bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Gas Chromatographic-Mass Spectrometric Assay of Five Sulfonamide Residues in Animal Tissue
Authors: Simpson Randall M , Suhre Francis B , Shafer J W
Published: February 2020

A gas chromatographic-mass spectrometric procedure using isotopically labeled internal standards and the technique of selective-ion monitoring was used to assay sulfamethazine, sulfadimethoxine, sulfabromethazine, sulfathiazole, and sulfaquinoxaline in liver and muscle tissue of swine, poultry, and cattle. The data presented clearly demonstrate the applicability of this procedure for confirmation of sulfonamide residues in animal tissue.
Determination of Neomycin in Animal Tissues, Using Ion-Pair Liquid Chromatography with
Fluorometric Detection
Authors: Shaikh Badar , Allen Edward H , Gridley John C
Published: February 2020

A liquid chromatographic (LC) method is described for the determination of neomycin in animal tissues. Tissues are homogenized in 0.2M potassium phosphate buffer (pH 8.0); the homogenate is centrifuged, and the supernate is heated to precipitate the protein. The heat-deproteinated extract is acidified to pH 3.5-4 and directly analyzed by LC. The LC method consists of an ion-pairing mobile phase, a reverse phase ODS column, post-column derivatization with o-phthalaldehyde reagent, and fluorometric detection. The LC method uses paromomycin as an internal standard, and separates neomycin from streptomycin or dihydrostreptomycin because they have different retention times. The LC column separates neomycin in 25 min; the detection limit is about 3.5 ng neomycin. The overall recovery of neomycin from kidney tissues spiked at 1-30 ppm was 96% with a 9.0% coefficient of variation. The method was also applied to muscle tissue.
Determination of Nitrate in Dried Foods by Gas Chromatography-Thermal Energy Analyzer
Authors: Ross Holly D , Hotchkiss Joseph H
Published: February 2020

The method described for determining N03~ in dried foods is based on extraction of N03~ from the sample with subsequent nitration of benzene. The nitrobenzene is extracted with ethyl acetate, analyzed by using a gas chromatograph-thermal energy analyzer (GC-TEA), and quantitated against a nitrobenzene standard. Sensitivity is 100-200 μg/ kg. Coefficients of variation for analyses of dried foods were 3-13%. Recovery of N03" from nonfat dry milk spiked at 10 mg/kg averaged 100%.
Determination of Phosphine: Comparison of Rates of Desorption by Purge-and-Trap Method and by Sulfuric Acid Treatment
Authors: Saeed Talat , Abu-Tabanja Rohi
Published: February 2020

Two methods were compared for quantitative determination of phosphine present on fumigated food and materials. The rate of desorption of PH3 by using a purge-and-trap method was shown to be much slower when compared with sulfuric acid treatment and was also simpler. Application of the modified sulfuric acid treatment for real samples is described.
Residue Methodology for AMDRO Fire Ant Insecticide (AC 217,300) in Pasture Grass and
Crops
Authors: Stout Steven J , Steller William A , Tondreau Robert E , Manuel Arthur J , Dacunha Adrian R
Published: February 2020

Residue methodology is described for the determination of AC 217,300 residues in pasture grass and crop samples. After extraction and subsequent cleanup on an XAD-2 column, residues of AC 217,300 are determined by liquid chromatography (LC), using a reverse phase paired-ion chromatographic system and detection at 300 nm. The method has a validated limit of sensitivity of 0.05 ppm with corresponding control values for the commodities analyzed of <0.01 ppm. Apparent residues over 0.05 ppm can be confirmed by either gas chromatography with an electron capture detector (GC-EC) or gas chromatographynegative ion chemical ionization mass spectrometry (GC-NICI). The direct GC-NICI method circumvents the need for sample cleanup on the XAD-2 column, and offers a greatly simplified procedure that is useful for screening samples. Recoveries of AC 217,300 from the commodities analyzed have been satisfactory with all methods of analysis
Extraction of Organic Acids by Ion-Pair Formation with Tri-w-Octylamine.
Part 6. Determination of Sorbic Acid, Benzoic Acid, and Saccharin in Yogurt
Authors: Puttemans Marc L , Branders Chris , Dryon Louis , Massart Desire L
Published: February 2020

The sorbate content of commercial yogurt samples is determined by reverse phase liquid chromatography following ion-pair extraction with tri-n-octylamine. Mean recoveries (70-88%), precision (1.1-3.3% RSD), and detection limit of the method are presented for sorbic acid, benzoic acid, and saccharin.
Colorimetric Determination of Sympathomimetic Amines Methyldopa and Noradrenaline
Authors: Walash Mohamed I , Ouf Abed Abou , Salem Fatma B
Published: February 2020

The chromogenic reagent p-dimethylaminocinnamaldehyde (PDAC) is introduced for the determination of the sympathomimetic amines methyldopa and noradrenaline. The method is based on measurement of the orange color developed when the alkaline solution of methyldopa and noradrenaline is allowed to react with PDAC at pH 5.0. The color developed obeys Beer's law in the concentration range 0.1-1.5 mL of 2 x 103M solution of noradrenaline and methyldopa. The results are compared with those obtained with another chromogenic reagent, pdimethylaminobenzaldehyde (PDAB). Determinations on dosage forms of the drugs, using PDAC and PDAB reagents, agreed well with results of determinations by official pharmacopoeia! methods.
Liquid Chromatographic Determination of Vitamin D in Milk and Infant Formula
Authors: Sertl David C , Molitor Bruce E
Published: February 2020

Vitamin D2 or vitamin D3 is determined by liquid chromatography (LC) in milk and infant formula. Vitamin D is extracted from the saponified sample, passed through an amino-cyano LC cleanup column to remove major interferences, and quantitated using normal phase LC. Within-day precision is 4.5% relative standard deviation (RSD); the overall method RSD (reflecting technician-to-technician, day-today, and within-day variability) is 7.7%. Overspike recoveries averaged 97% for milk, 98% for milk-based infant formula, and 93% for soy-based infant formula. The performance of the method is compared with that of the official AOAC vitamin D method (rat bioassay). The method is applicable to the determination of vitamin D in milk and in the major milk- and soy-based infant formulas available in the United States. The method can quantitate (but not distinguish) either vitamin D2 or vitamin D3. The method is applicable to milk and infant formula samples containing between 100 and 1500 IU vitamin D/L. Sample throughput is between 4 and 8 replicates per da
Performance Characteristics of Methods of Analysis Used for Regulatory Purposes.I. Drug Dosage Forms. D. High Pressure Liquid Chromatographic Methods
Authors: Horwitz William , Albert Richard H
Published: February 2020

Precision parameters of high pressure liquid chromatographic methods approved by AOAC for the analysis of drug dosage forms were recalculated on a consistent statistical basis, using the computer program "FDACHEMIST." Eleven collaborative studies of 12 compounds in 66 dosage forms analyzed by an average of 9 laboratories per study, with a total of 1150 determinations, were reviewed. For the approved methods and methods awaiting approval (9 studies, 11 compounds, 54 dosage forms, and 959 determinations), the average repeatability relative standard deviation (within-laboratory; RSDo) was 1.0%; reproducibility relative standard deviation (among-laboratories, including within-; RSDX) was 2.5%; the ratio RSD„/RSDX was an unusually low 0.40, with an average outlier rate of 0.6% of the reported values. The line of best fit for RSDX plotted against — log concentration increases with decreasing concentration, extending approximately from RSDX =2% at 100% concentration to RSDX = 3.6% at 0.01% concentration,a change in RSDX of about 0.4% for each 10-fold decrease in concentration,independent of analyte and matrix.
Atomic Absorption Spectrophotometric Determination of Tin in Canned Foods, Using Nitric Acid-Hydrochloric Acid Digestion and Nitrous Oxide-Acetylene Flame: Collaborative Study
Authors: Dabeka Robert W , Mckenzie Arthur D , Albert Richard H
Published: February 2020

Twenty-six collaborators participated in a study to evaluate an atomic absorption spectrophotometric (AAS) method for the determination of tin in canned foods. The 5 foods evaluated were meat, pineapple juice, tomato paste, evaporated milk, and green beans, each spiked at 2 levels. The concentration range of tin in the samples was 10-450 μg/ g, and each level was sent as a blind duplicate. Statistical treatment of results revealed no laboratory outliers and 6 individual or replicatetotal outliers, accounting for 3.3% of the data. Repeatability (withinlaboratory) coefficient of variation (CVo) ranged from 2.2 to 48%, depending on the tin level and food evaluated. For samples containing >80 μg/g of tin, repeatability CV averaged 5.6% including outliers and 3.7% after their rejection. Overall among-laboratories coefficient of variation (CVX) varied from 3.3 to 58%; at levels >80 μg/g, it averaged 7.3% with outliers and 5.3% after their rejection. Recovery of tin, based on spiking levels, ranged from 100.0 to 112.8% and averaged 105.4%. Detection limit range is 2-10 μg/g, and lower quantitation limit is 40 μg/g. This method has been adopted official first action.
Quantitative Colorimetric Method for Sulfamethazine in Swine Feeds
Authors: Schwartz Daniel P
Published: February 2020

Sulfamethazine (SM) in swine feeds is quantitated colorimetrically by using a relatively simple procedure. The drug is isolated from an extract of feed by trapping it on a small bed of anion-exchange resin buffered at pH 7.9 following the removal of possible interfering compounds by pre-columns. SM is then eluted, diazotized, and coupled using the Bratton-Marshall reagents. The intensity of color developed is determined spectrophotometrically at 540 nm and the concentration of SM is calculated using a molar absorptivity of 52 500. Feeds containing from 1 to 130 ppm can be analyzed with very good accuracy and precision. The method has satisfactory specificity, is inexpensive, and can be applied to a relatively large number of samples per day. A simple and safe method for preparing N1-methyl SM at the low microgram level is described together with a thin layer chromatographic system for tentatively verifying the presence of SM in the feed both as the underivatized drug and as N1-methyl SM
Gas Chromatographic Determination of Pentachlorophenol in Gelatin: Collaborative Study
Authors: Yip George
Published: February 2020

Eleven collaborators participated in this study of a gas chromatographic method for the determination of pentachlorophenol (PCP) in gelatin. Following acid hydrolysis of a 2 g sample, PCP is extracted with hexane and partitioned into KOH solution. After reacidification, PCP is again extracted with hexane for determination by electron capture gas chromatography on a 1 % SP-1240DA column. Three duplicate practice samples (0.0, 0.5, and 1.5 ppm) and 5 blind duplicate collaborative samples (0.0, 0.02, 0.1, 0.5, and 2.0 ppm) were analyzed by each collaborator. Mean recoveries of PCP in the collaborative samples ranged from 88% at the 0.02 ppm fortification level to 102% at the 0.1 ppm level; the overall mean recovery was 96%. Interlaboratory coefficients of variation ranged from 16.4% for the 0.1 ppm fortification level to 22.9% for the 0.5 ppm level; the overall interlaboratory coefficient of variation was 19.5%. The method has been adopted official first action.
Formulas for Calculation of Extraction Volumes for Commonly Used Pesticide Residue Extraction Procedures
Authors: Jeffus Marshall T , Stewart James G
Published: February 2020

Formulas are presented for the calculation of extraction volume for pesticide residue procedures that use a single extraction with acetone, acetonitrile, or methanol, with or without prior dilution of these solvents with water. These formulas account for the volume change on mixing and for the volume contribution from the soluble sugars sucrose, glucose, and fructose. Results using these formulas are in agreement with the observed volumes of such mixtures within 0.3% throughout the following ranges, expressed as percent water in the mixtures: 15- 38% for acetone, 4.8-59% for acetonitrile, and 9.3-33% for methanol
Radiocarbon 14C Differentiation of Sparkling and Carbonated Wines
Authors: Martin Glenn E , Krueger Harold W , Burggraff James M
Published: February 2020

Specific 14C-activities, percent of modern 14C-activity, and calculated percent of fermentation CO2 are presented for CO2 contained in commercial sparkling wines, labeled as champagne or produced by the bulk (charmat) process. These data are given for the production years 1976–1982. The survey encompassed effervescent wines produced in Spain, Italy, West Germany, California, and New York. Addition of synthetic CO2 to approximately 40 samples represented as sparkling wines was indicated by low 14C-activities of CO2 in these wines. Data for 14C-activity were also presented for the ethanol distilled from sparkling wines for the years 1977–1980. In all cases, the 14C-activity of ethanol was appropriate to the year of vintage.
Modification of the Rapid Screening Method for Aflatoxin in Corn for Quantitative Use
Authors: Spilmann Joseph R
Published: February 2020

A study was made to determine if the official AOAC method for screening of aflatoxin in corn could be modified for use as a quantitative method. Several different corn products were analyzed using the modified method, with an average savings of over 1 h/sample vs the CB method. Average recoveries for aflatoxin Bt were 94% for the low level spiked samples and 108% for the high level. Samples of corn and corn products containing naturally incurred aflatoxin were also analyzed with the modified method, and the results compared favorably with those obtained by the CB method.
Liquid Chromatographic Determination of Intermediates in D&C Yellow No. 7 and D&C Yellow No. 8
Authors: Calvey Robert J , Goldberg Allen L
Published: February 2020

A sensitive, reproducible method that uses liquid chromatography in the reverse phase mode has been developed for the determination of phthalic acid, resorcinol, and 2-(2',4'-dihydroxybenzoyl)benzoic acid in D&C Yellow No. 7 and D&C Yellow No. 8. The method uses a 10 p, C-8 column, a 1% acetic acid-methanol gradient, and UV absorption detection at 280 nm. Average recoveries of phthalic acid, resorcinol, and 2-(2',4'-dihydroxybenzoyI)benzoic acid were 100, 98, and 1(12%, respectively, from fluorescein standard (certifiable as D&C Yellow No. 7) spiked with each compound at levels ranging from 0.13 to 1.3%.
Liquid Chromatographic Determination of 2,4-Dinitroaniline and 2-Naphthol in D&C Orange No. 17
Authors: Scher Alan L
Published: February 2020

A method is described for the determination of the intermediates in D&C Orange No. 17 by reverse phase liquid chromatography. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, which is followed by a wash and equilibration. Peak area calibrations were linear. At the provisional specification levels, 99% prediction limits were 0.200 ± 0.0012% 2,4-dinitroaniIine (2,4-DNA) and 0.200 ± 0.006% 2-naphthol. The limits of determination were 0.0023% for 2,4-DNA and 0.013% for 2-naphthol at the 99.5% confidence level. Recoveries were 98- 100% for 2,4-DNA added at the 0.005-2% level, and 93-103% for 2- naphthol added at the 0.025-2% level. A survey of certified D&C Orange No. 17 samples showed that the lots contained higher levels of the intermediates than were determined previously by a cellulose column method, in which the pigment is not dissolved.
Liquid Chromatographic Determination of Barbaloin (Aloin) in Foods
Authors: Yamamoto Masatoshi , Ishikawa Masaaki , Masui Toshio , Nakazawa Hiroyuki , Kabasawa Yozo
Published: February 2020

A simple and rapid liquid chromatographic method is described for the determination of barbaloin (aloin, 10-D-gIucopyranosyl-l,8-dihydroxy- 3-(hydroxymethyI)-9(10#)-anthracenone) in foods. Barbaloin is extracted with water from foods containing aloe and the extract is cleaned up on a disposable cartridge by using methanol-water (55 + 45) as eluant. The eluted barbaloin is separated by liquid chromatography on a YMC A-302 column with methanol-water (50 + 50) mobile phase, and detected at 293 nm. Recoveries of barbaloin added to foods at the levels of 0.05 and 0.50 mg/g were 94.4-100%. Assay results for commercial food samples indicated that the present method is applicable to a variety of foods supplemented with aloe.
Rapid Microchemical Identification of Four Phenothiazine Antiemetics with Gold Bromide and Iodine-Potassium Iodide Reagents: Collaborative Study
Authors: Rabkin Marshall
Published: February 2020

A microchemical method was developed for the rapid identification of 4 phenothiazine antiemetics. Perphenazine, promethazine, thiethylperazine, and triflupromazine were positively identified and differentiated with the aid of a gold bromide reagent and an iodine-potassium iodide reagent. Only promethazine and triflupromazine yielded microcrystalline derivatives with gold bromide; only perphenazine and thiethylperazine reacted with iodine-potassium iodide. For each pair of positive reactions, the crystalline products were morphologically distinguishable under a microscope. The 2 tests were collaboratively studied by 7 independent laboratories and found to be simple, rapid, and effective for identifying the phenothiazines of interest. The method has been adopted official first action
Reverse Phase Liquid Chromatographic Determination of Bisacodyl in Dosage Forms
Authors: Valenti Leonard P , Lau-Cam Cesar A
Published: February 2020

A method is described for the determination of bisacodyl in entericcoated tablets and suppositories by liquid chromatography (LC). The method will also determine the hydrolysis degradation products monoacetylbisacodyl and desacetylbisacodyl. The sample is dissolved in 2- propanol, and the extract is diluted with the mobile phase and injected into a liquid chromatograph fitted with a μBondapak C18 column and an ultraviolet detector set at 254 nm. The column is eluted with methanol- acetonitrile-0.01M citric acid (25 + 25 + 50). The pooled mean recovery value for bisacodyl from commercial enteric-coated tablets and suppositories was 99.7 % with a pooled coefficient of variation (CV) of 0.72%. For content uniformity assays, the CVs were 0.7 and 1.0% for groups of 10 individual commercial suppositories and tablets, respectively. Differences between assay values by the LC and USP XX methods were 0.2% of declared for enteric-coated tablets (n = 5) and 1.0% of declared for suppositories (n = 2). The LC method can determine as little as 0.015 μg of the monoacetyl or desacetyl degradation product.
Liquid Chromatographic Determination of Diazepam in Tablets: Collaborative Study
Authors: Tsougros Michael
Published: February 2020

A stability indicating liquid chromatographic method for the determination of diazepam in tablets was collaboratively studied by 6 laboratories. The method uses a Cig reverse phase column, a methanolwater mobile phase, p-tolualdehyde as the internal standard, and photometric detection at 254 nm. The collaborators were supplied with a synthetic tablet powder and 3 commercial tablet samples. The mean recovery of diazepam from the synthetic tablet powder was 100.2%. For all samples analyzed, the coefficient of variation was < 1.5%. The method has been adopted official first action.
Improved Enrichment for Recovery of Shigella sonnei from Foods
Authors: Mehlman Ira J , Romero Aida , Wentz Barry A
Published: February 2020

Shigella species were recovered from foods by the procedure described in the Bacteriological Analytical Manual, 5th Ed. The method is effective if Shigella species are present at about 106 cells/g. A 25 g food portion was incubated in Gram-negative (GN) and selenite cystine broths for 16 h at 35°C and streaked onto MacConkey, Levine's eosin methylene blue, desoxycholate citrate, and xylose lysine desoxycholate agars. 5. sonnei cells were recovered quantitatively at 44.5°C, and along with other Shigella species, were grown with Escherichia coli in a tryptone broth under anaerobic conditions. Shigella species were also grown in a mixed microflora from foods. 5. sonnei cells were inoculated into an enrichment broth containing 20 g tryptone, 2 g K2HPO4, 2 g KH2PO4, 1 g glucose, 5 g NaCl, 1.5 mL Tween 80, and 0.5 mg novobiocin/L (pH 7.0) and incubated for 20 h at 44°C. Enrichments were streaked onto MacConkey agar and the plates were incubated 20 h at 35°C. Suspect Shigella colonies were screened in glucose, tryptone, and lysine broths and in triple sugar iron and motility agars. The sensitivity varied from 0.3 to 1000 bacteria/g. The method has been examined with artificially inoculated lettuce, celery, brussels sprouts, mushrooms, and hamburger. It is also applicable to S. flexneri if incubation is conducted at 42°C.
Proton Magnetic Resonance Spectroscopic Assay of Propoxur
Authors: Lesser Joseph H , Kreps Saul I , Friedman Ella
Published: February 2020

A procedure is described for the assay of propoxur (o-isopropoxyphenyl N-methylcarbamate) by nuclear magnetic resonance (NMR) spectroscopy. Methanol was used as internal standard and chloroform as solvent. Known standard and technical materials were analyzed and results of NMR and liquid chromatographic methods were compared. The NMR method is straightforward, with a precision of ± 1.6% (95% confidence limits) for 2 sample weighings.
Gas Chromatographic Determination of Alachlor in Formulations: Collaborative Study
Authors: Tomkins David F
Published: February 2020

An isothermal gas chromatographic method for measuring alachlor in formulations was tested by 26 collaborators. The samples were prepared in acetone and determined with a gas chromatographic column of 10% SP 2250 on 100-120 mesh Supelcoport and with di-n-pentyl phthalate as internal standard. Collaborators made single determinations on each of 2 similar materials (matched pairs) on 2 days for 3 pairs of samples. The study generated 44 matched pairs which were used in Youden's matched-pair calculations. The coefficients of variation (CV,) for liquid formulations were 1.23% and 0.94%, while the CV, for the granular formulation was 1.60 %. The method was simple to use and did not reveal any interferences in the samples tested. The method has been adopted official first action.
Gas Chromatographic Method for Determination of Fenitrothion in Technical and in Emulsifiable Concentrate and Water-Dispersible Powder Formulations: Collaborative Study
Authors: Mount Dwight L , Miles James W
Published: February 2020

A variety of column packings and internal standards were evaluated to determine the most satisfactory system to use in a gas chromatograhpic (GC) method for analysis of fenitrothion, technical and formulations. Fenitrothion and the most closely related isomer, 00- dimethyl 0-(4-methyl-3-nitrophenyl) phosphorothioate, were resolved on columns packed with OV-210 and with polyphenyl ether, 6-ring (PPE-6R). A method based on the separation of fenitrothion on a PPE- 6R column with fluoranthene as internal standard was selected for use in a limited collaborative trial and later for use in a full-scale collaborative trial with 21 collaborators participating. Each collaborator was furnished matched pairs of samples of technical fenitrothion, emulsifiable concentrate, and water-dispersible powder. The coefficients of variation (CV) for the paired samples were 1.02,1.11, and 1.01, respectively, for technical fenitrothion, emulsifiable concentrates, and waterdispersible powders. Data are also presented for an alternative method in which compounds are separated on an OV-210 column with dibutyl sebacate as the internal standard. The method has been adopted official first action.
Gas Chromatographic Determination of Chlordimeform in Pesticide Formulations: Collaborative Study
Authors: Gale Thomas G , Hofberg Arthur H
Published: February 2020

Agaschromatographic (GC) procedure for the determination of chlordimeform in emulsiflable concentrate formulations containing about 46% active ingredient was collaboratively studied using the matched pair scheme. Chlordimeform was extracted from the formulation with methylene chloride containing diethyl terephthalate as the internal standard, chromatographed on CBWX-20M, and detected by flame ionization. Determinations on the 4 samples by 20 government, university, and industrial collaborators using peak area measurements showed within-laboratory repeatability of better than 1%. Reproducibility was 1.2% for the formulation. The method has been adopted official first action.
Capillary Gas Chromatographic Determination Of Cypermethrin In Formulations:
Collaborative Study
Authors: Bland Peter D
Published: February 2020

A method is described for the determination of cypermethrin, 3-(2,2- dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate cyano-(3- phenoxyphenyl)methyl ester, in technical and formulated material by capillary gas chromatography (CGC). Samples of technical or formulated material are dissolved in CH2Cl2 containing dicyclohexyl phthalate as internal standard. The solution is injected into a gas chromatograph fitted with a flame ionization detector and capillary column of 25 m x 0.32 mm fused silica with a thick film OV-1 phase at 240°C. Injection is made into a heated injection port fitted with an antidiscrimination device in a split mode. Peak areas obtained at retention times of the internal standard and active ingredient are measured with an integrator. The quantity of cypermethrin is determined by comparing the internal standard and active ingredient peak areas with those obtained from a calibration solution containing known amounts of internal standard and pure active ingredient. Five samples were chosen for collaborative study: technical cypermethrin, 70% liquid concentrate, 3 lb/US gal. emulsifiable, 3 ib/US gal. oil concentrate, and 40% wettable powder. Twelve collaborators carried out replicate determinations on each sample on separate days. Coefficients of variation between laboratories (CVX) were 2.13 for the technical, 2.94 for the emulsifiable concentrate, 3.51 for the liquid concentrate, 2.66 for the wettable powder, and 2.29 for the oil concentrate. The method was adopted official first action.
Liquid Chromatographic Monitoring of the Depletion of Carbadox and Its Metabolite Desoxycarbadox in Swine Tissues
Authors: Macintosh Agnes I , Lauriault Ginette , Neville George A
Published: February 2020

A liquid chromatographic method was used to monitor a depletion study of carbadox (and its most important metabolite, desoxycarbadox) in young pigs fed carbadox-treated rations for 1 week. Carbadox was found in blood (20 ppb), blood serum (26 ppb), and muscle tissue 24 h after withdrawal from treated ration; residues were reduced to a trace (< 2 ppb) in 48 h, and eliminated by 72 h. Desoxycarbadox, although not detected in blood, was found in muscle (17 ppb) 24 h after withdrawal; it was reduced to 9 ppb at 48 h and to a trace by 72 h. Although no carbadox was detected in liver 24 h after withdrawal, appreciable desoxycarbadox (125 ppb) was found in liver 24 h after withdrawal; it was reduced to 17 ppb at 48 h and to a trace by 72 h. Whereas only a trace of carbadox was found in kidney 24 h after withdrawal, 186 ppb desoxycarbadox was found in kidney at 24 h, 34 ppb at 48 h, and a trace at 72 h. No metabolite of carbadox other than desoxycarbadox was found in extracts of swine tissues during this medicated feed trial, and no metabolite was found in blood extracts by using the established 'methodology. The effect of tissue storage (aging) at - 20°C on levels of the drug and its metabolite was a modest alteration of residue levels. The inadvertent use of feed adulterated with furazolidone and initially medicated with chlortetracycline, sulfamethazine, and penicillin G, did not affect the uptake of carbadox in this depletion study or interfere ) with the analytical methodology.
Determination of Internal Insect Infestation of Oats: Collaborative Study
Authors: Trauba Richard L
Published: February 2020

An improved method has been developed for determining internal insect infestation of oat kennels. The method involves alcohol defatting and acid hydrolysis of the cracked oats, wet sieving to remove the acid, transfer to a 2 L Wildman trap flask, deaeration by boiling, and treatment with Tween 80-Na.tEDTA. Insects are extracted with light mineral oil. Reports from 6 collaborators showed that recoveries averaged 88.98% for adult insect heads and 97.22% for larvae. The method has been adopted official first action.
Organochlorine Pesticides and Polychlorinated Biphenyls in Sediment and Fish from Wetlands in the North Central United States
Authors: Martin Dan B , Hartman William A
Published: February 2020

Sediment samples collected in 1980-1982 from riverine and pothole wetlands at 17 locations in the north central United States were analyzed for organochlorine pesticides, certain of their metabolites, and polychlorinated biphenyls (PCBs). Concentrations were above minimum detection levels (5 ng/g of organochlorines and 20 ng/g of PCBs) in less than 4% of the samples taken. Fish samples taken at 9 of these 17 locations, and analyzed for the same compounds, showed a higher frequency of detectable contaminants. The most common compound found in fish was DDE, which was found in 51% of the samples at levels up to 512 ng/g. a-BHC was present at concentrations of 5 to 27 ng/g in 36% of the fish samples, and DDD was found at levels of 5 to 60 ng/g in 14%. Four other compounds, DDT, dieldrin, PCB, and Ira/ts-nonachlor, were detected in fish at relatively low concentrations in less than 10% of the samples. This survey, thus, indicated little contamination by organochlorine pesticides or PCBs in the wetland habitats of this region.
Capillary Gas Chromatographic Determination of Prometryn and Its Degradation Products in Parsley
Authors: Bardalaye Promode C , Wheeler Willis B
Published: February 2020

Residue analysis of the herbicide prometryn (2,4-bis(isopropylamino)- 6-methylthio-l,3,5-triazine) is widely known, but an analytical method for determining its metabolities or degradation products in addition to the parent chemical has not yet been reported in the literature. The procedure reported here is for the extraction and determination of prometryn and 2 metabolites, 2-amino-4-isopropylamino-6-methylthio- l,3,5-triazine and 2,4-diamino-6-methylthio-l,3,5-triazine, in parsley. Crops were extracted with 2-propanol followed by concentration of the extract and partitioning with a minimum amount of hexane in the presence of a large excess of water to remove most of the green pigment. The aqueous phase was divided into 2 equal halves: (A) Onehalf portion was partitioned with dichloromethane in the presence of saturated sodium chloride solution, the dichloromethane phase was separated, and the aqueous phase was discarded. The organic solvent was evaporated, and the contents were reconstituted in petroleum ether before prometryn analysis. (B) The other half was made slightly alkaline with ammonium hydroxide solution and was partitioned with ethyl acetate in the presence of saturated sodium chloride solution. The ethyl acetate phase was concentrated, centrifuged to remove any turbidity, and analyzed for the 2 metabolities above. Fused silica capillary gas chromatography (GC) with nitrogen-phosphorus (N-P) detection was used for quantitation. The limit of detection was 0.05 mg/kg for all the compounds examined. Recoveries from fortified parsley samples ranged from 59 to 73% at fortification levels of 0.05 to 1.0 mg/kg.
Liquid Chromatographic Assay of Tetracyclines in Tissues of Food-Producing Animals
Authors: Ashworth Raymond B
Published: February 2020

A survey of the literature is presented on liquid chromatographic (LC) determination of tetracyclines in plasma, urine, and tissues of foodproducing animals. Food Safety and Inspection Service (FSIS) research on tetracyclines during 1973-1984 is discussed, including the thin layer chromatographic qualitative identification method for tissues. Research on development of LC column packings for trace level chromatography of tetracyclines and anhydrotetracyclines is also discussed. Data are shown for recovery, ruggedness testing, and analyst qualification studies on the tentative version of the LC method
Enzymatic-Ultraviolet Determination of Glucose and Fructose in Wine: Collaborative Study
Authors: Henniger Guenther , Mascaro Leonard
Published: February 2020

This collaborative study on the determination of glucose and fructose in wine was performed by 18 laboratories on 4 matched pairs of commercial wine. The method uses the enzymes hexokinase, glucose-6- phosphate dehydrogenase, and phosphoglucose isomerase and the coenzyme nicotinamide-adenine dinucleotide phosphate. Both glucose and fructose can be determined in the same sample without separation. The method is simple but care is necessary to ensure precise transfer of small volumes. Repeatability and reproducibility standard deviations for glucose ranged from 2.6 to 14.6 mg/L and 4.7 to 16.5 mg/L, respectively. Repeatability and reproducibility values for fructose ranged from 2.4 to 16.1 mg/L and 6.0 to 21.3 mg/L, respectively. The method has been adopted official first action
Enzymatic-Ultraviolet Determination of L-Citric Acid in Wine: Collaborative Study
Authors: Henniger Guenther , Mascaro Leonard
Published: February 2020

A collaborative study was carried out on an enzymatic method for the determination of L-citric acid in wine, using the enzymes citrate lyase, malate dehydrogenase, and lactate dehydrogenase and the coenzyme nicotinamide-adenine dinucleotide phosphate. The study was performed by 18 laboratories using 4 blind duplicates of commercial wine. The method is simple and shows good precision. Coefficients of variation (CV) for reproducibility ranged from 1.8 to 3.4%; CVs for repeatability ranged from 0.76 to 2.62%. Analysts are cautioned to check the linear absorbance response of their spectophotometers when performing this assay and also to take care in pipetting the relatively small volumes used in this procedure. The method has been adopted official first action
Ion-Pair Column Chromatographic Determination of Trimethobenzamide Hydrochloride in
Capsule and Injection Dosage Forms: Collaborative Study
Authors: Naviasky Helen
Published: February 2020

An ion-pair column chromatographic method was developed for the determination of trimethobenzamide hydrochloride in capsules and injection dosage forms. Detection is by UV spectrophotometry at 261 nm. Recoveries by the Associate Referee ranged from 98.3 to 101.0% for the drug substance. Results by 5 collaborators for capsules averaged 99.1% of labeled or theoretical with coefficients of variation (CVs) of 1.81% (reproducibility) and 1.17% (repeatability); results for injec- , tions averaged 100.4% of labeled or theoretical with CVs of 1.91% (reproducibility) and 0.69% (repeatability). The method has been adopted official first action
Sample Preparation for Chromatography of Amino Acids: Acid Hydrolysis of
Proteins
Authors: Gehrke Charles W , Wall Larry L , Absheer Joseph S , Kaiser Floyd E , Zumwalt Robert W
Published: February 2020

A number of variations were evaluated in the techniques and procedures of the classical 6N hydrochloric acid, 110°C, 24 h hydrolysis of protein. Variations included the use of glass tubes with Teflon-lined screw caps as the hydrolysis vessel, high-temperature short-time hydrolysis, performic acid oxidation of cystine and methionine, multiple hydrolysis times at 145°C, and interlaboratory preparation of hydrolysates. A diverse sample set used in the study included a range of protein-containing matrices, and automated ionexchange chromatography was used for the amino acid analysis. Results show that for hydrolysis in glass tubes with Teflon-lined screw caps at 110°C for 24 h, recoveries of amino acids were in good agreement with recoveries by classical hydrolysis in sealed glass ampoules at reduced pressure. Recoveries from a higher temperature hydrolysis, i.e., 145°C for 4 h and using sealed ampoules, were also in agreement with 110°C, 24 h, sealed ampoule results; the former procedure yielded increased isoleucine and valine and decreased serine and threonine values. Glass tubes with Teflon-lined screw caps for hydrolysis were found to be a practical and convenient alternative to sealed glass ampoules; the improved precision with the former was probably due to the simplicity of the method.

The average recovery of cystine from a wide range of matrices without the use of performic acid was 55.5% compared with results obtained with performic acid oxidation. Similarly, methionine is preferably analyzed as methionine sulfone.

Interlaboratory evaluation of 145°C, 4 h hydrolysis, in which one laboratory used sealed ampoules and the other laboratory used Teflon-lined screw-cap tubes, demonstrated excellent agreement of amino acid values.
Analysis of Fat-Soluble Vitamins. XXIX. Liquid Chromatographic Determination of Vitamin D in AD Concentrates: Collaborative Study
Authors: De Vries Ellen J , Borsje Ben
Published: February 2020

A simplified liquid chromatographic (LC) method for determining vitamin D in vitamin AD concentrates (> 5000 IU vitamin D/g) was collaboratively studied. In the simplified method, the 2 columns specified in AOAC LC method 43.101-43.109 are replaced by a single column, which separates the vitamin D isomers and the vitamin A esters. The procedure for oils includes dissolution and quantitation by normal phase LC. Dry multivitamin concentrates and aqueous dispersions are treated with an enzyme system and the vitamins are extracted with n-pentane. Six coded samples were distributed to 16 laboratories; 15 collaborators returned their results. Estimates of repeatability and reproducibility for the oil samples were 1.1 and 3.1%, respectively; for the high-level concentrated dry preparation 1.4 and 3.9% and for the low-level concentrated dry preparation 1.3 and 11.4%, respectively. These values are a considerable improvement over the results obtained in the 1979 multivitamin collaborative study. The method has been adopted official first action for determination of vitamin D in vitamin AD concentrates containing s 5000 IU vitamin D/g.
Ruggedness Testing of the Official Method for Rot Fragments in Comminuted Tomato Products
Authors: Russell Gerald E
Published: February 2020

The official AOAC method for rot fragments in comminuted tomato products (44.224) has been revised on the basis of Youden's ruggedness testing procedures to provide better control over the sources of variability. Two sets of ruggedness tests were carried out to evaluate the type of balance used to weigh the sample, amount of stain, staining time, sieve design, technique used to transfer stained material from beaker to sieve, washing technique used to accumulate stained material at edge of sieve, diameter of eye dropper used to transfer sample from sieve to graduated tube, number of 0.5 mL portions examined, and magnification used to examine prepared slides. A 3-way analysis of variance conducted on amount of stain, transfer technique, and washing technique showed that the transfer and washing techniques were significant areas of variability.
Simultaneous Gas Chromatographic Determination of Carboxylic Acids in Soft Drinks and Jams
Authors: Tsuda Taizo , Nakanishi Hiroshi , Morita Takashi , Takebayashi Junko
Published: February 2020

A method was developed for simultaneous gas chromatographic determination of sorbic acid, dehydroacetic acid, and benzoic acid used as preservatives, and succinic acid, fumaric acid, malic acid, and tartaric acid used as acidulants in soft drinks and jams. A sample was dissolved in NH4OH-NH4CI pH 9 buffer solution, and an aliquot of the solution was passed through a QAE-Sephadex A 25 column. The column was washed with water, and the carboxylic acids were eluted with 0.1N HC1. Sorbic acid, dehydroacetic acid, and benzoic acid were extracted with ethyl ether-petroleum ether (1 + 1), and determined on a 5% DEGS + 1% H3PO4 column. Succinic acid, fumaric acid, malic acid, and tartaric acid in the lower layer were derivatized with N,0- bis(trimethylsilyl)acetamide and trimethylchlorosilane, and determined on a 3% SE-30 column. Recoveries from soft drink and jam samples fortified with 0.1% each of 7 carboxylic acids ranged from 92.4 to 102.6% for preservatives, and from 88.1 to 103.2% for acidulants.
Analysis of d-Phenothrin and Its Optical Isomers in Technical Preparations and Formulations
Authors: Doi Tadashi , Sakaue Shigeyuki , Horiba Masao
Published: February 2020

The content of d-phenothrin in technical preparations was determined by gas chromatography (GC) on a column of 2% PEG-20M or 2% DEGS, using suitable internal standards. The cis- and trans-isomers were separated from each other and determined on a 2% QF-1 column. The 4 optical isomers of rf-phenothrin were hydrolyzed in alkaline conditions to liberate chrysanthemic acid, which was derivatized to diastereoisomeric </-2-octyl esters, and the isomer ratio was determined by GC. The 4 optical isomers were also separated from one another directly on a chiral Sumipax OA-2000 column by liquid chromatography (LC). Also, after the propellant gas in an aerosol formulation was released, and the remaining liquid was analyzed using the same GC conditions as those used for technical preparations
Impurity Problems in Chromatographic Method Studies for Fenthion Formulations
Authors: Boyd Willard G
Published: February 2020

Several gas chromatographic (GC) methods for analyzing fenthion were studied, and flame ionization detection, a glass column packed with SE-52 on Chromosorb GHP, and on-column injection were selected as parameters. No suitable internal standard was found because of coeluting, bias-producing impurities in fenthion. Several liquid chromatographic (LC) methods were also studied, and UV detection, a Zorbax ODS column, and a methanol-water-H3P04 mobile phase were finally selected as parameters. Dipentyl phthalate was selected as internal standard. After testing, this LC method was submitted for collaborative study. During the collaborative study, the manufacturer found an impurity, 3-methyl-4-(methylthio)anisole, co-eluting with fenthion in the collaborative method. The manufacturer's method was then evaluated as an alternative for collaborative study, but a significant unidentified impurity from the formulation blank, used for formulating emulsifiable concentrates, was also found co-eluting with fenthion. The anisole impurity was verified by LC, and the presence of the S-isomer and bis-methylthio-fenthion impurities was found by gas chromatographic- mass spectrometric (GC-MS) analyses. An anisole material obtained from Mobay was also verified by GC-MS analysis. Several other impurities were identified from literature references and from private communication with the manufacturer.
Rapid Liquid Chromatographic Determination of Patulin in Apple Juice
Authors: Forbito Pedro Rafael , Babsky Norma Elena
Published: February 2020

A rapid method is described for the quantitative determination of patulin in apple juice. The mycotoxin is extracted from the sample with ethyl acetate and the extract is cleaned up by extraction with a sodium carbonate solution. Patulin is determined by reverse phase liquid chromatography using a μ.Bondapak C18covery is >75%.
Liquid Chromatographic Determination of a-Zearalenol and Zearalenone in Corn: Collaborative Study
Authors: Bennett Glenn A , Shotwell Odette L , Kwolek William F
Published: February 2020

The liquid chromatographic determination of a-zearalenol and zearalenone in corn was collaboratively studied. Each of 13 collaborators received 7 corn samples; 2 were blanks and 5 were spiked to contain 50, 100, and 200 ng α-zearalenol/g and 50, 100, 500, 1000, and 4000 ng zearalenone/g. Four sets (including blanks) of blind duplicates were included in the study. Five naturally contaminated corn samples (one in duplicate) were also provided. AH collaborators detected both mycotoxins at 50 ng/g. Average recoveries reported by all collaborators ranged from 81.9% at 200 ng/g to 100.3% at 50 ng/g for a-zearalenol and from 77.8% at 1000 ng/g to 123% at 50 ng/g for zearalenone. Three collaborators reported false positives for both a-zearalenol and zearalenone. The within-laboratory CV values based on blind duplicates were 22.6% for α-zearalenol and 31.4% for zearalenone. The CV values based on laboratory-sample interaction were 25.6 and 33.8% for α-zearalenol and zearalenone, respectively. The CV values for naturally contaminated samples (including duplicates) were 47.0% for a-zearalenol and 37.7% for zearalenone. The method has been adopted official first action.
National Bureau of Standards Reference Materials as Organic Nutrient Standards: A Preliminary Study
Authors: Tanner James T , Smith Jeffrey S , Angyal Gerald , Defibaugh Phillip W , Villalobos Melina C , Bueno Martin P
Published: February 2020

A preliminary study was conducted to determine if the available National Bureau of Standards (NBS) Standard Reference Materials (SRM) Non- Fat Powdered Milk, Oyster Tissue, Wheat Flour, Rice Flour, Spinach, and Albacore Tuna would be suitable for use as organic nutrient standards. These materials were assayed for folates, total pantothenates, vitamin B6, thiamine, riboflavin, niacin, and protein. Vitamins A, E, D, K, and C were also assayed but, for the most part, were not detected. Based on results from this study, it appears that at least some of the NBS SRMs would be useful as organic nutrient standards.
Purge and Trap Method for Determination of Ethylene Dibromide in Whole Grains, Milled Grain Products, Intermediate Grain-Based Foods, and Animal Feeds
Authors: Heikes David L
Published: February 2020

An improved method has been developed for the determination of ethylene dibromide (EDB; 1,2-dibromoethane) in whole grains, milled grain products, intermediate grain-based foods, and animal feeds. Samples are mixed with water and sparged with nitrogen for 1 h with stirring in a water bath at 100°C. The EDB collected on the adsorbent Tenax TA is eluted with hexane and determined by gas chromatography (GC) with electron capture detection (ECD) and confirmed with Hall electrolytic conductivity detection (HECD) using a second GC column. The highest levels of EDB were also confirmed by full scan GC/mass spectrometry (GC/MS). A total of 24 whole grains, milled grain products, intermediate grain-based foods, and animal feeds analyzed by using this method contained EDB levels up to 840 ppb (wheat). Recoveries from fortified samples ranged from 90 to 105%. Values from this method were compared with those obtained from the acetone soak method; for all 24 samples, this purge and trap method gave equivalent or superior recoveries and detected levels of EDB. Chromatograms for this purge and trap method were clean, enabling a quantitation level of 0.5 ppb to be achieved.
Simultaneous Liquid Chromatographic Determination of Warfarin and Sulfaquinoxaline in Cornmeal-Based Rodenticide
Authors: Akhtar Selina , Bailey Leonard C
Published: February 2020

A method is reported for the simultaneous determination of warfarin and sulfaquinoxaline in a cornmeal-based commercial rodenticide by extraction of the 2 components with acetonitrile followed by liquid chromatographic separation. A reverse phase C-18 column is used with a simple buffered mobile phase (acetonitrile-water (50 + 50) 0.005M inheptanesulfonic acid sodium salt, pH 3.5) that elutes sulfaquinoxaline as a paired-ion and warfarin as an ion-suppressed non-ionic species. The 2 compounds are detected at 280 nm after separation and are quantitated using ethyl p-nitrobenzoate as an internal standard. The method compares favorably with existing methods of analysis for the 2 compounds in terms of accuracy and precision, and is superior to those methods in speed as well as specificity.