Development and Validation of a Method for Quantification of 28 Psychotropic Drugs in Postmortem Blood Samples by Modified Micro-QuEChERS and LC-MS-MS

Determination of drugs of abuse and metabolites in plasma microsamples by LC-MS/MS after microQuEChERS extraction

Aim: Identifying drugs of abuse and their metabolites in plasma is vital in both forensic and clinical toxicology. While the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method offers an efficient approach to sample preparation, its application is complex due to the wide-ranging properties of target analytes and the challenges posed by biological matrix interferences. This study aims to develop a microQuEChERS approach for the quantification of 14 drugs of abuse and metabolites utilizing minimal sample and solvent volumes.Methods: The microQuEChERS method involved using 10 μl plasma samples, 25 mg of a salt mixture and 150 μl of acetonitrile. Extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with a 7.5 min run. The assay was validated according to bioanalytical guidelines.Results: The accuracy was 96.8-112.4%. The within-assay precision was within 2.0-8.9% and the between-assay precision was within 3.2-8.2%. Matrix effects were found to range from -5.7 to 13.5%. The extraction yield was higher than 74.7%.Conclusion: This study described a microQuEChERS sample preparation approach for determining drugs of abuse and metabolites using plasma microsamples and LC-MS/MS. The approach is efficient, environmentally friendly and suitable for scenarios with limited amounts of biological samples.

Development and application of a mini-QuEChERS method for the determination of pesticide residues in anuran adipose tissues

The expansion of monocultures to regions close to conservation areas has put biodiversity at risk, mainly due to the intense use of pesticides. Anurans are highly susceptible to pesticides and may be a biological marker in the contamination of an area. However, methods for determining pesticides in anurans are incipient. In this work, a miniaturized QuEChERS method was developed for the extraction of atrazine, chlorpyrifos, α- and β-endosulfan, α-, β-, θ- and ζ-cypermethrin in anuran adipose tissues. The method was optimized for the tissue sample size scale according to sample mass availability. Extracting solvent and adsorbents for the clean-up step was evaluated, achieving recoveries next to 100% with acetonitrile and without a clean-up step. The mini-QuEChERS method, using 500 mg of adipose tissue, 50 mg of NaCl and 200 mg of MgSO4, 100 μL of ultrapure water, and 1.50 mL of acetonitrile with no purification step, followed by high-performance liquid chromatography analysis and photodiode array detection was validated following the European Community guidelines. The methodology showed a moderate matrix effect for some pesticides, which was corrected using the matrix-matched calibration. The limits of quantification for the pesticide residues in adipose tissues ranged from 10 to 75 μg kg-1. Pesticide recoveries ranged from 74% to 115%, and repeatability and within-lab reproducibility showed relative standard deviations < 11%. The mini-QuEChERS method was applied to extract pesticide residues from the adipose tissues of two species of anurans: Leptodactylus macrosternum and Scinax x-signatus. 25% of samples were positive, detecting endosulfan and chlorpyriphos, confirmed by liquid chromatography coupled to tandem mass spectrometry. The mini-QuEChERS was a simple, economical, and eco-friendly method for extracting pesticide residues in anuran adipose tissue samples.

Recent Advances in Analytical Techniques for Antidepressants Determination in Complex Biological Matrices: A Review

Depression is one of the most prevalent but severe of mental disorders, affecting thousands of individuals across the globe. Depression, in its most extreme form, may result in self-harm and an increased likelihood of suicide. Antidepressant drugs are first-line medications to treat mental disorders. Unfortunately, these medications are also prescribed for other in- and off-label conditions, such as deficit/hyperactivity disorders, attention disorders, migraine, smoking cessation, eating disorders, fibromyalgia, pain, and insomnia. This results in an increase in the use of antidepressant medications, leading to clinical and forensic overdose cases that could be either accidental or deliberate. The findings revealed that people who used antidepressants had a 33% greater chance of dying sooner than expected, compared to those who did not take the medications. Analytical techniques for precisely identifying and detecting antidepressants and their metabolic products in a variety of biological matrices are greatly needed to be developed and made available. Hence, this study attempts to discuss various analytical techniques used to identify and determine antidepressants in various biological matrices, which include urine, blood, oral fluid (saliva), and tissues, which are commonly encountered in clinical and forensic science laboratories.

Evaluation of a Chaotrope and Kosmotrope in the Multivariate Optimization of PHW-ATPE of Solasodine from Leaves of Solanum mauritianum

A hyphenated pressurized hot water—aqueous two-phase extraction (PHW-ATPE) method was applied to extract solasodine from Solanum mauritianum (S. mauritianum). A central composite design (CCD) was applied to determine the optimal conditions for the extraction of solasodine. The parameters evaluated included the percentage concentration of salt (NaCl or Na2CO3) and temperature. The fit of the central composite design response surface model for PHW-ATPE to the data generated a model with a good quadratic fit (R2 = 0.901). The statistically significant (p < 0.05) parameters, such as the linear and quadratic effects of the concentration of salt (%) powder, had a significant impact on the extraction of solasodine. The application of multiply charged salts such as Na2CO3 (kosmotrope) was shown to be a comparably better extractant of solasodine than NaCl (chaotrope) due to the salting-out effect. The optimized conditions for extraction of solasodine with NaCl or Na2CO3 were a temperature of 80 °C at a salt concentration of 20%. The maximum extraction of solasodine was 300.79 mg kg−1 and 162.34 mg kg−1 for Na2CO3 and NaCl, respectively.

Development of analytical method for the determination of methylphenidate, the analog ethylphenidate and their metabolite ritalinic acid in oral fluid samples by micro-QuEChERS and liquid chromatography-tandem mass spectrometry

The aim of this study was to develop a quantitative method for the analysis of methylphenidate, the analog ethylphenidate and their metabolite ritalinic acid in oral fluid, using micro-QuEChERS extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Oral fluid samples were collected with Quantisal™ device, extracted by micro-QuEChERS technique and analyzed by LC-MS/MS. The developed method met the validation criteria of Academy Standards Board (ASB) Standard Practices for Method Validation in Forensic Toxicology (Standard 036, 2019) with limits of detection and quantification of 0.5 ng/mL and calibration curve from 0.5 to 50 ng/mL. Within-run imprecision was greater than 18.7% while between-run imprecision was greater than 17.0 % for all analytes. Bias did not vary more than 7.7 %. No evidence of carryover was found. Stability studies presented satisfactory results for 24 h on autosampler (10 °C), after 3 cycles of freeze/thaw, 7 days on freezer (-20 °C) and until 7 days on refrigerator (4 °C) for methylphenidate. The validated method was further successfully applied to the analysis of 5 authentic oral fluid samples collected from volunteers at parties and music festivals from different cities in Brazil. Four samples had positive results for methylphenidate and ritalinic acid, and only one sample was positive for methylphenidate. Ethylphenidate was not detected in the samples. The method showed acceptable analytical performance and is environmentally friendly, requiring reduced use of solvents and reagents, with potential to be applied to clinical and forensic analyses.

Novel Applications of Microextraction Techniques Focused on Biological and Forensic Analyses

In recent years, major attention has been focused on microextraction procedures that allow high recovery of target analytes, regardless of the complexity of the sample matrices. The most used techniques included liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME), dispersive liquid-liquid microextraction (DLLME), microextraction by packed sorbent (MEPS), and fabric-phase sorptive extraction (FPSE). These techniques manifest a rapid development of sample preparation techniques in different fields, such as biological, environmental, food sciences, natural products, forensic medicine, and toxicology. In the biological and forensic fields, where a wide variety of drugs with different chemical properties are analyzed, the sample preparation is required to make the sample suitable for the instrumental analysis, which often includes gas chromatography (GC) and liquid chromatography (LC) coupled with mass detectors or tandem mass detectors (MS/MS). In this review, we have focused our attention on the biological and forensic application of these innovative procedures, highlighting the major advantages and results that have been accomplished in laboratory and clinical practice.

Optimization of QuEChERS extraction for detection and quantification of 20 antidepressants in postmortem blood samples by LC-MS/MS

In this study, a comprehensively optimization of QuEChERS (quick, easy, cheap, effective, rugged and safe) method using design of experiments (DOE) was conducted to evaluate the best conditions to obtain the most effective extraction. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis was performed to identify and quantify the antidepressants, with electrospray ionization acquired in positive mode. The method was validated for all analytes; the calibration curves were linear from 10-1000ng/mL, with R²>0.98, and with LOD and LOQ defined as 10ng/mL. Method imprecision and bias were less than 14.3% and 18.9%, respectively. Neither carryover nor interferences were observed. Overall, the optimized method was applied in postmortem real sample analysis to quantify the antidepressants. This study showed a viable method that can be applied for routine forensic analysis, with a quick and easy sample preparation and a rapid total run time of 8min for each analysis.