Study On The Determination Of Phthalic Acid Esters In Drink By Gas Chromatography

Six kinds of phthalic acid esters (PAEs), including Dimethyl phthalate (DMP), Dithyl phthalate(DEP), Dibuthyl phthalate (DBP), Di-n-amyl phthalate (DAP), Di-(2-ethylhexyl) phthalate (DEHP), Di-n-octyl phthalate (DnOP) were systematically investigated by gas chromatography in the thesis with the purpose of establishing the simultaneous analysis method of above environmental hormone. And the resulting method was used to determine the content of six phthalates in milk, fruit juice, tea drink and cola in the market.The optimum operating conditions of GC-FID for PAEs detection was obtained as follows.A HP-35 capillary column (30m×0.32mm i.d. Agilent Technologies) coated with 0.5μm film was employed for separation of the analytes. The oven temperature was programmed elevation from initially 120℃for 1 min, then increased to 220℃at 15℃/min and held 2 min, finally reached 280℃at 8℃/min and kept 5 min. Nitrogen was used as carrier gas at a flow rate of 1 mL/min. The injector and detector temperature were set at 200℃and 340℃.The injection volume of liquid sample was 1μL. Linear responses were obtained for the six kinds of PAEs in 0.424～193mg/L (r>0.999), and the detection limits were 6.2～25.4μg/L.The developed method is simple, sensitive, and accurate for the PAEs analysis in drink.The analysis and determination method has been established by a series of experimentation such as extraction method, extraction solvent, extraction time and extraction temperature.The samples were extracted with n-Hexane using constant temperature shocker at 25℃in 1.5h. The average recoveries of six kinds of phthalic acid esters were 86.3～104.2%, and the relative standard deviationa were 3.1～7.0%, The inter-day stabilities, measured as relative standard deviations(RSDs),were 1.8～5.4%.The results show that this method is accurate and credible.According to World Health Oragnization "Guidelines for Drinking-water Quality" and Ministry of Health of the People's Republic of China "Standard for Drinking water Quality", the allowable maximum concentration of DEHP standard is 0.008mg/L, the PAEs concentration of the sample of drink to exceed to these standard level. Attentiona should be paid to the PAEs pollution about drink in China.