Determination of Phtlalic Acid Esters in Different Water Bodies in Huai'an by SPE-UHPLC-MS/MS and Study on Their Pollution Characteristics

A method was developed for trace determination of PAEs (including BMPP, DHXP, DCHP, DBEP, DEHP, DNP) in water by SPE coupled with UHPLC-MS/MS. Waters Oasis HLB SPE column was selected for extraction of PAEs in water, and SPE conditions were optimized by Box-Behnken Design response surface design:when the water sample volume was 200 mL, flow rate of sample introduction of 3 mL·min^-1, 9 mL of 10% (volume fraction) methanol solution as rinsing solvent, a mixed solution composed of 6 mL of methanol and 3 mL of ethyl acetate as eluent. The collected eluate was blown to near dryness by nitrogen, then redissolved by methanol and filtered through 0.22 μm organic filter membrane. The filtrate was analyzed by UHPLC-MS/MS. Agilent Poroshell 120EC-C₁₈ chromatographic column was used as stationary phase, and the mixed solutions consisting of methanol and water with different volume ratios were used as mobile phase for gradient elution. The PAEs after chromatographic separation were introduced into MS/MS and detected under ESI⁺ and MRM modes. The results showed that 6 PAEs could be completely detected within 9 min under the optimized test conditions. Linearity relationships between mass concentrations of 6 PAEs and their respective peak areas were found in the same range of 1-20 μg·L^-1, with limits of detection in the range of 0.05-0.12 μg·L^-1. Recovery test on the actual sample was made by standard addition method in the 3 concentration levels, giving values of recovery ranged from 79.2% to 103%, and RSDs (n=6) of determined values ranged from 1.3% to 9.2%. The proposed method was used for determination of 6 PAEs in source water, tap water and secondary water supply in Huai'an from the abundant water period and low water period, and the pollution characteristics of water bodies were studied. Results obtained showed as follows:all the 6 PAEs were detected in different degrees; the content of DEHP with carcinogenic risk was higher in water sample from low water period, and the contents of DNP, DCHP and DHXP were higher in water sample from abundant water period; the contents of PAEs in water sample from abundant water period were higher than those in water sample from low water period. According to the exposure risk assessment method of EPA, the health risk assessment of DEHP in water sample from low water period showed that the risk values of 1.26×10^-7 (for female) and 1.03×10^-7 (for male) were lower than the standard limits (10^-4-10^-6) stipulated by EPA and other international organizations.