Analysis Of Cyclic Methylsiloxanes And Its Polymers

Due to the excellent performance,various organosilicon products have obtained a promising prospect in their industry application.However,the mass production and consumption of organosilicon products result in their entrance into human body and the environment,which will do the potential harm to human health and the environment due to their natural absence.Therefore,it is very necessary to detect these organosilicon compounds in various media.Whereas,there are very limited reports on the relavent analysis.In this thesis,several representative organosilicon compounds in several media were selected as models to perform analytical investigation.The content mainly includes the following four parts:1.Simultaneous determination of 4 cyclic volatile methylsiloxanes in the polydimethylsiloxanes-contained complex matrix has been developed by using by headspace gas chromatography.With optimization of the operation parameters,satisfatory results have obtained.In addition,the analytical method has been applied to the quantitative analysis of the 4 cyclic volatile methylsiloxanes in several actual products.2.Several low viscosity silicone oils have been analysized by high performance liquid chromatography-high resolution mass spectrometry(HPLC-HRMS)and interpretation of the MS/MS.The methoxyl-blocked ploydimethylsiloxanes have been determined in the aging methanol solution of hydroxyl silicone oil.The hydroxyl-blocked ploydimethylsiloxanes have been determined in the aging polyhydroxylsilicones.3.A quantitative method has been developed to determine low molecular weight hydroxyl silicone oil in surface water by liquid chromatography-mass spectrometry combined with solid phase extraction.The operation parameters of solid phase extraction and the parameters of liquid chromatography-mass spectrometry had been optimized.The results indicated that low molecular weight hydroxyl silicone oil had good linear relationships within the range of 1~100 μg/mL withthe correlation coefficient more than 0.999.The limit of quantification was 0.25μg/mL,the limit of detection was 0.06 μg/mL and the recoveries were in the range of66.8%~74.3%.4.Various viscosity silicone oils have been characterized by matrix assisted laser desorption ionization mass spectrometry(MALDI-TOF MS).The crystallization of traditional 2,5-dihydroxy benzoic acid matrix was improved by adding organic base,and the corresponding reproducibility was improved significantly.The hydroxyl silicone oil was quantitatively analyzed by using polyethylene glycol 400 as the internal standard.