraction times, reduced solvent consumption, and enhanced analyte recovery. Using microwaves, heat is directly applied to the sample, leading to rapid and efficient extraction of target compounds by enhancing the solubility and diffusion of the target compounds, thus requiring lower solvent volume. Therefore, MAE can be considered a more environmentally friendly and cost-effective option facilitating the transition toward greener and more sustainable analytical chemistry workflows. This contribution systematically reviews the application of MAE to a selection of target compounds/compounds classes of relevance for food quality and safety assessment. As inclusion criteria, MAE active temperature control and molecularly-resolved characterization of the extracts were considered. Contents include a brief introduction of the principles of operation, available systems characteristics, and key parameters influencing extraction efficiency and selectivity. The application section covers functional food components (e.g., phenols, diterpenes, and carotenoids), lipids, contaminants (e.g., polycyclic aromatic hydrocarbons and mineral oil hydrocarbons), pesticides, veterinary drug residues, and a selection of process contaminants and xenobiotics of relevance for food safety.

Advancements in nanomaterial-based aptasensors for the detection of emerging organic pollutants in environmental and biological samples

The combination of nanomaterials (NMs) and aptamers into aptasensors enables highly specific and sensitive detection of diverse pollutants. The great potential of aptasensors is recognized for the detection of diverse emerging organic pollutants (EOPs) in different environmental and biological matrices. In addition to high sensitivity and selectivity, NM-based aptasensors have many other advantages such as portability, miniaturization, facile use, and affordability. This work showcases the recent advances achieved in the design and fabrication of NM-based aptasensors for monitoring EOPs (e.g., hormones, phenolic contaminants, pesticides, and pharmaceuticals). On the basis of their sensing mechanisms, the covered aptasensing systems are classified as electrochemical, colorimetric, PEC, fluorescence, SERS, and ECL. Special attention has been paid to the fabrication processes, analytical achievements, and sensing mechanisms of NM-based aptasensors. Further, the practical utility of aptasensing approaches has also been assessed based on their basic performance metrics (e.g., detection limits, sensing ranges, and response times).

Utilization of Waste Biomaterial as an Efficient and Eco-Friendly Adsorbent for Solid-Phase Extraction of Pantoprazole Contaminants in Wastewater

The objective of this analysis is to establish the potential of biodegradable agro-industrial waste materials as biosorbents in the solid-phase extraction (SPE) technique for sample preparation. In this regard, waste coffee husk (CH) powder was collected, washed, treated chemically, characterized, and applied as an SPE adsorbent to extract pantoprazole from the wastewater samples. Sample detection was accomplished using the UPLC-MS/MS system. The positive mode of electrospray ionization was exploited for the ionization of the sample, and quantification of the target analyte was performed by the multiple reaction monitoring modes. The precursor to product ion transition of 384.02→1380.05 and 384.02→200.05 was used as qualifiers and quantifiers, respectively. Optimization of the particle size, adsorbent dose, and contact time were evaluated to select the best combination of features. The efficiency and regeneration capability of the CH were compared with respect to a commercially available silica-based C18 SPE adsorbent, and it was found that CH possessed comparable (~50%) extraction, as well as regeneration capacity (~95%). The developed biosorbent was applied in a wastewater sample spiked with the target analyte and recovery studies were performed, which found a range of 93.0 to 102.0% with a %RSD of 3.72 to 12.7%. Thus, CH can be exploited as a ‘greener’ replacement for the commercially available adsorbents for the extraction/retention of active pharmaceutical ingredients present in water/wastewater samples.

Green Extraction Processes for Complex Samples from Vegetable Matrices Coupled with On-Line Detection System: A Critical Review

The detection of analytes in complex organic matrices requires a series of analytical steps to obtain a reliable analysis. Sample preparation can be the most time-consuming, prolonged, and error-prone step, reducing the reliability of the investigation. This review aims to discuss the advantages and limitations of extracting bioactive compounds, sample preparation techniques, automation, and coupling with on-line detection. This review also evaluates all publications on this topic through a longitudinal bibliometric analysis, applying statistical and mathematical methods to analyze the trends, perspectives, and hot topics of this research area. Furthermore, state-of-the-art green extraction techniques for complex samples from vegetable matrices coupled with analysis systems are presented. Among the extraction techniques for liquid samples, solid-phase extraction was the most common for combined systems in the scientific literature. In contrast, for on-line extraction systems applied for solid samples, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, and pressurized liquid extraction were the most frequent green extraction techniques.

Aroma determination in alcoholic beverages: Green MS-based sample preparation approaches

Aroma determination in alcoholic beverages has become a hot research topic due to the ongoing effort to obtain quality products, especially in a globalized market. Consumer satisfaction is mainly achieved by balancing several aroma compounds, which are mixtures of numerous volatile molecules enclosed in challenging matrices. Thus, sample preparation strategies for quality control and product development are required. They involve several steps including copious amounts of hazardous solvents or time-consuming procedures. This is bucking the trend of the ever-increasing pressure to reduce the environmental impact of analytical chemistry processes. Hence, the evolution of sample preparation procedures has directed towards miniaturized techniques to decrease or avoid the use of hazardous solvents and integrating sampling, extraction, and enrichment of the targeted analytes in fewer steps. Mass spectrometry coupled to gas or liquid chromatography is particularly well suited to address the complexity of these matrices. This review surveys advancements of green miniaturized techniques coupled to mass spectrometry applied on all categories of odor-active molecules in the most consumed alcoholic beverages: beer, wine, and spirits. The targeted literature consider progresses over the past 20 years.

Green bioanalysis: an innovative and eco-friendly approach for analyzing drugs in biological matrices

Green bioanalytical techniques aim to reduce or eliminate the hazardous waste produced by bioanalytical technologies. A well-organized and practical approach towards bioanalytical method development has an enormous contribution to the green analysis. The selection of the appropriate sample extraction process, organic mobile phase components and separation technique makes the bioanalytical method green. UHPLC-MS is the best option, whereas supercritical fluid chromatography is one of the most effective green bioanalytical procedures. Nevertheless, there remains excellent scope for further research on green bioanalytical methods. This review details the various sample preparation techniques that follow green analytical chemistry principles. Furthermore, it presents green solvents as a replacement for conventional organic solvents and highlights the strategies to convert modern analytical techniques to green methods.

Tissue-Specific Accumulation, Biotransformation, and Physiologically Based Toxicokinetic Modeling of Benzotriazole Ultraviolet Stabilizers in Zebrafish (Danio rerio)

Benzotriazole ultraviolet stabilizers (BUVSs) are high-production-volume chemicals with ubiquitous occurrence in the aquatic environment. However, little is known about their bioconcentration and biotransformation, and physiologically based toxicokinetic (PBTK) models for BUVSs are lacking. This study selected six BUVSs for which experiments were performed with zebrafish (Danio rerio) exposed to two different levels (0.5 and 10 μg·L^-1). Higher kinetic bioconcentration factors (BCFs) were observed at the lower exposure level with environmental relevance, with BCF of 3.33 × 10³ L·kg^-1 for 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327). This phenomenon was interpreted by a nonlinear adsorption mechanism, where binding with specific protein sites contributes to bioconcentration. Muscle exhibited the lowest accumulation, in which depuration half-life of UV-327 was 19.5 d. In kidney, muscle, ovary, gill, and skin, logBCF increased with increase in log K_OW of the BUVSs until log K_OW was ca. 6.5, above which logBCF decreased. However, the trend was not observed in the liver and intestine. Six biotransformation products were identified and mainly accumulated in the liver and intestine. Considering the nonlinear adsorption mechanism in the PBTK model, the prediction accuracy of the model was improved, highlighting the binding of xenobiotics with specific protein sites in assessing the bioconcentration of chemicals for their risk assessment.

Ultrasound-microwave-assisted extraction of polyphenolic compounds from Mexican "Ataulfo" mango peels: Antioxidant potential and identification by HPLC/ESI/MS

INTRODUCTION

Mango is used in traditional medicine in many countries. However, the processing by-products are not currently used and generate large pollution problems and high handling costs.

OBJECTIVE

To study the effect of different parameters in the extraction of polyphenolic compounds from mango peels using modern and ecological ultrasound-microwave-assisted extraction technology.

METHODOLOGY

Various parameters of these processes were studied: the extract was recovered by liquid chromatography using Ambetlite XAD-16. The total polyphenol content was determined by Folin-Ciocalteu's and HCl-butanol methods. Antioxidant activity was determined by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS+), 1,10-diphenyl-2-20-picrylhydrazyl (DPPH), and lipid oxidation inhibition methods. The recovered compounds were identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS).

RESULTS

The best extraction conditions were solid/liquid ratio of 1/5 g/mL, ethanol percentage of 50%, and an extraction time of 10 min. Under these conditions, the total polyphenol content was 54.15 mg/g, and the antioxidant activities were greater than 90% inhibition in the three assays evaluated. According to the high-performance liquid chromatography/electrospray ionization/mass spectrometry (HPLC/ESI/MS) analysis, nine polyphenolic compounds were identified; most of them were gallotannins, such as pentagalloyl glucose.

CONCLUSION

Ultrasound-microwave-assisted extraction was shown to be effective and allowed the recovery of antioxidant polyphenolic compounds. The results indicated that mango peel extracts can be used as natural antioxidant components in the pharmaceutical and functional food industries.

Fabric-Phase Sorptive Membrane Array As a Noninvasive In Vivo Sampling Device For Human Exposure To Different Compounds

This study introduces an innovative device for the noninvasive sampling and chromatographic analysis of different compounds present in exhaled breath aerosol (EBA). The new sampling device, especially in light of the recent COVID-19 pandemic that forced many countries to impose mandatory facemasks, allows an easy monitoring of the subject’s exposure to different compounds they may come in contact with, actively or passively. The project combines the advantages of a fabric-phase sorptive membrane (FPSM) as an in vivo sampling device with a validated LC-MS/MS screening procedure able to monitor more than 739 chemicals with an overall analysis time of 18 min. The project involves the noninvasive in vivo sampling of the EBA using an FPSM array inserted inside an FFP2 mask. The study involved 15 healthy volunteers, and no restrictions were imposed during or prior to the sampling process regarding the consumption of drinks, food, or drugs. The FPSM array-LC-MS/MS approach allowed us to effectively exploit the advantages of the two complementary procedures (the convenient sampling by an FPSM array and the rapid analysis by LC-MS/MS), obtaining a powerful and green tool to carry out rapid screening analyses for human exposure to different compounds. The flexible fabric substrate, the sponge-like porous architecture of the high-efficiency sol–gel sorbent coating, the availability of a large cache of sorbent coatings, including polar, nonpolar, mixed mode, and zwitterionic phases, the easy installation into the facemask, and the possibility of sampling without interrupting regular activities provide FPSMs unparalleled advantages over other sampling techniques, and their applications are expected to expand to many other clinical or toxicological studies.

Distribution and Chemical Analysis of Pharmaceuticals and Personal Care Products (PPCPs) in the Environmental Systems: A Review

PPCPs are found almost everywhere in the environment especially at an alarming rate and at very low concentration in the aquatic systems. Many methods-including pressurized hot water extraction (PHWE), pressurized liquid extraction (PLE), ultrasound-assisted extraction (UAE), and micro-assisted extraction (MAE)-have been employed for their extraction from both surface waters and biota. Solid-phase extraction (SPE) proved to be the best extraction method for these polar, non-volatile, and thermally unstable compounds in water. However, ultrasonic extraction works better for their isolation from sediment because it is cheap and consumes less solvent, even though SPE is preferred as a clean-up method for sediment samples. PPCPs are in groups of-acidic (e.g., diclofenac, ibuprofen, naproxen), neutral (e.g., caffeine, carbamazepine, fluoxetine), and basic pharmaceuticals, as well as antibiotics and estrogens amongst others. PPCPs which are present in trace levels (ng/L) are more often determined by liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography-ultraviolent (HPLC-UV). Of these, LC-MS and LC-MS-MS are mostly employed for the analysis of this class of compounds, though not without a draw-back of matrix effect. GC-MS and GC-MS-MS are considered as alternative cost-effective methods that can also give better results after derivatization.

Insight on a comprehensive profile of volatile compounds of Chlorella vulgaris extracted by two "green" methods

Some green extraction methods were selected and tested for the extraction of volatile compounds from different samples of the microalga Chlorella vulgaris: ultrasound-assisted liquid-liquid extraction using environment-friendly solvents (LLE) and solid-phase microextraction (SPME). The obtained profiles of volatile chemical compounds were different. Only one molecule was found in common to both extractions. Using the SPME method, the main chemical classes of identified volatile compounds were sulfuric compounds, aldehydes, and alcohols. Using the LLE method, the volatile profile was more balanced with alkanes, fatty acids, terpenes, alcohols, and aldehydes. Multivariate data analyses permitted discrimination among samples. Additionally, the relationship between the physicochemical properties of identified volatile compounds and the methods of extraction was studied. The results showed that the LLE extraction allowed the extraction of volatile compounds having a high boiling point (>160°C) and a high log P (>3). The SPME method was more effective to extract volatile compounds with a low boiling point (<160°C) and a low log P (<3). It is thus necessary to combine several extraction methods to obtain a complete view of the volatile profile for microalgae samples.

Determination of plasma concentrations of organochlorine pesticides and polychlorinated biphenyls in pet cats and dogs

The aim of this study was the determination of plasma concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in cats and dogs and evaluation of their prevalence and possible effects. The concentrations of nine OCPs, such as α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, hexachlorobenzene (HCB), aldrin, 2,4′-dichlorodiphenyltrichloroethane (2,4′-DDT), 4,4′-DDT, 2,4′-dichlorodiphenyldichloroethylene (2,4′-DDE) and 4,4′-DDE and 16 PCBs (PCB-28, -52, -70, -74, -81, -99, -101, -118, -138, -153, -156, -170, -180, -183, -187 and -208) were evaluated in the plasma samples of pet cats ( n = 15) and dogs ( n = 21). The concentrations of OCPs ranged from 1.12 ng g−1 lipid weight (lw) to 7.65 ng g−1 lw in cats and from 1.25 ng g−1 lw to 6.79 ng g−1 lw in dogs. In addition, mean PCB levels were 0.58–5.66 and 0.52–6.62 ng g−1 lw in cats and dogs, respectively. β-HCH, γ-HCH and PCB-138 levels were significantly higher in dogs ( p < 0.05). As far as could be determined, OCPs and PCBs were detected in the plasma samples of domestic cats and dogs in Turkey for the first time. Their concentrations were similar to those reported in earlier studies abroad. However, in contrast to other research, the levels of some OCPs were higher in dogs than in cats. It is concluded that, because of their high prevalence and potential health effects in animals and humans, OCP and PCB levels should be monitored systematically in domestic cats and dogs.

Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination

This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5μgL^-1 and 1.7μgL^-1, respectively, and intraday and interday precision expressed in terms of relative standard deviation were >6%.The maximum adsorption capacity was 138mgg^-1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water.

Validation and application of an analytical method for the determination of selected acidic pharmaceuticals and estrogenic hormones in wastewater and sludge

This study was undertaken to develop an extraction method for seven acidic pharmaceuticals and five steroidal estrogens from wastewater, treated wastewater and sludge samples. The temperature and time of sample derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide was optimized. Our results show that pretreatment combined with solid phase extraction (SPE) for wastewater samples (using an ENVI-C18 cartridge) and liquid-solid extraction combined with SPE (using an HLB cartridge) for sludge samples increased the analytical efficiency for acidic pharmaceuticals and estrogenic hormones using gas chromatography-mass spectrometry (GC-MS). The derivatization conditions were optimized at 40°C for 2 h. In addition, the derivatized samples were stable at ambient temperature. The new method was validated and applied to the analysis of real wastewater and discharged sludge samples from a local wastewater treatment plant. Except for 17α-ethinylestradiol, all acidic pharmaceuticals and estrogens were detected in the influent, effluent and discharged sludge samples. The concentrations of these compounds were particularly high in the discharged sludge samples.

Quantification of emerging micropollutants in an amphipod crustacean by nanoliquid chromatography coupled to mass spectrometry using multiple reaction monitoring cubed mode

An innovative analytical method has been developed to quantify the bioaccumulation in an amphipod crustacean (Gammarus fossarum) of three micropollutants regarded as anthropic-pollution markers: carbamazepine, oxazepam, and testosterone. A liquid-liquid extraction assisted by salts, known as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) was miniaturised and optimised, so it could be adapted to the low mass samples (approximatively 5mg dry weight). For this same reason and in order to obtain good sensitivity, ultra-trace analyses were carried out by means of nanoliquid chromatography. A preconcentration system by on-column trapping was optimised to increase the injection volume. In order to improve both sensitivity and selectivity, the multiple reaction monitoring cubed mode analyses (MRM(3)) were carried out, validated and compared to the classic MRM. To the best of our knowledge, this is the first time that MRM(3) is coupled to nanoliquid chromatography for the analysis and detection of organic micropollutants <300Da. The optimised extraction method exhibited recoveries superior to 80%. The limits of quantification of the target compounds were 0.3, 0.7 and 4.7ng/g (wet weight) for oxazepam, carbamazepine and testosterone, respectively and the limits of detection were 0.1, 0.3 and 2.2ng/g (wet weight), respectively. The intra- and inter-day precisions were inferior to 7.7% and 10.9%, respectively, for the three levels of concentration tested. The analytical strategy developed allowed to obtain limits of quantification lower than 1ng/g (wet weight) and to establish the kinetic bioconcentration of contaminants within G. fossarum.

Numerical simulation of hot-spot effects in microwave heating due to the existence of strong microwave-absorbing media

Hot spots exist and may trigger temperature gaps at the magnitude of several hundred degrees Celsius in certain microwave heating.