Evolution of Laboratory Procedures for Water Quality Analysis

Abstract

The growing interest in the monitoring of emerging pollutants like Glyphosate and AMPA in drinking water led Veritas Laboratory to buy a high performance IC chromatograph coupled to an HRMS Orbitrap detector with the aim of determining these analytes by direct injection. That means without derivatization and/or preconcentration despite reaching an instrumental limit of quantification of nanograms/l, which is essential for ensuring compliance with the regulatory limits of most pesticides. Performing analysis by direct injection is a very important requirement for Veritas Laboratory, which analyses about 20,000 samples per year. Besides being simpler, much less expensive and less time-consuming, direct injection also minimizes the chances of contamination or bad recovery due to any sample handling that may occur. In relation to the detection, a high-resolution mass spectrometer with Orbitrap technology was used in order to isolate the molecular masses with accuracy and precision at very low concentrations. This choice was made because the high sensitivity of the instrument (molecular masses to 4th decimal digit) allows it to work in full-scan mode, i.e., recording all detected masses, within an established range, that enter the detector in a file. Thus, the instrument can perform a kind of “snapshot” of the sample from which analytes’ masses can be retrieved, even after the analysis has been completed. Up to now, Veritas Laboratory has been the first lab performing analysis of Glyphosate and AMPA in drinking water by direct injection, through an IC/HRMS system.