Study On System Detection Technology Of Antiseptic / Antioxidant Additive In Condiment

BackgroundsThe food additives benefit food industry, but abuse will endanger human health. Recently, food safety issues about excess additives added to food attracted public attention. It is necessary to establish an effective and convenient qualitation and quantitation method for monitoring the proper use of additives. In this work, the comprehensive, effective, and rapid technique of sample preparation and detection for preservatives and antioxidants in condiment was developed, it is helpful to develop the method for detection of food additives in food. Five chapters in the dissertation are described as follows.Chapter1ReviewThe definition and classification of preservatives and antioxidants were introduced. Besides, a detail summary of analytical methods for the detection methods were also reviewed.Chapter2The sample preparation for preservativesA comprehensive sample preparation of multi-preservatives in condiment according the content of fat. The method for28preservatives in low-fat (soy sauce), middle-fat (soybean paste), high-fat (hot pot seasoning) was developed. The high-fat sample was diluted and extracted with hexane, then purified using GPC, the rest was liquid-liquid extraction using acetonitrile and saturated NaCl solution, the acetonitrile was purified using solid phase extraction with C8and NH2cartridge. The middle-fat and low-fat sample was diluted with saturated NaCl solution, then extracted using acetonitrile and hexane, after centrifuge the acetonitrile was analysed for low-fat sample, while for middle-fat sample was purified with C8and NH2cartridge. The recoveries ranged from55.1%to99.6%, except for long chain alkane parabens in high-fat sample and heptyl paraben and biphenyl in middle-fat and low-fat sample, with recoveries of46.4%to81.7%, and54.5%～87.0%, respectively. The method can be applied for simultaneous detection of multi-preservatives.Chapter3The sample preparation for antioxidantsA comprehensive sample preparation of multi-antioxidants in condiment according the content of fat. The method for12preservatives in low-fat (soy sauce), middle-fat (soybean paste), high-fat (hot pot seasoning) was developed. The high-fat sample was diluted and extracted with hexane, then purified using GPC, the rest was liquid-liquid extraction using acetonitrile and saturated NaCl solution, the acetonitrile was purified using solid phase extraction with Cg cartridge. The middle-fat and low-fat sample was diluted with saturated NaCl solution, then extracted using acetonitrile and hexane, after centrifuge the acetonitrile was analysed for low-fat sample, while for middle-fat sample was purified with C8and CN cartridge. The recoveries and RSDs of DLTP and BHT were low due to their low stability. In high-fat sample the recoveries of OG ranged from69.5%to72.4%, that of BHA, IONOX, quinoline, DG ranged from80.7to95.7%, others ranged from66.0%to83.0%. In middle-fat sample the recoveries of OG and DG ranged from58.4%to68.3%, others ranged from70.1%to95.6%. In low-fat sample the recoveries ranged from64.7%to98.7%. The method can be applied for simultaneous detection of multi-antioxidants.Chapter4The qualitative method for preservatives and antioxidantsA method using sample preparation above and UPLC-Q/TRAP was developed for28preservatives and antioxidants in condiments. The compounds were separated by ultra performance liquid chromatography on C18column using acetonitrile-ammonium acetate as mobile phase by gradient elution, and determined by tandem mass spectrometry in the negtive electrospray ionization (ESI) mode using multiple reactions monitoring (MRM) mode, qualified using enhanced product ion. The limits of detection of TBHQ and SA were2000μg/L, and of BA, PPBP and BHA are20μg/L, others ranged from0.02μg/L to5μg/L. The recoveries at three spiked level ranged from52.3%to118%, RSDs ranged from0.57%to21.3%. A method using sample preparation above and GC-MS/MS was developed for15preservatives and antioxidants in condiments. The compounds were separated by gas chromatography on DB-17MS capillary column, and determined by tandem mass spectrometry in the El mode using multiple reactions monitoring (MRM) mode. The limits of detection of SA, BA, and HP were200μg/L,100μg/L,200μg/L, respectively, others are10μg/L. The recoveries at three spiked level ranged from49.3%to105%, RSDs ranged from3.15%to19.4%except for BHT with low recoveries.A rapid method using stir bar sorptive extraction(SBSE) and GC-MS/MS was developed for15compounds in low-fat condiment. Samples were diluted with30%NaCl solution and stir bar was used for sorptive extraction. After extraction, the preservatives were thermally desorbed, followed by injected into gas chromatography. Targets were analyzed in MRM mode. The limits of quantification of BA and SA were40mg/L,50mg/L, respectively, of biphenyl was0.008mg/L, others ranged from0.05mg/L to8mg/L. The recoveries at three spiked level ranged from72.2%to125%, RSDs ranged from3.08%to19.4%except for BHT with low recoveries.The above methods can be applied for determination of preservatives and antioxidants in condiment.Chapter5Fast Screening analysis of32preservatives and antioxidants in condiment by GC*GC-TOFA rapid screening method using GC*GC-TOF was developed for32compound in condiment. The compounds were separated by GC*GC on Rtx-5capillary column for1D and Rtx-17capillary column for2D, second dimension saparation time was3s, and determined by TOF in the El mode, acquisition rate was100spectra/s and mass range50-500u. The compounds was qualified using retention time of1D and2D and spectrum. The limits of detection ranged from0.5μg/L to50μg/L. The method can be applied for screening of target and non-target compounds in food.