bluuebunny/crossref_metadata_2025 huggingface dataset:
Net Protein Ratio Data: AACC-ASTM Collaborative Study
Authors: Happich Muriel L , Bodwell C E , Ross Hackler L , Phillips John G , Derse Philip H , Elliott Elliott G , Hartnagel Ralph E , Hopkins Daniel T , Kapiszka Eugene L , Mitchell Geraldine V , Parsons Grace F , Prescher Elmer E , Robaidek Eugene S , Womack Madelyn
Published: February 2020

Seven- and 14-day net protein ratio (NPR) data were obtained from 7 laboratories for 6 protein sources: ANRC casein, lean beef, Iactalbumin, textured vegetable protein, and peanut flour were fed as 10% protein (N × 6.25) in the test diet. Wheat flour, casein, and textured vegetable protein were fed as 6% protein (N × 6.25) in the test diet. Weighed dry ingredients for each diet were sent to each collaborator, who mixed the dry ingredients, then added specified amounts of corn oil and water and mixed each complete diet thoroughly. Rats were adapted for 0, 2, or 4 days, and then were fed the test diets for 28 days for protein efficiency ratio (PER) diets. The animal weight gain and feed consumption data obtained after 7 or 14 days of feeding were used to calculate NPR values. Analyses of data were done before [net protein ratio (NPR)] and after (R-NPR [relative-NPR]) adjustment of the data from each laboratory by its results for the reference protein casein. From the analysis of variance for NPR, significant (P <0.05) interactions were observed among laboratories, protein sources, and adaptation times of the animals (0,2, or 4 days). Inter- and intralaboratory variability were decreased by use of 14-day values compared with 7- day values. Adjustment of the NPR data to R-NPR did not lower the intralaboratory variability but did lower the interlaboratory variability of the data. Increasing adaptation time did not consistently decrease interlaboratory or intralaboratory variability or decrease coefficients of variation (CV) of R-NPR values. The 14-day NPR inter- and intralaboratory variations for the 10 % protein diet over all factors (5 protein diets, 3 adaptation periods, and 7 laboratories), as measured by CV values, were 13.2 and 7.7%, respectively. The corresponding R-NPR values were 9.2 and 8.0%, respectively.
Gas Chromatographic Determination of Ametryn and Its Metabolites in Tropical Root Crops
Authors: Bardalaye Promode C , Wheeler Willis B
Published: February 2020

Residue analysis of the herbicide ametryn (2-methyIthio-4-ethylamino-s-isopropylamino-s-triazine) is widely known but an analytical method for determining its metabolites has not yet been reported in the literature. A method has been developed for the extraction and determination of ametryn and 3 metabolites, 2-methylthio-4-amino-6-isopropylammo- s-triazine (GS-11354), 2-methylthio-4,6-diamino-.s-triazine(GS- 26831), and 2-methylthio-4-amino-6-ethylamino-s-triazine (GS-11355) in taniers, yams, cassava. Residues were extracted from crops with ethyl acetate-toluene (3 + 1 v/v), using a Polytron homogenizer and anhydrous sodium sulfate added for drying. The extracts were cleaned up by automated gel permeation chromatography on Bio-Beads SX-3 gel in the same solvent system. Quantitative determination was performed by gas chromatographic (GC) analysis on a column packed with 5% DEGS-PS on 100-120 mesh Supelcoport using either an N-P detector or a flame photometric detector (FPD) in the sulfur mode. Minimum detection by the flame photometric detector is 10 ng each for ametryn, GS-11354, and GS-11355 and 21 ng for GS-26831; by the N-P detector, 0.3 ng of each component gives easily quantitatable peaks. On a parts per million basis, starting with 25 g sample, the FPD detected a minimum level of 0.04 p.g/g each for ametryn, GS-11354, and GS-11355, and 0.08 p.g/g for GS-26831. The N-P detector could detect 0.0024 p.g/g for all 4 compounds. In addition to superior sensitivity, instrumental conditions allowed the complete separation of components in 10 min, for the N-P detector; more than 30 min was required for the FPD. Recoveries from fortified crops ranged from 67 to 111% at levels of 0.1-1.0 μg/g.
Recent Advances in Cleanup of Fats By Sweep Co-Distillation. Part 1: Organochlorine Residues
Authors: Luke Barry G , Richards Jeffrey C , Dawes Ernest F
Published: February 2020

A redesigned fractionation tube has resulted in development of a new, commercial sweep co-distillation unit. It is compact, reliable, costefficient, and permits cleanup of pesticides in up to 10 fat samples simultaneously. Recovery of several organochlorine residues (HCB, ; BHC, lindane, heptachlor epoxide, dieldrin, p,p'-DDE, p,p'-DDD, p,p'-DDT) at ppm and ppb levels in meat (beef) fat are 83-105%, with coefficients of variation between 4 and 6%. Cleaned up extracts are quantitated by gas chromatography using an electron capture detector with a vitreous silica capillary column containing a medium polarity bonded phase.
Liquid Chromatographic Determination of the Plant Estrogens Coumestrol and Isoflavones in Animal Feed
Authors: Pettersson Hans , Kiessling Karl-Heinz
Published: February 2020

A simplified procedure is described for the cleanup and determination of the 5 main plant estrogens in animal feed: coumestrol, genistein, biochanin A, daidzein, and formononetin. The estrogens are extracted with ethanol and purified on a Sep-Pak C18 cartridge. All 5 plant estrogens are separated in an isocratic liquid chromatographic system and quantitated by UV and fluorescence responses. The method is sensitive to about 2.5 ppm coumestrol and 10 ppm of the isoflavones.
Capillary Gas Chromatographic Determination of Pentachlorophenol Residues in Tallow Following Automated Gel Permeation Cleanup
Authors: Lee Barbara E , Lacroix Mario D , Dupont Guy A J , Scott James A
Published: February 2020

A gas chromatographic method for the determination of pentachlorophenol (PCP) in tallow is described. Samples are melted and mixed with the solvent used for automated gel permeation chromatographic (GPC) cleanup. The methyl ether derivative of PCP is prepared by treating the appropriate GPC fraction with an ethereal solution of diazomethane. The extract is further cleaned up on Florisil, and the PCP methyl ether is easily identified and quantified by capillary column gas chromatography (GC) with electron capture detector. The detection limit was 0.001 ppm in tallow. Recoveries varied from 80 to 107% over the fortification range of 0.005–0.05 ppm. Capillary GC-high resolution mass spectrometry is used to confirm PCP methyl ether in the sample extract.
Evidence for Transformation of Sulfamethazine to its N4-Glucopyranosyl Derivative in Swine Liver During Frozen Storage
Authors: Parks Owen W
Published: February 2020

An analytical procedure for determining N4-glucopyranosylsulfamethazine (GPS) in swine livers is described. The sulfamethazine derivative is extracted from the tissues with water. GPS is isolated in sufficient purity for liquid chromatographic determination by a series of adsorption chromatographic procedures. Recovery of the conjugate from spiked swine livers was 82.2% with a coefficient of variation of 4.5%. Evidence is presented suggesting that sulfamethazine in swine livers is transformed to GPS during frozen storage. Two samples of swine liver in which incurred sulfamethazine residues were substantially depleted during frozen storage were analyzed for GPS. The conjugate accounted for 96.2% and 92.2% of the depleted sulfamethazine residues.
Comparison of AOAC and EEC Methods for Determining Available P2O5 in Fertilizer
Authors: Johnson Frank J , Parks Kenneth L
Published: February 2020

Three interlaboratory studies are described in which AOAC method 2.053 was compared with the neutral ammonium citrate method for direct available P2O5 recommended by the European Economic Community (EEC). The initial study comprised 5 laboratories and 7 samples. Significantly more available P205 was found by the AOAC method in 5 of 7 samples tested. Fifteen laboratories analyzed 8 samples in the second study; only 2 samples yielded more P2O5 by the AOAC method. The final study included 9 samples and 14 laboratories. Results for the AOAC method were higher on 4 samples. Conclusions reached from the 3 studies are (1) The AOAC method gave consistently higher values for available P2O5, especially for triple superphosphate samples; and (2) the difference between methods increased with increasing amounts of citrate-insoluble P2O5. All data were reported to the International Standards Organization Working Group on phosphorus in fertilizer.
Apparent Nitrogen Digestibility Data: AACC–ASTM Collaborative Study
Authors: Happich Muriel L , Bodwell C E , Hackler L Ross , Phillips John G , Derse Philip H , Elliott James G , Hopkins Daniel T , Parsons Grace F , Prescher Elmer E , Robaidek Eugene S
Published: February 2020

Apparent nitrogen digestibility data were obtained from 4 laboratories for 6 protein sources and 2 diet levels, 6 and 10% protein, after a 2-day adaptation period during the AACC–ASTM protein efficiency ratio (PER) and net protein ratio (NPR) collaborative studies. For 5 protein sources fed as 10% of the diet, the interlaboratory variation as measured by coefficient of variation (CV) values was low (1.5–3.5%), indicating high precision of the method. Wheat flour (6% protein diet) had the highest variation and, therefore, the lowest precision (CV of 7.10%). The interlaboratory variation (CV value) for 3 of the 4 laboratories was considerably lower, less than half that for the 4 laboratories. An analysis of variance of apparent nitrogen digestibility data indicated significant (P <0.05) effects for the 4-Iaboratory group due to laboratories and protein diets at both 10 and 6% protein levels, and for the 3-laboratory group at the 10% protein level. The 3-laboratory ANOVA for the 6% diets indicated a significant effect (P <0.05) due to diet only.
Performance Characteristics of Methods of Analysis Used for Regulatory Purposes. I. Drug Dosage Forms. B. Gas Chromatographic Methods
Authors: Horwitz William , Albert Richard
Published: February 2020

Gas chromatographic methods for the analysis of drug dosage forms consist of a simple extraction, dilution with an internal standard solution, and injection, or, even simpler, dilution with the internal standard solution and injection. These methods were used in 7 collaborative studies of the determination of 12 pharmaceuticals, published in the Journal of the AOAC during 1973–1983. A total of 43 individual materials consisting of various dosage forms were each analyzed, usually in duplicate, by an average of 8 laboratories, with a total of 582 reported determinations. The average within-laboratory coefficient of variation (CVo) was 1.25% and the average among-laboratories coefficient of variation (CVx) was 2.41%, for a CVo/CVx ratio of 0.52, at an average outlier rate of 1.4% of the reported values. The line of best fit for CVx plotted against concentration increases with decreasing concentration, extending from a CVx of approximately 1.8% at 100% concentration to a CVx of approximately 3.2% at 1% concentration. The change in CVx for a 10-fold decrease in concentration is approximately 0.7% CVx, independent of analyte and matrix.
Injection–Extraction Procedure for Rapid Determination of Relative Pungency in Fresh Jalapeño Peppers
Authors: Rymal Kenneth S , Cosper Richard D , Smith Durward A
Published: February 2020

A unique injection-extraction procedure allowing the direct spectrophotometric determination of relative pungency of fresh Jalapeño pepper is described. Intact pepper pods were injected with absolute methanol, using a hypodermic syringe. After 30 min, pods were flushed with additional methanol, and capsaicinoids in the extract were determined by absorbance at 275 nm. Mean percent recovery was 66.5%, sx = 3.43. The method eliminates the time consuming chromatographic cleanup needed with other spectroscopic methods.
Polarographic and Colorimetric Methods for Determination of Cyclophosphamide
Authors: Ellaithy Moustafa M , El-Tarras M Fayez , Tadros Nabil B , Amer Mohamed M
Published: February 2020

Polarographic and colorimetric methods for analysis of cyclophosphamide and its dosage forms were investigated. Both methods are based on the reaction of cyclophosphamide with nitrous acid. A single cathodic diffusion-controlled wave was used for dc polarographic determination of cyclophosphamide, with an accuracy of 99.98 ± 1.09%. The wave was well defined and irreversible. By differential pulse polarographic analysis, as little as 10 ppm cyclophosphamide was determined; overall accuracy at 10-60 ppm was 100.16 ± 0.99%. The linear relationship between absorbance for the lemon-yellow nitroso derivative and the concentration of cyclophosphamide was further used in colorimetric analysis; overall accuracy was 100.2 ± 0.99%.
Liquid Chromatographic Determination of Primary and Secondary Amines as 8-Quinolinesulfonyl Chloride Derivatives
Authors: Noggle F Taylor , Clark C Randall
Published: February 2020

The normal phase and reverse phase liquid chromatographic properties of seven 8-quinolinesulfonyl derivatives of primary and secondary amines are examined using dual wavelength ultraviolet detection. The amines are further identified by infrared spectrophotometry with emphasis on structural elucidation based on absorption bands at characteristic wavelengths.
Liquid Chromatographic Method for Quantitative Determination of Free Fatty Acids in Butter
Authors: Reed Alan W , Deeth Hilton C , Clegg Donald E
Published: February 2020

A liquid chromatographic method has been developed for the determination of free fatty acids in butter. The fatty acids are converted to the p-bromophenacyl esters, via a crown ether-catalyzed reaction, without separation from the other butter components. The esters are separated on a Cis-bonded silica column by using an acetonitrile-water solvent gradient and quantitated using the ester of heptadecanoic acid as internal standard. Cu, and C ,S:i co-elute in the acetonitrile-water system but are separated using an isocratic methanol-acetonitrile-water system. Limits of detection range from 7 ng for butyric acid to 45 ng for linoleic acid. The average coefficient of variation (n = 10) for 10 free fatty acids from,a butter was 5.83%.
Liquid Chromatographic Determination of Aflatoxin M1 in Milk
Authors: Tyczkowska Krystyna , Hutchins James E , Hagler Winston M
Published: February 2020

The official AOAC method for aflatoxin M, in milk was modified by replacing cellulose column chromatography with cartridge chromatographic cleanup and replacing thin layer chromatographic (TLC) determination with liquid chromatographic (LC) quantitation to yield a new method for bovine and porcine milk. An acetone extract of milk is treated with lead acetate and defatted with hexane, and M1 is partitioned into chloroform as in the AOAC method. Chloroform is removed by evaporation under a stream of nitrogen at 50°C. The residue is dissolved in chloroform, the vessel is rinsed with hexane, and the 2 solutions are applied in sequence to a hexane-activated silica Sep-Pak cartridge. Less polar impurities are removed with hexane-ethyl ether, and M1 is eluted with chloroform-methanol, and determined by C18 reverse phase LC using fluorescence detection. Recoveries of M, added to bovine milk at 0.25, 0.50, and 1.0 ng/mL were 90.8, 93.4, and 94.1%, respectively. The limit of detection was less than 0.1 ng M,/mL for both bovine and porcine milk.
Liquid Chromatographic Determination of Sodium Saccharin, Caffeine, Aspartame, and Sodium Benzoate in Cola Beverages
Authors: Tyler Theodore A
Published: February 2020

A rapid method has been developed for the determination of sodium saccharin, caffeine, aspartame, and sodium benzoate in cola beverages. The sample is degassed, diluted in water, and injected onto a C18 column. The mobile phase consists of 15% acetonitrile in triethylammonium phosphate buffer adjusted to pH 4.3 with NaOH. The total run time is less than 10 min and the active compounds are determined using absorbance detection at 214 nm.
Simple and Rapid Portable Chromatographic Method for Separation and Detection of Phenylmercuric Acetate in Seeds and Water
Authors: Devi Yalavarthy Prameela , Nanda Kumar Nanguneri V
Published: February 2020

Phenylmercuric acetate can be detected by horse liver acetone powder succinate dehydrogenase inhibition, using a mixture of 2-(4-iodophenyl)- 3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT), sodium succinate, and N-methylphenazonium methosulfate as the chromogenic reagent. The simple cleanup involves extraction of phenylmercuric acetate in chloroform and concentration by evaporation. In the extract, the compounds in seeds or water could be separated and identified by paper chromatography in the field or laboratory at microgram levels with an acetone-water (70 + 30) solvent system.
Monocrotophos and Dicrotophos Residues in Birds as a Result of Misuse of Organophosphates in Matagorda County, Texas
Authors: Flickinger Edward L , White Donald H , Mitchell Christine A , Lamont Thair G
Published: February 2020

About 1100 birds of 12 species died from organophosphate poisoning in Matagorda County on the Texas Gulf Coast in March and May 1982. Birds died from feeding on rice seed that was illegally treated with dicrotophos or monocrotophos and placed near rice fields as bait to attract and kill birds. Brain acetylcholinesterase inhibition of affected birds averaged 87% (range 82-89%), and contents of gastrointestinal tracts contained residues of dicrotophos (5.6-14 ppm) or monocrotophos (2.1-13 ppm). Rice seed collected at mortality sites contained 210 ppm dicrotophos or 950 ppm monocrotophos. Mortality from dicrotophos poisoning continued for almost 3 weeks. The practice of illegally treating rice seed with either of these 2 organophosphates appears to be infrequent but widespread at present.
Some Effects of Replacement of Metaphosphoric Acid/Acetic Acid Solvent System with Trichloroacetic Acid in Microfluorometric Determination of Vitamin C
Authors: Visser Frans R
Published: February 2020

Trichloroacetic acid (TCA) is suggested as a substitute for the metaphosphoric acid/acetic acid (HPO3-HOAc) solvent system in the AOAC microfluorometric determination of vitamin C. Comparative advantages of TCA are easier handling, greater stability, and the approximate 10-fold increase in sensitivity. For both solvent systems, the influence of acid concentration on fluorescence is described. TCA provides maximum fluorescence enhancement at pH 5.5-6.0.
Potassium Interferences in Flame Emission Method for Determining Sodium in Fertilizers
Authors: Corominas Luis F , Navarro Roberto A , Lopez Ruben J
Published: February 2020

Several sodium concentrations ranging from 5.2 to 20 ppm at K:Na ratios ranging from 0 to 40 were studied to determine potassium interferences in the AOAC official first action method, 2.147-2.150, for flame emission spectrophotometric (FES) determination of sodium in fertilizers. According to an analysis of variance performed with recoveries of sodium in solution, potassium interference is the same at low (5.2 ppm) or high (20 ppm) sodium concentrations but is different when the K:Na ratio is changed. A Duncan test showed that potassium interference is equivalent only in the adjacent ratios studied (0, 1, 2, 5, 10, 20, 40) and not for larger ranges. We obtained an average recovery of 98.8% using a calibration curve for a K:Na ratio from a preliminary determination with a calibration curve without potassium content. It is essential to know the potassium content of the sample to enable preparation of a calibration curve for correction. We recommend a collaborative study of NPK samples to determine whether to modify the FES method.
Determination of Ammoniacal and Total Nitrogen in Fertilizers by Ammonia-Selective Electrode
Authors: Navarro Roberto A , Rojas Pedro
Published: February 2020

A method was studied for determining ammoniacal nitrogen in fertilizers by using an ammonia-selective electrode. Recovery for the method was evaluated with synthetic samples, and the method was also compared with the magnesium oxide method by analyzing 3 Magruder Check Samples. The method was adapted to determine total nitrogen in fertilizers by using the digestion procedure of the modified comprehensive nitrogen method and eliminating metal interferences by forming soluble complexes with tartaric acid. Recovery was evaluated and a comparison with AOAC official methods was made by performing a /-test on results for 3 Magruder Check Samples. Recoveries were good for determinations of both ammoniacal and total nitrogen by the method described, and results were not significantly different from those for AOAC methods.
Recent Advances in Cleanup of Fats by Sweep Co-Distillation. Part 2. Organophosphorus Residues
Authors: Luke Barry G , Richards Jeffery C
Published: February 2020

This paper describes the isolation of 5 organophosphorus residues in beef fat by a commercial sweep co-distillation unit (Unitrex). The operating conditions specified 233°C and nitrogen flow at 230 niL/min. Recoveries of chlorpyriphos, monodechlorchlorpyriphos, bromophosethyl, debromobromophos-ethyl, and ethion ranged from 84 to 99%, with coefficients of variation between 3 and 5%.
Liquid Chromatographic Determination of Adulteration of Sesame Oil
Authors: Han Li Ming , Adams James M
Published: February 2020

A liquid chromatographic (LC) procedure is presented for quantitative determination of adulteration of sesame oil with soybean oil. A portion of the oil is dissolved in chloroform, diluted in the eluant 2-propanolacetone- methanol-acetonitrile (1 + 2 + 3 + 4), and subjected to reverse phase LC. A linear calibration curve is prepared by chromatographing known mixtures of the 2 oils and plotting the volume percent of sesame oil against the peak height ratio of a selected pair of peaks. The relative standard deviation, based on 4 determinations of each of 8 sample mixtures, is less than 2.5% and the correlation coefficient is 99%. Because the LC curve for a given vegetable oil is characteristic and reproducible, the procedure can be extended to detect the adulteration of sesame oil with oils other than, or in addition to, soybean oil. An example of adulteration with rapeseed oil, in addition to soybean oil, is discussed.
Gas Chromatographic Determination of Clopidol in Chicken Tissues
Authors: Lars-Gösta Ekström , Kuivinen Jorma
Published: February 2020

A method has been developed for the determination of clopidol residues in chicken tissues. After extraction and cleanup, clopidol is esterified in a 2-phase system to clopidol propionate, which is determined by gas chromatography. The 2-phase system includes, in addition to the clopidol dissolved in methanol, aqueous borax solution, hexane, propionic anhydride, and pyridine. Use of these reagents precludes the use of explosive or carcinogenic chemicals in the derivatization step, and the method is therefore suitable for routine laboratory analysis. Levels of 0.5 ppb clopidol in tissue can be determined.
Mycotoxins in Grain Dust: Method for Analysis of Aflatoxins, Ochratoxin A, Zearalenone,Vomitoxin, and Secalonic Acid D
Authors: Ehrlich Kenneth C , Lee Louise S
Published: February 2020

A multimycotoxin method is presented to quantitate aflatoxins, ochratoxin A, zearalenone, secalonic acid D, and vomitoxin in grain dust. Dust spiked with these mycotoxins was extracted sequentially with methylene chloride followed by acetonitrile-water (86 + 14). Vomitoxin was recovered in the latter extract and all other mycotoxins were recovered in the methylene chloride. Aflatoxins and ochratoxin were quantitated by fluorescence measurement on silica thin layer chromatographic plates. The other mycotoxins were quantitated after cleanup by reverse phase liquid chromatography and ultraviolet detection. Recoveries from dust spiked in the parts per billion (ng/g) range were approximately 80% (SD = 15-29%) for all mycotoxins. Minimum detectable amounts ranged from less than 0.5 ng/g for aflatoxins to 20 ng/g for zearalenone.
Rapid, Sensitive Liquid Chromatographic Method for Determination of Zearalenone and α- and β-Zearalenol in Wheat
Authors: Trenholm H Locksley , Warner Robert M , Fitzpatrick Dennis W
Published: February 2020

A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and α- and β-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanolchloroform( 2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and α-zearalenol standards on the fluorescence detector and 4 ng for β-zearaIenol on the UV detector, which is equivalent to 20 μg zearalenone and 20 μg α-zearalenol/kg, and 160 μg β-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and α-zearalenol on the fluorescence detector and 0-50 ng β-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).
Determination of Histamine in Fish by Liquid Chromatography with Post-Column Reaction and Fluorometric Detection
Authors: Walters Milda J
Published: February 2020

A liquid chromatographic (LC) system, using a bonded cation-exchange column, resolves histamine from histidine and other related compounds. Detection sensitivity and specificity are enhanced by introduction of a post-column reaction with o-phthalaldehyde to form a fluorescent derivative. The limit of detection is 1.5 ng histamine, and the response is linear over a range of 7-750 ng. The average histamine recovery from fortified tuna and mahimahi samples was 98.4% with a relative standard deviation of 2.18%. The results for canned tuna and mahimahi were comparable to those obtained by using the official AOAC method. The LC method requires only simple extraction of the sample before introduction into the LC system, which resolves and detects cadaverine and putrescine in addition to histamine.
Detection of Adulteration in Grated Cheese by Using Calcium, Phosphorus, Magnesium, and Lactose Indices
Authors: Pollman Roger M
Published: February 2020

Calcium, phosphorus, and magnesium levels and calcium/phosphorus and calcium/magnesium ratios were determined for 74 authentic cheeses. Lactose was determined for 40 authentic grating cheeses. Phosphorus was measured by an AOAC method, calcium and magnesium by a modified AOAC atomic absorption method, and lactose by liquid chromatography. The average calcium/phosphorus and calcium/magnesium ratios were 1.55 and 23.3, respectively, and were used with lactose data as criteria for evaluating grated cheese adulteration.
Improved Gas Chromatographic Method for Quantitation of Deoxynivalenol in Wheat, Corn, and Feed
Authors: Terhune Stuart J , Nguyen Nhieu V , Baxter James A , Pryde Diane H , Qureshi Saeed A
Published: February 2020

A gas chromatographic (GC) method is described to determine deoxynivalenol in wheat and corn at levels as low as 20 ppb. Ground samples are extracted with water, adsorbed onto a Clin Elut column, extracted with ethyl acetate, and passed through a silica gel Sep-Pak cartridge. The final extract is then derivatized with N-heptafhiorobutyrylimidazole and quantitated by GC using an electron capture detector. Recoveries are greater than 85% for spiked samples at levels of 50-1000 ppb. Results for wheat, corn, and mixed feed samples are given as well as the results of an interlaboratory study on a naturally contaminated wheat sample.
Development of a Quality Assurance Program for Determination of Ultratrace Background Levels of Lead and Cadmium in Raw Agricultural Crops by Differential Pulse Anodic Stripping Voltammetry
Authors: Satzger R Duane , Bonnin Evelyn , Fricke Fred L
Published: February 2020

Data on the background levels of lead and cadmium in the food supply are essential in order to establish a baseline from which to evaluate the extent of contamination in transport, processing, industrial atmospheric particulate fallout, and soil treatment (e.g., fertilizers, sewage sludge, etc.). This requires the establishment of site selection and sampling criteria as well as the development of a rigorous analytical method capable of performing routine analyses of Pb and Cd at ultratrace levels. The method used in this study, which was published previously, was designed to provide high sample throughput with minimal contamination. This involved control and measurement of blank levels and the establishment of quality control procedures to maintain confidence in the accuracy and precision of the method.
Determination of Phosphorus in Processed Cheese: Collaborative Study
Authors: Steiger Gerald , Horwitz William , Poortvliet Lambrecht J , Soderhjelm Petter
Published: February 2020

A second interlaboratory collaborative study of the determination of phosphorus in processed cheese products by the molybdenum blue method verifies that this method is prone to producing a laboratoryinduced systematic error. It would be useless to continue to make minor modifications in the details of the method, which will improve only the within-laboratory precision, until an accuracy control of the final measurement step is incorporated into the method.
Comparison of Carr-Price Analysis and Liquid Chromatographic Analysis for Vitamin A in Fortified Milk
Authors: Mills Robert S
Published: February 2020

The determination of the vitamin A concentration in fortified milk was compared using Carr-Price analysis and liquid chromatography (LC). Carr-Price analysis required saponification of the sample with alcoholic potassium hydroxide, extraction with ether, and colorimetry with antimony trichloride in chloroform. LC analysis required hexane extraction of a 71% alcohol-sample solution and centrifugation at 2000 rpm. A 100 μL aliquot of the extract was analyzed on a LiChrosorb Si-60, 5 μm column, using an ethyl ether-hexane (2 + 98) mobile phase and detection at 313 nm. Each method was statistically evaluated for precision and sample-to-sample reproducibility. The LC extraction procedure was examined for efficiency. Each LC value was divided by the Carr-Price value obtained for the same sample; an average value of 0.975 with a coefficient of variation of 6.90% was obtained. It was concluded that the procedures were statistically equivalent.
Gas Chromatographic Determination of Picloram in Fish
Authors: Rieger Allan W , Muir Derek C G , Hendzel Marilyn R
Published: February 2020

A simple method for determining picloram in fish is described. The sample is homogenized with ethyl acetate, acidified with IN HC1, and extracted twice more with ethyl acetate. Ethyl acetate fractions are pooled, derivatized with diazomethane, cleaned up by column chromatography, and analyzed by electron capture gas chromatography. Rainbow trout exposed to I4C-picloram were used to evaluate the efficiency of 2 methods of extraction* and to provide data on the rate of uptake and the bioconcentration factor. The detection limit for this method is 5 ng/g, using a 4 g sample
Simple Colorimetric Method for Determination of Thiamine Hydrochloride in Pharmauceuticals
Authors: Sane Ramesh T , Doshi Vipul J , Jukar Swati , Joshi Sanjay K , Sawant Satish V , Pandit Ulhas R
Published: February 2020

A simple colorimetric method is described for the determination of thiamine hydrochloride (vitamin B,) in dosage forms. The method is based on measurement of a yellow complex formed when thiamine HC1 is treated with /7-methylaminophenol sulfate (Metol) under alkaline conditions. Compounds such as vitamins A, B2, B6, B,2, C, D, and E, and niacinamide, citric acid, liquid glucose, calcium pantothenate, biotin, liver extract, and folic acid do not interfere in the reaction. Extracting the complex into chloroform before quantitation enhances the stability of the reaction product and removes interference of watersoluble colored constituents in syrup samples. Statistical validation shows that the method is precise and accurate. Results agree well with those obtained by other methods in the literature
Colorimetric Determination of Stanozolol in Pharmaceutical Formulations
Authors: Shingbal Dattatray M , Barad Uday G
Published: February 2020

In acidic medium, stanozolol reacts with phenoldisulfonic acid to form a stable yellow chromophore, which is quantitated by spectrophotometry at 385 nm. The reaction gives a linear response at concentrations from 5 to 50 μg/mL. The method is suitable for routine analytical control of stanozolol and its formulations.
Assay of Calcium Borogluconate Veterinary Medicines for Calcium Gluconate, Boric Acid, Phosphorus, and Magnesium by Using Inductively Coupled Plasma Emission Spectrometry
Authors: Lyons David J , Spann Kelvin P
Published: February 2020

An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are ± 1.4% (calcium), ± 1.8% (boron), ± 2.6% (phosphorus), and ± 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.
Capillary Gas Chromatographic Determination of Technical Chlordane in Emulsifiable Concentrates and Aqueous Dilutions
Authors: Stringham Rodger W , Schulz Ray P
Published: February 2020

Technical chlordane is extracted in acetone, diluted with hexane, and determined via capillary gas chromatography with electron capture detection. Quantitation is based on the sum of areas or heights of 6 well resolved major peaks. The method was tested for precision, linearity, recovery, and applicability to aqueous dilutions of emulsifiable concentrate formulations. Comparison of quadruplicate analysis of 5 formulations by this method with the AOAC official titrimetric method gave average relative standard deviations of 1.4 and 0.9 %, respectively. Results were comparable for the 72% formulations, but were lower using this method for the 45% samples. Linearity and recovery were excellent (regression coefficient = 0.9996, recovery = 100.7%). Application of this method to aqueous dilutions was simple and resulted in an average recovery of 97%. The method is faster, safer, and more specific than the AOAC titrimetric method.
Rapid Reverse Phase Liquid Chromatographic Determination of Aflatoxin M1 in Milk
Authors: Yousef Ahmed E , Marth Elmer H
Published: February 2020

A rapid, economical, and reliable liquid chromatographic (LC) method is described for determination of aflatoxin M, in milk. The method includes an improved AOAC extraction procedure, cleanup of the extract on a silica cartridge, and LC quantitation. Alternatively, a rapid column cleanup procedure can be used. Milk artificially spiked with aflatoxin M1 at 0.05, 0.1, and 0.5 ppb was analyzed using both new approaches as well as an AOAC method coupled with LC for quantitation of the toxin. Recovery of aflatoxin M1 by the first approach of the new method ranged between 93.4 and 99.1%, and for the alternative procedure between 92.4 and 96.8%. The AOAC method gave lower recovery (85.6-90.7%) of toxin, but the results from this method had a somewhat smaller standard deviation for replicate analyses than did results of the new method.
Rapid Quantitative Method for Simultaneous Determination of Benzoic Acid, Sorbic Acid, and Four Parabens in Meat and Nonmeat Products by Liquid Chromatography
Authors: Ali Sher M
Published: February 2020

A liquid chromatographic (LC) method for the simultaneous determinations of benzoic acid, sorbic acid, and methyl, ethyl, propyl, and butyl parabens (methyl, ethyl, propyl, and butyl-p-hydroxybenzoates) in meat and nonmeat products was developed. Benzoic acid, sorbic acid, and parabens were extracted from meat and nonmeat products with 70% ethanol. After filtration, extracts were analyzed by reverse phase liquid chromatography. Homogeneously ground samples of fresh sausage and hamburger were fortified with benzoic acid, sorbic acid, and each paraben at 5 different concentrations. Average recovery (after discarding outliers) for each preservative at all 5 levels was greater than 95% with a coefficient of variation less than 5%.
Methods of Analysis for Infant Formula: Food and Drug Administration and Infant Formula Council Collaborative Study
Authors: Tanner James T , Barnett Stephen A
Published: February 2020

Because the U.S. Infant Formula Act of 1980 requires manufacturers to produce formula containing a specific minimum amount of nutrients, it became necessary to establish analytical methods for the nutrients listed in the Act. The Food and Drug Administration, the Infant Formula Council, its member companies, contract laboratories, and other government laboratories undertook a collaborative study of available methods; the specific nutrients studied to date include vitamins A, B6, C, riboflavin, and niacin, and the elements calcium, magnesium, iron, zinc, copper, manganese, sodium, and potassium. The coefficients of variation in most cases have been as good as those that could be predicted from other collaborative studies. The methods studied for these nutrients have been adopted official first action except the method for vitamin A.
Quantitation of Indomethacin, Naproxen, and Ibuprofen in Pharmaceutical Dosage Forms by First and Second Derivative Ultraviolet Spectrometry
Authors: Mahrous Mohamed S , Abdel-Khalek Magdi M , Abdel-Hamid Mohamed E
Published: February 2020

First and second derivative ultraviolet spectrometric methods are described for the estimation of indomethacin, naproxen, and ibuprofen in pharmaceutical dosage forms. The proposed methods permit the rapid, precise, and accurate determination of indomethacin capsules BP, naproxen capsules, and ibuprofen tablets BP. Matrix interference is successfully corrected. The results obtained by first and second derivative techniques are in accord with those obtained by the official assay method.
Liquid Chromatographic Determination of Organic Nitrogenous Bases in Dosage Forms: A Progress Report
Authors: Walker Samuel T
Published: February 2020

A liquid chromatographic (LC) method has been developed as a general procedure for the assay of the salts of organic nitrogenous bases in a variety of dosage forms. The method uses a nitrile-bonded reverse phase column, a methanol-0.003M ammonium acetate (90 + 10) mobile phase, and photometric detection at 254 nm. The sample is dissolved in the mobile phase and an aliquot is injected through a 20 μL injection loop. Average recovery values for duplicate assays were chlorpheniramine maleate injection 97.8%, chlorpheniramine maleate tablets 99.1%, cyclizine hydrochloride tablets 100.0%, doxylamine succinate tablets 103.3%, mesoridazine besylate tablets 100.4%, pentazocine hydrochloride tablets 103.0%, promethazine hydrochloride injection 98.4%, protriptyline hydrochloride tablets 101.2%, pyrilamine maleate tablets 97.8%, pyrimethamine tablets 100.0%, tripelennamine citrate elixir 100.0%, and tripelennamine hydrochloride tablets 97.2%. Results by this method were in good agreement with those obtained by the USP XX method. This study, which is being continued, will be expanded to include additional drugs.
Gas Chromatographic Determination of Metolachlor in Pesticide Formulations: Collaborative Study
Authors: Gale Thomas G , Hofberg Arthur H
Published: February 2020

A gas chromatographic (GC) procedure for the determination of metolachlor in emulsifiable concentrate formulations containing about 76% active ingredient was collaboratively studied using the matched pair scheme. Metolachlor was extracted from the formulation with acetone containing dipentyl phthalate as the internal standard, chromatographed on OV-101, and detected by flame ionization. Determinations on the 4 samples by 21 government, university, and industrial collaborators using peak area measurements showed within-laboratory repeatability of better than 0.5%. Reproducibility was better than 1% for the formulation. The method has been adopted official first action.
Liquid Chromatographic Determination of Morantel Tartrate in Cattle Feed
Authors: Goras John T , Gauthier Allen R
Published: February 2020

A liquid chromatographic (LC) method is proposed for measuring 0.485-0.970% morantel tartrate in cattle feeds. The drug is leached from feed, diluted, separated from interfering substances on a silica column, and measured in the effluent stream by 313 nm spectrophotometric detection. Two potential degradation products, i.e., m-isomer of morantel tartrate and N-(3-methylaminopropyl)-/ra/w-3-(3-methyl- 2-thienyl)acrylamide, and a related anthelmintic, i.e., pyrantel tartrate, do not interfere. Average recovery of drug from liquid spiked samples and laboratory blends was 98-100% with a maximum coefficient of variation (CV) of 2.3%. Results for pelleted and crumbled commercial scale feeds ranged from 94 to 102% of label claim, with a maximum CV of 1.5%.
Calibration of Skim Milk-Test Bottles
Authors: Hankin Lester , Wickrosk Alphonse , Hornig Lois
Published: February 2020

The method described uses a 250 μL syringe to calibrate skim milktest bottles. Mercury is injected into the bore of the test bottle, and the amount is recorded. The bore of the bottle can contain 100 μL mercury, and those bottles shown to contain between 98 and 102 μL are acceptable for certification.
Negative Ion Chemical Ionization Mass Spectrometric Method for Confirmation of Identity of Aflatoxin B,: Collaborative Study
Authors: Park Douglas L , Diprossimo Vincent , Abdel-Malek Emil , Trucksess Mary W , Nesheim Stanley , Brumley William C , Sphon James A , Barry Thomas L , Petzinger Glenn
Published: February 2020

An interlaboratory study of a negative ion chemical ionization mass spectrometric (MS) confirmation procedure for aflatoxin B1 was conducted in laboratories in the United States, England, and West Germany. Twelve partially purified, dry film extracts from naturally and artificially contaminated roasted peanuts, cottonseed, and ginger root containing varying quantities of aflatoxin B1 were distributed to the participating laboratories. The extracts required additional cleanup before MS analysis, using either an acidic alumina column and preparative thin layer chromatography (TLC) or a 2-dimensional TLC procedure. Recovery of purified aflatoxin B1 was influenced by the degree of recovery of sample from acid alumina and/or the TLC plate and incomplete elution of aflatoxin Bt from silica gel. Factors affecting MS confirmation included the purity and recovery of aflatoxin and MS instrument sensitivity. Aflatoxin Bi identity was confirmed in 19.5, 90.9, and 100% of samples containing <5,5-10, and >10 ng aflatoxin B1/g product, respectively, by solid probe introduction using full mass scans. The MS method has been adopted official first action.
Interlaboratory Variability of Methods Used for Detection of Economic Adulteration in Apple Juice
Authors: Zyren John , Elkins Edgar R
Published: February 2020

Thirteen laboratories participated in a study to determine the interlaboratory variability of 4 methods used to detect economic adulteration in apple juice. The methods included the determination of individual sugars, 5-(hydroxymethyl)-2-furaldehyde, chlorogenic acid, organic acids, and L-malic acid. The coefficients of variation found depended on the method and level of analyte, but were often 5% or less. At this point, the most important test for detecting economic adulteration is the total malic/L-malic acid ratio. Any ratio of 0.9 or less would indicate a nonauthentic sample. The 0.9 ratio represents an addition of 20% synthetic malic acid in the unknown juice sample. A 0.75 ratio would indicate 50% adulteration, while a 0.5 ratio would indicate a totally synthetic juice. Fumaric acid, a minor contaminant in synthetically produced malic acid, shows great promise as an indicator of economic adulteration. The results support the view that the methods are now ready for AOAC collaborative study.
Effect of Cooking on Levels of Ethylene Dibromide Residues in Rice
Authors: Clower Marion , Mccarthy James P , Rains Diane M
Published: February 2020

Two studies were conducted to determine the effect that cooking has on the level of residues of ethylene dibromide (EDB) in rice. In the first study, 4 samples of long and medium grain polished white rice containing 113, 295, 956, and 1568 ppb EDB were cooked according to typical label directions. Three batches of cooked rice were prepared from each sample of polished rice and frozen until analysis; each batch was analyzed in duplicate. EDB levels in all cooked rice samples were <10 ppb. In the second study, conducted jointly by the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA), a sample of medium grain polished white rice containing about 1600 ppb EDB was cooked by each laboratory. Overall average EDB levels in rice analyzed immediately after cooking were 16 and 37 ppb for FDA and EPA, respectively. The corresponding frozen samples contained 8 and 39 ppb EDB. The 2 laboratories exchanged these frozen samples and reanalyzed them to check variability in the analytical procedure. FDA found 49 ppb EDB in the sample cooked by EPA and EPA found 8 ppb EDB in the sample cooked by FDA, thus indicating that analytical methodology was not a major source of variability. The range of EDB levels was therefore attributed to minor differences in the way the rice was cooked or handled immediately after cooking.
Capillary Gas Chromatographic-Mass Spectrometric Determination of Fluoroacetate Residues in Animal Tissues
Authors: Casper Howard H , Mcmahon Terence L , Paulson Gaylord D
Published: February 2020

A method for the quantitative determination of fluoroacetate (FAC) residues in animal tissues is described. The procedure involves tungstic acid extraction, partitioning into ethyl acetate, evaporation of ethyl acetate, derivatization with pentafluorobenzyl bromide (PFB), and analysis of the resulting derivative (PFB-FAC) by capillary gas chromatography- mass spectrometry (CGC-MS) with specific ion monitoring (SIM). The tungstic acid system extracted 96.8 ± 4.2% of the endogenous 14C-1080 residues in rat tissues. Recovery of FAC during the extraction, purification, and derivatization procedures is established by use of a 14-FAC spike. 1,2-Dibromobenzene is used as an internal standard for the CGC-MS analysis. PFB-FAC is identified on the basis of comparative retention times and the relative intensities of m/z 257.9 and 181.0. PFB-FAC is quantitated by comparing the response at m/z 257.9 to a PFB-FAC standard curve. Routine sensitivity of the method allows determination of 10 ppb fluoroacetate in tissue.
Electron Capture Detection-Gas Chromatographic Determination of Diaminotoluenes in Polyurethane Foam as Heptafluorobutyryl Derivativ
Authors: Hirayama Teruhisa , Ono Mayumi , Uchiyama Kazumi , Nohara Motoshi , Fukui Shozo
Published: February 2020

A simple gas chromatographic (GC) method has been developed to determine 2,4- and 2,6-diaminotoluenes in polyurethane foam. Diaminotoluenes were reacted with heptafluorobutyric anhydride in toluene, and the products, bis-heptafluorobutyrates, were determined by GC, using a 3% silicone OV-330 column. The 2,4- and 2,6-diaminotoluenes can be detected as heptafluorobutyryl derivatives by using an electron capture detector at levels of 5 and 2 pg, respectively. Finally, 2.7-3.0 (μg/g of 2,4- and 1.3-1.9 (μg/g of 2,6-diaminotoluene were detected in 3 commercial polyurethane foams.