Evaluation of Accuracy of GC/MS Target Screening Method for Monitoring Agricultural Chemicals in Drinking Water

Abstract

We have developed a database of calibration curves of 172 agricultural chemicals for GC/MS target screening analysis using two instruments (GCMS-QP2010 Plus and JMS-Q1050GC). We compared the slopes of each calibration curve and the quantification values determined from the calibration curve of each agricultural chemical. The best repeatability was found for the calibration curves constructed using the internal standard of the nearest retention time for each agricultural chemical. Furthermore, maintaining the instrument sensitivity was found to be the most important factor for obtaining good repeatability. The quantification values in the lower limit of the calibration curves of each agricultural chemical were compared. The quantification errors were 5 times or lesser for almost all the agricultural chemicals when employing the database developed using the same instrument. Based on these results, we confirmed that the GC/MS target screening method was useful for analyzing many agricultural chemicals and evaluating the excess with respect to the target value of each agricultural chemical in drinking water. Variation in instrument sensitivity is the main factor influencing the quantification error, and maintaining the detection sensitivity of the instrument is important when applying the target screening method to drinking water samples.