A rapid analytical strategy for the determination of ayahuasca alkaloids in non-ritualistic approaches by UHPLC-MS/MS.

INTRODUCTION: Ayahuasca is a beverage composed by a mixture of herbs which contain the compound N,N-dimethyltriptamine (DMT) and the ß-carbolines. Although its use is legalized in Brazil only for religious and spiritual ceremonies, there is a growing black market specialized in the distribution of these compounds in form of herbal material through internet and mail. The purpose of this work was the development of an ultra-high-performance liquid chromatography-tandem mass spectrometry method for the determination of ayahuasca alkaloids and its application in seized ayahuasca products. METHODS: An aliquot of seized products was weighted and diluted with methanol. An aliquot of this solution was added with internal standard (DMT-d6), followed by injection in the analytical system. RESULTS: The limit of quantitation was 10ng/mL for DMT and 25ng/mL for harmine, harmaline and tetrahydroharmine. The concentration ranges used were 10-100ng/mL for DMT, harmine and harmaline and all analytes presented a coefficient of determination (r2)≥0,99. Analysis of four seized samples presented concentrations of DMT ranging between 31.5 and 46.5mg/g. Presence of ß-carbolines was not detected in the products. The variability of DMT concentrations can be correlated with the potential intoxications described in the literature. CONCLUSION: This work successfully established a determination method for ayahuasca alkaloids in herbal material. In addition, the workflow proved to be simple, rapid and useful to estimate the concentration of psychoactive compounds in seized materials, leading to further investigation of ayahuasca ritualistic or recreational exposure.

Refrigerated sorptive extraction: determination of BTEX in water samples.

Benzene, toluene, ethyl benzene, o-xylene, m-xylene, and p-xylene (BTEX) enrichment from aqueous samples is performed using refrigerated sorptive extraction (RSE). RSE implies the sorption of volatiles compounds into polydimethylsiloxane (approximately 0.39 mg) coated on an open stainless steel tube internally refrigerated by cold water. A metal tube is inserted into a 30-mL headspace vial through a hole at both sides of the vial. The sample inside the vial is equilibrated with stirring for 60 min at 40 degrees C. After the extraction, the analytes are desorbed with 280 microL of methanol under ultrasonic bath. BTEXs are analyzed by high resolution gas chromatography-flame ionization detection. Optimization of temperature and extraction time were carried out, as well validation in terms of linearity, precision, recuperation, limits of detection and quantification. Linearity is the range 0.999-0.998, linear range between 50 and 1000 microg/L, precision is 6.1% to 14.7% in the 0.1 microg/mL level and 3.5% to 5.6% in the 1 microg/mL level. Recovery ranged from 30% to 50%, detection limits from 1.7 to 19.6 microg/L, and quantification limits from 6.7 to 64.6 microg/L. The optimized method was applied to the analysis of water samples collected near a gas station, which was suspected of contamination by gas oil leaking from storage tanks.

Recent developments and applications of stir bar sorptive extraction.

The theoretical aspects of stir bar sorptive extraction (SBSE), as well as the recent applications of this technique in pharmaceutical, biomedical, environmental, and food analysis, and recently developed new coating procedures are reviewed. A general overview of the important factors to be evaluated in the optimization of extraction efficiency such as extraction time, matrix pH, ionic strength, effect of organic additives, temperature, agitation, pre-extraction derivatization reactions, influence of proteins, and desorption conditions are discussed. An impressive number of applications using SBSE have been published in different areas including biological, environmental, and food, showing the advantages of this technique over the classical extraction techniques (liquid-liquid extraction (LLE), Soxhlet). Although the different SBSE applications use PDMS phase as sorbent, developments of new phases are necessary for specific applications. In this review, recent SBSE developments are shown with a focus on the development of new instrumental approaches and sorbent phases.

A novel HS-SBSE system coupled with gas chromatography and mass spectrometry for the analysis of organochlorine pesticides in water samples.

A methodology to analyze organochlorine pesticides (OCPs) in water samples has been accomplished by using headspace stir bar sorptive extraction (HS-SBSE). The bars were in house coated with a thick film of PDMS in order to properly work in the headspace mode. Sampling was done by a novel HS-SBSE system whereas the analysis was performed by capillary GC coupled mass spectrometric detection (HS-SBSE-GC-MS). The extraction optimization, using different experimental parameters has been established by a standard equilibrium time of 120 min at 85 degrees C. A mixture of ACN/toluene as back extraction solvent promoted a good performance to remove the OCPs sorbed in the bar. Reproducibility between 2.1 and 14.8% and linearity between 0.96 and 1.0 were obtained for pesticides spiked in a linear range between 5 and 17 ng/g in water samples during the bar evaluation.