Vertical distribution of targeted, suspected, and non-targeted organophosphate esters in sediment core from the East China Sea.

Organophosphate esters (OPEs), including triesters (OPTEs) and diesters (OPDEs), are widely used as flame retardants and plasticizers, but the vertical distribution of OPEs in marine sediments remains largely unexplored. To address this, we developed an effective strategy for target, suspect, and non-target screening of OPTEs and OPDEs with ultrahigh-performance liquid chromatography-Q Exactive hybrid quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). This study reports 17 OPTEs and 10 OPDEs, including five OPTEs and six OPDEs that were detected for the first time in sediment cores from the East China Sea. Through the target screening detected 10 OPTEs from 27 tested and 5 OPDEs from 10 tested. Suspect screening identified 7 OPTEs and 5 OPDEs. Priority OPEs, including tributyl phosphate (TnBP), tris(2-butoxyethyl) phosphate (TBOEP), and bis(2-ethylhexyl) hydrogen phosphate (BEHP), were frequently detected (up to 97 %). The total concentration of OPTEs significantly decreased with sediment depth (r = -0.7376, p < 0.0001), suggesting surface inputs, whereas OPDEs showed no such trend (r = -0.0610, p = 0.7444). Certain priority compounds, such as tricresyl phosphate (TCrP) and diphenyl phosphate (DPHP), shown rapid environmental input, with short doubling times of 6.4 and 6.8 years, respectively.