Investigating a new approach for magnetic ionic liquids: Dispersive liquid-liquid microextraction coupled to pyrolysis gas-chromatography-mass spectrometry to determine flame retardants in sewage sludge samples.

This study addresses the analysis of emerging contaminants, often using chromatographic techniques coupled to mass spectrometry. However, sample preparation is often required prior to instrumental analysis, and dispersive liquid-liquid microextraction (DLLME) is a viable strategy in this context. DLLME stands out for its ability to reduce sample and solvent volumes. Notably, dispersive liquid-liquid microextraction using magnetic ionic liquids (MILs) has gained relevance due to the incorporation of paramagnetic components in the chemical structure, thereby eliminating the centrifugation step. A pyrolizer was selected in this work to introduce sample onto the GC column, since the MIL is extremely viscous and incompatible with direct introduction through an autosampler. This study is the first to report the use of a DLLME/MIL technique for sample introduction through a pyrolizer in gas chromatography coupled to mass spectrometry (GC-MS). This approach enables the MIL to be compatible with gas chromatography systems, resulting in optimized analytical and instrument performance. The analysis of polybrominated diphenyl ether flame retardants (PBDEs) was focused on the PBDE congeners 28, 47, 99, 100, and 153 in sewage sludge samples. The [P6,6,6,14+]2[MnCl42-] MIL was thoroughly characterized using UV-Vis, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, as well as thermal analysis. In the chromatographic method, a pyrolyzer was used in the sample introduction step (Py-GC-MS), and critical injection settings were optimized using multivariate approaches. Optimized conditions were achieved with a temperature of 220 °C, a pyrolysis time of 0.60 min, and an injection volume of 9.00 µL. DLLME optimization was performed through central compound planning (CCD), and optimized training conditions were achieved with 10.0 mg of MIL, 3.00 µL of acetonitrile (ACN) as dispersive solvent, extraction time of 60 s, and volume of a sample of 8.50 mL. Precision was observed to range from 0.11 % to 12.5 %, with limits of detection (LOD) of 44.4 µg L-1 for PBDE 28, 16.9 µg L-1 for PBDE 47 and PBDE 99, 33.0 µg L-1 for PBDE 100 and 375 µg L-1 for PBDE 153. PBDE 28 was identified and analyzed in the sludge sample at a concentration of 800 µg L-1. The use of MIL in dispersive liquid-liquid microextraction combined with pyrolysis gas chromatography-mass spectrometry enables identification and quantification of PBDEs in sewage sludge samples at concentrations down to the µg L-1 level.

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.