Study On Analytical Methods Of Organic Contaminants In Food And Food Packages

In recent years, much attention has been paid to food safety problems. Studies on theanalysis methods of organic pollutants in food and packaging materials become a cutting edgeresearch. The previously reported procedures for the determination of bisphenol A and phenolin polycarbonate (PC), and phthalate esters in edible oils are expensive, time-and organicsolvent consuming, labor intensive and not environment-friendly. In this thesis, novelmethods for the analytes by using the subcritical water extraction and dispersive liquid-liquidmicroextraction followed by high performance liquid chromatography have been developed.The main research achievements are as follow:1. A new method was established to determinate simultaneously the migration contentsof bisphenol A (BPA) and phenol from polycarbonate (PC) bottles based on subcritical waterextraction (SWE) and high performance liquid chromatography. The optimum extractionconditions included an extraction temperature of120℃, a pressure of1000psi, a staticextraction time of1h and one cycle. Under this condition, the migration contents of BPAranged from6.81to11.16μg/g in11samples. Phenol was not detectable in5samples, and inother ones the migration contents of phenol varied in the range of3.25-6.08μg/g. Thetraditional soaking extraction experiments showed that PC was subjected to weak hydrolyzeafter long-time leaching. BPA and phenol were separated in8min. A good linearity wasobtained in the range of0.05-20μg/mL for BPA and0.02-20μg/mL for phenol (r>0.9997).The limits of detection were7.6ng/mL for BPA and2.0ng/mL for phenol. Intra-day andinter-day repeatability expressed as%RSD were less than5.21%and11.63%，respectively.Compared with traditional water soaking extraction,49-106times increase of extractionefficiencies was observed when using this developed SWE method. The procedure is simple,rapid and environment friendly, and can be utilized to determinate the migration contents ofBPA and phenol in PC bottles2. A novel method for the determination of four phthalates content in edible oils wasdeveloped using dispersive liquid-liquid microextraction coupled with high performance liquid chromatography. Some important parameters such as the kind and volume ofextraction solvent and dispersive solvent and salt effect were investigated. The optimizedextraction conditions for1.5g of the edible oil sample were: ultrasonic extraction,8mL ofacetonitrile, extractant solution,2mL of the extract mixed with100μL carbon tetrachloridefollowed by8mL of5%NaCl (w:v); extraction time,3min. The method offered excellentlinearity over a range of0.05-1.0μg/mL for the four phthalates (r>0.99). The detection limitwas15.2-31.2ng/mL (S/N=3), and the average recoveries varied from71.5%to91.2%, withRSD less than7.6%. This method was simple, low organic solvent consuming and reliable,and could be used for the analysis of phthalates in various fat food.