Application of fully automatic hollow fiber liquid phase microextraction to assess the distribution of organophosphate esters in the Pearl River Estuaries

Organophosphate esters (OPEs) are widespread organic pollutants that could be detected in various environmental matrices. In this study, a sample pretreatment method was developed for the determination of 9 OPEs by automatic hollow fiber-liquid phase microextraction (HF-LPME) coupled with gas chromatography-mass spectrometry (GC-MS). High sensitivity of OPEs could be achieved after optimization of several important parameters with the limits of detection (LODs) ranging from 2.6 to 120 ng L(-1) for different individual OPEs, and the relative standard deviations (RSDs) ranged from 2.1% to 10.4%. Acceptable recoveries were observed and the proposed method was then successfully applied to determine OPEs in seawaters collected from 23 sampling sites of the Pearl River Estuaries in dry and wet seasons, respectively. All of the OPEs could be detected, except tris(2-ethylhexyl) phosphate (TEHP). The total concentrations of 9 OPEs in seawaters were ranging from 2.04 (Hemen) to 3.12 (Humen) μg L(-1) in the dry season and from 1.08 (Hemen) to 2.50 (Jitimen) μgL(-1) in the wet season. By using spatial interpolation method of ordinary kriging, the most polluted area of ΣOPEs was found in Humen in the dry season, while it was Jitimen in the wet season. Moreover, the annual input of ΣOPEs discharged via eight estuaries ranged from 384 tons (Jitimen) to 1,225 tons (Modaomen), and the total annual input was 5,694 tons.