Supramolecular solvent (SUPRASs) extraction method for detecting benzodiazepines and zolpidem in human urine and blood using gas chromatography tandem mass spectrometry

Development and Validation of a Sonication-Assisted Dispersive Liquid-Liquid Microextraction Procedure and an HPLC-PDA Method for Quantitative Determination of Zolpidem in Human Plasma and Its Application to Forensic Samples

The use of z-drugs has increased worldwide since its introduction. Although the prescribing patterns of hypnotics differ among countries, zolpidem is the most widely used z-drug in the world. Zolpidem may be involved in poisoning and deaths. A simple and fast HPLC-PDA method was developed and validated. Zolpidem and the internal standard chloramphenicol were extracted from plasma using a sonication-assisted dispersive liquid-liquid microextraction procedure. The method was validated including selectivity, linearity, precision, accuracy, and recovery. The calibration range (0.15-0.6 µg/mL) covers therapeutic and toxic levels of zolpidem in plasma. The limit of quantification was set at 0.15 µg/mL. Intra- and interday accuracy and precision values were lower than 15% at the concentration levels studied. Excellent recovery results were obtained for all concentrations. The proposed method was successfully applied to ten real postmortem plasma samples. In our series, multiple substances (alcohol and/or other drugs) were detected in most cases of death involving zolpidem. Our analytical method is suitable for routine toxicological analysis.

Ultrasound assisted membrane-assisted solvent extraction for the simultaneous assessment of some drugs involved in drug-facilitated sexual assaults by liquid chromatography-tandem mass spectrometry

A simple and highly efficient ultrasound assisted membrane-assisted solvent extraction (MASE) pre-treatment method for urine has been developed and validated for the simultaneous determination of twenty-two drugs involved in drug-facilitated sexual assaults (DFSAs) by liquid chromatography-tandem mass spectrometry. MASE was performed with 4.0 mL of urine (pH adjusted at 12), 400 μL of hexane as an organic solvent inside the polypropylene membrane, and ultrasonication (45 kHz, 120 W) for 10 min. A pre-concentration factor of 40 was achieved after evaporation (N2 stream) and re-dissolution in 100 µL of methanol. Analytes were separated using a Zorbax Eclipse Plus C18 column under gradient elution with aqueous 10 mM NH4HCO3 (pH 8.0) and methanol as mobile phases. Matrix-matched calibrations allowed the assessment of DFSA drugs of quite different octanol-water partition coefficients (Ko/w), from 1.32 101 for pregabalin to 2.45 105 for clomipramine (Log P values from 1.12 (pregabalin) to 5.39 (clomipramine)). The limit of detection (LOD) was between 0.0075 to 0.37 µg L-1, with analytical recoveries ranging from 73 to 103%, and relative standard deviations (RSDs) within the 2-20% range. The applicability of the method was demonstrated after analysing urine samples under forensic investigation.

Extensive evaluation of plasma metabolic sample preparation process based on liquid chromatography-mass spectrometry and its application in the in vivo metabolism of Shuang-Huang-Lian powder injection

Shuang-Huang-Lian powder injection (SHLPI) is a natural drug injection made of honeysuckle, scutellaria baicalensis and forsythia suspensa. It has the characteristics of complex chemical composition and difficult metabolism research in vivo. LC-MS platform has been proven to be an important analytical technology in plasma metabolomics. Unfortunately, the lack of an effective sample preparation strategy before analysis often significantly impacts experimental results. In this work, twenty-one extraction protocols including eight protein precipitation (PPT), eight liquid-liquid extractions (LLE), four solid-phase extractions (SPE), and one ultrafiltration (U) were simultaneously evaluated using plasma metabolism of SHLPI in vivo. In addition, a strategy of "feature ion extraction of the multi-component metabolic platform of traditional Chinese medicine" (FMM strategy) was proposed for the in-depth characterization of metabolites after intravenous injection of SHLPI in rats. The results showed that the LLE-3 protocol (Pentanol:Tetrahydrofuran:H2O, 1:4:35, v:v:v) was the most effective strategy in the in vivo metabolic detection of SHLPI. Furthermore, we used the FMM strategy to elaborate the in vivo metabolic pathways of six representative substances in SHLPI components. This research was completed by ion migration quadrupole time of flight mass spectrometer combined with ultra high performance liquid chromatography (UPLC/Vion™-IMS-QTof-MS) and UNIFI™ metabolic platform. The results showed that 114 metabolites were identified or preliminarily identified in rat plasma. This work provides relevant data and information for further research on the pharmacodynamic substances and in vivo mechanisms of SHLPI. Meanwhile, it also proves that LLE-3 and FMM strategies could achieve the in-depth characterization of complex natural drug metabolites related to Shuang-Huang-Lian in vivo.

Highly Efficient Dual-Color Luminophores for Sensitive and Selective Detection of Diclazepam Based on MOF/COF Bi-Mesoporous Composites

Currently, studies on electrochemiluminescence (ECL) mainly focused on the single emission of luminophores while those on multi-color ECL were rarely reported. Here, a bi-mesoporous composite of the metal-organic framework (MOF)/covalent-organic framework (COF) with strong and stable dual-color ECL was prepared to construct a novel ECL sensor for sensitive detecting targets. A PTCA-COF with excellent ECL performance was loaded with a great amount of another ECL emitter Cu₃(HHTP)₂. Remarkably, the integrated composite had both ECL properties of PTCA-COF at 520 nm and Cu₃(HHTP)₂ at 600 nm wavelengths. Furthermore, Cu₃(HHTP)₂ with good electron transfer ability can greatly enhance the electrical conductivity and promote electrochemical activation. Thus, the simultaneous enhanced two-color ECL intensity and the catalytic properties of the conductive MOF exerted a dual enhancement effect on the ECL signal of the composite. Significantly, diclazepam can not only be adsorbed well on the multi-stage porous structure MOF/COF composite by π-π interactions but also selectively quench the ECL signal of the PTCA-COF, realizing the sensitive detection. The ECL sensor showed a wide detection range from 1.0 × 10^-13 to 1.0 × 10^-8 g/L, and the limit of detection (LOD) was as low as 2.6 × 10^-14 g/L (S/N = 3). The proposed ECL sensor preparation method was simple and sensitive, providing a new perspective for the potential application of multi-color ECL in the sensing field.

Establishment and application of a screening method for 354 organic toxicants in blood and urine with high-performance liquid chromatography-high-resolution orbitrap mass spectrometry

A rapid and sensitive high-performance liquid chromatography-high-resolution orbitrap mass spectrometry method was developed for the simultaneous screening of 354 organic poisons and metabolites in blood and urine, including drugs, medications, pesticides, rodenticides, veterinary drugs, alkaloids, and mycotoxins with a multi-toxicant chromatography-mass spectrometry information library. The method and library showed good prospects in clinical poisoning screening and forensic toxicological identification. Blood and urine samples were extracted successively with ethyl acetate in acidic and alkaline conditions; then, the extract was blown to nearly dry by nitrogen gas and redissolved with methanol-aqueous solution (v:v, 50:50), and the dissolved solution was analyzed by LC-MS/MS after filtering. Precursor ions' m/z was set for identification, retention time, fragment ions, and isotopic pattern which were used for confirmation. No interference peaks were found in the blank samples, showing good specificity. The LODs of toxicants in urine and blood were 1.00×10^-3-50.0 ng/mL and 2.07×10^-3-50.0 ng/mL, respectively, while the LOQs were 3.30×10^-3-1.67×10² ng/mL and 6.91×10^-3-1.67×10² ng/mL. The intra-day precision and inter-day precision of urine samples were 2.31-9.13% and 4.75-12.3%, respectively, which were 1.92-10.8% and 2.01-12.1% in blood samples. The established method was applied to analyze 9 cases of clinical poisoning patients, and bromadiolone, carbofuran, and amanitins were detected, respectively. A total of 382 biospecimens from drug abusers were analyzed with the proposed method, which indicated that some drugs were detected in 62 cases, mainly including methamphetamine, heroin, and MDMA. The results were consistent with the information from traditional liquid chromatography-triple quadrupole mass spectrometry.

Development and validation of the UPLC-MS method for simultaneous determination of six new psychoactive substances

The combined abuse of benzodiazepines and antipsychotics has become a global problem, and to develop a highly sensitive and selective method for monitoring of benzodiazepine hypnotics and antipsychotics is urgently necessary. In this work, we established a rapid method for the simultaneous determination of benzodiazepines (diazepam, alprazolam, triazolam, and estazolam) and antipsychotic drugs (clozapine, and chlorpromazine) based on ultra performance liquid chromatography-mass spectrometry (UPLC-MS). The accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), specificity, matrix effect and carry-over effect were verified in detail. The results of the recovery and repeat experiments proved that the proposed UPLC-MS method possessed very satisfactory accuracy and precision. The LOD and LOQ of the six psychoactive substances were as low as 0.001-0.005 and 0.005-0.01 μg L-1, respectively. The proposed method was employed to analyze urine samples which were pretreated with a protein precipitation process. The potential influences of precipitants on the analysis results were evaluated statistically, and 0.1% formic acid/acetonitrile/water was selected as the optimum precipitation agent. The detection of the targets was free from matrix and carryover effects.

Trends in hollow fibre liquid phase microextraction for the preconcentration of pharmaceutically active compounds in aqueous solution: A case for polymer inclusion membrane

Low concentrations of pharmaceutically active compounds have been reported in samples from highly complex aqueous environments. Due to their low concentrations, efficient sample pretreatment methods are needed to clean samples and concentrate the compounds of interest prior to instrumental analysis. Hollow fibre liquid-phase microextraction (HF-LPME) is an effective alternative to conventional techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) because it consumes less organic solvent and is less labour intensive with a short extraction time. HF-LPME involves the preconcentration and mass transfer of target analytes from an aqueous sample into an acceptor solution in the lumen of the fibre using a supported liquid membrane (SLM) impregnated in the hollow fibre pores. However, despite the high contaminant selectivity, reproducibility, and enrichment that HF-LPME offers, this technique is limited by membrane instability. Although several advances have been made to address membrane instability, they are either too costly or not feasible for industrial application. Hence, hollow fibre polymer inclusion membrane liquid-phase microextraction (HF-PIM-LPME) was introduced to ameliorate membrane instability. This new approach uses ionic liquids (ILs) as a green solvent, and has demonstrated high membrane stability, good contaminant enrichment, and similar selectivity and reproducibility to HF-SLM-LPME. Hence, this review aims to raise awareness of HF-PIM-LPME as a viable alternative for the selectivity and preconcentration of pharmaceuticals and other contaminants in aquatic environments.

Miniaturized green sample preparation approaches for pharmaceutical analysis

The development of green sample preparation procedures is an extremely important research field in which more and more applications are constantly being proposed in different areas, including pharmaceutical analysis. This review article is aimed at providing a general overview of the development of miniaturized green analytical sample preparation procedures in the pharmaceutical analysis field, with special focus on the works published between January 2017 and July 2021. Particular attention has been paid to the application of environmentally friendly solvents and sorbents as well as nanomaterials or high extraction capacity sorbents in which the solvent volumes and reagents amounts are drastically reduced, with their subsequent advantages from the sustainability point of view.

Synergistic Combination of Facile Thiol-Maleimide Derivatization and Supramolecular Solvent-Based Microextraction for UHPLC-HRMS Analysis of Glutathione in Biofluids

Glutathione (GSH) is the most abundant non-protein thiol in biofluids, enabling diverse physiological functions. Among the proposed methods for GSH detection, ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS) has the advantages of high sensitivity and efficiency. In this study, a novel analytical method was developed for the determination of GSH using supramolecular solvent (SUPRAS)-based dispersive liquid–liquid microextraction (DLLME) and UHPLC–HRMS. N-Laurylmaleimide was dissolved in tetrahydrofuran, which served three functions: 1) precipitate the proteins present in the biofluid sample, 2) provide a reaction environment for derivatization, and 3) enable the use of SUPRAS as the dispersing agent. Critical parameters were optimized based on single factor testing and response surface methodology. The established method was validated in terms of linearity, accuracy, precision, and successful quantitative analysis of GSH in saliva, urine, and plasma samples. Experimental results showed that SUPRAS as an extraction solvent was particularly suitable for the extraction of GSH from complex matrices. The current study provides a useful tool for accurate measurements of GSH concentrations, which could potentially be used for clinical diagnostics.