Simultaneous and confirmative detection of multi-residues of ß2-agonists and ß-blockers in urine using LC-MS/MS/MS coupled with ß-receptor molecular imprinted polymer SPE clean-up.

ABSTRACT

A liquid chromatography-linear ion-trap spectrometry (LC-MS³) method using ß-receptor molecular-imprinted polymer (MIP) solid-phase extraction (SPE) as clean-up was developed to determine simultaneously and confirmatively residues of 25 ß2-agonists and 21 ß-blockers in urine samples. Urine samples were subjected to enzymatic hydrolysis by ß-glucoronidase/arylsulphatase, and then extracted with perchloric acid. Sample clean-up was performed using ß-receptor MIP SPE. A Supelco Ascentis® express Rp-Amide column was used to separate the analytes, and MS³ detection used an electrospray ionisation source in positive-ion mode. Recovery studies were carried out using blank urine samples fortified with the 46 analytes at the levels of 0.5, 1.0 and 2.0 µg l⁻¹. Recoveries were obtained ranging from 60.1% to 109.9% with relative standard deviations (RSDs, n = 7) from 0.5% to 19.4%. The limits of detection (LODs) and limits of quantitation (LOQs) of the 46 analytes in urine were 0.02-0.18 and 0.05-0.60 µg l⁻¹, respectively. As a result of the selective clean-up by MIP SPE and MS³ detection of the target drugs, the sensitivity and accuracy of the present method was high enough for monitoring ß2-agonist and ß-blocker residues in urine samples. Satisfactory results were obtained in the process of the determination of positive urine samples.