Development of pretreatment method for analysis of fungicides and hormones in seawater using LC-MS/MS

Abstract

A simultaneous analytical method for two prohibited fungicides and their metabolites was developed alongside a simultaneous analytical method for two hormone compounds. For the fungicides, conditions such as the SPE cartridge type, pH conditions, and additives were varied while for the hormones, the elution solvents and pH conditions were varied, and finally, the optimal conditions were selected for each compound group. Target fungicide compounds and medroxyprogesterone acetate were ionized in positive mode while diethylstilbestrol was ionized in negative mode. For the fungicides, with the injection of additives and buffer, the MCX cartridge showed more stable recoveries (85.1-140.0%) compared to the HLB (82.3-251.7%) and combined cartridges (56.1-277.2%). The accuracy and precision of the analytical method were 83.2-130.1% and 6.8-15.0%, respectively. The method detection limit and limit of quantification from this study were lower than those reported in previous studies. Meanwhile, for hormones, methanol was the most appropriate elution solvent in the presence of ascorbic acid additive and at pH 2.5. Accuracy and precision ranged from 75.3-106.6% and 4.3-9.1%, respectively. This study's optimized simultaneous analytical methods can be used to proactively detect prohibited substances in seawater and aquaculture farms.