Development and Validation of LC–MS/MS and LC-Q-Orbitrap/MS Methods for Determination of Glyphosate in Vaccines

Abstract

We developed and validated a simple and an accurate method for determination and quantification of glyphosate residue in vaccines. Vaccines were centrifuged in the first step of sample preparation to eliminate matrix effects. The sample was washed with a mixture of dichloromethane and chloroform, and was directly analysed without derivatisation. The extract was injected into a liquid chromatography tandem mass spectrometry (LC–MS/MS) system and liquid chromatography quadrupole-orbitrap mass spectrometry (LC-Q-Orbitrap/MS) with a Hypercarb column. The methods were validated through a series of assessments including specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, precision and accuracy, recovery, and stability. In LC–MS/MS, LOD and LOQ of glyphosate in DPT and pneumococcal vaccines were 0.078 and 0.258 ng mL−1, whereas MMR was 0.156 and 0.515 ng mL−1. In Q-Orbitrap/MS, LOD and LOQ of glyphosate in DPT and pneumococcal vaccines were 2.425 and 8.803 ng mL−1, whereas MMR was 4.850 and 16.166 ng mL−1. The linear correlation coefficients (r 2) were higher than 0.999. Relative standard deviation (RSD) was 0.9–11.7% for both intra-day and inter-day precisions. Accuracy was evaluated to be in the range of 86.3–110.4% both for intra-day and for inter-day. Mean recoveries of three different fortification levels were within 93.1–108.3% for DPT and pneumococcal vaccines and 71.1–73.4% for MMR vaccine. The RSD of stability of spiked samples was within 8%.