Optimization of ultrasound assisted dispersive liquid-liquid microextraction of six antidepressants in human plasma using experimental design

Comparative study of sample preparation procedures to determine the main compounds in ayahuasca beverages by QuEChERS and high-performance liquid chromatography analysis

INTRODUCTION

Ayahuasca is a psychoactive drink originally consumed by indigenous people of the Amazon. The lack of regulation of this drink leads to uncontrolled consumption, and it is often consumed in religious contexts.

OBJECTIVE

The aim of this work is to compare three miniaturised extraction techniques for extracting the main ayahuasca compounds from beverages.

METHODOLOGY

Three sample pretreatment techniques were evaluated (dispersive liquid-liquid microextraction [DLLME], microextraction by packed sorbent [MEPS] and QuEChERS [Quick, Easy, Cheap, Effective, Rugged and Safe]) for the simultaneous extraction of N,N-dimethyltryptamine (DMT), tetrahydroharmine (THH), harmine, harmaline, harmol and harmalol from ayahuasca beverage samples. Then, the most promising technique (QuEChERS) was chosen to pre-concentrate the analytes, subsequently detected by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD).

RESULTS

The procedure was optimised, with the final conditions being 500 μL of extractor solvent, 85 mg of primary secondary amine (PSA) and 4 s of vortexing. The analytical method was validated, showing to be linear between 0.16 and 10 μg/mL for β-carbolines and between 0.016 and 1 μg/mL for DMT, with coefficients of determination (R2) between 0.9968 and 0.9993. The limit of detection (LOD) and lower limit of quantification (LLOQ) were 0.16 μg/mL for all compounds, except for DMT (0.016 μg/mL) and extraction efficiencies varied between 60.2% and 88.0%.

CONCLUSION

The analytical methodology proved to be accurate and precise, with good linearity, LODs and LLOQs. This method has been fully validated and successfully applied to ayahuasca beverage samples.

Dispersive liquid-liquid microextraction (DLLME) for determination of tricyclic antidepressants in whole blood and plasma samples and analysis by liquid chromatography with diode array detector (LC-DAD)

Microextractions have been developed for the tricyclic antidepressants (TCAs) analysis in biological matrices, including dispersive liquid-liquid microextraction (DLLME). The proposed DLLME employed 490 µL of biological sample (whole blood or plasma), which were added 15 mg of NaCl, 10 µL of medazepam as internal standard (10 µg/mL) and 100 µL of 2 M NaOH. This mixture was homogenized by vortex (2800 rpm/10 s) and 400 µL of hexane (extractor solvent) with 600 µL of methanol (dispersing solvent) were added to the sample. After the vortex step (2800 rpm/5 s), an ultrasonic bath for 300 s was employed. Then, this content was centrifuged (10 min/10000 rpm), organic phase was collected and dried under air flow. After, 30 µL of the mobile phase was used for resuspension and 20 µL is injected into LC-DAD. This method was optimized and fully validated according to UNODC and SWGTOX guidelines, reaching limits of detection equivalent to analytical methodologies that employ mass spectrometry (MS). Also, it was applied in real cases involving suspected exposure to TCAs. So, the developed DLLME for the determination of TCAs in whole blood and plasma samples proved to be a simple, reliable, robust and reproducible method that can be used in toxicology and clinical laboratories.

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.

Developments of Microextraction (Extraction) Procedures for Sample Preparation of Antidepressants in Biological and Water Samples, a Review

Antidepressants are an important class of drugs to treat various types of depression. The determination of antidepressants is crucial in biological samples to control adverse effects in humans and study pharmacokinetics and bioavailability. Direct measurement of antidepressants in biological and water samples is a considerable challenge for analysts due to their low concentration, the high matrix effects of real samples, and the presence of metabolites of these drugs in biological samples. The challenge leads to using sample preparation processes as a critical step in determining antidepressants. Extraction and microextraction procedures have been widely utilized as sample preparation procedures for these drugs. The purposes of extraction or microextraction methods for antidepressant medications are to preconcentrate the analyte, reduce the matrix effects, increase the selectivity of the procedures, and convert the sample to a suitable format for introducing it into detection systems. In the review, the various extraction and microextraction methods of these drugs in biological, real water, and wastewater samples were investigated. The theory of each technique was briefly addressed to understand the features and factors affecting each method. The extraction and microextraction methods were classified based on their application for antidepressants, and the advantages and disadvantages of each technique were reviewed. The new developments to overcome the limitations of each procedure were discussed. The investigation indicated the number of applications of liquid-phase microextraction for extracting antidepressants has been almost equal to that of solid-phase microextraction.

Recent sample pretreatment methods for determination of selective serotonin reuptake inhibitors (SSRIs) in biological samples

Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (FLU), sertraline (SER), paroxetine (PAR), fluvoxamine (FLV) and citalopram (CIT) have been the first treatment drugs for pregnant and breastfeeding women. Quantitative analysis of SSRIs in biological samples is extremely needed in public health and clinical practice. During the analysis, sample pretreatment is an important step that can obtain an accurate quantitative analysis of SSRIs in the complex samples. The present paper discussed the recent development of sample preparation methods for SSRI analysis. Traditional sample preparation techniques such as liquid liquid extraction (LLE) and solid phase extraction (SPE), which have been widely used in the separation of SSRIs in biological samples, were extensively presented. Moreover, the new sample preparation techniques including liquid phase microextraction (LPME), solid phase microextraction (SPME), electromembrane extraction (EME) and other miniaturized extraction techniques, which are becoming highly popular in SSRI analysis, were also critically reviewed. In this review, both the advantages and disadvantages of these sample pretreatment methods were addressed. As a summary, we prospected the challenges and promising directions for the future of sample pretreatment methods in SSRI analysis.

Development of a method for assessing the accumulation and metabolization of antidepressant drugs in zebrafish (Danio rerio) eleutheroembryos

Antidepressant drugs are widely used for the treatment of common mental or other psychiatric disorders such as depression, which affect about 121 million people worldwide. This widespread use has contributed to the input of these pharmaceuticals and their metabolites into the environment. The aim of this work was to develop an analytical method to quantify the most widely used antidepressant drugs, selective serotonin reuptake inhibitors (SSRI), and their main metabolites in the environment. For this, a new and reliable miniaturized extraction method based on dispersive SPE cleanup procedure for extraction of SSRI followed by derivatization with n-heptafluorobutyrylimidazole, and detection by GC-MS was developed. The methodology, including a first-order one-compartment model, was then applied to a bioconcentration study in zebrafish (Danio rerio) eleutheroembryos. The results showed low bioaccumulation of these compounds; however, a biotransformation evidence of the parent compounds into their metabolites was observed after 6 h of exposure. These results indicate the need to integrate metabolic transformation rates to fully model and understand the bioaccumulation patterns of SSRI and their metabolites.

Simultaneous Quantification of 38 Psychotropic Drugs and Relevant Metabolites in Blood using LC-MS-MS

The trend for the concomitant prescription of antidepressants and antipsychotics is increasing. This calls for a veracious screening and quantifying method for forensic and clinical use. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the simultaneous determination and quantification of 38 antidepressants, antipsychotics and relevant metabolites in small volumes (200 μL) of human whole blood. Analytes and deuterated internal standards were extracted using liquid-liquid extraction. The separation, determination and quantification of the analytes were performed using an LC-MS-MS system equipped with an ACQUITY UPLC® BEH Phenyl Column under a positive electrospray ionization mode. After validation, the analytical procedure was proved to be highly sensitive, with a limit of detection ranging from 0.0005 to 1 ng/mL and a lower limit of quantification ranging from 0.002 to 2 ng/mL. Bias and within- and between-run precision were within 14.7% for all analytes. Recoveries were reproducible and those of 35 analytes were >50%. Dilution integrity was evaluated to ensure that the therapeutic and toxic blood concentration ranges of target compounds were fully covered. Finally, this method was applied to authentic whole blood samples collected from two forensic cases, which demonstrated its practical usefulness of providing accurate and comprehensive information concerning the previous medication of the deceased.

Application of Tandem Dispersive Liquid-Liquid Microextraction as an Efficient Method for Preconcentration of Two Antidepressant Drugs in Real Samples Combined with High Performance Liquid Chromatography

In the present work, tandem dispersive liquid-liquid microextraction (TDLLME) coupled with liquid chromatography was used for the determination of the two antidepressant drugs citalopram (CIT) and sertraline (SER) in complicated matrices. Indeed, the present approach was used to improve the suitability and appropriateness of the dispersive liquid-liquid microextraction (DLLME) method in complicated matrices. Firstly, 10 mL of the sample solution containing the two understudied drugs was extracted into an organic solvent (200 μL of 1,2-dichloromethane) using the DLLME method. Then the extracted analytes were back-extracted into 100 μL of an aqueous acceptor phase. The total extraction time of this method is about 6 min. To achieve the best efficiency for this method, efficient parameters like the kind and volume of the organic solvent and the effect of the ionic strength on the effectiveness of extraction were reviewed and improved. Under the optimized experimental conditions, TDLLME showed good linearity in the range of 100.0-7000.0 ng mL-1. The limits of detection were found to be 10.0 ng mL-1 for CIT and 2.0 ng mL-1 for SER. The relative standard deviation (RSD) is obtained in the range of 0.7-4.1%.

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.

Efficient dispersive micro solid-phase extraction of antidepressant drugs by a robust molybdenum-based coordination polymer

A molybdenum-based coordination polymer {[Mo(PDA)(NO)(μ-O)MoO₃]·1.42H₂O·0.58C₂H₅OH}_n (1) (PDA is 1,10-phenanthroline-2,9-dicarboxylate) was synthesized using solvothermal reaction conditions and characterized using a suite of analytical techniques. Single-crystal X-ray diffraction studies reveal a 1D chain structure, with close contacts expanding the structure into 3D including π-interactions and hydrogen bonding. The utility of 1 as a sorbent for dispersive micro solid-phase extraction (D-μSPE) of basic organic compounds such as antidepressants is supported by the presence of many functional groups on the surface of 1 (such as pendant carboxylates, Mo=O, Mo-NO, and CH groups) as well as extensive electrostatic interactions. Therefore, 1 can be a suitable choice as sorbent in the D-μSPE of antidepressant drugs from human plasma samples via appreciable adsorbate-adsorbent interactions. Determination of the extracted antidepressant drugs was conducted using high-performance liquid chromatography-ultraviolet (HPLC-UV), with calibration plots being linear in the concentration range 0.1-500 ng mL^-1 for amitriptyline and nortriptyline, 0.2-500 ng mL^-1 for imipramine, and 0.5-300 ng mL^-1 for sertraline. The relative standard deviation (RSD) values were calculated for both intra-day and inter-day precision, and the RSD% values were in the range 3.9 to 5.2% and 4.6-5.4%, respectively. The limits of detection (LODs) was determined as 0.03-0.2 ng mL^-1. Due to the good stability and reusability of the sorbent, the adsorption capacity had no obvious decrease after being used 20 times. Finally, the D-μSPE-HPLC-UV method was applied for the determination of antidepressant drugs in human plasma samples with recoveries of the analytes in the range 94.9 to 102%. The article describes the synthesis of a robust molybdenum-based coordination polymer, and its application as sorbent for dispersive micro solid-phase extraction of antidepressant drugs from human plasma samples.

Quantification of amphetamine and derivatives in oral fluid by dispersive liquid-liquid microextraction and liquid chromatography-tandem mass spectrometry

The abuse of stimulants such as amphetamine, methamphetamine, ecstasy (MDMA), and their analogues (MDEA and MDA) has been increasing considerably worldwide since 2009. In this work, an analytical method using dispersive liquid-liquid microextraction (DLLME) to determine amphetamine and derivatives in oral fluid samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. Linearity was achieved between 20 to 5000 ng/mL (r>0.992, 1/x² weighted linear regression), with a limit of quantification (LOQ) of 20 ng/mL. Imprecision (%relative standard deviation) and bias (%) were not higher than 9.1 and -12.3%, respectively. The matrix effect was lower than 14.6%, with no carryover observed up to 5000 ng/mL and no interference with 10 different oral fluid matrix sources and against 14 pharmaceuticals and other common drugs of abuse. MDMA, MDA, and MDEA in processed samples were stable up to 24 h at autosampler (10°C); and amphetamine and methamphetamine up to 18 h. The developed method was successfully applied to authentic oral fluid analyses (n = 140). The proposed method is an example of the Green Analytical Toxicology, since it reduces both the amount of solvent required in samples preparation and the quantity of solvents and reagents used in analytical-instrumental stage, as well as requires a minimal sample volume, being a cheaper, quicker and more ecological alternative to conventional methods. Obtained results showed that DLLME extraction combined with LC-MS/MS is a fast and simple method to quantify amphetamine derivatives in oral fluid samples.

Determination of Seven Antidepressants in Pericardial Fluid by Means of Dispersive Liquid-Liquid Microextraction (DLLME) and Gas Chromatography-Mass Spectrometry (GC/MS)

Although blood is often used to detect and quantify the presence of drugs, there are some instances where samples obtained from other biological matrices, like pericardial fluid (PF), are necessary since adequate blood samples may not be available. PF is an epicardial transudate, which contains plasma components that include toxicological substances making this sample useful when blood samples are not available. This fluid is a well preserved postmortem sample and can easily be collected in larger amounts without significant contamination, compared with other body fluids. Although studies involving PF began around the 1980's, the adequacy of such fluid as a biological matrix has been poorly investigated. Antidepressants are frequently detected in postmortem samples from forensic cases. Nowadays, they constitute some of the most commonly prescribed drugs worldwide. A total of seven antidepressants (venlafaxine, mirtazapine, olanzapine, paroxetine, sertraline, fluoxetine and citalopram) were evaluated in this study. A new extraction method involving dispersive liquid-liquid microextraction (DLLME) is presented in which chloroform and acetonitrile are determined to be the best extraction and dispersing solvents. The experimental design was achieved using StatGraphics 18. The Response Surface Methodology enabled us to know the optimal volume for the two solvents used in the DLLME. The detection technique used was gas chromatography-mass spectrometry (GC-MS) with electron impact ionization as ionization source. A temperature gradient has been used and the total chromatographic separation time was 19.43 min. Validation results met the international validation guidances (FDA). Under the optimal condition, the method offered good validation parameters showing a new efficient, simple, rapid, and sensitive method. The analytical method was applied to thirty-one pericardial fluid samples. Twenty-one samples were positive with concentrations between 0.19 and 8.48 µg/mL. Venlafaxine and olanzapine were the antidepressants most frequently found.

Effective extraction methodology for the isolation of antidepressants from human blood

Abstract

The objective of this study is to choose the best methodology containing a high-efficiency extraction technique and an extraction agent for the isolation of antidepressants, such as citalopram, fluoxetine, paroxetine, sertraline, and venlafaxine, from human blood samples. In this research, various extraction agents have been examined to achieve the highest efficiency of the conducted process. Moreover, the following most available extraction techniques have been investigated and compared: liquid–liquid extraction, ultrasound-assisted extraction, and microwave-assisted extraction. The obtained extracts have been analysed with the application of the ultra-high performance liquid chromatography with mass spectrometry. The conducted research has confirmed that the microwave-assisted extraction with ethyl acetate—the average extraction efficiency is 77.4 ± 2.7%—onstitute the most promising extraction method and the agent. Furthermore, the developed method was successfully applied to the analysis of the whole blood samples collected from patients treated with the analysed drugs. It should be emphasised that choice of extraction and solvent methods are the first steps to develop the methods allowing for determination of antidepressants in whole blood for toxicological and clinical purposes.

Graphic abstract

Investigating the Utility of Fabric Phase Sorptive Extraction and HPLC-UV-Vis/DAD to Determine Antidepressant Drugs in Environmental Aqueous Samples

Depression is considered to be one of the most prevalent mental disorders in humans. Antidepressant drugs are released in large concentrations and cause adverse effects on the environment and/or human health. Fabric Phase Sorptive Extraction (FPSE), a contemporary solid sorbent-handling technique, is a quick, sensitive, and simple analytical process. This paper describes a micro-extraction FPSE procedure coupled with High-Performance Liquid-Chromatography–Photodiode Array Detection (FPSE-HPLC–DAD) for the simultaneous extraction and analysis of five antidepressants, namely citalopram, clozapine, mirtazapine, bupropion and sertraline. Three fabric media (Whatman Cellulose filter, Whatman Microfiber Glass filter and Polylactic acid disks) and two different sol–gel sorbents (polyethylene glycol (PEG 300), alongside poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG 5.800)) were tested. The best FPSE device was observed to be the microfiber glass filter coated with PEG 300 sol–gel sorbent. In addition, the parameters that affect the efficiency of the process (FPSE media and sorbents, sample pH, extraction time, elution time, etc.) were optimized. The proposed methodology displays a linear range with absolute recovery values higher than 60%, RSD% of less than 13% and LOQs in the range between 1.9–10.7 μg·L−1. Finally, the method was applied in hospital and urban effluents and lake water samples, but none of the analytes were detected.

Dispersive liquid-liquid microextraction followed by green high-performance liquid chromatography for fluconazole determination in cerebrospinal fluid with the aid of chemometric tools

A new method, simple and fast, for fluconazole (FLU) quantification in cerebrospinal fluid (CSF) samples using dispersive liquid-liquid microextraction (DLLME) and an eco-friendly mobile phase for HPLC-PDA was developed. The study of DLLME extraction condition covered the investigation of 12 combinations of extraction and disperser solvents followed by a fractional factorial design 2(7-3) to determine the influence of seven factors. After this stage, a central composite design was performed for three factors and a response surface was obtained. Aiming a compromise between a good recovery and a low organic solvent use it was established an extraction condition that consists of: 100 μL of chloroform, 100 μL of isopropyl alcohol, 200 μL of CSF, 200 μL of 50 mM phosphate buffer pH 7.3 and centrifugation for 5 min at 2200g and 4 °C. The HPLC analysis used an Ascentis® Express C18 column (100 mm × 4.6 mm, 2.7 μm) and an Ascentis® Express C18 guard column (3 mm × 4.6 mm, 2.7 μm), ethanol : water (15 : 85, v/v) as mobile phase, temperature of 45 °C, flow rate of 0.8 mL min-1 and phenacetin as internal standard. The method validation was performed according to European Agency's Guideline on Bioanalytical Validation Methodology and a linear range was obtained from 0.25 to 62.5 μg mL-1, with precision and accuracy within the recommended limits and recovery of 70% for FLU and 81% for phenacetin. Samples were stable in the studies performed and the method showed to be selective and with no carryover effect. The feasibility of the obtained method was confirmed by FLU determination at a CSF from a patient who was treated for neuromycosis. Therefore, here is described a method that meets many principles of green analytical chemistry and is useful for FLU therapeutic monitoring.

Dispersive Liquid-Liquid Microextraction Based Preconcentration of Selected Pesticides and Escitalopram Oxalate, Haloperidol, and Olanzapine from Wastewater Samples Prior to Determination by GC-MS

Background

Determination of emerging pollutants including pharmaceuticals, pesticides, industrial chemicals and hormones in different environmental samples is very important for human health.

Objective

Experimental design enabled parameters to be evaluated for their effects onextraction output as well as their interactive effects.

Method

A multivariate experimental design was used to attain optimum conditions of a dispersive liquid-liquid microextraction method for preconcentration of pesticides and pharmaceuticals for determination by GC-MS.

Results

The optimum parameters suggested by the design model were 200 µL of chloroform, 1.96 mL of ethanol, and 40 s vortexing period. LOD and LOQ were calculated using linear calibration plots of the analytes developed in the standard concentration range of 2.0 μg/L–2.0 mg/L.

Conclusions

Enhancement in detection power of the analytes recorded by the optimized method with respect to direct GC-MS determination (based on LOD values) was in the range of 3.6 and 539 folds. Spiked recovery experiments for municipal, medical, and synthetic wastewater samples yielded low recovery results when calculated against aqueous standard solutions. Matrix matched calibration standards were used to mitigate interferences from the waste samples and the percent recoveries obtained were close to 100%. This established accuracy and applicability of the developed method.

Highlights

The detection limits were found between 0.50 ng/mL and 37 ng/mL. An accurate, simple and sensitive analytical method was developed for the analytes.

Magnetic solid-phase extraction coupled with UHPLC-MS/MS for four antidepressants and one metabolite in clinical plasma and urine samples

Aim: Routine therapeutic drug monitoring is highly recommended since common antidepressant combinations increase the risk of drug-drug interactions or overlapping toxicity. Materials & methods: A magnetic solid-phase extraction by using C₁₈-functionalized magnetic silica nanoparticles (C₁₈-Fe₃O₄@SiO₂ NPs) as sorbent was proposed for rapid extraction of venlafaxine, paroxetine, fluoxetine, norfluoxetine and sertraline from clinical plasma and urine samples followed by ultra-HPLC-MS/MS assay. Results: The synthesized C₁₈-Fe₃O₄@SiO₂ NPs showed high magnetization and efficient extraction for the analytes. After cleanup by magnetic solid-phase extraction, no matrix effects were found in plasma and urine matrices. The analytes showed LODs among 0.15-0.75 ng ml^-1, appropriate linearity (R ≥ 0.9990) from 2.5 to 1000 ng ml^-1, acceptable accuracies 89.1-110.9% with precisions ≤11.0%. The protocol was successfully applied for the analysis of patients' plasma and urine samples. Conclusion: It shows high potential in routine therapeutic drug monitoring of clinical biological samples.

Antipsychotic drugs in hospital wastewater and a preliminary risk assessment

The residues of pharmaceutical and personal care products are the cause of increasing concern around the world. The aim of this study was to carry out the quantification of six antipsychotic drugs in hospital wastewater with the aid of liquid chromatography-mass spectrometry and, subsequently, make a preliminary assessment of the environmental risk posed. Dispersive liquid-liquid microextraction and solid phase extraction were optimized by multivariate design and validated in compliance with international guidelines. The extraction procedures were successfully applied to the quantification of the six selected antipsychotics in samples that were formed each day and collected at two main sampling points of the sewage network over the period of a week, in December 2017. Olanzapine (0.31─0.52 µg L^-1), clozapine (0.56─0.97 µg L^-1), haloperidol (1.43─2.73 µg L^-1), risperidone (0.92─0.98 µg L^-1) and chlorpromazine (0.52 µg L^-1) were found in at least one sampling point. In the case of most analytes, the highest concentrations were determined at sampling point A, which are derived from the psychiatric wing. The environmental risk quotient for clozapine, chlorpromazine and risperidone was ˃600, a very high-risk index, which signals the need for a better control of the emission of antipsychotics and an improvement of the wastewater treatment, especially, with regard to wastewater discharged from the hospital psychiatric wing.

Current direction and advances in analytical sample extraction techniques for drugs with special emphasis on bioanalysis

Analytical techniques may not be compatible or sufficiently sensitive to the analytes, unless it undergoes a specific sample extraction procedure. Sample extraction can be considered as one of the key steps in analysis. Analysis of a poorly treated sample may produce inferior quality of analytical data. Continuous advancement and development of newer sample extraction techniques such as solid phase microextraction, ultrasound, magnetically and microwave assisted magnetic extraction; electro-membrane extraction and dried blood spotting are to address the shortcomings of the existing techniques and to provide more automation, minimizing preparation time and make them high throughput. This review summarizes the suitability of application of the advanced sample preparation techniques available for chemical and bioanalysis in a comprehensive manner. This review also provides a scientific guidance for selecting the appropriate sample extraction technique based on sample type.

Opportunities for green microextractions in comprehensive two-dimensional gas chromatography / mass spectrometry-based metabolomics - A review

Microextractions have become an attractive class of techniques for metabolomics. The most popular technique is solid-phase microextraction that revolutionized the field of modern sample preparation in the early nineties. Ever since this milestone, microextractions have taken on many principles and formats comprising droplets, fibers, membranes, needles, and blades. Sampling devices may be customized to impart exhaustive or equilibrium-based characteristics to the extraction method. Equilibrium-based approaches may rely on additional methods for calibration, such as diffusion-based or on-fiber kinetic calibration to improve bioanalysis. In addition, microextraction-based methods may enable minimally invasive sampling protocols and measure the average free concentration of analytes in heterogeneous multiphasic biological systems. On-fiber derivatization has evidenced new opportunities for targeted and untargeted analysis in metabolomics. All these advantages have highlighted the potential of microextraction techniques for in vivo and on-site sampling and sample preparation, while many opportunities are still available for laboratory protocols. In this review, we outline and discuss some of the most recent applications using microextractions techniques for comprehensive two-dimensional gas chromatography-based metabolomics, including potential research opportunities.

A simple poly(styrene-co-divinylbenzene)-coated glass blood spot method for monitoring of seven antidepressants using capillary liquid chromatography-mass spectrometry

A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of the widely-prescribed antidepressants agomelatine, bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, trazodone in just a human blood drop is here developed and validated. This methodology is based on the use of lab manufactured poly(styrene-co-divinylbenzene)-coated glass (PS-DVB) blood spot for the extraction of the analytes and their subsequent separation and detection by capillary liquid chromatography-mass spectrometry (CLC-MS). Briefly, 10 mm-side squares were punched out from blood spots collected on glass substrate coated by 10 µg of the PS-DVB polymer and eluted with 1.0 mL of 2.0% acetic acid in methanol. The analytes were then separated and detected in less than 20 min by capillary CLC-MS using a Jupiter 4 µm Proteo 90 Å column and water: acetonitrile (20:80 v/v) and ammonium acetate (5 mM, pH 3.0) as mobile phase. Limit of detection (LOD) ranged from 0.018 to 0.038 µg mL^-1, and remarkable precision values for the responses and retention times lower than 5.89% and 1.92% were calculated, respectively. Moreover, accuracy values ranging between 85% and 104% were obtained.

Application of a tandem air-agitated liquid–liquid microextraction technique based on solidification of floating organic droplets as an efficient extraction method for determination of cholesterol-lowering drugs in complicated matrices

To enhance sample clean-up in dispersive liquid–liquid microextraction in complicated matrices, a low-toxicity and sensitive extraction method, tandem air-agitated liquid–liquid microextraction, based on solidification of floating organic droplets is introduced.