bluuebunny/crossref_metadata_2025 huggingface dataset:
High Performance Liquid Chromatographic Determination of Aflatoxins in Animal Tissues and Products
Authors: Gregory III Jesse F , Manley Doris
Published: February 2020

A method was developed for the determination of aflatoxins M1, B1, G1, B2, and G2 in animal tissues, meat, eggs, and dairy products by high performance liquid chromatography (HPLC). Previous extraction procedures were modified to optimize the precision and recovery of the method. HPLC is performed isocratically with a 5 μm microparticulate octadecylsilica column and fluorometric detection. The analysis is based on treatment of the purified sample extract or standard with trifluoroacetic acid (TFA) to catalyze the hydration of aflatoxins M1, B1, and G1 to the highly fluorescent M2a, B2a, and G2a derivatives. Analysis by HPLC with and without TFA treatment of the extract provides quantitative and qualitative data. The recovery of added aflatoxins and the precision of the recovery depend on the type of sample; mean coefficient of variation for all recovery values was 19.7±11.0% for the analysis of liver, ground beef, dairy products, and eggs. The method was sensitive, with a detection limit of 0.05+0.10 ng/g for each aflatoxin. This procedure provides an alternative to existing thin layer chromatographic methods for determining aflatoxins in animal tissues and products.
Identification of Cephalosporins. I. Spectroscopic Methods
Authors: Roets Eugéne E , Hoogmartens Jos H , Vanderhaeghe Hubert J
Published: February 2020

The ultraviolet, infrared, and proton magnetic resonance spectra of 16 commercially available cephalosporins were recorded. The spectra are interpreted, and their value for identification is discussed.
Gas-Liquid Chromatographic Determination of Congeners in Alcoholic Products with Confirmation by Gas Chromatography/Mass Spectrometry
Authors: Martin Glenn E , Burggraff James M , Dyer Randolph H , Buscemi Peter C
Published: February 2020

A procedure is described for the separation and determination of the following compounds which are found as congeners in alcoholic products: acetaldehyde, ethyl acetate, methanol, ethanol, n-propanol, isobutanol, n-butanol, acetic acid, and the amyl alcohols (2-methyl-l-butanol and 3-methyl-l-butanol). These compounds were separated by gas-liquid chromatography (GLC) using 5% Carbowax 20M on Carbopack B as the column packing. The results obtained by using this method were compared with those obtained using the present AOAC methods for these compounds. GLC chromatograms show better resolution by the method presented.
Extraction of Thrips and Other Whole or Equivalent Insects from Frozen Blackberries and Raspberries: Collaborative Study
Authors: Dent Russell G ,   Collaborators:, Boese J , Chaput M P , Floyd D , Glaze L E , Nakashima M J , Washbon E C
Published: February 2020

A method was developed for the extraction of thrips and other whole or equivalent insects from frozen blackberries and raspberries. The method consisted of a thawing and drained weight step, followed by acid maceration. Berries were wet-sieved over a No. 25 sieve nested in a No. 80 sieve. The berry tissue retained on the No. 80 sieve was dehydrated with isopropanol and then treated with chloroform. The chloroform was stripped from the residue with isopropanol. The berry residue was extracted with light mineral oil from a 40% isopropanol-Tween 80- Na4EDTA mixture. The collaborative study was successfully completed with 83.3% average recoveries of thrips and a 19.2% coefficient of variation. The method has been adopted official first action.
Simultaneous Determination of Aluminum, Iron, Calcium, and Magnesium in Wet-Process Phosphoric Acid by DC Argon Plasma Emission Spectrometry
Authors: Hunter G Bradley , Woodis Terry C , Johnson Frank J
Published: February 2020

A method has been developed for the simultaneous determination of Al, Fe, Ca, and Mg in wet-process phosphoric acid by dc argon plasma emission spectrometry. The suppression of Ca and Mg emission by phosphate encountered in flame analyses was nonexistent, and other interferences were minimal. Results obtained by the procedure were compared with those obtained by atomic absorption spectrometry. The paired t-test showed no significant difference between the 2 methods at the 95% confidence level.
Fish Species Identification by Isoelectric Focusing: Sarcoplasmic Protein Polymorphism in Monkfish (Lophius americanus)
Authors: Lundstrom Ronald C
Published: February 2020

Monkfish (Lophius americanus) sarcoplasmic protein patterns were found to be polymorphic with respect to separations using isoelectric focusing. Reproducible protein pattern variations were not detected using cellulose acetate or polyacrylamide gel disc electrophoresis. Monkfish sarcoplasmic proteins separated on pH 3.5-9.5 Ampholine PAGplates or on pH 2.5-9.0 agarose IEF gels yielded similar patterns showing 3 distinct, reproducible variations. On close examination, the pH 3.5-9.5 Ampholine PAGplate patterns could be further subdivided into 3 additional variations. A high resolution pH 3.5-5.0 agarose IEF gel was able to resolve a total of 10 different monkfish pattern variations in a sample of 24 individuals. A model was proposed suggesting the existence of 16 distinct variations in the monkfish sarcoplasmic protein pattern, based on the various combinations of 4 protein bands. In identifying samples of monkfish meat, it is necessary to compare the unknown pattern with the possible variant patterns to effect a reliable identification. On recommendation by the Associate Referee, the method for fish species identification based on polyacrylamide gel isoelectric focusing, 18.A01-18.A04, has been adopted official final action with no restrictions as to the species that may be identified.
Survey for Cadmium, Cobalt, Chromium, Copper, Nickel, Lead, Zinc, Calcium, and Magnesium in Canadian Drinking Water Supplies
Authors: Méranger Jean C , Subramanian Kunnath S , Chalifoux Chantal
Published: February 2020

A second national survey was done to ascertain the levels of Cd, Co, Cr, Cu, Ni, Pb, Zn, Ca, and Mg in Canadian drinking water supplies. Raw, treated, and distributed water samples collected from 71 municipalities across Canada were analyzed both by atomic absorption spectrophotometry using the direct method and by an APDC-MIBK extraction procedure. As in the first national survey, the amounts of trace metals found in the 3 types of water samples were essentially the same. Contamination of the water supplies with these metals except Cu and Zn was minimal during treatment and distribution. For Canadian drinking water, the median and extreme values expressed as ng metal/mL water were: Cd ≤0.02 (≤0.02-0.07), Co ≤2.0 (≤2.0-6.0), Cr ≤2.0 (≤2.0-4.1), Cu ≤10 (≤10-900), Ni ≤2.0 (≤2.0-69.0), Pb ≤1.0 (≤1.0-79.7), and Zn ≤10 (≤10-750). Hardness values as mg CaCO3/L, ranged from 6.7 in St. John’s, Newfoundland, to 328.3 in Portage La Prairie, Manitoba. The median values for the Canadian drinking water supplies were well below the maximum permissible limits set by Health and Welfare Canada and the World Health Organization.
Analysis of Fat-Soluble Vitamins. XXIV. High Performance Liquid Chromatographic Determination of Vitamin D in Vitamin D Resin Containing Powders: Collaborative Study1
Authors: Mulder Frits J , Vries Ellen J De , Borsje Ben ,   Collaborators:, Ameika L , Gillingham P J , Richter E F , Vries E J de
Published: February 2020

Further study of vitamin D methodology solved the discrepancy between the AOAC chemical method, 43.068-43.078, and the HPLC assay for vitamin D3 in resin containing dry powders. The discrepancy is caused by the difference in solubility of the vitamin D3 resin in benzene and in pentane. The method has been modified accordingly, and has been adopted official first action for vitamin D3 resins and vitamin D3 resin containing powders and aqueous dispersions.
Acid Digestion Determination of Iodine in Foods
Authors: Fischer Peter W F , L’abbé Mary R
Published: February 2020

A method for determining iodine in food is described. The samples were digested using a mixture of sulfuric, nitric, and perchloric acids. The iodine was determined by an automated colorimetric method based on the iodide-catalyzed reduction of Ce+4 by As+3. For milk samples, the relative standard deviation for the method was less than 3%, and the recovery of 125I added to milk and carried through the method ranged from 96 to 102%. The method was compared with 4 other procedures and was superior to alkaline dry ashing methods.
Sodium Hypophosphite as Reducing Agent for Determination of Submicrogram Quantities of Mercury in Animal Feeds and Manures
Authors: El-Ahraf Amer , Willis W Van , Vinjamoori Dutt V
Published: February 2020

The reduction of mercury in samples of dairy cattle and chicken feed rations and manures prepared by acid digestion for determination by flameless atomic absorption is rapidly, smoothly, and quantitatively effected by sodium hypophosphite. The reducing agent is air-stable, is effective over a wide range of mercury concentrations, and is useful in the presence of many mineral acids commonly used for wet digestion of these matrices. The accuracy and precision obtained in determinations with this reagent are equivalent to those obtained using stannous chloride at the same conditions. Recovery efficiencies for the total analytical procedure were studied using cattle manure and feed rations spiked to 0.6 ppm Hg as phenylmercuric nitrate; the range of recoveries varied from 93 to 102% (97% average). The absolute detection limit of the method is 10 ng Hg, and the precision varies in the range of 2.2-6% for samples containing 3 ppt-10 ppm Hg. The advantages of sodium hypophosphite lie in the elimination of premature reduction of mercury caused by traces of stannous chloride adhering to the walls of the reaction vessel, the elimination of several wash steps in the determination, and the long shelf life of the reagent.
Hydrogen Selenide Evolution-Electrothermal Atomic Absorption Method for Determining Nanogram Levels of Total Selenium
Authors: Cox Dennis H , Bibb Ann E
Published: February 2020

A hydrogen selenide (H2Se) evolution-electrothermal atomic absorption method is described for determining nanogram concentrations of total selenium (Se) in biological and environmental materials. A mixed acid digestion procedure is used to decompose organic material. Sodium borohydride, a redesigned hydride generator, and an electric-heated absorption tube are used for H2Se evolution and conversion to atomic Se. The method has a detection limit of 4 ng/mL and a sensitivity of 0.6 ng/mL, and is linear from 0 to 90 ng Se/mL. As determined on urine, water, and bovine liver, total and within-run precision had relative standard deviation values of 5-17.2 and 5.5-12.6%, respectively. Accuracy was established with 2 NBS and 3 EPA reference materials, and mean errors of 0 to +0.8 were obtained. Mean recoveries of 109 and 101% were obtained for 10 and 50 ng Se added to human urine.
Gas-Liquid Chromatographic Detection and Determination of Diacetyl Tartaric Acid Ester of Diglyceride in Dairy and Nondairy Coffee Cream Powders
Authors: Inoue Tetsuo , Iwaida Masahiro , Ito Yoshio , Tonogai Yasuhide
Published: February 2020

Diacetyl tartaric acid ester of diglyceride was directly extracted from dairy or nondairy coffee cream powder under acidic conditions with ethyl acetate; then the extract was saponified with methanolic potash. After acidification with HC1, free fatty acid was removed with ether and the reaction mixture was adsorbed on an anion exchange column. Tartaric acid was eluted with 2N HCl-acetone (1+1). An aliquot of the trimethylsilyl (TMS) derivative of the eluate was injected into a gas chromatograph with flame ionization detection, and a 1.5% SE-30 column. Recoveries of diacetyl tartaric acid ester of diglyceride at 50, 200, and 2000 ppm were 85.6-99.5%.
Extraction of Light Filth from Tea: Collaborative Study
Authors: Lim Faith F ,   Collaborators:, Barnett J , Bright A , Chaput M P , Cox C , Floyd D M , Gentry J , Thrashe J , Washbon E C
Published: February 2020

The present AOAC method for determining insect and rodent filth in tea is time-consuming because it produces filter papers which are heavy in plant residue and therefore requires long paper-reading times. Anew method for the analysis of light filth in tea was developed to remedy existing problems and to improve recoveries. The method consists of the following steps: sample preparation, wet sieving, dilution with 40% isopropanol, extraction with Tween 80-Na4EDTA-40% isopropanol, flotation with mineral oil-heptane, and trapping off in a Wildman trap flask. In an interlaboratory collaborative study, analysts reported combined insect fragment recoveries of 99.2% for the proposed method and 93.0% for the AOAC method; the same analysts recorded combined rodent hair recoveries of 92.2% for the proposed method and 47.6% for the official method. Average times for reading individual subsamples were 9 min for the proposed method and 27 min for the AOAC method. The proposed method has been adopted official first action.
High Pressure Liquid Chromatographic Determination of Antihistamine-Adrenergic Combination Products: Collaborative Study
Authors: Bachman William J ,   Collaborators:, Alpert M Y , Bargo E , Draper R E , Hock W H , Illuminati J , Lookabaugh M , Margosis M , Thompson D W
Published: February 2020

A reverse phase high pressure liquid chromatographic method in which ion-pairing is used for the determination of combinations of pseudoephedrine hydrochloride with triprolidine hydrochloride or chlorpheniramine maleate in syrups and tablets was collaboratively studied by 8 laboratories. Collaborators were supplied with 12 samples including synthetic and commercial syrup formulations and commercial tablet composites. Mean recoveries of pseudoephedrine hydrochloride and triprolidine hydrochloride from synthetic syrup formulations were 100.5 and 99.6%, respectively. Mean recoveries of pseudoephedrine hydrochloride and chlorpheniramine maleate from synthetic syrups were 98.8 and 100.5%, respectively. Mean coefficients of variation for syrups and tablets ranged from 1.68 to 3.07% for pseudoephedrine hydrochloride, from 2.92 to 3.85% for triprolidine hydrochloride, and from 1.34 to 2.15% for chlorpheniramine maleate. The method has been adopted official first action.
Determination of Alkaline Phosphatase in Casein: Collaborative Study
Authors: Murthy Gopala K , Peeler James T ,   Collaborators:, Bone E E , Dickerson B , Johnson W , Maifarth P , Marchetti D , Mullen R , Pyett M M , Riggs T
Published: February 2020

A collaborative study was made to determine alkaline phosphatase in casein samples by the rapid colorimetric test. Six to eight collaborators tested 10 unknown casein samples containing various amounts of residual phosphatase with and without the addition of magnesium acetate. Results indicated that magnesium acetate significantly increased phosphatase activity. The collaborators correctly analyzed 95% of the samples with the added magnesium acetate. The method has been adopted official first action.
Sampling Procedure and Determination of Lead in Canned Foods
Authors: Suddendorf Ronald F , Wright Steven K , Boyer Kenneth W
Published: February 2020

A method is presented for improving within-can homogeneity and simplifying the determination of lead in canned foods. The entire content of a canned food product is blended with 2N HNO3 and allowed to stand 16 h; then the sample is again blended and a subsample is taken. The subsample is digested by wet ashing using nitric acid-perchloric acid or nitric add-sulfuric acid-hydrogen peroxide. The pH of the sample is adjusted with ammonium hydroxide, and the lead is extracted into butyl acetate as the pyrrolidinecarbodithioate complex. Lead concentration is determined by flame atomic absorption spectrometry. Recoveries of lead ranged from 92 to 104% for added 100-mesh lead particulate. Within-sample variability for green beans was reduced from 37% obtained with blending alone to 3.7% using the proposed procedure at the 3.1 μg/g added lead level. Variability was 7.6% at the 0.68 μg/g level and 16.4% at the 0.20 μg/g level of added lead. The use of nitric add-sulfuric acid-hydrogen peroxide for digestion has the advantage of not forming a precipitate during the neutralization step, as occurs when nitric acidpercloric acid is used for dissolution.
Generic Identification of Cooked and Frozen Crabmeat by Thin Layer Polyacrylamide Gel Isoelectric Focusing: Collaborative Study
Authors: Krzynowek Judith , Wiggin Kate ,   Collaborators:, Allsup M G , Annand C , Braddon S A , Carter K , Choromanski J , Haard N F , Kariel N , Laterza A F , Little B W , Lundstrom R C , Martin A M , Morrison R , Odense P , O′leary G P , Pike J , Stiles S , Wittingham L
Published: February 2020

Ten collaborators were required to focus the ureaextracted proteins from 14 crabmeat samples. Six of the samples were knowns and were labeled as to their species. Eight samples were unidentified as to species and were labeled with letters. The 8 unknowns were identified by comparing the focused patterns with the patterns of the 6 species-labeled crabmeat samples. Seventy-nine samples were identified with 97.5% accuracy. This method has been adopted official first action.
Preparation and Characterization of Af latoxin Q1-Hemisuccinate
Authors: Lau H P , Fan S L , Chu F S
Published: February 2020

A method for the preparation and purification of aflatoxin Q1-hemisuccinate is described. The overall yield after final purification was about 80-85% of the starting aflatoxin Q1. The new aflatoxin derivative was characterized by thin layer chromatographic, high performance liquid chromatographic, ultraviolet, mass spectroscopic, and nuclear magnetic resonance spectral analyses.
Molecular Weight Characterization of Food Grade Polyethylenes and Extractables by Size Exclusion Chromatography
Authors: Snyder Roger C , Breder Charles V
Published: February 2020

Size exclusion chromatography (SEC) was used to characterize the molecular weight distribution (MWD) of 6 low density and 6 high density food grade polyethylene resins. The hexane and xylene extractable fractions of these 12 resins were also analyzed by SEC. An IBM 370/168 computer with an APL program was used to analyze the chromatograms and correct for chromatographic band spreading and skewing. Calculated weight average molecular weights (Mw) for the resins ranged from 40 000 to 200 000 and number average molecular weights (Mn) ranged from 6000 to 60 000. Median values of Mw and Mn were 1800 and 950, respectively, for hexane extractables from the low density resins, and were 310 and 290, respectively, for hexane extractables from the high density resins. Corresponding Mw and Mn values for xylene extractables were consistently larger than those for hexane extractables.
Thin layer Chromatographic and Atomic Absorption Spectrophotometric Determination of Methyl Mercury
Authors: Margler Lawrence W , Mah Robert A
Published: February 2020

A method is presented for determining methyl mercury that combines thin layer chromatography and atomic absorption spectrophotometry. The procedure is based on a previously reported method and entails isolating methyl mercury on a thin layer chromatogram, scraping adsorbent into an ignition tube, heating the tube, and moving the mercury vapor under vacuum into an absorption cell where it absorbs light at 253.7 nm. The procedure is sensitive to 0.7 ng Hg. Methyl mercury is extracted from biological samples by distilling, and then extracting with dithizone-chloroform. The extract is concentrated and applied to a thin layer chromatographic plate. The overall sensitivity of the method varies with sample size. For 100 g samples, the method is sensitive to about 9 ng Hg (as methyl mercury)/g (9 ppb).
Distinguishing Common Food-Contaminating Bat Hairs from Certain Feather Barbules
Authors: Olsen Alan R
Published: February 2020

Differences are described between common food-contaminating vespertilionid bat hairs (Chiroptera: Vespertilionidae) and similar-appearing downy feather barbules of passeriform birds, including cuticular scales, pigment distribution, and basal characteristics. Fifteen imported food samples analyzed over a 1½ year period were contaminated with these bat hairs.
Gas-Liquid Chromatographic Determination of Sulfamethazine in Swine and Cattle Tissues
Authors: Manuel Arthur J , Steller William A
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for determining sulfonamide residues in animal tissues, with specificity for 7 sulfonamides. Residues are extracted from tissues with acetonechloroform, fatty substances are removed, and the sulfonamide residue is methylated with diazomethane in acetone-ether to render it amenable to determination by gas-liquid chromatography on an all-glass column suitable for direct on-column injection and a Ni electron-capture detector. Quantitation is achieved by external standardization. The method has a validated limit of sensitivity of 0.10 ppm with the corresponding control values for all tissues being less than 0.01 ppm. Satisfactory recoveries have been obtained for sulfamethazine in swine and cattle tissues. Specificity for sulfamethazine in the presence of sulfathiazole, sulfaquinoxaline, sulfadimethoxine, sulfabromomethazine, sulfaethoxypyridazine, and sulfachloropyrazine is attained by resolution of the respective methyl derivatives on the GLC column.
High Pressure Liquid Chromatographic Determination of Nifursol in Finished Feeds
Authors: George Glenn M , Frahm Larry J , Mcdonnell J Patrick
Published: February 2020

Nifursol is extracted from feed with acetonitrile, and then washed with carbon disulfide to remove feed interferences. An aliquot is concentrated, diluted with 5% NaCl solution, filtered, and then subjected to high pressure liquid chromatography on a strong anion exchange column, using 365 nm photometric detection. The average recovery of nifursol from fortified feed samples was 100.6% with an average coefficient of variation of 3.5%. The nifursol determination is not subject to interference from the other commonly used nitrofurans.
Liquid Chromatographic Method for Determination of Arprinocid in Feed: Collaborative Study
Authors: Fink David W ,   Collaborators:, Andres C N , Brignac P J , Carr K E , Davis E J , Ferder T W , Fin H C , Georg G M , Lawrence A A , Leseney J L , Lowie D , Martin R P , Minyar J P , Pivnichn J V , Quick F , Rowe W D , Shim J -S K , Smallidge R L , Thorp V A , Tola J W , Van Antwer W P
Published: February 2020

An HPLC method for determining arprinocid [9-(2-chloro-6-fluorophenyl)methyl-9H-purin-6-amine] in feed was evaluated in an interlaboratory collaborative study. The samples were prepared in pairs from feeds obtained from 2 commercial feed manufacturers to cover the concentration range 0.0050- 0.0070% arprinocid and were distributed to 14 laboratories. Each collaborator was requested to perform one determination on each of 6 samples. In this analytical procedure, the drug is extracted into CHCI3 and, after appropriate sample preparation by liquid- liquid partitioning, determined using a silica column and ultraviolet detection. The means of the analyses reported by the collaborators ranged from 97 to 104% of the true concentration of arprinocid and were not significantly different (P >0.1) from the true values. The average coefficient of variation was 6.8%. The precision standard deviations of the 3 unit blocks (sr) were each <0.0004% arprinocid, and the F-test demonstrated that systematic error (sb,) did not make a statistically significant contribution (P >0.1) to the standard deviation of the data (sd). This method has been adopted official first action.
Analytical Methodology for Sample Preparation, Detection, Quantitation, and Confirmation of N-Nitrosamines in Foods
Authors: Hotchkiss Joseph H
Published: February 2020

Significant advances have been made over the past decade in methodology for the analysis of foods and other samples for volatile N-nitrosamines. Procedures for the isolation, cleanup, and concentration of N-nitrosamines were developed and applied to a broad range of food types. Several chromatographic techniques and systems have also been developed which are capable of resolving AT-nitrosamines in complex mixtures in a single run, and the use of highly selective detectors has decreased sample preparation time while increasing sensitivity and precision. Unequivocal confirmation of N-nitrosamines in foods can now be achieved by mass spectrometry at low to sub-μg/kg levels. However, further development of methodology for nonvolatile N-nitroso compounds is needed. This review paper discusses these and other topics related to the analysis of foods for N-nitrosamines.
Simultaneous Detection of Several Fusarium Mycotoxins in Cereals, Grains, and Foodstuffs
Authors: Kamimura Hisashi , Nishijima Motohiro , Yasuda Kazuo , Saito Kazuo , Ibe Akihiro , Nagayama Toshihiro , Ushiyama Hirofumi , Naoi Yasuta
Published: February 2020

A systematic method is described for the simultaneous determination of Fusarium mycotoxins (nivalenol, deoxynivalenol, fusarenon-x, diacetoxyscirpenol, neosolaniol, T-2 toxin, HT-2 toxin, butenolide, moniliformin, and zearalenone) in cereals, grains, and foodstuffs. Mycotoxins were extracted with aqueous methanol and purified by a 2-step chromatographic procedure using Amberlite XAD-4 and Florisil columns. The column eluates were concentrated and spotted on a thin layer chromatographic (TLC) plate which was then developed in CHCL3-methanol (93 + 7) and toluene-acetonemethanol (5 + 3 + 2). Each mycotoxin was quantitated by gas chromatography (GO and TLC densitometry. The minimum detectable concentrations (μg/kg) in various test materials were: nivalenol, deoxynivalenol, and fusarenon-x, 2.0; diacetoxyscirpenol, neosolaniol, T-2 toxin, and HT-2 toxin, 80; zearalenone, 10; butenolide, 30; and moniliformin, 50. Recoveries of the mycotoxins added to various cereal samples at 1.0-2.0 Mg/g were greater than 71% and averaged 85%.
High Performance Liquid Chromatographic Determination of Aflatoxicol in Milk, Blood, and Liver
Authors: Trucksess Mary W , Stoloff Leonard
Published: February 2020

Samples of milk were extracted with chloroform, the extract was transferred to methanol, and residual interferences were removed by liquid-liquid partition against hexane and by silica gel column chromatography. Aflatoxicol (AFL) in the purified extract was resolved on a μBondapak C18 column, using water - methanol - acetonitrile - tetrahydrofuran (70 + 15 + 20 + 3) as the mobile phase, and measured with a fluorescence detector (excitation 325-385 nm, emission >408 nm). Recoveries of AFL added to samples of whole pasteurized milk at levels ranging from 0.025 to 0.10 ng/mL averaged 92% (range 78- 100%). The method for AFL has also been applied to the analysis of raw milk, whole beef blood, and beef liver, with recoveries of 70-88%.
Potentiometric and Atomic Absorption Spectrometric Determination of Sulfonamides in Pharmaceutical Preparations
Authors: Hassan Saad S M , Eldesouki Mohamed H
Published: February 2020

Potentiometric and atomic absorption spectrometric (AAS) methods are described for the determination of various sulfonamides in tablets, suspensions, and injections, based on reactions with silver and copper ions. The methods involve direct titration at pH 8, using either a graphite electrode in which silver and copper sulfides have been precipitated, or ion selective electrodes to monitor the potential change. AAS measurements of the excess metal ions after metalsulfonamide reaction are also reported. Results compare favorably with those obtained using USP XIX procedures. The methods described are selective, simple, and precise.
Nuclear Magnetic Resonance Spectroscopic Method for Determination of Penicillamine in Capsules
Authors: Nelson James
Published: February 2020

A rapid and specific nuclear magnetic resonance (NMR) spectroscopic method for the determination of penicillamine in capsules is presented. The sample is directly dissolved in D2O and its spectrum recorded on a 90 MHz instrument. The 2 singlets appearing at 1.58–1.64 ppm, due to the nonequivalent gem-dimethyl groups, were integrated and compared with the integral obtained for the phenyl proton signals of sodium saccharin, which is the internal standard. The results obtained by the proposed method closely agreed with those found by the method of USP XX.
Improved Multiresidue Gas Chromatographic Determination of Organophosphorus, Organonitrogen, and Organohalogen Pesticides in Produce, Using Flame Photometric and Electrolytic Conductivity Detectors
Authors: Luke Milton A , Froberg Jerry E , Doose Gregory M , Masumoto Herbert T
Published: February 2020

The multiresidue procedure of Luke et al., which uses extraction with acetone and partition with petroleum ether and methylene chloride, was simplified and shortened by eliminating the Florisil cleanup. Double concentration with petroleum ether in the Kuderna-Danish evaporator following the initial concentration removed the last traces of methylene chloride. The extract was then injected into a gas chromatograph, using a Hall electrolytic conductivity detector for organohalogen, organonitrogen, and organosulfur pesticides or a flame photometric detector for organophosphorus pesticides. Recoveries of 79 pesticides are presented.
Gas-Liquid Chromatographic-Mass Spectrometric Confirmation of Endosulfan and Endosulfan Sulfate in Apples and Carrots
Authors: Wilkes Perry S
Published: February 2020

A gas-liquid chromatography-mass spectrometric (GLC-MS) procedure is described for the confirmation of endosulfan I, endosulfan II, and endosulfan sulfate in apples and carrots. After extraction, cleanup, and determination by electron capture gasliquid chromatography using current AOAC methodology, residues are confirmed by GLC-MS. The chemical ionization (CI) mode is used with methane as a reagent gas. Each residue is confirmed by a scan of only 4 regions of its mass spectrum rather than the full mass range. The 4 mass regions for the 2 endosulfan isomers are 274-280, 340-346, 368-374, and 404-412 atomic mass units (amu). For endosulfan sulfate, the mass regions are 286-294, 322-330, 384-392, and 420-428 amu. Four ions and their chlorine isotopic distributions are detected for each compound by this scanning technique. This method was developed by using carrots and apples to which had been added 0.1 ppm (50% of the current legal tolerance on carrots) of each of the 3 pesticides. The gas chromatographic retention times and the mass spectra of the 4 mass regions specified for the 3 pesticides were compared to those of reference standards injected under identical GLC-MS conditions and were used as the basis for confirming identity of the 3 compounds.
Novel Thin Layer Chromatographic Techniques for Aflatoxin Analysis
Authors: Kozloski Richard P
Published: February 2020

Some procedures for improving thin layer chromatographic (TLC) spot size and fluorescence intensity are described. By using strong eluting solvents, diffuse TLC spots can be reduced in size and poorly resolved chromatograms returned to their original state for redevelopment. The blanketing of weak aflatoxin bands with an inert layer of gas results in an increase in UV fluorescence
Examination of the Use of Glass Filter Paper in Asbestos-Free Fiber Determination
Authors: Craddick Richard C , Hatfield Linda
Published: February 2020

A modification is presented of asbestos-free method 7.066 for the determination of crude fiber in feeds. In the final filtering step, the fritted glass crucible is replaced with a 7.5 cm disc of glass filter paper in a California Buchner funnel. The data supporting the use of filter paper indicate that good precision and accuracy can be achieved.
Gas-Liquid Chromatographic Determination of Pirimicarb in Formulations: Collaborative Study
Authors: Bland Peter D ,   Collaborators:, Bagness J , Black W , Brown L , Gentry M , Ginther B , Hayes E , Holland P , Jackling S , Padmore J , Torma L , Winstead G
Published: February 2020

A method is described for the determination of pirimicarb (2-(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate) in formulated products by gas-liquid chromatography (GLC). Samples are dissolved in a chloroform solution of an internal standard and injected into a gas chromatograph equipped with a flame ionization detector. Quantitative data are obtained by comparing peak areas of the compound and internal standard with those obtained by injecting a standard solution. Eleven collaborators made replicate determinations on 6 samples including a technical product, a granular product, and 4 powder products. The average coefficient of variation was 1.14% for the technical product, 1.82% for the granular product, and 0.73% for the powder products.
Evaluation of Ion Exchange Resins and Various Enzymes in Thiamine Analysis
Authors: Ellefson Wayne C , Richter Earl , Adams Mark , Baillies N Thomas
Published: February 2020

Four ion exchange resins and 9 enzyme preparations are evaluated for use in the official AOAC thiamine method because Decalso and Clarase or Mylase P either are no longer available or are available in a form that is not suitable for use in the assay. The enzymes are prepared in the same manner described for Clarase or Mylase P in the AOAC method and are compared with Clarase T300 for their effectiveness in releasing thiamine from thiamine phosphate, and their ability to produce similar results on samples. Rhozyme S is 90–100– as effective as Clarase T300 in both of these respects. The other enzymes tested were not satisfactory. Further study is necessary because Rhozyme S also is no longer manufactured. The ion exchange resins are prepared for use in the manner described for Decalso in the AOAC method. Recoveries of thiamine range from 95 to 100%, using Bio-Rex 70 (hydrogen form) ion exchange resin. The other resins tested were not satisfactory.
Gas Chromatography with Electron Capture and Mass Spectrometric Detection of Deoxynivalenol in Wheat and Other Grains
Authors: Scott Peter M , Lau Pui-Yan , Kanhere Shriniwas R
Published: February 2020

A method for determining deoxynivalenol (DON) in wheat has been developed in conjunction with an assessment of contamination in Canada. The sample is extracted with methanol-water; the extract is treated with 30% aqueous ammonium sulfate solution and extracted with 4 portions of ethyl acetate. After further cleanup by column chromatography, the sample extract is derivatized with AT-heptafluorobutyrylimidazole, and the DON tris-heptafluorobutyrate is determined by gas-liquid chromatography with electron capture detection. Mass spectrometric single ion monitoring at m/z 884 is used for confirmation. Detection limits are ≤0.01 μg DON/g and recoveries from wheat, using the proposed method, averaged 72 and 80% in 2 different laboratories, with coefficients of variation of 10.2 and 10.0%, respectively. The method is also applicable to determining DON in barley and corn and T-2 toxin in wheat. Virtually 100% contamination by DON of the 1980 Ontario white winter wheat and Quebec red spring wheat crops was found, based on 72 analyses made in this laboratory, but western Canadian wheat contained little or no DON.
Estimation of Lactose Hydrolysis by Freezing Point Measurement in Milk and Whey Substrates Treated with Lactases from Various Microorganisms
Authors: Chen Shih-Ling Yeh , Frank Joseph F , Loewenstein Morrison
Published: February 2020

β-Galactosidase concentrates obtained from several microorganisms were used to hydrolyze skim milk, low fat (2%) milk, sweet whey, acid whey, acid whey permeate, and acid whey concentrate. Among acid substrates, the freezing point depression for each 1% lactose hydrolyzed was the greatest with the lactase from Aspergillus niger (0.0501°H); among neutral substrates, the depression was greater in sweet whey (0.0495°H) and lesser in low fat milk (0.0445°H). All data were statistically significant. The average freezing point depression for each 1% lactose hydrolyzed was 0.0468°H (range 0.0436-0.0501°H). Oligosaccharides formed in the lactose hydrolysis, inconsistent freezing point readings of the cryoscope at the low freezing points measured, and protease contamination in some lactases may affect the precision of freezing point determination. Hydration and volume of non-protein components in commercial enzymes, unstable color complex formed by lactose in methylamine solution, and difficulty in the use of methylamine solution might cause variations in determination of lactose by the analytical procedure. These factors can be eliminated or minimized. This method is the simplest and quickest estimation of lactose hydrolysis, and it offers great accuracy and consistency
Protein Nitrogen Unit Precipitation Procedure for Allergenic Extracts: Collaborative Study
Authors: May Joan C , Sih Jenny T C ,   Collaborators:, Laboratories Allergy , Best J , Douglas G , Rancour J M , Renker H R , Spingola F , Daele L Van , Zudeck S
Published: February 2020

Protein nitrogen unit (PNU) determination is one of the methods used to test and label the concentration of allergenic extracts. This recently standardized method is applicable to all allergenic extracts. One PNU/mL is equivalent to 1 × 10−5 mg nitrogen determined to be in the material precipitated from 1 m l allergenic extract by phosphotungstic acid (PTA), a protein precipitant. The nitrogen is quantitated by the Kjeldahl method or another analytical method of equivalent accuracy and precision. A collaborative study of the optimized PNU precipitation method in which 6 samples were analyzed in duplicate by 6 laboratories using the Kjeldahl method for the determination of nitrogen yielded a mean of 0.1358 mg N/ml, a repeatability standard deviation and coefficient of variation of 0.0071 mg N/mL and 5.23%, respectively, and a reproducibility standard deviation and coefficient of variation of 0.0188 mg N/mL and 13.84%, respectively. The method has been adopted official first action.
Gas-Liquid Chromatographic-Thermal Energy Analyzer Method for N-Nitrosodiethanolamine in Cosmetics
Authors: Black Donald B , Lawrence Robert C , Lovering Edward G , Watson James R
Published: February 2020

A gas-liquid chromatography-thermal energy analyzer (GLC-TEA) method has been developed for the quantitation of N-nitrosodiethanolamine (NDELA) in a variety of cosmetic products. Samples are cleaned up by a preliminary shakeout of an aqueous mixture of the cosmetic with ethylene dichloride, followed by removal of other polar and nonpolar constituents from the aqueous layer with commercial extraction columns, separation cartridges, and selected solvents. Common transnitrosating 1,3-diol preservatives sometimes found in cosmetics were eliminated after conversion to less polar cyclic boronates. The isolated NDELA fraction was trimethylsilylated at room temperature and the product was subjected to GLC-TEA, with N, N’-dinitrosopiperazine (DNPiz) used as the internal standard. Recoveries of NDELA from spiked samples usually ranged from 60 to 90%. The limit of detectability was about 5-10 ppb. The identity of NDELA was confirmed by GLC-mass spectrometry.
Fish Species Identification by Thin Layer Agarose Isoelectric Focusing and Densitometric Scanning
Authors: Hamilton Warren D
Published: February 2020

Examination of sarcoplasmic proteins of fish by thin layer polyacrylamide gel isoelectric focusing as a means of fish species identification is a powerful and reliable technique, but it displays a number of disadvantages. These problems include the care required when handling acrylamide monomer (a neurotoxin), the mechanical skill needed in molding the gel, the difficulties in ensuring correct gel polymerization, and the extensive destaining periods. Specially treated agarose has been used to obtain protein patterns for an interval of pH 5-8. The patterns so produced were scanned by a densitometer in the visible range after completing staining and destaining. Most of the problems associated with polyacrylamide gels have been overcome by using agarose is a support medium.
Determination of Polysorbate 60 in Salad Dressings by Colorimetric and Thin Layer Chromatographic Techniques
Authors: Daniels Daniel H , Warner Charles R , Selim Sami
Published: February 2020

Methods are described for the quantitation and verification of polysorbate 60 (PS 60) in salad dressing. The sample is partitioned between methylene chloride and water. The methylene chloride extract is further treated by silica gel column chromatography. The isolated PS 60 is complexed with ammonium cobaltothiocyanate and determined spectrophotometrically at 620 nm. Additional evidence indicating the presence of PS 60 is obtained from thin layer chromatographic analysis using the modified Dragendorff reagent for visualization of spots.
Gas Chromatographic-Mass Spectrometric Analysis, Identification, and Detection of Adulteration of Natural and Concentrated Lemon Oils
Authors: Prager Manfred J , Miskiewicz Michael A
Published: February 2020

Lemon oils were characterized by quantitative glass capillary gas chromatography. Components present to the extent of more than 0.05% were measured and identified by mass spectrometry. In expressed lemon oils, monoterpenes and geranial were the only components present at concentrations of 1.0% or more. In concentrated lemon oils, β-caryophyllene, linalool, neral, β-terpineol, neryl acetate, and geranyl acetate were present in some samples in amounts of 1% or more. Adulteration was detected by component concentrations outside characteristic ranges for oils judged to be authentic.
Manual Headspace Gas-Solid Chromatographic Determination of Sub-Parts per Trillion Levels of Acrylonitrile in 3% Acetic Acid
Authors: McNeal Timothy , Breder Charles V
Published: February 2020

A procedure was developed for determining acrylonitrile (AN) in 3% acetic acid, the solvent used to simulate carbonated beverages. Manual headspace sampling, a detector output amplifier/filter, and vapor phase enhancement using an ionic material were combined to give a detection limit in the low parts per trillion range. AN standards were analyzed using the method, and the results are presented.
Simple Colorimetric Method for Determination of Organothiophosphate Insecticides in Technical Materials and Formulations
Authors: Sane Ramesh T , Kamat Sudhir S
Published: February 2020

A simple colorimetric method based on the reaction of benzophenone with thiophosphate is described. The method is specific for compounds containing the P═S moiety, gives recoveries of 99 ± 1%, and obeys Beer's law for the concentration range 35-350 μ/mL. Other sulfur-containing compounds such as sulfa drugs, thiobarbiturate, thiourea, carbon disulf ide, and dithiocarbamates do not interfere in the reaction. The method is useful in studying the shelf-life of formulations.
High Pressure Liquid Chromatographic Determination of Supplemental Methionine in Poultry Premix
Authors: Matešič Dubravka
Published: February 2020

Supplemental methionine was extracted from a feed sample with O.IM HCI and separated by reverse phase or ion-exchange high pressure liquid chromatography and isocratic elution with KH2PO4 buffer solution as the mobile phase. Methionine was detected at 205 nm. The most reliable results were obtained by using reverse phase chromatography, 0.05M KH2PO4 buffer at pH 2.6 as mobile phase, and tyrosine as internal standard.
Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods
Authors: Casey Patrick J , Speckman Keevin R , Ebert Frank J , Hobbs William E
Published: February 2020

A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.
Comparison of Rapid High Pressure Liquid Chromatographic and CB Methods for Determination of Aflatoxins in Corn and Peanuts
Authors: Devries Jonathan W , Chang Henry L
Published: February 2020

A method is described for the rapid determination of aflatoxins in corn and peanut samples by high pressure liquid chromatography. The method was compared with the current CB method (AOAC 26.026). For 7 samples of corn and 14 samples of peanut meal and peanut butter, the correlation between methods is 0.991, and no significant difference exists between methods, using the Student's t-test at 15.7% a-risk.
Density Meter Determination of Proof of Ethanol-Water Solutions: Collaborative Study
Authors: Strunk Duane H , Aicken John C , Hamman Jack W , Andreasen Arthur A ,   Collaborators:, Cherolis J , Daggs W D , Feeny F J , Hamman J W , Holmes R N , Jones J C , Mark F G , Martin G E , O'Bryan W C , Olson R E , Perrault A W , Rapp F L , Rehn B W , Timmel B M , Worden D
Published: February 2020

Density meter procedures and the official AOAC pycnometer method to measure proof of ethanol-water solutions in the 25-79° proof range were collaboratively studied. Measurement of proof by density meter is simpler, requires less time and smaller samples, and gives more reproducible results than the AOAC pycnometer method. Differences of —0.05 to +0.02° proof between averages of results reported for density meter and pycnometer are acceptable, considering that proof of finished alcohol products is reported to 0.1°. The density meter method has been adopted official first action.
Spectrophotometric Determination of Color Intensity of Whisky: Collaborative Study
Authors: Strunk Duane H , Timmel Bertha M , Hamman Jack W , Andreasen Arthur A
Published: February 2020

A method for measuring color intensity of whisky was developed to replace the present AOAC method, which has become obsolete. The new method was collaboratively studied by 20 persons. Color intensity of whisky was measured as absorbance by a spectrophotometer, using a 1 cm cell, a bandwidth ≤10 nm, and a wavelength of 525 nm. Water was used as reference. Collaborator results appear acceptable for whisky samples that vary in color intensity from 29 to 374 CIU (absorbance X 1000 = Color Intensity Units (CIU)). The maximum standard deviation and coefficient of variation were 5.8 CIU and 6.68%, respectively. The method has been adopted official first action.
Comparison of Azomethine H Microcolorimetric and AOAC Titrimetric Methods for Boron in Fertilizer: Collaborative Study
Authors: Melton James R ,   Collaborators:, Coggin D M , Erickson M , Hunter G B , Jones N , Kummer J A , Minyard J P , Pelletier M F , Price R N , Reynolds B L , Sensmeier R K , Smith J L , Sweeney R , Vickery R M , Wetherbee R T
Published: February 2020

Sixteen fertilizer samples were sent to 11 collaborating laboratories for boron determinations. Each sample was analyzed once by the azomethine H microcolorimetric method and once by the AOAC titrimetric method (2.114-2.116). There were no statistical differences in matched pairs by the 2 methods at the 98% confidence level even though quantities ranged from 0.01 to 15%. The azomethine H microcolorimetric method has been adopted official first action.