Advantages of MS/MS/MS (MRM3) vs classic MRM quantification for complex environmental matrices: Analysis of beta-lactams in WWTP sludge

When dealing with complex matrices such as wastewater treatment plant (WWTP) sludge or animal manure, usual MRM quantification may lack enough sensitivity or accuracy due to the presence of numerous interfering compounds co-extracted from the matrix. To circumvent the sensitivity and specificity loss, the method development can be focused on sample extraction, purification or/and optimisation of the detection. In this study, we propose an enhancement of a method for the analysis of five beta-lactams (Amoxicillin, Ampicillin, Cefapirin, Ceftiofur, and Cloxacillin) in WWTP, with the use of a hybrid triple quadrupole-Linear Ion Trap (LIT) spectrometer, enabling triple stage MS acquisition, namely MRM3, in place of the usual MS/MS detection. The adaptation of various parameters such as the secondary fragmentation energy, excitation, and accumulation times of the secondly generated ion are described. The method was then validated and enabled quantification limits between 0.8 and 14.7 ng g(-1) associated with accurate quantification (between 98% and 113%). This method is the first to report the use of MRM3 acquisition in an environmental matrix as complex as sludge. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, an enhanced method for analyzing five beta-lactams in wastewater treatment plant sludge was proposed, using a hybrid triple quadrupole-Linear Ion Trap spectrometer for triple stage MS acquisition. The method achieved improved sensitivity and specificity.