Chemical ionization mass spectrometry (CI-MS) permits rapid analysis of fatty acids without methyl esterification of samples and even without gas chromatographic separation. It is capable of qualitative determinations with samples of trace quantity level. The quasimolecular ions obtained provide information on the type and the degree of unsaturation of the fatty acid components. Shimadzu-LKB 9 000 gas chromatograph mass spectrometer combined system was used. with a chemical ionization source. Sample introduction to mass spectrometer were made by the direct sample introducing unit. The mass spectrometric conditions for CI-MS were as follows. The ion source temperature was held at 200°C dualing the CI-MS runs. The mass spectra were all obtained at 500 eV of electron energy, 3. 5 kV of accelerating voltage, and 500 μA of emission current. The scan speed was 6. The pressure in ionization source was 0.5-1 torr. Methane and iso-butane were used as the reagent gas, and iso-butane proved to be more suitable for fatty acid analysis, because of fewer dehydrated ions and fewer fragment ions from alkanes. In the CI-MS analysis of fatty acids in coconut oil, nine fatty acids ranging from six to eighteen in the number of carbon atoms were identified. There was a good agreement between these data and the data obtained by GC (FID). The fatty acids in rapeseed oil were analyzed as the more complicated sample, and C120, C140, C150, C160, C161=, C162=, C163=, C170, C180, C181=, C182=, C183=, C190, C191=, C200, C201=, C202=, C203, C220, C221=, C222=, C240, C241=, and C261= were identified. These data agreed quite well with the result of GC analysis by a BDS capillary column (50 ft×0.01 in.). As other fatty acid samples, cottonseed oil, corn oil, peanut oil, linseed oil and Chinese paulownia oil were analyzed.
The effects of various additives such as benzoyl peroxide, 2, 2'-azobisisobutyronitrile, anthraquinone, benzoquinone, anthracene, acetic acid-boron trifluoride complex, tin chloride, zinc chloride, zinc stearate, lead naphthenate and sodium methoxide on the thermal polymerization of linseed oil under the decreased pressure at 280°C were studied. In all of the case, the following relationship between the reaction time and the viscosity of the obtained oil was found. logηt=logη0+kt (ηt<<100st.) wherein η0; initial viscosity of linseed oil η0; viscosity of the obtained oil after reaction time t t; reaction time k; constant There existed the above relationship when the viscosity of the obtained oil was below 100 st. and when it was above 100 st., the viscosity increased very rapidly without any relationship. In the structures of double bond and the fractionation by acetone, all of them showed the same behavior. The molecular weight of the acetone soluble part (yielded 15-20%) was about 1,000 and that of the acetone insoluble part (yielded 80-85%) was about 2,000. From the measurement of the viscosity of the obtained oil, it was found that anthraquinone, tin chloride, zinc chloride, and lead naphthenate accelerated the thermal polymerization reaction of linseed oil markedly. The addition of tin chloride or zinc chloride gave the dark coloured products due to the thermal decomposition reaction occurred during the thermal polymerization. Adding of zinc or lead salts, the obtained products were turbid by the insoluble heavy metal soaps in the polymerized oils.
Thermal stability of azo lake pigments (Orange II, Alizarin Yellow GG) was studied by thermal glavimetric analysis. The pigments were decomposed through two or three stages from room temperature to 600°C on heating. In the first stage the azo group of Orange II was decomposed, then the aromatic rings were decomposed in the residue of thermal degradation and the color changed completely. The influence of the metal salts on thermal stability was better in order Ba, Sr and Ca. The enolform of Alizarin Yellow GG was preferentially decomposed in the first stage and the ketoform was decomposed in the second stage and the color changed through both stages. These tendency was indistinct in order Ca, Sr and Ba salt.