Application Of Gas Chromatography-Ion Trap/Mass Spectrometry In The Determination Of Phthalates And Preservatives In Food And Cosmetics

The hyphenated technique of gas chromatography -ion trap mass spectrometiy (GC-IT/MS), based on the powerful separating ability of GC and high sensitivity and specificity of MS, is widely applied to many fields such as environmental, biomedical, food analysis and so on. Food and cosmetic have deep influence on people daily live. Phthalates are the indispensable property modifying additives. As time goes on, they may be leached into food and beverages from the packaging material. Parabens are the most common preservation of cosmetics, EEC directive permits their use with maximum concentration for them. In this work, a new and simple method of single-drop microextraction (SDME) combined with GC-IT/MS was proposed for trace determination of phthalates. It is a novel and more environmentally friendly sample preparation technique.The studies in this thesis are included as follows:The application of GC/MS in food and cosmetics analysis was reviewed. The advance in GC/MS, SDME technique and application of these techniques were also reviewed. The researches of phthalate esters were discussed.A method for simultaneous separation and determination of dimethyl phthalate (DMP), diethylphthalate (DEP), di-n-butylphthalate (DOP), methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP), in cosmetics by gas chromatography/mass spectrometiy was developed. The recoveries (n=5) ranged from 82.44% to 97.16%. The relative standard deviations (n=5) were among 1.22~ 4.50%. The method was simple, sensitive, accurate and rapid.Studies on the optimized analysis condition including the column temperature program, the spit ratio, the ion trap temperature, scan range, duration of scan, the number of micro scan and selective ion storage, etc. for four kinds of phthalates, e.g. DMP, DEP, DBP, DOP, by gas chromatography in combination with mass spectrometry detector (GC-MS) in electronic ionization mode (El).The performance of static SDME (S-SDME), coupled with GC-IT/MS, was assessed for the determination of four dialkyl phthalates in the table salt. Experimental parameters impacting the performance of SDME, such as extraction solvent, time, microdrop volume, stirring rate, sampling depth, amount of salt (Na2SO4) addition were studied. Overall, extraction was achieved by suspending a 2.0 uL toluene drop to the tip of a microsyringe immersed in a 5 mL donor aqueous solution stirred at 800 rpm. Once SDME was optimized, under the selected ion storage (SIS) mode, analytical parameters such as linearity, precision, the limits of detection and relative recoveries were evaluated. Overall, SDME proved to be a fast and simple tool for the preconcentration of phthalates in salt samples.A novel method for determination of DMP in table samples has been developed using dynamic SDME (D-SDME) and GC-IT/MS, those facts' influence to the extraction effect were analyzed, such as organic extracting agent, the number of extraction, the dwell time and volume of solvent. At the same time, this paper compares S-SDME with D-SDME for the analysis of DMP in table salt samples.