“Prep-and-Shoot”: The completely Automated Workflow for Hydrolysis and Analysis of Urine Samples by LC/MS/MS
In this report, a completely automated, 96 well plate format “Prep-and-Shoot” workflow including enzymatic hydrolysis, dilution and injection is described. A GERSTEL MultiPurpose autosampler (MPS) coupled to an AB SCIEX QTRAP® 4500 LC/MS/MS system was used for a fast enzymatic hydrolysis process (15 minutes), dilution and injection of urine samples. The procedure was applied to the analysis of multiple drug classes (e.g., opiates, opioids, benzodiazepines, muscle relaxants, hallucinogens) in urine. This automated workflow employed an ultra-pure β-Glucuronidase enzyme yielding hydrolysis efficiencies of glucuronide conjugates above 80 % for the analytes tested. The methodology developed allowed the reproducible injection and analysis of over 960 samples on the same analytical column, with % RSDs ≤ 10 %. Moreover, the combined automation of urine hydrolysis, injection and analysis allowed the system to process more than 200 samples in a day.