Automated Sample Pretreatment and Measurement of Benzodiazepines in Serum Using a Biomek i7 Hybrid Workstation and LC-MS/MS

Abstract

Benzodiazepines are psychoactive agents due to their effect on the central nervous system. They are widely used as psychotropic drugs and pharmaceuticals. Benzodiazepines are characterized by high effectiveness and rapid action. Due to their effect on the nervous system and their high potential for dependency and misuse, researchers are interested in understanding the pharmacology and physiology. Typically, benzodiazepines are detected in human urine, whole blood, plasma and serum as well as in meconium. Such measurement tasks belong to compound-oriented measurements, which often require a labor-intensive sample pretreatment—including sample clean-up, matrix change and reformatting the sample containers. To ensure a stable quality in the entire measurement process, the sample preparation for serum treatment were automated using a Biomek i7 Hybrid Workstation and a positive pressure unit. The benzodiazepines Alprazolam, Clonazepam, Diazepam, Lorazepam, Midazolam, Nordazepam, Oxazepam and Temazepam were determined using liquid chromatography and tandem mass spectrometry (LC-MS/MS). The performance of the automated method— repeatability, recovery rate, within-laboratory precision, measurement precision, as well as limits of detection and quantification—was compared with measurements of benzodiazepine standards in acetonitrile.