Study On The Detection Methods Of Chemical Contaminants In Food

With chemicals and new technology widely used in the food processing, illegalbusinessmen add cheap poisonous chemicals in food to replace expensive non-toxicadditives for profit. The food safety has being seriously threatened to human health.Therefore, the determination of contaminants in foods is an important and necessaryresearch subject. The PAEs in the drinks and abalone crisp samples had beenextracted using ultrasonic bath, and the method based on QuEChERS technology forthe pretreatment of the acrylamide in fried food was developed. The analytes werequantitatived by high performance liquid chromatography (HPLC) in this work. Themain contents are described as follows:(1) The HPLC conditions such as the ratio of mobile phase, flow rate, columntemperature, were selected by the appropriate concentration of the standard solutionof DEHP. The optimum extracting conditions were established to detect the contentof DEHP in drinks by single factor and orthogonal experiments. The DEHP ofdifferent types of drinks was extracted by n-hexane using ultrasonic bath undertemperature of the40℃, followed by centrifugation、concentration and filtration.The extraction parameters such as type and volume of extracting solvent、PH ofsolvent、 salt addition、ultrasonic time and centrifugation time were optimized. C18column was employed in the HPLC determination with water and acetonitrile(V/V=5:95) as eluent and a UV detector was adjusted at224nm. The contents ofDEHP in different kinds of beverage were detected with the developed method. Thecontents of DEHP of the drinking water in the plastic bottled were also investigatedwith the influence of the heating time.The results showed that there is a good linearrelationship (R=0.9999) in the concentration range of0.050~5mg/kg. The detectionlimit of DEHP is0.5μg/kg. The recoveries are in the range of96.0~101%; withrelative standard deviation of2.32~5.17%.(2) The HPLC conditions were selected by the appropriate concentration of thestandard solution of DEHP. DEHP in abalone crisp was extracted by methanol usingultrasonic bath under the room temperature, merged multiple extracting solution, followed by dehydration with anhydrous Na2SO4, centrifugation, concentration andfiltration. C18column was employed and a UV detector was adjusted at224nm inthe HPLC. The results showed that there is a good linear relationship (R=0.9996) inthe concentration range of2~20mg/kg. The detection limit of DEHP is1.0μg/kg.The recoveries are in the range of82.16~92.30%; with relative standard deviation of2.11~3.67%.(3) The determination of AAM in fried food was developed by HPLC. AAM insamples based on QuEChERS was extracted with pure water using ultrasonic bathand cleaned up by primary secondary amine (PSA). To determine the content ofAAM, C18column with water and acetonitrile (V/V=1:99) as eluent and a UVdetector adjusted at208nm were employed in HPLC. Under the optimal experimentconditions, the results showed that there is a good linear relationship (R=0.9994) inthe concentration range of0.020~0.800mg/kg and the detection limit of AAM is5μg/kg. The recoveries of AAM in samples are in the range of83.96~89.43%, withrelative standard deviations of2.13~5.87%.