Comprehensive contamination evaluation of organophosphate flame retardants in aquatic products across South Korea using modified QuEChERS with EDTA and LC-MS/MS

In a study supporting the South Korean government's assessment of exposure and risk related to organophosphate flame retardants (OPFRs), a novel method was developed. This method simultaneously determines 11 common OPFRs in various aquatic products using modified QuEChERS with EDTA and LC-MS/MS. The method successfully passed validation for range, linearity (r2 ≥ 0.993), quantitation limit (0.048–1.113 ppb), recovery (70.02–111.95 %), repeatability (1.88–28.96 %), and intermediate reproducibility (2.62–17.69 %). Applying this validated method to 259 samples across South Korea (including 37 commonly consumed aquatic items, 16 of which were previously unstudied), the presence of 10 out of 11 OPFRs (up to 40.33 ppb) was confirmed. Additionally, OPFR contamination was experimentally confirmed in the previously unstudied 16 items. This study represents the first use of EDTA during QuEChERS for the study on OPFRs and the first comprehensive assessment of OPFR contamination in aquatic products across South Korea, supporting national risk assessments. Also, the present method has a unique position in monitoring OPFR contamination in seaweed for scientific as well as regulatory purposes, as the first and only validated method to determine OPFRs in seaweed.