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The 2,4-xylenol method was modified and a gas-liquid chromatographic (GLC) method was developed for nitrate and nitrite determinations in several foods. Either a flame ionization (FID) or an electron capture detector (ECD) can be used. Proteins and fats are removed from warm alkaline water with zinc sulfate and filtered. The filtrate is evaporated to dryness, redissolved in water, and reacted with 2,4-xylenol in the presence of sulfuric acid to form 6-nitro-2,4-xylenol. Interfering chlorides are precipitated with silver sulfate and the nitrosylenol is extracted with hexane, concentrated, and injected. Nitrite in the filtrate is distilled at pH 5, collected in alkaline solution, and dried. The residue is oxidized to nitrate with permanganate in the presence of sulfuric acid, and then chromatographed in the same manner as nitrate. Recoveries from several foods were 83--100% for nitrate and 80--100% for nitrite. The limit of sensitivity was 0.1 ppm for both residues.

A gas-liquid chromatographic (GLC) method was developed for the detection and determination of thiourea in citrus peels. After the peel is extracted with ethyl ether, the ether extract is adsorbed on sodium sulfate together with water. Thiourea is recoverd from both the sodium sulfate and the peel residue with ethyl acetate-acetone(2+1). The extracted mixture is cleaned on an alumina column, the eluate is concentrated under vacuum, and thiourea is extracted from the concentrate with sodium carbonate solution. GLC was carried out on the prepared benzoyl derivative of thiourea. The average recoveries of thiourea from lemon peel were 85.3, 93.1, and 97.6% at the fortification levels of 1, 10, and 100 ppm, respectively. The detection limit was low as 0.08 ppm.

A procedure was developed for the simple and rapid determination of adipic acid in crackling candy and also in soft drinks. An alkaline solution of sample was extracted with ethyl ether to remove fatty substances, and H2SO4 was added to water layer to adjust the pH to less than 2. The acidified layer was saturated with NaCl and then extracted with ether. After drying, the ether layer was concentrated and the adipic acid in the concentrate was methylated using the diazomethane methograph equipped with a flame ionization detector. Recovery of adipic acid from crackling candy and from 2 kinds of soft drinks that had been fortified at the 200 ppm level was 96%. An interlaboratory test was carried out on the determination of adipic acid in orange soft drink. The results obtained by 6 laboratories were between 91 and 100% compared with the theoretical value.

Diacetyl tartaric acid ester of diglyceride was directly extracted from dairy or nondairy coffee cream powder under acidic conditions with ethyl acetate; then the extract was saponified with methanolic potash. After acidification with HCl, free fatty acid was removed with ether and the reaction mixture was absorbed on an anion exchange column. Tartaric acid was eluted with 2N HCl-acetone (1+1). An aliquot of the trimethylsilyl (TMS) derivative of the eluate was injected into a gas chromatograph with flame ionization detection, and a 1.5% SE-30 column. Recoveries of diacetyl tartaric acid ester of diglyceride at 50, 200, and 2000 ppm were 85.6-99.5%.

Orthophenylphenol (OPP) content in lemon peels was reduced to less than half of its original content with the procedure used to remove bitter substances. OPP content in peels decreased little after dipping them in water. The increment of OPP content in marmalade was proportional to the ratio of peeled pieces of lemon. OPP content of lemon marmalade prepared by an ordinary procedure from lemons containing 2.3 ppm of OPP on whole basis was 0.39 ppm, about 17% of the initial amount of OPP being present in the final product.

A method for simultaneous determination of residues of three herbicides containing nitrogen, propanil (3',4'-dichloropropionanilide), linuron and diphenamide, in agricultural commodites was established. The herbicides were extracted by acetone from samples, transferred into dichloromethane, then the dichloromethane extract was dried. The residue was dissolved in n-hexane, and purified from oily contaminants by partition with acetonitrile. The acetonitrile extract was further purified by Florisil column chromatography with dichloromethane. Diphenamide was determined directly by use of gas chromatograph equipped with a flame-thermoionic detection system (FTDGC). DCPA and linuron were derivatized into their N-monomethyl derivatives by a strong methylation method by use of sodium hydride and methyl iodide in a mixture of dimethyl sulfoxide and benzene, and then subjected to determination by FTD-GC. Recoveries of the three herbicides from brown rice, barley, corn, potato, carrot and onion were not less than 80% at the additional level of 1.0 ppm, while not less than 70% at 0.1 ppm level, respectively.

Ortho-, poly (pyro- and higher)- and meta-phosphates can be separated from each other with two dimensional thin layer chromatography, the detection level being 1 μg as P 2 O 5 . For determination of ortho- and poly (including polymeta-)-phosphates, an ion-exchange column chromatography was used. A single concentration elution with 0.2 M potassium chloride was effective for separating of orthophosphates from polyphosphates, and the residual polyphosphates could be recovered with 6 N hydrochloric acid. This system was used for a survey of polyphosphates in 61 samples of soft drinks sold in Osaka. Results showed that the total phosphate contents within the range of 0 - 0.420 g of P 2 O 5 /kg. Only three samples contained polyphosphates. The highest being 0.261 g of polyphosphate/kg in a soft drink containing 20% mango juice.

Attempts were made to develop a sensitive and reproducible method to determine nitrite in cod roe. Two diazotation-coupling reaction methods were considered; (a) the method defined by the Ministry of Health and Welfare of Japan (Method 1) and (b) the reference method of ISO (Method 2). Since the nitrite content in cod roe was much less than in meat products, Method 2 was modified to make it suitable for microanalysis at 1 ppm level as NO 2 . Modifications included reducing volumes of color-development solutions and making changes in the color development process, thus making the color intensity four times as great as before. Carrying out corrections with both reagent and water blanks made the effect of the blank on measured values negligible. Recoveries of nitrite at 20- and 2-ppm levels were 94.7 and 88.1%, respectively, reproducibility being ± 7 .9%, as the coefficient of variation. The obtained values by the modified method were, on the average, higher than those of the original method by 37.1%. Nitrite contents obtained by Method 1 were lower than those by the original Method 2. These low values might be attributed to loss of nitrite during extraction from the sample without pH adjustment, since the measured value showed a remarkable increase by addition of alkaline solution before extraction. Nitrite contents in imported cod roe were within the range 0.16-1.03 ppm expressed as NO 2 .

Borate was directly chelate-extracted from foods with 5% 2-ethyl-1,3-hexanediol (EHD) in n-hexane-n-butyl acetate mixture (8 + 2), from which borate was selectively transferred into 1% NaOH, since EHD-chelated boron did not react with curcumin to develop color. Finally, an aliquot of the alkaline solution was acidified with HCl and reacted with curcumin in a rotary evaporator. Color development was increased by heating for 8 min at 80 degrees C under reduced pressure of 16 mm Hg. Frozen shrimp and prawns (peeled and with shells) and salted jelly fish were analyzed by the proposed method. Results were compared with the contemporary official method of Japan based on curcumin reaction on an incinerated sample. Over 90% of the boric acid was recovered by the proposed method when samples were fortified with 20 ppm boric acid. Recoveries were superior to those of the official method especially for shrimp and prawns with shells and salted jelly fish. Detection limit of boric acid is 1 ppm. Moreover, the method requires only about 1 hr for analysis of one sample, making it suitable for routine analysis.

A simple and rapid fluorometric method for determining benzo (a) pyrene in foods was developed. Benzo (a) pyrene is extracted from foods with n-hexane:ether mixture (4:1), purified through a column of activated alumina and determined fluorometrically. An excitation wavelength of 295 nm and emission wavelength of 403 nm were used for calculating concentrations of benzo (a) pyrene. The peak height at 403 nm and baseline between 392 and 418 nm were employed to derive a standard curve for quantitating benzo (a) pyrene. A calibration curve for between 0.04 - 4 ng/ml of benzo (a) pyrene was used. Recoveries of benzo (a) pyrene from 14 kinds of food spiked at levels of 20 and 2ppb were within the range of 79.5 - 93.8% and 50.0 - 80.6%, respectively. The entire procedure takes only one hour with the detection limit being 0.1 ppb. Benzo (a) pyrene detected was reconfirmed by thin-layer chromatography.

In Japan artificial colors and pigments can be used for food packages if they are processed so that the artificial color or pigment will not be eluted to contaminate food. Ten samples of cardboard and five samples of wrapping paper were subjected to the elution test. One hundred cm 2 of cardboard or paper was immersed in water at 40 C and held for 30 min. Artificial color was eluted from all samples of whole cardboard and, when it was divided into three parts (surface, inner part and reverse side) to do the elution test separately, artificial color was eluted from all parts except with one sample when color was eluted only from inner part. By comparing R f values on a paper chromatogram as well as its maximal absorbance with color standards, the eluted color was identified to be croceine orange. Congo red and croceine orange were eluted each from one sample of wrapping paper.

A comparison of the combined solvent-extraction gas liquid chromatography (GLC) method with the AOAC method was carried out by use of two lots of processed cheese manufactured from Samsoe and Cheddar cheeses, containing 14.5 and 72.3 ppm of sorbic acid, respectively. On the whole, higher values were obtained by AOAC method, the ratio to theoretical values ranging from 98.6 to 135.9%. Such results indicate that substances other than sorbic acid might have reacted with 2-thiobarbituric acid to develop color. Contrary to this, results by the combined solvent-extraction GLC method were within the range of 97.5 to 106.2% of the theoretical values. The difference of the determined values by the two methods was significant at the 5% level for the lot containing 72.5 ppm of sorbic acid. The advantages of the combined method of solvent-extraction and GLC over the AOAC method include rapidity, simplicity and accuracy.

Twenty kinds of coal-tar dyes were subjected to median tolerance limit (TLm) test by use of Himedaka (Oryzias latipes) for the comparision of their acute toxicities. It became clear that 4 kinds of halogens substituted xanthene compounds dyes showed strong acute toxicities. From the fact that uranine had the lower acute toxicity than halogens substituted compounds and the toxicities of these 4 dyes increased through irradiation, it was assumed that halogen atoms in dyes might be responsible for these strong acute toxicities to fish.

A fluorescent substance was found in imported fruit candy. In the elution test of the fluorescent substance, it reacted in the same manner as fluorescent dyes. Further pursuit revealed that the fluorescence was derived from the grape flavor preparation added during manufacture and the fluorescence spectra of the candy and the grape flavor were quite coincident with that of methyl anthranilate. Methyl anthranilate contents in the candy and grape flavor were determined gas chromatographically to be 40.0 and 33,000 ppm, respectively, and it was calculated that the addition level of grape flavor to the candy was about 0.12%.

Forty-four kinds of organic nitrogen compounds as well as 37 kinds of dyes which contained nitrogen were subjected to TLm test by use of Himedaka (Oryzias latipes) and the results were compared with their partition coefficients between n-octanol and water. Concerning organic nitrogen compounds, such good correlation was observed among them that the larger the partition coefficient was, the smaller was the TLm value. Their acute toxicity to fish was supposed to be revealed after their passage through cell membrane of fish to be accumulated in the body. As far as coal-tar dyes and dyestuffs were concerned, there was a correlation between partition coefficient and TLm value. Methylene blue and rose bengale showed strong acute toxicity to fish and it was assumed that high affinity of these dyes to gill was responsible to depressing the function of gill, to make fish suffer from anoxemia and die.

Biochemical degradation test of food coal-tar dyes using sludge was studied in order to evaluate their safety. It was found that some dyes were little decomposed under aerobic condition but four azo dyes were readily decomposed under anaerobic condition. These were Food Yellow No. 4, No. 5, and Food Red No. 2, No. 102. Decomposed products of these four azo dyes by sludge under anaerobic condition were identified as sulfonilic, naphthionic acids and so on.