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Gas chromatographic determination of sulfanilamides in egg and animal tissue was studied. The volatile derivatives of sulfanilamides were prepared with a diazomethane only and determined by the gas chromatograph equipped with an electron capture detector.Sulfadimethoxine and sulfaquinoxaline were detected in commercial egg and chicken tissue by this method. Linear calibration curves for the gas chromatographic determination were obtained in ranges of 0.025 to 0.25μg/ml for sulfamonomethoxine, 0.1 to 1.0μg/ml for sulfadimethoxine and 0.2 to 2.0μg/ml for sulfaquinoxaline, respectively. The separation was found to be good with QF-1 on Gas chrom Q.

13 C NMR spectroscopy of the sterols isolated from seeds of bottle gourd ( Lagenaria leucantha var. gourda ) and water melon ( Citrullus battich ) has demonstrated the co-occurrence of the C-24 epimers spinasterol and chondrillasterol.

Polychlorinated biphenyls (PCB) were determined after being converted to biphenyl by dechlorination. Sodium hydro-bis- (2-methoxy ethoxy) aluminate (RDB) was used for dechlorination of PCB. Outline of the procedure is as follows.The mixture of hexane extract from the sample and toluene solution of RDB was refluxed on a boiling water bath for 1 hour in 50ml centrifuge tube attached to a reflux condenser with ground glass joint. After cooling the mixture, unreacted RDB was decomposed with distilled water by cooling and the mixture was neutralized with hydrochloric acid. The content in the centrifuge tube was shaken for 30 seconds, then was centrifuged for 5 minutes. The content was decanted into a graduated cylinder to measure the amount of hexane. Liberated biphenyl in hexane was determined by the gas chromatography equipped with flame ionization detector.The lower limit of the biphenyl concentration identified was 0.3ppm.

A liquid chromatographic method is described to determine simultaneously the following 11 synthetic antibacterial agents used in a fishery: nitrofuran derivatives furazolidone, nifurpirinol, difurazone, and furamizole; sulfa drugs sulfamerazine, sulfisozole, sulfamonomethoxine, and sulfadimethoxine; and, oxolinic, nalidixic, and piromidic acids. A Nucleosil C18 column was used with tetrahydrofuran- acetonitrile-phosphoric acid-water (29 + 1 + 0.06 + 69.94) as the mobile phase. Pretreatment of the fish meat sample with acetone extraction and alumina column cleanup gave good separation of the LC peaks without interference from any other components. Recovery of the antibacterial agents was ca 80%. The lower limit of detection of the drugs was 1-2 ng for 10 μL injection.

The determination of nicotinamide as 3-cyanopyridine after dehydration by heptafluorobutyric anhydride (HFB) was performed by gas-liquid chromatography (GLC) with flame ionization detection (GLC-FID) and a column of 5% OV-17 on Chromosorb W AW DMCS at 130 degrees C. Determination was possible with 3-100 micrograms of the dehydrated reaction mixture. The procedure for determining nicotinamide in various meats and meat products involves direct analysis by GLC-FID without a clean-up stage; the detection limit is 5 ppm and the recovery ranged from 93.4 to 104.6% (average 98.0%). Various possible interferents in the samples did not interfere in the production or determination of 3-cyanopyridine. The procedure is suitable for routine use. The dehydrated derivative of nicotinamide was confirmed as 3-cyanopyridine by combined gas chromatography-mass spectrometry and infrared spectrometry.

A simple, sensitive, and practical method is described for determination of nitrite in egg, egg white, and egg yolk. Egg is deproteinized by adding a mixture of ammonium thiocyanate, mercuric chloride, and zinc acetate, and centrifuged. Nitrite in the supernate is converted to tetrazolophthalazine by reaction with hydralazine in acidic solution and then determined by gas-liquid chromatography with an electroncapture detector (GLC-ECD) and a column of OV-225 on Chromosorb W(HP). Nitrite concentrations from 5 to 50 ng/mL are calculated from peak height; the detection limit is 3 ng/mL extract. Recoveries from eggs, egg whites, and egg yolks ranged from 91.7 to 98.0%. The mean nitrite concentration in 50 egg samples was 0.04 ppm (0.01-0.11 ppm) with a detection limit of 4 ng nitrite/g.

The trimethylsilyl (TMS) derivative of sterigmatocystin showed high response to a electron-capture detector, so the micro analysis of sterigmatocystin in cereals was investigated by gas-liquid chromatography with electron-capture detector (ECD-GLC).The sterigmatocystin was extracted with a mixture of methanol and 1% Sodium chloride solution (55:45) from sample and was re-extracted with chloroform.After cleaned up by silica gel plus Florisil column chromatography and Sephadex LH-20gel permeation chromatography, it was silylated with N, O-bis (trimethylsilyl) trifluoroacetamide in ethyl acetate. The TMS-derivative was determined by ECD-GLC with a column (3mm×50cm) of 2% OV-17 on gas-chrom Q.The limit of detection by the present method was about 10ppb and recoveries of sterigmatocystin added to various cereals at the level of 40ppb were 82.3-92.0%.

A method of the quantitative determination of saccharin in foods by gas liquid chromatography (GLC) was described.Saccharin was methylated with dimethylformamide dimethylacetal (DMF-Me) heating for 30min in glycerin bath at 110±5°C. After reaction with DMF-Me, methyl derivative of saccharin obtained was determined by GLC equipped with a flame ionization detector (FID) and an electron capture detector (ECD). GLC was performed using DC-200 (10%) on gas chrom Q as the column and β-BHC as an internal standard.The recoveries of sodium saccharin added in various foods by the present method were 88.1-94.7%, and the limit of detection as saccharin was about 0.02μg with FID-GLC and 0.02ng with ECD-GLC.Furthermore, the determination with ECD-GLC was an effective method for the ultramicro-analysis.

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.

Nicarbazin (NCZ) is an equimolar complex of 4, 4-dinitrocarbanilide (DNC) and 2-hydroxy-4, 6-dimethylpyrimidine.Gas chromatographic determination with an electron capture detector (ECD) was carried out for p-nitroaniline (NA) obtained by acid hydrolysis of NCZ in a liquid paraffin bath at 150°C for 15 minutes. NA, a reaction product, was extracted with ethyl acetate in the presence of supersaturated sodium chloride in alkaline solution and the NA was determined by gas liquid chromatography.Gas chromatography: A Shimadzu GC 4CMPFE gas chromatograph with an ECD was used for NA. The column consisted of a glass tube (1mm×3mm ID) packed with 5% Thermon 3000 on Chromosorb W (AW DMCS, 80-100 mesh) and conditioned at 190°C. The temperature of the bath detector and injector was 230°C and the flow rate of nitrogen carrier gas was 20ml/min.A sample was extracted with methanol in an electric blender. The extract was cleaned up by ion exchange column chromatography on Amberlite CG-400 (OH form). The eluent was a mixture of hydrochloric acid and methanol (2:98).The recoveries of NCZ added to chicken tissues and eggs were in the range of 85-97%. The minimum detectable concentration was 0.02ppm as NCZ.

Residues of clopidol (3, 5-dichloro-2, 6-dimethyl-4-pyridinol) in chicken tissues and eggs were studied. Clopidol isolated from various tissues was determined by gas chromatography. Chickens of 10 weeks of age were given feed containing 250, 375 and 750ppm of clopidol for 10 days before laying eggs. The average contents of clopidol in the eggs were 6ppm, 10ppm and 19ppm, respectively. The concentration ratio (clopidol in whole egg/clopidol in feed ×100) of clopidol was found to be 2.64% on average, and clopidol in the egg disappeared within approximately one week.In other experiment, chickens of 4 weeks of age were given clopidol-containing feed (250, 375 and 750ppm) for 8 weeks. High concentrations of clopidol were found in the liver, blood and kidneys as compared with the breast, thigh muscle and fat. After cessation of medication, the clopidol concentration in each tissue fell below 0.1ppm within 3 days.

In this paper a method of phenacyl esterification determination of propionic acid after steam distillation for foods was described.Para-chlorophenacyl bromide (PCPB) was used as a phenacylation agent. Outline of the procedure was as follows: The mixture of the distillate and dimethylformamide solution of PCPB was stood for 30 minutes in a boiling water bath. After cooling of phenacyl ester of propionic acid was extracted with n-hexane. The phenacyl ester of propionic acid was determined by a gas chromatograph equipped with electron capture detector. The glass column for analysis was 2m long and was packed with 5% OV-17 on gaschrom Q 80-100mesh. The column operated at 200°C.Because of including chlorine, the compound could be measured with high sensitivity by electron capture detector. The lower limit of identification of the concentration of propionic acid was 0.1ppm solution.

Chikens were given feed containing antibacterial agents at the maximum legal levels for 6 weeks and then control feed for up to 14 days. Chickens were sacrificed on days 0, 1, 2, 3, 5, 7, 10 and 14 after withdrawal of the drug and the drug concentrations in various tissues were determined. In addition, 3 hens for each drug were given drug-containing feed for 14 days and then control feed for a further 14 days, and all eggs laid during this period were analyzed.These antibacterials were readily eliminated within 3-5 days, except for nicarbazine, which remained detectable in tissues for 10 days and in eggs for 28 days. The biological half-lives of antibacterials were calculated to be 0.4-4.3 days from these data.

Extraction technique and determination method of 3, 5-dinitro-o-toluamide (zoalene) were described in this paper.The mixture of sample and anhydrous sodium sulfate was ground to fine powder by a homogenizer. The mixture was packed in a glass column of 38mm in diameter tightly.As eluting agent acetonitrile was used. Zoalene was eluted efficiently by the column chromatography, and after clean up it was treated by florisil column chromatography, condensate of eluent was made to react with heptafluoro-n-butyric anhydride. The determination was performed by ECD gas chromatography on the solution of reaction product. A linear calibration curve was obtained in range of 0.1μg/ml to 1.0μg/ml of zoalene. The lower limit of the sample size of zoalene for identification was 0.03ng.