On the gas chromatography of fatty acid methyl esters prepared from trace amounts of lipids, the accurate analysis of the esters is sometimes interfered with phthalates which are eluted from various materials used in the course of sample preparations for gas chromatography. We devised a simple method for removal of the contaminative phthalates from a sample for gas chromatography. The method was comprised of a sequence of methanolysis and thin-layer chromatographic separation, and this simple combination technique was effectively applied to gas chromatographic microanalysis of fatty acid methyl esters which were contaminated with a wide variety of phthalates. By re-methanolysis of fatty acid methyl esters containing phthalates with 0.5% (wt/vol) sodium methoxide at 80°C for 30 min, the phthalates were converted into dimethyl phthalate and small amounts of heterogeneous phthalates containing one methyl group, but the fatty acid esters were unchanged during the treatment. The resulting mixture was spotted on thin-layer plate which was cleaned up with ether before use, and developed with a solvent mixture of hexane-ether-acetic acid (80/20/1, vol/vol/vol). The fatty acid methyl esters were separated on the plate from the contaminative phthalates, by taking advantage of higher Rf values of the fatty acid esters than those of the methanolysis products from the contaminants. The purified fatty acid methyl esters could be re-analyzed by gas chromatography without any interferences. This method had no influence on the fatty acid methyl esters to be analyzed.
An oligomer type surfactant was prepared by cooligomerization of acrylic acid, acrylonitrile and 1-dodecanethiol, followed by neutralization with KOH. The chemical structure of the oligomer was established by elemental analysis and IR spectrum as follows; _??_ The cmc of the oligomer was 0.24g/100ml and the surface tension at the cmc was about 25dyn/cm at 25.0°C. The curves of surface tension against the oligomer concentration on the addition of HCl was divided into three regions. The surface tension in the presence of KOH, KCl or CaCl2 was also measured. The cmc was increased by the addition of KOH and lowered by the addition of KCl or CaCl2. The lowering degree of the cmc by the addition of CaCl2 was greater than that by KCl. The results may be attributed to the change of dissociation of ionized groups in the oligomer molecule by the additives.
Quantitative determinations of homologous impurities contained in purified and impurified potassium 5, 8-diisopropyl-2-naphthalenesulfonate [KDNS] by means of GLC and MS were investigated, after KDNS was converted to methyl ester [MeDNS]. The GLC method was unadaptable to determining the homologous impurities because of peaks of the homologues were overlapped each other. On the contrary, MS method determined by In-beam EI method under an electron beam energy of 20eV was useful for these determinations, and lower limits of determination on the homologues contained in MeDNS were estimated as 0.2mol%. As the results, it was recognized that the purified KDNS which have been used hitherto in our studies was of purity over 99.8mol% with respect to the homologues.
Autoxidation of benzaldehyde derivatives (BA derivatives) were investigated in aqueous solutions of a nonionic surfactant. In the micellar systems, partition constants (Km) between the micelle and bulk phase for BA derivatives and antioxidants were calculated. In addition, the binding site of those substrates within the micelles were determined. The summary of the results is shown below. 1) In the micellar systems, the autoxidation of p-hydroxybenzaldehyde (HBA) was inhibited, but that of benzaldehyde (BA) and p-isopropylbenzaldehyde (PBA) was promoted, especially in PBA. 2) In the micellar systems, n-propyl gallate (PG) for HBA, and dl-α-tocopherol (α-T) for BA and PBA showed strong antioxidative activities. 3) HBA and PG molecules within the micelles penetrated only to a small extent into the mantle layer, BA penetrated deeply the mantle layer, and PBA and α-T were the core. On the basis of the experimental results, it was suggested that the inhibition of HBA oxidation in the micellar systems was due to the influence of the mantle layer under the unaerobic condition, while the promotion of BA and PBA oxidation was due to the influence of the core under the aerobic condition. It was found that the antioxidants indicating the binding sites similar to those of the BA derivatives within the micelles showed strong antioxidative activity.
Syntheses of rose oxide (6a) and dihydrorose oxide (6b) from readily avairable stairable starting material are described. The synthetic route route is shown in Scheme-1. The radical addition reaction of 3-ethoxy-3-methylbutanal (2a) to 3-butenyl-3-methyl acetate (1) initiated by benzoyl peroxide gave 7-ethoxy-3, 7-dimethyl-5-oxooctyl acetate (3a) in 42% yield. 7-Ethoxy-5-hydroxy-3, 7-dimethyloctyl acetate (4a) was obtained from (3a) with sodium borohydride in 96% yield. Hydrolysis of (4a) with 10% NaOH gave 7-ethoxy-3, 7-dimethyl-1, 5-octanediol (5a) in 95% yield. Transformation of (5a) into rose oxide (6a) was accomplished by deethoxylative cyclization of (5a) on treatment with 10% H2SO4 at 100°C (60% yield). The product (6a) was a mixture of cis-and trans-rose oxide (cis/traps=90/10). Similarly, dihydrorose oxide (6b) was prepared from 3, 7-dimethyl-5-oxooctyl acetate (3b) which was obtained from (1) and 3-methylbutanal (2b).
The essential oil was obtained by steam distillation from leaves and stalks of Nelumbo nucifera Gaertner which were collected at Neyagawa-shi (Osaka prefecture) in September 1980. Each essential oil was chemically separated into three parks, i.e. neutral, sodium hydrogencarbonate soluble, and sodium hydroxide soluble parts. Each fraction was investigated by means of IR, GC-MS, NMR, and comparison with authentic samples. Essential oils consisted of aliphatic hydrocarbons of C12C27, linalool, α-terpineol, phytol, lauric acid, phenolic compounds, and miscellaneous. The major components were aliphatic hydrocarbons, which occupied 40% in essential oil.
The content of tocopherols in the fat fractions of each 24 sample of fresh meat, liver, stomach, and intestines from several species of domestic animals, which are commonly used for meat materials, was determined by high-performance liquid chromatography. Commercially available butter also was subjected to this determination. 1) The content of total tocopherols in body fat was found to vary depending upon animal species with the highest (2.85mg/100g) for horses and the lowest (0.45mg/100g) for pigs. The content of α-tocopherol, a major component in the total tocopherols, varied also depending on species with the highest (95.6% of total tocopherols) for horses and the lowest (58.0%) for chicken. Although the content of total tocopherols in lamb was obviously less than that in sheep, there was little difference in the tocopherol composition between these animals. 2) The content of total tocopherols in each fat of liver, stomach, and intestines was generally higher than that in body fat, with the highest for liver. The content of α-tocopherol in the total tocopherols of these organs was also higher than that of body fat. The liver contained it at the highest level for cows and pigs. Contrary to these animals, chicken was found to contain α-tocopherol much more in intestines than in liver. 3) On the average, commercial butter contained 1.61mg/100g of total tocopherols, of which about 95% was α-tocopherol.
Quality of a high and consistent standard is the main objective and concern of the Malaysian palm oil industry. The quality deterioration of palm oil is mainly due to oxidation process between unsaturated fatty acids with oxygen which is enhanced by prooxidants such as trace metals and to excessive hydrolysis of the oil. These will result in poor bleachability and poor keepability of palm oil.