The Application Of Solvent Flotation In Phthalate Esters Contaminant Detection

Phthalate esters (PAEs) are used as additives in the produce of plastics, because they can make plastics flexible and workable. Among all of the PAEs, about half are environment hormones. They work as estrogen when they enter human bodys and disrupt the endocrine system, they possess carcinogenesis, mutagenieity, teratogenicity. In recent years, for plastics'widely use and large manufacture amount, they have caused a wide distribution of PAEs in environment, now they have become one of the most prevalent contaminants.Four phthalte esters(DMP, DEP, DBP, DOP) have been studied in this paper. Solvent flotation is used as pretreatment for the first time in separate and enrich trace PAEs in water samples. In the tests, the optional oven temperature was programmed form 140℃held 2 min, then increased to 280℃at the rate of 15℃/min, held 3 min, the total run time of GC is 14.33 min. Conditions which affect the flotation were optimized during the experiment. The optimal parameters for flotation were established:chose cyclohexane as the flotation solvent with the amount of 15 mL, flotation time chose 60 min, solution pH= 7, the concentration of NaCl was 2.0 mol/L, gas flow rate was 20 mL/min. Under the optimal conditions, samples collected from river, lake, running water in laboratory were analyzed, the recovery rate of the four PAEs were between 81.0% and 101.8%, standerd deviation(RSD) values were between 3.2% and 6.0%. The precision was well, it can meet the experiment requirements.In addition, ultrasonic extraction was used to extract the four PAEs in plastic lunch boxes. Different extract solvents'extraction rate were compared during the ultrasonic extraction, and finally ethanol was selected as the best extract solvent. The recovery rate of each PAEs was between 85.6% and 112.1%. RSD were less then 5.0%.15%(volume ratio of water and ethanol)ethanol was used as simulation water solvent to soak plastic lunch boxes. Temperature and time's affect on the four PAEs' migration were studied. The experimental results showed that at 80℃the migrate amount was the largest, and the migrate amout have something to do with time, more time more migration amout.