Study On Food Analysis By GC-MS Technology

This thesis studies the methods of determination for daminozide and 4 pyrethroids pesticides residues in apple juice concentrate and volatile oil from punica granatum L. seeds and husks by GC-MS. It includes SIX parts as follows:Part I : Review . A revive of analytic methods of pesticide in food and essential oil ingredients of plants .Part II : An efficient method with solid phase extraction (SPE) technique for the determination of 4 pyrethroids pesticide residues in apple juice concentrate by gas chromatography-mass spectrometry (GC-MS) has been established. The pyrethroids were extracted from a sample with acetone and hexane. The extract was clean-up with a column of 3 mL C18 of SPE (SUPELCO VISIPEREP? .The 4 pyrethroids were separated from each other through HP-5 capillary column (MS 30m X 0.25mm X0.25um) and determined by GC-MSD. The recoveries ranged from 96.6%~108.34 and the limits of determination were 0.02-0. 10(4.g/kg. When added levels were 40ug/kg~2ug/kg , RSD were 1.72%~6.86% (n=6) . The method is rapid, sensitiveand suitable for the analysis of the 4 pyrethroids.Part III : A gas chromatographic/mass spectrometric (GC/MS) method of determination for daminozide in apple juice concentrate has been developed .Damionzide was hydrolyzed in the presence of a strong base to form unsymmetrical dimethylhydrazone .This derivative was separated and quantified by GC/MS using selected ion monitoring(SIM) of key ions in the Fragamentation pattern :m/z 164,120,121, 74, 50. The limit of detection was 3.0 ug/kg, and relative standard deviations were 0.72%~5.95% , and recoveries were 96.11-109.16%. The method is effective, sensitive reproducible and suitable for the analysis ofdaminozide.Part IV : The volatile oil from punica granatum L. seeds was obtained by steam distillation approach .The chemical ingredients were separated and identified by gas chromatography-mass spectrometry (GC-MS). 66 peaks were separated by gas chromatography and 58 of them were identified by MSD with "Nist 98. L" Massspectral data Registry. The main compounds were decane, hyacinthin, undecane, pelargonic aldehyde, dodecane, benzothhiazole, butylated hydroxy toluene, palmitic acid, tetracosane.Part V : The volatile oil from sweet and acid punica granatum L. husks were obtained by steam distillation approaches .The collected distillate was identified by gas chromatography-mass spectrometry (GC-MS). 81 and 91 peaks were separated by gas chromatography , 66 and 82 of them were identified by MSD with "Nist 98. L" Massspectral data Registry. The main compounds were butylated hydroxytoluene, palmitic acid, myristic acid,linoleic acid, dihexyl.Part VI : An analytical method of headspace-GC for the determination ofvolatile pernicious organic compounds such as benzene, toluene, p-xylene and n-hexane in Qinlongkusu was studied. Factors influencing the determination such as flow rate, oven temperature, equilibrium time, times of extraction etc. were discussed .The experimental results showed that the lowest detection limits were 3~98ug/L, and relative standard deviations were 0.59%~2.64%, and the recoveries of benzene, toluene, p-xylene, n-hexane fell within the rang of 97.2%~120%.The method is effective, quick, sensitive and reproducible.