Determination of Tranquilizers in Swine Urine by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Abstract

A rapid, reliable, and sensitive method was developed for the determination of ten tranquilizers in swine urine. Sample preparation was based on solid-phase extraction, which combined isolation of the compounds and sample cleanup in a single step. Separation was performed on a reversed phase C18 column by gradient elution with a chromatographic run time of seven minutes, consisting of 0.1% formic acid in water and acetonitrile as the mobile phase. Multiple reaction monitoring in positive mode was applied for data acquisition. Matrix-matched calibration was used for quantification and good linearity was obtained with coefficients of determination higher than 0.99. The average recoveries of fortified samples at concentrations between 0.05 and 10 µg/L ranged from 85% to 106% with interday relative standard deviations of less than 13% in all cases. The limits of detection and limits of quantification obtained for tranquilizers in the urine were in the ranges of 0.03–0.1 µg/L and 0.05–0.25 µg/L, respectively. The applicability of the proposed method was demonstrated by analyzing real samples; diazepam was detected at concentrations between 0.3 and 0.6 μg/L.

Development of a method for the determination of sedatives in bovine and porcine urine and kidneys by liquid chromatography–tandem mass spectrometry

“…The first step in the optimisation of the method was to establish the best mass spectrometer conditions. Because most of the published protocols for determination of these substances used electrospray ionisation in positive ionisation mode (1,4,7,20,23,25,35,36,38,39), we also used this type of ionisation for its high sensitivity and reproducibility. After optimisation of the analytes and selection of appropriate characteristic ions, we optimised the chromatographic conditions.…”

“…A more conservative approach granting better purification of the extract but requiring longer sample preparation time is the SPE technique. In this technique, the most commonly used columns are those containing silica, C 18 , and the polymeric reversed-phase sorbent ( 1 , 4 , 22 , 35 , 38 ). The difficulty of determining these substances in kidney tissue prompted some authors to test the possibility of combining the LLE technique with SPE for better purification of the extracts ( 1 , 38 ).…”

“…Mass spectrometry's specificity made it possible to confirm or possibly exclude the tested substance. This technique accelerated the development of analytical methods and the determination of residues of these substances in biological material (1,4,7,20,23,25,35,36,38,39). Better possibilities for the determination of these substances resulted in the simplification of sample preparation.…”

Prioritising veterinary drug residues for monitoring in animal products

“…Unauthorised sedatives (Group A3f) (Wang, 2018). Midazolam was additionally added based on Regulation (EU) 122/2013 (the list of substances essential for treatment of equidae).…”