Gas chromatographic peaks of four kinds of Kanechlor (KC 300, 400, 500, & 600) were separated by OV-1 column with use of a flame ionization detector (FID), of which chlorine numbers were analyzed, respectively, by GC-Mass spectrometry.
It has been certified that there is a good relation between chlorine numbers in fourteen kinds of technical PCBs and gas chromatographic (FID) peak areas.
Consequently, those peak contents of four kinds of Kanechlor Products were quantified, respectively.
It has been confirmed that those peaks in the same retention time on four gas chromatograms (KC-300, 400, 500, & 600) have almost negligible difference in chlorine numbers.
Then, a mixture containing exactly the same amount of KC-300, 400, 500, & 600, was prepared as a standard whose gas chromatographic peaks had been quantitative.
This specific standard enables the quantitative analysis of total PCB contents within±10% accuracy from the theoretical value, compared with these obtained from gas chromatographic measurements of thirty-five combinations of four kinds of Kanechlors (KC-300, 400, 500, & 600) by use of an electron capture detector (ECD).
This standard works for eliminating individual human errors which may be encountered with the pattern-combination method, as well as does for shortening the analysis time.
In addition, it has another feature of obtaining extra more informations, as PCBs composition-ratio could be clarified according to chlorine numbers.

View full abstract

The method for the qualitative analysis of polysorbate in foods was studied. Polysorbate in foods was extracted with a mixture of dichloromethane and ethanol, and the extracts were applied to thin-layer chromatography (TLC) using silica gel plate.
Comparison of the recovery of polysorbate added in soft drink was carried out with 8 kind of extraction solvents, the highest recovery was obtained by the use of the dichloromethane·ethanol (1: 1v/v) mixture. Polysorbate was identified by thin-layer chromatography using chloroform, methanol, acetic acid and water and n-propanol, chloroform·methanoland 28% ammonia water as the solvents for thin-layer chromatography, since there were some color positive substances to cobalt thiocyanate reagent in food extracts.
This method was applied to eighteen kinds of food, for example, bread, cake mix, pudding etc, but no blue spot was found corresponding to polysorbate 80 except canned pudding, into which polysorbate 80 was used. The method, however, could net discriminate polysorbate and polyoxyethylene higher alcohol as were the case in the analytical methods by FDA or Hall et al.

View full abstract

The iodometric determination method (titration method) of hydrogen peroxide (H₂O₂) extracted with methanol was studied in previous papers. This method was found to be excellent in reproducibility and simplicity, however, it is not suitable because the extract is colored frequently. For the purpose of improvement of the method above-mentioned, H₂O₂ extracted with methanol was reacted with titanic sulfate, and the colored solution was determined colorimetrically. The color was stable for a week. The color reaction was not inhibited by the oxidizing agent such as potassium bromate or benzoyl peroxide, and not by phosphates and some amino acids added in noodle. The recovery was 97-102%. The range of determination was 2-200ppm of H₂O₂ in noodles. The presented method was more superior to the previous method in simplicity and precision.

View full abstract

The absorption and decomposition of hydrogen peroxide (H₂O₂) on Japanese noodle was studied in previous papers. The sterilizing effect of H₂O₂ on Japanese noodle where the residual amount was under 100ppm and the relation between the concentration of H₂O₂ residue and the viable cell counts in the commercial Japanese noodles were studied in this papers.
In case of combined treatment of H₂O₂ and steaming (100°C, 4 minutes), the satisfying concentration of H₂O₂ to sterilize the packed 20g of Japanese noodle-paste increased proportionally with the logarithm of the added viable cell counts.
The viable cell counts less than 10⁴/g in the most of the commercial Japanese noodles containing more than 20ppm of H₂O₂.

View full abstract

The mode of the antifungal action of peracetic acid was investigated and the following results were obtained. Peracetic acid had a strong fungicidal action against the strains tested and this action was observed in any phase of the growth process of mold. Further, peracetic acid inhibited the action of enzymes extracted from mold, protease and glucose-6-phosphate dehydrogenase, and the site of action was considered to be the amino acid residues of enzyme protein. In addition, peracetic acid acted on the biological substances such as vitamins, amino acids, nucleic acid related substances and deoxynucleic acid in vitro. From the results obtained in this studies, it was deduced that the mode of the fungicidal action of peracetic acid is based on the non-specific interaction between the cell components and peracetic acid, and the cells may cease to live as a result of these actions.

View full abstract

An investigation was made on 10 cubed frozen pork, to assess both bacteriological and chemical changes when they were preserved at 2 and 10°C for 10 days after thawing.
Viable counts immediately after the thawing demonstrated an average of 10⁶ cells/g which consisted of 60% of gram-positive and 40% of gram-negative organisms. The viable counts reached the level of 10⁸ cells/g on the 7th day when the specimens were stored at 2°C in a refrigerator and on the 3rd day with the ones kept at 10°C. Then the counts rose to the level of greater than 10⁹ cells/g on the 10th day with the former group and on the 7th day with the latter. At this stage, it was found that more than 85% of bacterial flora had been replaced by Pseudomonas and almost of all the specimens were malodorous. There was also an increase in pH and the amount of volatile basic nitrogen compounds.

View full abstract

An attempt has been made to clarify on the absorption and excretion of BHC in rats by using β- and γ-BHC labelled with ¹⁴C.
The results of tracer experiments indicated that about 95% of β-BHC and about 85% of γ-BHC ingested was absorbed from the digestive tract. The BHC once deposited in the organs and tissues was excreted mostly to urine and partly to feces.

View full abstract

Spores ef Clostridium botulinum type A 190 were germinated rapidly under suitable conditions in a chemically defined medium consisting of 5mM L-alanine, 10mM L-laetate, 60mM bicarbonate, and 100mM phosphate buffer (pH 6.7). Heat activation did occur only when spores were heated at 70°C for 10min in the medium or in a phosphate buffer (250mM, pH 6.7), but not when spores were heated sublethally in water. Germination took place under both aerobic and anaerobic conditions regardless of Eh levels. Maximum germination (more than 90% in 3hr) in the defined medium was obtained in the pH range of 6.7 to 7.2 and in the incubation temperature of 30° or 37°C. Some α-hydroxy acids, including lactate and its analogues, as well as thiogllycolate were found to be effective in promoting the germination in combination with L-alanine and bicarbonate.

View full abstract

Spores of Clostridium botulinum types A 190 undergo germination without proceeding of subsequent outgrowth in the ALB medium (5mM L-alanine, 10mM L-lactate, 60mM bicarbonate, and 100mM phosphate buffer, pH 6.7). The effects of some chemicals, including curing agents, food preservatives, and enzyme or germination inhibitors on the spore germination in this medium were studied.
D-Alanine at a concentration ratie to L-alanine 1: 1 had no effect on germination but inhibited completely at the ratio 30: 1. The addition of increasing concentrations of NaCl up to 8% to the medium pregressively decreased the rate and extent of germination over a 3 hours period, but could not prevent germination of spores which were incubated for more prolonged periods. Nitrite concentratiens of less than 0.1% had little effect on the spore germination in the medium. Higher concentrations (more than 1%) reduced slightly the rate of germination but allowed germination to occur to the same extent as those obtained in the absence of NaNO₂. Furthermore, nitrite-induced germination occurred with NaNO₂ concentrations as high as 4% at pH 6.0. Neither of the two chelating agents, EDTA and DPA, were inhibitory to germination in any concentration used. Of the enzyme inhibitors tested, only HgCl₂ and N-ethylmaleimide were inhibitory to germination. The two food preservatiyes, sodium sorbate and nitrofuryl furyl acrylamide, had no apparent effect on germination at even greater than commercially acceptable concentrations, although 1% sorbate prevented both the rate and extent of germination over a 3 hours period to some extent.

View full abstract

The analytical method of 1-naphthyl-N-methylcarbamate (NAC) residues in agricultural products was investigated.
It was found that the color formed by coloring reaction in basic medium is much more stable than that in acidic one, however, some carbamates may prevent the determination of NAC in basic medium.
In clean-up of NAC by coagulating solution, removal of colored materials was uncomplete when the samples contain abundantly colored materials. In these cases, further purification procedures were required. Therefore, when there are many samples in the routine work, the column chromatographic purifications are convenient rather than the coagulation procedure.
The recoveries of NAC added into vegetables were examined by the proposed method, and it was shown that recoveries are between 91% and 96.5%.

View full abstract

Natural substances derived from fragrant vegetables, such as parsley and onion, are known to disturb an analysis of the residual pesticides by a gas chromatography significantly.
It is suggested in the present study that those interfering substances can be eliminated effectively by silicagel column chromatography prior to application of gas chromatographic analysis.
The proposed procedure gave a fairly good detection of α-, β-and γ-BHC, heptachloroepoxide, dieldrin, pp′-DDE and pp′-DDT from the vegetables for domestic supply, in the chromatogram.
Good recovery of organochlorine pesticides was also obtained through the new combination of silicagel column and gas chromatography; the range of recovery was from 110 to 127% for α-BHC, 65-106, 110-130, 83-96, 101-104, 95-102, and 93-101 for β-BHC, γ-BHC, heptachlor epoxide, dieldrin, pp′-DDE, and pp′-DDT, respectively.
With these results, the possible application of the present method for practical purpose is discussed.

View full abstract

In order to detect malathion in waxes of wheat, a chromatography was tried on the extract of the plant through a column of the silica gel and charcoal double layers.
The wax contaminants were effectively eliminated by the column and the following gas chromatography resulted in a good detection of malathion.
The recovery of malathion added to the sample was good enouglh for a practical purpose.
The range of reeovery was essentially 100% (99-118%).
For the mass spectroscopic idelntification of malathien, the further purification was necessary and a combination of the double layer chromatography and the silica gel thinlayer chrematography were tested to eliminate the residual waxes.
Identification of the eharacteristic peaks owing to malathion was achieved on the mass spectrogram after the sample was pretreated through the combined purification procedure.

View full abstract

The determination of insectiside, 1-naphthyl-N-methylcarbamate (NAC) in unpolished rice has been made by the photometric method with pretreatment. This work involved the extraction of NAC with CH₂Cl₂- (CH₃) ₂CO-H₂O (1: 1: 1), the clean-up procedures consisted of distirbution between n-hexane and acetonitrile, and of alumina column and active carbon column chromatography. The eluates were concetrated and NAC was hydrolyzed to corresponding phenol, which was then coupled with 4-nitrobenzenediazonium ion to produce colored compound. It was dissolved in methanol and determined by colorimetry. The recovery of NAC added to unpolished rice was 90%. This method can be applied to the test of NAC residues in unpolished rice produced.

View full abstract