An ion chromatographic method was established for the quantitative determination of bromate in bread and fish paste products.
Samples were homogenized with water. After centrifugation, the supernatant was filtered through a 0.45μm filter prior to injection. In ion chromatographic fractionation, bromate was eluted separately from the other anions, especially chloride, which interfered with the determination of bromate.
The bromate was absorbed on a concentrator column, then analyzed quantitatively by ion chromatography.
The average recoveries were 96.4% in bread and 93.9% in fish paste products. The determination limits were 1ppm and 2ppm in the former and the latter, respectively.
In this method, bromate can be measured directly, in contrast to iodometry.
A total of 9 food samples (bread 3, fish paste products 6) was analyzed. One sample, chikuwa, contained 10.1ppm of bromate, while the other samples contained indetectably small amounts of bromate.

View full abstract

A high performance liquid chromatographic (HPLC) method was established for the quantitative determination of sesamolin, sesamin and sesamol in sesame oil.
Sesamolin, sesamin and sesamol were eluted at approximately 8min, 13min and 35min by using a 4.6mm∅×250mm Lichrosorb-Si 60 column with n-hexane·chloroform (80:20). The ultraviolet absorption detector was set at 280nm. Sesame oil was diluted with the eluting solvent and a sample was directly injected into the HPLC machine.
The results were as follows:
1. The extracted sesame oil were found to contain 0.42% sesamolin and 0.54% sesamin.
2. No sesamol was detected in a survey of sesame oil by this procedure (detection limit 0.0005%).
3. The average recoveries of sesamolin, sesamin and sesamol from sesame oil were 99.3%, 97.3%, 99.0%, respectively.

View full abstract

Ion exchange resin column chromatography was applied to analyze residual penicillin G (PC) in the muscles and liver of swine.
PC was extracted with aqueous acetone, then absorbed on a Dowex 1×1 (Cl form) resin column and eluted with 50% acetone containing 2.0% potassium chloride. The disk plate method with Bacillus stearothermophilus var. calidolactis as the test organism was employed for the assay, and the average recoveries were 93.3% and 87.5% in muscle and liver, respectively. As little as 0.004u/g of PC was readily detectable.
The extraction and the column chromatography were carried out on samples spiked with other antibiotics in order to check the specificity of the present method. Chlortetracycline (1.0-2.5μg/g), oxytetracycline (2.5μg/g), flavophospholipol (2.5μg/g), tylosin (5.0μg/g), kitasamycin (5.0μg/g), kanamycin (5.0μg/g), bacitracin (5.0u/g) or monensin (5.0μg/g) showed no inhibition zone when the eluate from column chromatography was tested by the disk plate method.
Bioautography was suitable for confirmation of the identity of PC.

View full abstract

A simple and practical method for the simultaneous determinations of nitrite and nitrate in various foods is described. It is based on the formation of tetrazolophthalazine, by the reaction of nitrite and hydralazine in an acidic medium (pH 1.0-3.0) at 70°C for 10min, and the formation of 4-nitro-2-sec-butylphenol, by the reaction of nitrate and 2-sec-butylphenol in aqueous (5+7) sulfuric acid at room temperature for 15min and subsequent pentafluorobenzoylation to form the pentafluorobenzyl ester of 4-nitro-2-sec-butylphenol in the alkaline range. The two products were simultaneously analyzed by means of gas liquid chromatography with a flame-ionization detector and a column of 5% OV-17 on Chromosorb W, HP; the detection limits are 0.05μg/ml for nitrite and 0.10μg/ml for nitrate.
For the determinations of nitrite and nitrate in foods, clean-up of crude extracts by florisil column chromatography and by addition of silver sulfate allows the satisfactory elimination of interfering compounds. The recoveries from several foods were 95.1-98.1 for nitrite and 95.7-98.3 for nitrate, and the standard deviations for the whole procedure (28 determinations) were 1.1% for nitrite and 1.0% for nitrate.

View full abstract

It was confirmed that single-cell protein (SCP) contains relatively large amounts of odd-numbered (uneven) fatty acids (UEFA); the contents of 9-heptadecenoic and heptadecanoic acids as percentages of total fatty acid were 39.1 and 9.6, respectively. When lactating cows were fed a diet containing SCP, the contents of 9-heptadecenoic and heptadecanoic acids increased to some extent in all classes of milk lipid tested. Heptadecanoic acid was accumulated preferentially in milk compared to 9-heptadecenoic acid. The contents of these fatty acids in milk decreased rapidly to the control level upon the cessation of feeding SCP.

View full abstract

Toxic oil that caused the disease called Kanemi “Yusho” contained polychlorobiphenyl (K-PCB) and polychlorodibenzofuran (K-PCDF). K-PCB and K-PCDF were separated from the toxic oil, and administered to two groups of mice orally. K-PCB (15.4μg/mouse/day) or a mixture of K-PCB and K-PCDF (15.4μg+1.0μg/mouse/day) was administered every day for 7 consecutive days. In both groups the concentration and biological half-life (B. H. L.) of each PCB isomer were estimated in the liver and adipose tissue.
The PCB isomers containing 4--7-chlorinated compounds showed the highest concentrations in the liver in both groups 1 day after the last oral administration. In the adipose tissue of both groups, 4- and 5-chlorinated PCBs exhibited the highest concentration on day 1, and 6- and 7-chlorinated PCBs on day 10.
The CB% of each PCB isomer (the concentration of each PCB isomer relative to that of the total PCB isomers as a percentage) was examined on day 1 in the K-PCB group. In both liver and adipose tissue, the total CB% of 4- and 5-chlorinated PCBs containing 2, 4-3′, 4′-tetrachlorobiphenyl (peak 9), 3, 4-2′, 4′, 5′-pentachlorobiphenyl (peak 25) and 3, 4-2′, 3′, 4′-pentachlorobiphenyl (peak 28) as the main components was 66.2% in adipose tissue and 57.3% in the liver. On day 50, however, the total CB% of 6- and 7-chlorinated PCBs containing 2, 4, 5-2′, 4′, 5′-hexachlorobiphenyl (peak 29), 2, 3, 4-2′, 4′, 5′-hexachlorobiphenyl (peak 32), 3, 4-2′, 3′, 4′, 5′-hexachlorobiphenyl (peak 47) and 2, 4, 5-2′, 3′, 4′, 5′-heptachlorobiphenyl (peak 49) as the main components was 89.6% in adipose tissue and 86.8% in the liver. A similar tendency was seen in the K-PCB+K-PCDF group. Moreover, in both groups the residual amount of PCBs unsubstituted with chlorine atoms in the meta and para positions (3, 4; 4, 5; 3′, 4′; 4′, 5′) with respect to the biphenyl bridge was small.
B. H. L. of each PCB isomer ranged from 1.92 days at peak 9 to 40.85 days at peak 47 in adipose tissue and from 1.64 days at peak 9 to 21, 71 days at peak 29 in the liver. In general, B. H. L. was shorter in the liver than in adipose tissue. When mice were administered with K-PCB plus K-PCDF, B. H. L.'s at peaks 9, 25 and 28 in liver and adipose tissue were reduced markedly to about one-half of those in mice administered with K-PCB alone. K-PCDF had little effect upon the B. H. L. of the total PCB.

View full abstract

Nine kinds of synthetic antibacterials being used as feed additives were separated into four fractions by chromatography on an ion exchange column and a florisil column. Clopidol, caprylohydroxamic acid, sulfaquinoxaline and nicarbazine were adsorbed on Amberlite GC-400 (OH) from the methanol extract of chiken muscle or egg and were eluted with 25ml of a mixture of 10% sodium chloride, hydrochloric acid and methanol (10:0.5:90) as fraction I. Washings and effluent containing unadsorbed materials were passed through a florisil column. Dinitolmide and ethopabate were eluted with 100ml of ethylether as fraction II, robenidine and decoquinate were eluted with 20ml of 1% calcium chloride in methanol as fraction III, and then amprolium was eluted with 25ml of 18% potassium chloride in methanol as fraction IV.
Each fraction was concentrated and analyzed by gas chromatography except for fraction IV, which was analyzed fluorometrically for amprolium.

View full abstract

In order to elucidate the distribution and chemical forms of total mercury and selenium in the myofibrillar protein fraction, the ordinary muscle of marine fish was fractionated into subactomyosin and actomyosin at an ionic strength of μ=0.2 after being dissolved in 0.6M potassium chloride. The samples used were skipjack (Katsuwonus pelamis), Japanese sea bass (Lateolabrax japonicus) and red sea bream (Chrysophrys major).
For skipjack muscles, 50 to 70% of total mercury in the myofibrillar protein was found in the subactomyosin fraction. The total mercury contents in the actomyosin fraction of Japanese sea bass and red sea bream muscles were 70 to 75 and 85 to 90%, respectively, of those in the myofibrillar protein. Approximately 90% of selenium in the myofibrillar protein was found in the actomyosin fraction regardless of the fish species.
The concentration ratios of total mercury to selenium in the subactomyosin fraction of skipjack samples were 10-30 times those in the actomyosin fractions. However, the ratios of red sea bream samples showed no appreciable difference between the two protein fractions. The ratios of mercury to selenium concentrations in the subactomyosin fraction of skipjack samples containing high levels of mercury were far higher than 1:1 on a molecular basis.
The total mercury in the myofibrillar protein of skipjack samples was distributed approximately 50% in the native tropomyosin fraction from the actomyosin fractionated at ionic strength ranging from 0.05 to 0.6. Since the total nitrogen contents in the native tropomyosin fractions were about twice those in the subactomyosin fractions, subactomyosin seems to be a component of the native tropomyosin.

View full abstract

A method was developed for the determination of pyrethroid insecticides (Allethrin, Resmethrin, Phthalthrin and Permethrin) absorbed on dish, apple and spinach surfaces.
The analytical method consists of four procedures: extraction with n-hexane, clean-up by partition with acetonitrile: n-hexane (2:1), separation by high performance thin-layer chromatography with a concentration zone and measurement by dual-wavelength densitometry.
The recoveries of pyrethroid insecticides from dish, apple and spinach were 76-104%, 88-98% and 87-98%, respectively.

View full abstract