Analysis Of Additives And Pesticide Residues In Foods By High Performance Liquid Chromatography

At present, problem of food safety has been caused wide public concern. Food additives and pesticide residues are two important aspects. In the first chapter of this paper, we summarized the characteristics and hazards of food additives and pesticide residues, and the main analytic research progress in foods. In chapter two, a novel method is established for the separation and determination of benzoic acid (BA), sorbic acid(SA) and p-hydroxybenzoic acid esters (methylparaben, ethylparaben, butylparaben) in soya bean jam by normal phase high performance liquid chromatography (NP-HPLC).The components were analyzed by Allsphere Cyano (CN) (250 mm×4.6 mm i.d., 5μm) using a UV detector at 240 nm.The mobile phase was methene dichloride-acetonitrile (92:8) (pH adjusted to 5.5 with acetic acid) at a flow rate of 1.0 mL/min.The methodology exhibited good linearity between 0.01-50μg/mL.The detection limits range were 0.05-0.1μg/g.The average recovery ranged from 80.61% to 98.36%. In chapter three, High performance liquid chromatography (HPLC)-differential refractometer detector has been developed for extraction and determination of choline chloride from baby formula milk powder samples. The protein of milk powder was adjusted by buffer solution to its isoelectric point; the absolute ethyl alcohol was used for extraction. The component was separated by a Diamonsil C18 (250 mm×4.6 mm i.d., 5μm). Mobile phase was a mixture of methanol and 25 mmoL/L 1-heptanesulfonic acid sodium solution (the ratio of volume was 15:85). The methodology exhibited good linearity between 0.1-10.0 g/L with correlation coefficiency of 0.9996. The detection limits of quantification were 70μg/g. The average recovery ranged from 79.57% to 90.94%. The relative standard deviations (RSDs) (n=6) were 4.9%-6.5%. In chapter four, simple and efficient single-drop microextraction in conjunction with high performance liquid chromatography has been developed for extraction and determination of insecticides residues from juice drink samples. The impact of extractant, extraction time, extraction temperature, stirring speed and other conditions on analysis result were investigated. The Floated Organic Drop Microextraction (FDME) exhibited good linearity between 0.01-10.0μg/mL with correlation coefficiency of 0.9999. The detection limits of quantification were 0.005-0.01 mg/L. The average recovery of pesticides ranged from 88.49% to 101.86%. The relative standard deviations (RSDs) (n=6) were 2.0%-3.5%.