Ionic liquid based dispersive liquid–liquid microextraction coupled with micro-solid phase extraction of antidepressant drugs from environmental water samples

In-situ growth of covalent organic framework on stainless steel needles as solid-phase microextraction probe coupled with electrospray ionization mass spectrometry for rapid and sensitive determination of tricyclic antidepressants in biosamples

Tricyclic antidepressants (TCAs) including amitriptyline (AT), doxepin (DOX) and nortriptyline (NT) are the first-line drugs for the clinical treatment of depression; however, monitoring TCA concentrations in biological fluids and tissues is necessary to improve therapeutic effect and determine the cause of death in patients. It is of great significance to develop a rapid and sensitive method for real-time monitoring of TCAs in various biosamples. In this work, we fabricated a novel covalent organic framework (COF) based solid-phase microextraction (SPME) probe by an in-situ step-by-step strategy, which was obtained by sequentially modifying 1,3,5-tri (4-aminophenyl) benzene (TPB) and 2, 5-divinylbenzaldehyde (DVA) on the surface of polydopamine layer. The TPB-DVA-COF-SPME probe possessed high specific surface area (1244 m²·g ^- 1), regular pores (3.23 nm), good hydrophobicity and stability, resulting in efficient enrichment for TCAs. Furthermore, the combination of TPB-DVA-COF-SPME probe and ambient electrospray ionization mass spectrometry system (ESI/MS) was firstly proposed for rapid and sensitive determination of TCAs in biosamples. As a result, the developed method exhibited low limits of detection (LODs) (0.1-0.5 μg∙L ^- 1), high enrichment factors (39-218), and low relative standard deviations (RSDs) for one probe (1.2-3.8%) and probe-to-probe (2.0-3.7%). Benefiting from these outstanding performance, TPB-DVA-COF-SPME probe was further successfully applied to biosamples (i.e., serum, liver, kidney, and brain) with excellent reusability, indicating the promising applicability of the TPB-DVA-COF-SPME-ESI/MS as a powerful tool for drug monitoring.

Investigation of the performance of cross-linked poly(acrylic acid) and poly(methacrylic acid) as efficient adsorbents in SPE columns for simultaneous preconcentration of tricyclic antidepressants in water samples

A solid phase extraction-based (SPE) procedure for simultaneous preconcentration of five tricyclic antidepressants (TCAs), amitriptyline hydrochloride (AMT), nortriptyline hydrochloride (NOR), doxepin hydrochloride (DOX), imipramine hydrochloride (IMI), and clomipramine hydrochloride (CLO) from water samples with determination by HPLC-DAD is proposed. Polymers were characterized by FT-IR, SEM, and thermogravimetric analysis. SPE-based methods were carried out by the preconcentration of 320.0 mL of TCAs at pH 7.0 (buffered with 0.01 mol L^-1 phosphate buffer) through 70.0 mg of adsorbent packed into a SPE cartridge, followed by elution with 1.0 mL of ACN : MeOH : acetic acid solution (45 : 45 : 10% v/v). Higher preconcentration factors were obtained ranging from 117.9 to 372.2 and 207.1 to 396.1 by using poly(MAA-co-EGDMA) and poly(AA-co-EGDMA), respectively, yielding lower limits of detection (0.03 to 0.12 μg L^-1) and (0.03 to 0.15 μg L^-1). These outcomes show satisfactory detectability of SPE-based methods, with slightly better performance using poly(MAA-co-EGDMA). On the other hand, poly(AA-co-EGDMA) was able to preconcentrate TCAs in the presence of humic acid (7.0 mg L^-1) without interference. The precision of methods assessed as RSD (%) was very similar, ranging from 1.7% to 16.3% for poly(MAA-co-EGDMA) and 1.7% to 13.4% for poly(AA-co-EGDMA). SPE cartridges packed with the polymers showed high reusability (52 cycles of preconcentration and elution) without losing adsorption efficiency. The methods were applied to determine TCAs in tap, lake, and stream water samples and the accuracy was attested by addition and recovery tests (86.7-116.0%), with determined nortriptyline ranging from 0.48 to 0.52 μg L^-1 in lake water samples.

Development of an easy and rapid analytical method for the extraction and preconcentration of chloroquine phosphate from human biofluids prior to GC-MS analysis

A vortex assisted spraying based fine droplet formation liquid phase microextraction (VA-SFDF-LPME) method was developed to determine chloroquine phosphate at trace levels in human serum, urine and saliva samples by gas chromatography–mass spectrometry (GC–MS) with single quadrupole mass analyzer. In the first part, several liquid phase microextraction (LPME) and magnetic solid phase extraction (MSPE) methods were compared to each other in order to observe their extraction ability for the analyte. VA-SFDF-LPME method was selected as an efficient and easy extraction method due to its higher extraction efficiency. Optimization studies were carried out for the parameters such as extraction solvent type, sodium hydroxide volume/concentration, sample volume, spraying number and mixing type/period. Tukey's method based on post hoc test was applied to all experimental data for the selection of optimum values. Optimum extraction parameters were found to be 12 mL initial sample volume, two sprays of dichloromethane, 0.75 mL of 60 g/kg sodium hydroxide and 15 s vortex. Under the optimum conditions, limit of detection and quantification (LOD and LOQ) were calculated as 2.8 and 9.2 μg/kg, respectively. Detection power of the GC–MS system was increased by approximately 317 folds with the developed extraction/preconcentration method. The applicability and accuracy of the proposed method was evaluated by spiking experiments and percent recovery results for human urine, serum and saliva samples were found in the range of 90.9% and 114.0% with low standard deviation values (1.9–9.4).

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.

Zeolitic imidazolate frameworks in analytical sample preparation

Zeolitic imidazolate frameworks are a class of metal-organic frameworks that are topologically isomorphic with zeolites. Zeolitic imidazolate frameworks are composed of tetrahedrally coordinated metal ions connected by imidazolate linkers and have a high porosity and chemical stability. Here, we summarize the progress made in the application of zeolitic imidazolate frameworks in sample preparation for analytical purposes. This review is focused on analytical methods based on liquid chromatography, gas chromatography, or capillary electrophoresis, where the use of zeolitic imidazolate frameworks has contributed to increasing the sensitivity and selectivity of the method. While bulk zeolitic imidazolate frameworks have been directly used in analytical sample preparation protocols, a variety of strategies for their magnetization or their incorporation into sorbent particles, monoliths, fibers, stir bars, or thin films, have been developed. These modifications have facilitated the handling and application of zeolitic imidazolate frameworks for a number of analytical sample treatments including magnetic solid-phase extraction, solid-phase microextraction, stir bar sorptive extraction, or thin film microextraction, among other techniques.

Selective Adsorption of Cationic Dyes for Stable Metal-Organic Framework ZJU-48

A cationic metal-organic framework (MOF) ZJU-48 with one-dimensional pores of about 9.1 × 9.1 Ų has been prepared from zinc ions, adenine, and carboxyl ligands. ZJU-48 displays excellent water stability for about one week, exhibiting its potential application for adsorption and separation of dyes. Cationic and anionic dyes with similar sizes are adopted to study the adsorbing and separating properties of ZJU-48. Cationic dyes are adsorbed better than anionic dyes because of the negatively charged zeta potential of the material surface, implying its selective adsorption to cationic dyes, and it is charge-based adsorption. Meanwhile, the adsorption ability of the MOF to cationic dyes with different sizes is also investigated. We find that the adsorbed amount decreases with increase in the size of organics ,indicating that it is size-based adsorption. Furthermore, the cationic dye methylene blue (MB) is employed and focused on for its suitable charge and fitting size to evaluate the maximum adsorption capacity and desorption progress of ZJU-48. The results show that the maximum loaded amount of MOF toward MB reaches 582.44 mg/g, and about 90% of loaded dyes can be released from frameworks in N,N-dimethylformamide with NaCl over 6 h, exhibiting satisfactory adsorptive property and possibility as a reusable adsorbent.

The Influence of Ionic Liquids on the Effectiveness of Analytical Methods Used in the Monitoring of Human and Veterinary Pharmaceuticals in Biological and Environmental Samples-Trends and Perspectives

Recent years have seen the increased utilization of ionic liquids (ILs) in the development and optimization of analytical methods. Their unique and eco-friendly properties and the ability to modify their structure allows them to be useful both at the sample preparation stage and at the separation stage of the analytes. The use of ILs for the analysis of pharmaceuticals seems particularly interesting because of their systematic delivery to the environment. Nowadays, they are commonly detected in many countries at very low concentration levels. However, due to their specific physiological activity, pharmaceuticals are responsible for bioaccumulation and toxic effects in aquatic and terrestrial ecosystems as well as possibly upsetting the body's equilibrium, leading to the dangerous phenomenon of drug resistance. This review will provide a comprehensive summary of the use of ILs in various sample preparation procedures and separation methods for the determination of pharmaceuticals in environmental and biological matrices based on liquid-based chromatography (LC, SFC, TLC), gas chromatography (GC) and electromigration techniques (e.g., capillary electrophoresis (CE)). Moreover, the advantages and disadvantages of ILs, which can appear during extraction and separation, will be presented and attention will be given to the criteria to be followed during the selection of ILs for specific applications.

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.

Occurrence and risk assessment of antidepressants in Huangpu River of Shanghai, China

Antidepressants are gaining public attention because of increasing reports of their occurrence in environment and their potential impact on ecosystems and human health. Continuous input of pharmaceuticals into rivers, through psychiatric hospital or wastewater treatment plant (WWTPs) effluent, may cause adverse effects on the aquatic ecosystems of the receiving water bodies. This work investigates the occurrence and sources of 8 antidepressants in main stream and tributaries of Huangpu River in Shanghai. The detected concentrations of the selected antidepressants ranged from low nanogram per liter to 42.9 ng L^-1 (fluoxetine) in main stream and ranged from low nanogram per liter to 33.7 ng L^-1 (fluoxetine) in tributaries. To study the effect of hospital or wastewater treatment plants (WWTPs) on environment, the upstream and downstream samples were analyzed. Generally, antidepressants had greater concentrations in downstream than that in upstream of the WWTPs or hospitals. It is suggesting that WWTPs and hospitals may introduce pollution into water environment. A preliminary risk assessment was conducted: none of the eight target compounds yielded risk quotient (RQ) values more than 0.1, thus indicating that no adverse effect is expected in water environment. These results will provide background data for future antidepressants pollution control and management in Shanghai, China.

Porous membrane protected micro-solid-phase extraction: A review of features, advancements and applications

Membrane protected micro-solid-phase extraction (μ-SPE) was introduced in 2006 as an alternative to multistep SPE. μ-SPE is based on packing of very small amount of sorbent inside the porous membrane sheet whose edges are heat sealed to fabricate a μ-SPE device. This device performs clean up, extraction, and pre-concentration in a single step. It suits best for extraction of complex samples as sorbent is effectively protected inside the membrane and extraneous matter cannot adsorb over it. This review summarizes most important aspects of μ-SPE including basic principles, extraction procedure, different formats, sorbents employed and affecting parameters. The article also provides a brief account on modified μ-SPE procedures where μ-SPE was either combined with other techniques or some major changes were introduced in original procedure. Finally, the applications of μ-SPE in environmental, food and biological analysis are described. At the end, advantages and pitfalls of μ-SPE are critically appraised.

In situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in Parkinson's rat brain microdialysates by ultra high performance liquid chromatography-tandem mass spectrometry

Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson's disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC-MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30μL of microdialysates, 150μL of acetonitrile containing LRSC, 50μL of bromobenzene and 800μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0min at 37°C. Under the optimized conditions, good linearity was observed with LODs (S/N>3) and LOQs (S/N>10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the reported studies through the introduction of a permanent charged moiety from LRSC into NTs. Taken together, this in situ DUADLLME method was successfully applied for the simultaneous determination of six NTs in biological samples.

Tris(pentafluoroethyl)trifluorophosphate-basd ionic liquids as advantageous solid-phase micro-extraction coatings for the extraction of organophosphate esters in environmental waters

Ionic liquids (ILs) containing the tris(pentafluoroethyl)trifluorophosphate [FAP] anion and various cations have great potential in sample preparation because of their excellent hydrophobicity, thermostability and low hydrolysity. In the present study, a [FAP]-based IL, 1-hexyl-3-methylimidazolium tris (pentafluoroethyl) trifluoro phosphate ([HMIM][FAP]), was used as coatings of solid-phase microextraction (SPME) for extracting organophosphate esters (OPEs) from environmental water samples. This SPME fiber was fabricated by coating a stainless steel wire substrate with [HMIM][FAP] via a simple direct dip-coating approach, and the extraction was conducted by the direct immersion solid phase microextraction. Coupling to gas chromatography mass spectrometry (GC-MS), the developed SPME method exhibited excellent selectivity and sensitivity towards the extraction of 11 OPEs from aqueous samples. Satisfactory linearity (R(2)≥0.99) of the calibration curves was obtained over the range of 0.05-50.0ngmL(-1) with the limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) ranged from 0.13-7.40ngL(-1) and 0.50-24.0ngL(-1), respectively. The proposed SPME method showed excellent extraction efficiency to OPEs with enrichment factors in the range of 168-2603, and acceptable reproducibility with relative standard deviations (RSDs) ≤15% for single fiber (n=7) and ≤16% for fiber-to-fiber (n=3×3) at a concentration level of 0.5ngmL(-1), respectively. The prepared IL-based fiber was successfully applied to determine eleven common used OPEs in tap water, influent and effluent of sewage treatment plant, with results are comparable to those determined by the reference (UPLC-MS/MS), and spiked recoveries in the range of 84.0-108%, 82.1-123% and 82.8-100%, respectively.

Application of hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction techniques in analytical toxicology

The recent developments in hollow fiber liquid phase microextraction and dispersive liquid –liquid microextraction are reviewed. Applications of these newly emerging developments in extraction and preconcentration of a vast category of compounds including heavy metals, pesticides, pharmaceuticals and abused drugs in complex matrices (environmental and biological matrices) are reviewed and discussed. The new developments in these techniques including the use of solvents lighter than water, ionic liquids and supramolecular solvents are also considered. Applications of these new solvents reduce the use of toxic solvents and eliminate the centrifugation step, which reduces the extraction time.

Adsorptive Separation of Olefin/Paraffin Mixtures with ZIF-4

The microporous zeolitic imidazolate framework ZIF-4 has been synthesized, and its ethylene/ethane and propylene/propane separation potentials have been evaluated by single-component adsorption isotherms and breakthrough experiments of the respective binary mixtures. In all experiments, a higher selectivity for the paraffin is observed that is manifested by a steeper equilibrium isotherm as well as a later breakthrough in the fixed-bed adsorber experiments. Microporous adsorbents with paraffin selectivity are rare but highly interesting for cyclic adsorption processes such as pressure-swing adsorption (PSA).

Low density solvent based dispersive liquid–liquid microextraction followed by vortex-assisted magnetic nanoparticle based solid-phase extraction and surfactant enhanced spectrofluorimetric detection for the determination of aflatoxins in pistachio nuts

A novel extraction method based on DLLME followed by VA-D-SPE was developed to determine total aflatoxins in pistachio.