Pooling strategy to construct in-house high-resolution electrospray ionization tandem mass spectrometry database of drugs

High-throughput and efficient identification of drugs in a complex mixture is required in many pharmaceutical industries and drug testing laboratories. The present study aims to utilize an efficient pooling strategy for the preparation of high-resolution tandem mass spectrometry (HR-MS/MS) library of drugs with different therapeutic properties. Compounds were classified into four classes of low, medium-low, medium-high and high log P values and were pooled into five pools (100 drugs pool). Compounds with isobaric and close log p values were placed in separate groups to overcome the co-elution problem. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was utilized to generate a high-resolution tandem mass spectrometry (MS/MS) spectral library in both positive and negative electrospray ionization modes of 491 drugs. Spectra were collected by LC-MS/MS analysis using system automated collision energy i.e. of 25-60 eV and four predetermined collision energies (10, 20, 30 and 40 eV) for each compound using schedule precursor list of [M + H]+ and [M + Na]+ ions. To validate the applicability of the library, serum samples spiked at three concentrations close to bioavailability (0.308 ng/mL, 3.08 ng/mL and 30.08 ng/mL) of drugs and were analyzed by LC-QTOF-MS/MS. The HRMS library search successfully identified all compounds present in the spiked serum samples based on exact masses of precursor ions, MS/MS data, and retention time etc. The accurate mass LC-QTOF-MS based tandem mass spectral libraries represent a useful tool for the identification of drugs in clinical samples, for pharmacological and forensic screening applications etc. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.