Quantification Of Bisphenol A In Drinking Water Of Beijing Using LC-MS

Bisphenol A(BPA)is usually used to synthesize polymer materials.BPA products are widely found in people’s daily lives,BPA can diffuse and transfer into the environment with its use.However,BPA is an environmental endocrine disruptors(EEDs),the requirement of the BPA concentration limit in drinking water of the Standards for Drinking Water Quality(GB 5749-2006)in China is 0.01 mg/L.Firstly,A solid phase extraction-liquid chromatography-mass spectrometry(SPE-LC-MS)method was established to determine BPA in drinking water,and the conditions of the SPE and LC-MS were optimized,and the method was evaluated.And then,using the established method to detecte BPA in tap water,bottled drinking water and barrelled drinking water of Beijing.Investigating the pollution of drinking water in Beijing,and analyzing the sources of BPA,providing the scientific basis for human dietary exposure assessment of BPA.The main results were as follows:The optimized SPE conditions: the solid phase extraction column was C18;The flow rate of sampling was 1-2 m L/min;The eluent was 9 mL methanol.The optimized LC-MS conditions: the extracted ion chromatogram was ZORBAX Extend-C18 column(4.6×150 mm,5 μm);The mobile phase consisted of methanol-water(95:5,V/V)at a flow rate of 1.0 m L/min;The dry gas flow velocity was 11 L/ min,the dry gas temperature was 350 ° C and the nebulizer pressure was 35 psi.Under these conditions,the separation of sample peak and impurity peak was good,with the symmetry of the peak.They could meet the requirements of the study.The standard samples were prepared with ultrapure water and BPA.After the sample was pretreated,the linear regression equation of level 1 mass spectrometry was y=69.4x+2186.1 with the correlation coefficient of 0.9929 within the concentration range of 122.9-1190.7 ng/L.The limit of detection was 7.0 ng/L,and the limit of quantitation was 23.5 ng/L.The recoveries were between 78.8% and 108.1%,and the relative standard deviations(n=6)were less than 13.5%.Owing to the advantages of excellent selectivity,high sensitivity and good reproducibility,this method could meet the detection demands of BPA in drinking water.Among 56 packaged drinking water products,BPA was detected in 36 products,the detection rate was 64.3%.Among 24 tap drinking water products from 8 urban areas of Beijing,BPA was detected in 3 samples,the detection rate was 12.5%.The highest detection concentration was 1592.8 ng/L.The BPA in drinking water were mainly from five areas: source water,packaging materials,transportation materials,water fountains,water containers.BPA widely exists in drinking water especially in barrelled drinking water in Beijing,and long-term drinking thus leads to health risks.