bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Geotrichum Mold in Cream Style Corn: Collaborative Study
Authors: Cichowicz Stanley M , Bandler Ruth ,   Collaborators:, Bandler R , Trauba R , Vassau N M
Published: February 2020

The official method for the determination of Geotrichum mold in canned fruits and vegetables, 44.079, is not satisfactory for use with cream style corn. The kernels are too small to be retained by the first 2 sieves, and the presence of starch interferes. The proposed method uses a smaller series of sieves (Nos. 16, 70, and 230), which enables more of the product to be separated from the mold before the No. 230 sieve, and specifies hot (45–55°C) wash water for the sieving steps to remove the starch. The method has been adopted official first action.
Gas-Liquid Chromatographic Determination of Organophosphorus Insecticide Residues in Fruits and Vegetables
Authors: Ferreira Julia R , Silva Fernandes Antonio M S
Published: February 2020

A method intended for regulatory purposes is described for the determination of organophosphorus insecticide residues in fruits and vegetables. Eighteen organophosphorus insecticides, azinphos-ethyl, chlorpyrifos, diazinon, dichlorvos, dimethoate, ethion, ethoate-methyl, fenitrothion, fenthion, formothion, malathion, methidathion, mevinphos, parathion, phosalone, phosphamidon, thiometon, and trichlorphon, and 7 metabolites, fenitrooxon, fenthion sulfoxide, fenthion sulfone, malaoxon, desethylphosphamidon, thiometon sulfoxide, and thiometon sulfone, were extracted from different crops with acetone and partitioned into hexane or ethyl acetate, according to their polarities. The hexane extract was cleaned up by eluting from a Florisil column with acetone-hexane (4+96). The ethyl acetate extract needs no cleanup. The concentrated extracts were analyzed by gasliquid chromatography using thermionic detectors. Recoveries conducted at fortification levels ranging from 0.1 to 2 mg/kg were in most cases above 80%. The limit of sensitivity is less than 0.1 mg/kg.
Modified Extraction Procedure for Direct Available P2O5 in Fertilizer
Authors: Sweeney Rose A
Published: February 2020

A modification of the direct available extraction procedure for P2O5 in fertilizer is presented. The modified extraction is used in our laboratory as a screening procedure to reduce work load associated with the lengthy official method. It is applicable to samples containing diammonium phosphate or other materials except triple superphosphate. Phosphorus is extracted from fertilizers with neutral ammonium citrate without prior removal of the water-soluble fraction. Samples are extracted by shaking 1 hr at 65°C on a water bath. The extract is cooled, diluted to volume, mixed, and an aliquot is taken for analysis. Average recovery of P2O5 from 9 selected Magruder samples by the modified extraction vs. the current official extraction was 99.5%, with a range of 98.7–99.9%. This study shows that the recovery of available P2O5 is not influenced by the level of CI P2O5 in the sample. Relative standard deviations for the modified extraction ranged from 0.20 to 0.86% with an average of 0.58%; relative standard deviation for the official extraction ranged from 0.30 to 0.89% with an average of 0.57%.
Difference Spectrophotometric Method for Estimation of Balsamic Acids in Presence of Resin Acids
Authors: Habib Abdel-Azim M , Saleh Mohamed R I
Published: February 2020

The acidic vs. alkaline difference spectra of cinnamic acid, benzoic acid, and total resin acids of tolu, benzoin, and colophony were studied. Characteristic maxima, minima, and isosbestic points of these spectra led to the development of a method for the quantitation of the individual balsamic acids and complete elimination of the spectral interference due to resin acids.
High Pressure Liquid Chromatographic Determination of Intermediates and Subsidiary Colors in FD&C Blue No. 2
Authors: Bailey John E
Published: February 2020

High pressure liquid chromatography (HPLC) is used in the reverse phase mode for the determination of intermediates and subsidiary colors in commercial samples of FD&C Blue No. 2. Isatin-5-sulfonic acid and the lower sulfonated subsidiary color are determined in one run. A second run at lower concentration is required to quantitate the isomeric subsidiary color, since it is present in large amounts and tends to saturate the detector. The calibration and recovery data are treated statistically to evaluate the performance of the method.
High Pressure Liquid Chromatographic Determination of Theobromine and Caffeine in Cocoa and Chocolate Products: Collaborative Study
Authors: kreiser Wesley R , Martin Robert A ,   Collaborators:, Bigornia R , Bond R , Cummings L J , Teja E de la , DeVries J W , Erwin R E , Heroff J C , Levi C , Maglone M , Schumacher D , Snyder K
Published: February 2020

Four duplicate samples of cocoa-containing materials, a practice sample, and standards were submitted to the collaborators for theobromine and caffeine analysis by HPLC. In the method the samples are defatted with petroleum ether, and dried. The fat-free residue is then extracted with water and an aliquot is injected into the chromatograph. Compounds are quantitated by comparison with internal or external standards, either by peak height or peak area. Results for all the analyses showed that few of the values were more than 2 standard deviations from the mean. The method has been adopted as official first action.
Gas Chromatographic Detection of the Mycotoxin Zearalenone in Blood Serum
Authors: Trenholm H Locksley , Warner Robert , Farnworth Edward R
Published: February 2020

A sensitive gas chromatographic method for the quantitative analysis of zearalenone in blood serum is described. Zearalenone is eluted from blood serum by column chromatography followed by base-acid extraction with dichloromethane as the organic phase. After epicoprostanol (internal standard) is added, the sample is evaporated to dryness, derivatized, and injected onto the gas chromatographic column. A number of silylating agents and reaction conditions were investigated. Derivatizing zearalenone with N-methyl-N-trimethylsilyltrifluoroacetamide in the presence of acetone at room temperature for at least 2 hr gave best results. Sensitivity limit is <0.5 ng injected, equivalent to 100 ng zearalenone/mL blood serum. A linear standard curve is observed when 0.5–30 ng zearalenone derivative is injected onto the Perkin-Elmer gas chromatograph. For quantitation, a standard curve is prepared by plotting amounts of zearalenone (ng) injected vs. ratios for peak areas of zearalenone and epicoprostanol derivatives. The internal standard procedure improves the precision by minimizing variations in sample injections and detector response. Percent recovery from blood serum is 68–75 in the range of 1.6–8.0 Mg zearalenone/mL blood
Liquid Chromatographic Determination of Tenuazonic Acids in Tomato Paste
Authors: Scott Peter M , Kanhere Shriniwas R
Published: February 2020

Tenuazonic acid is a mycotoxin produced by Alternaria alternata (A. tenuis) occurring in isolates from tomato. Several liquid chromatographic (LC) systems were compared for suitability in analyzing tomato pastes for tenuazonic acid. Tenuazonic acid was extracted from tomato paste with methanol and n-hexane and was partitioned into methylene chloride from the aqueous methanol following acidification. It was further partitioned into 5% NaHCO3, acidified, and reextracted with methylene chloride. LC separation of tenuazonic acid from interferences was best on a C12- dien (4-dodecyldiethylenetriamine) loaded C18 reverse phase column with a mobile phase containing C12-dien, Zn(II), and ammonium acetate, or on a tetraalkylammonium anion exchange columnat pH 7.5. Two isomeric tenuazonic acids could be partially separated in the C12-dien/metal system using acetonitrile in the mobile phase. Amounts of standard tenuazonic acid as low as 2–5 ng could be detected by UV absorbance at 280 nm. Recoveries of tenuazonic acid or isotenuazonic acid added to tomato paste at levels of 0.4–10 μg/g were 67–94%. Small amounts of tenuazonic acid were detected in several commercial tomato pastes at levels of 0.01–0.1 μg/g. Gas liquid chromatography/ mass spectrometric (GLC/MS) single ion monitoring showed that both isomers were present.
Determination of Roquefortine in Blue Cheese and Blue Cheese Dressing by High Pressure Liquid Chromatography With Ultraviolet and Electrochemical Detectors
Authors: Ware George M , Thorpe Charles W , Pohland Albert E
Published: February 2020

A method is described for the determination of roquefortine in blue cheese and blue cheese dressing. The method involves sample extraction with ethyl acetate, cleanup by liquid-liquid partition, and determination by high pressure liquid chromatography with ultraviolet and electrochemical detectors connected in series. Recoveries of roquefortine added to cheese at levels of from 16 to 320 ng/g averaged 74.9%. This method was applied to the analysis of 12 samples of blue cheese and 2 samples of blue cheese dressing, all of which were produced in the United States; roquefortine was found in all of the samples at average levels of 424 ng/g for the blue cheese and 45 ng/g for the blue cheese dressing.
Kjel-Foss Automatic Analysis Using an Antimony-Based Catalyst: Collaborative Study
Authors: Bjarn0 Ole-Christian ,   Collaborators:, Fry J C , Hoffman P H , Jensen K , Kaltwasser P , Lundberg A , Nolte A , Smith C A , Waltl K
Published: February 2020

Collaborators in 7 Kjel-Foss laboratories and 1 manual Kjeldahl laboratory performed protein determinations on fishmeal: 10 with traditional mercury catalyst and 10 with a new antimonybased catalyst. Repeatability, interlaboratory variation, and variation vs. manual Kjeldahl were equal to or better with the new catalyst than with the mercury catalyst. In addition, 48 different products were analyzed: 5-10 determinations were made on each product with the mercury catalyst and 5–10 were made with the new catalyst. After the Kjel-Foss procedure was modified slightly with higher acid settings, the differences in recovery and repeatability of the 2 procedures were not more than ±1%.
Spectrophotometric Determination of Sulfites, Benzoates, Sorbates, Ascorbates, and Added Blood in Ground Beef: Collaborative Study
Authors: Maxstadt John J , Pollman Roger M ,   Collaborators:, Calkins H , Dolan T S , Gilger V , Highley W , Inouye P G , Mayer D , McGill D L , Nickelsen L E , Soderberg D L , Srader L M , Thompson G , Wesson A , Webb N , Ziemer W A
Published: February 2020

A method for the determination of sulfite, benzoate, sorbate, ascorbic acid, and added blood in ground beef reported previously was studied collaboratively. Eleven laboratories reported results on 18 samples analyzed for the preservatives plus 6 samples analyzed for added blood. Average recoveries for sulfite added at the 0.02 and 0.04% levels were 44.3 and 70.6%, respectively; average recoveries for benzoate at 0.02 and 0.05% were 83.5 and 85.9%; average recoveries for sorbate at 0.01 and 0.02% were 82.7 and 87.3%; average recoveries for ascorbic acid at 0.02 and 0.04% were 71.0 and 69.8%. Only 5 of the 11 collaborators reported accurate results on the 6 samples for added blood, and further study of this procedure is recommended. The preservative method has been adopted as official first action.
On-Column Periodate Reaction Method for Analysis of Ephedrine Sulfate in Solid Dosage Forms: Collaborative Study
Authors: Clark Charles C ,   Collaborators:, Brittan W , Hezeau C , Hughes D , Knott T , Frick F , Sanders G , Schafer P K
Published: February 2020

Seven laboratories collaboratively studied a method for the quantitative ultraviolet (UV) determination of ephedrine sulfate in solid dosage forms. Ephedrine is separated from water-soluble impurities and strong acids by elution from a weakly basic Celite column, and further cleaned up by retention on a weakly acidic column while the weak acids, weak bases, and organic-soluble neutrals are eluted. Ephedrine is eluted from the column after neutralization with NH3 and is converted to benzaldehyde via an on-column periodate reaction. The samples collaboratively studied consisted of 3 synthetic preparations of known ephedrine sulfate concentrations and 2 commercial preparations containing ephedrine sulfate. One commercial sample was submitted as a blind duplicate. Recoveries for the synthetic preparations averaged 101.7, 101.2, and 100.5% for mixtures containing 7.93, 9.35, and 6.85% ephedrine sulfate, respectively. The means and standard deviations for the commercial preparations were 24.72 ± 0.376 mg/dosage unit for the preparation labeled to contain 25 mg/dosage unit, and 22.46 ± 0.643 and 22.29 ± 0.339 mg/dosage unit for the blind duplicate labeled to contain 24 mg/dosage unit. The method has been adopted as official first action.
Specific Programmed Multiple Development–Thin Layer Chromatography of Furazolidone in Chicken, Turkey, Swine, and Bovine Tissues: Collaborative Study
Authors: Heotis James P , Mertz James L , Herrett Ronald J , Diaz Joseph R , Van Hart Daniel C , Olivard Joanne ,   Collaborators:, Colman W F , Hornish R E , Koster J , Lawrence W , Miller J A , Neff A W , Neuman J F , Zietlow D C
Published: February 2020

A specific method for assay of furazolidone at 2 ppb has been developed using programmed multiple development-thin layer chromatography (PMD-TLC) and the conversion of the drug to a fluorescent species which is quantitated by fluorodensitometry on the TLC plate. The method requires only 5 g tissue, specifies an automatic spotter for PMD-TLC, and is capable of measuring <1 ng of drug when the fluorodensitometer is coupled with a computing integrator. This procedure requires an average of 2 man-hours per sample and can be completed in one day. Six laboratories collaboratively studied the method for assay of furazolidone at the 2, 3, and 6 ppb levels in chicken, turkey, swine, and bovine tissues. Tissues were fortified by each laboratory and then processed through extraction, solvent partition, programmed multiple development-thin layer chromatography, and fluorodensitometry. Results showed satisfactory recoveries and accuracy. A statistical comparison of the results demonstrated that 5 of the 6 laboratories obtained similar results. The higher responses from the sixth laboratory appeared to be due to an exceptional vacuum system and the use of silated flasks. The mean drug recovery response for the tissues spiked at 2 ppb from the 5 laboratories was 2.2324 ng ± 20.2% (SD), which at the 99.7% confidence level gives no overlap with control tissue data. The results can be expected to be repeatable within and among laboratories.
High Pressure Liquid Chromatographic Determination of Sulfamethazine or Sulfathiazole and Colorimetric Determination of Sulfathiazole in Feeds: Collaborative Studies
Authors: Cieri Ugo R ,   Collaborators:, Ameika L , Billings T , Brookhart G , Detablan N , Foster C L , Gardner A , George G M , Illuminati J C , Jeffres D , Jensen T , Lonn P D , Nandrea G , Reeves P
Published: February 2020

A high pressure liquid chromatographic method for sulfamethazine or sulfathiazole in feeds was studied collaboratively. The sample is extracted in 50% methanol and filtered, and an aliquot is injected into a liquid chromatograph. The column is μBondapak C18, the eluting solvent is acetonitrile–water (20+80), and the detection wavelength is 280 nm. Nine collaborators analyzed 3 different synthetic samples and 2 commercial samples labeled to contain 0.011% sulfamethazine, plus procaine penicillin and chlortetracycline. Average recoveries for the synthetic samples were 102.2% at the 0.005% level, 100.2% at the 0.01% level, and 103.6% at the 0.02% level; per cent standard deviations were 12.7, 10.4, and 8.67, respectively. Average sulfamethazine content of the 2 commercial samples was 77.8 and 82.9% of label with per cent standard deviations of 8.56 and 9.16. The same 2 samples, analyzed according to the official colorimetric procedure by 6 analysts, had an average sulfamethazine content of 81.7 and 89.4% of label with per cent standard deviations of 3.69 and 6.66. Eight collaborators analyzed 3 different synthetic samples and 2 commercial samples labeled to contain 0.011% sulfathiazole, plus procaine penicillin and chlortetracycline. Average recoveries of the synthetic samples were 101.6% at the 0.005% level, 103.0% at the 0.01% level, and 100.4% at the 0.02% level; per cent standard deviations were 9.52, 7.00, and 6.54. Average sulfathiazole content found by 9 collaborators was 0.0103% or 93.4% of label for Sample 1 and 0.0100% or 91.1% of label for Sample 2, with per cent standard deviations of 14.1 and 12.2. Colorimetric assays for sulfathiazole were made according to method 42.172–42.174 for sulfamethazine. Two synthetic samples were analyzed by 7 collaborators. Average recovery was 97.6% at the 0.01% level and 99.8% at the 0.02% level with per cent standard deviations of 5.05 and 8.16. The same 2 commercial samples used for the HPLC study were analyzed by 9 collaborators. Average sulfathiazole found was 86.4 and 87.9% of label with per cent standard deviations of 7.41 and 6.15.
Review of Soil and Plant Tissue Preparation Procedures
Authors: Lockman Raymond B
Published: February 2020

Soil and plant sample analyses for total nutrients or extractable forms of nutrients are variably affected by drying, grinding, storage, and even collection tools. In addition, plant analyses can be biased by washing techniques. This paper reviews many sample handling procedures and discusses their advantages and disadvantages.
Gas-Liquid Chromatographic Determination of Disulfoton in Formulations: Collaborative Study
Authors: Jensen Thomas L ,   Collaborators:, Audino J B , Bishop R , Chenery L , Conner D , Eggers R L , Ellis N D , Garret R A , Hodgins W E , Karr J J , Korger P , Topping A , Ullrich L , Wargacki R E , Willemsz-Geeroms B
Published: February 2020

A rapid method is described for the determination of disulfoton (0,0-diethyl S-[2-(ethylthio)-ethyl] phosphorodithioate) in formulations by gasliquid chromatography (GLC). Samples are dissolved in acetone, and, after an internal standard is added, the samples are diluted to volume with solvent. They are then injected into a gas chromatograph equipped with a flame ionization detector and quantitated by peak height or area measurements. Fourteen collaborators made duplicate determinations on 4 samples including the technical product, a liquid, and 2 granular formulations. The average coefficient of variation was 0.847% for the liquid samples and 1.90% for the granules. The method has been adopted as official first action.
Analytical Errors Resulting from Nitrate Contamination of Filter Paper
Authors: Muneta Paul
Published: February 2020

Certain brands and grades of filter paper can contribute significant errors up to 20–30 ppm nitrate nitrogen in the nitrate analysis of cured meats. Filter paper for qualitative filtration contained the largest quantity of nitrate. The brand of filter paper determined the nitrate extracted from the filter paper. Low ash or ashless quantitative filter paper contained no nitrate, except 1 box, from which a very small quantity of nitrate was extracted.
Aflatoxin Control: Past and Present
Authors: Stoloff Leonard
Published: February 2020

Domestic commodities most susceptible to aflatoxin contamination are peanuts, corn, cottonseed, and tree nuts (almonds, pecans, walnuts); the most susceptible imported commodities are Brazil nuts and pistachio nuts. The development, effectiveness, and shortcomings of the strategies used to limit consumer exposure to aflatoxin from these commodities are reviewed.
Gas-Liquid Chromatographic Determination of S-[(5-Methoxy-2-oxo-1,3,4-thiadiazol-3(2H)-yl)-methyl]O,O-dimethyl Phosphorodithioate (Supracide) and Its Monoxone Metabolite in Safflower Seed, Meal, and Oil
Authors: Winterlin Wray , Whitehead Eugene , Mourer Charles
Published: February 2020

A gas-liquid chromatographic (GLC) method for determining residues of the insecticide-acaricide Supracide (S-[5-methoxy-2-oxo-l,3,4-thiadiazol-3(2H)-yl)-methyl]O,O-dimethyl phosphorodithioate) and its monoxone metabolite in safflower seed, meal, and oil is presented. Supracide and its monoxone metabolite are separated by partitioning with acetonitrile-sodium sulfate and petroleum ether. The petroleum ether fraction containing the Supracide is extracted with acetonitrile and further cleaned up on a Florisil column before determination by GLC, flame photometric detection (FPD). The monoxone metabolite is partitioned from the acetonitrile-sodium sulfate fraction with chloroform and cleaned up on a Florisil column before GLC/FPD. Average Supracide recoveries were 86, 82.5, and 92%, and average Supracide monoxone recoveries were 85.7, 81.5, and 89%, in seed, meal, and oil, respectively. The limit of detection was 0.005 ppm for both compounds on all tissues analyzed.
Improved Method for Hexachlorobenzene and Mirex Determination with Hexachlorobenzene Confirmation in Adipose Tissue: Collaborative Study
Authors: Watts Randall R , Hodgson David W , Crist Howard L , Moseman Robert F ,   Collaborators:, Barquet A , Cain J , Colcolough J , Cox V , Enos H , Filonow A B , Gardner B , Gomes E , Hetzler H , Leavitt R A , Leventis A -M C , Morgade C , Morgner R , Richardson E , Slach E , Stringer R , Tessari J , Warnick S L , Welch R L
Published: February 2020

A previously published method for determination and confirmation of hexachlorobenzene (HCB) in adipose tissue was also applied to mirex residues. A modified procedure for both residues was collaboratively studied by 12 laboratories. The procedure specifies direct application of an extracted or rendered fat sample to a Florisil cleanup column and one-fraction elution. Mirex and HCB are determined by direct GLC of the concentrated eluate. HCB residues are then confirmed by reaction with isopropanol to form the disubstituted bis-isopropoxytetrachlorobenzene (BITB) derivative. Mirex residues are destroyed by this reaction. All participants were asked to analyze an unknown standard mixture of HCB and mirex and 10 rendered chicken fat samples consisting of one blank and 9 samples fortified with unknown amounts of HCB and mirex. The 9 fortified samples represented 3 samples at each of 3 fortification levels. The HCB fortifications of 20.0, 33.3, and 50.0 ppb yielded average interlaboratory recoveries of 89.6, 87.4, and 92.6%, respectively. The respective coefficients of variation (CV) for HCB results were 9.1, 6.8, and 10.0%. The mirex fortifications of 150, 300, and 500 ppb yielded average interlaboratory recoveries of 89.0, 90.2, and 92.3%, respectively. The respective CV values for mirex results were 7.6, 16.5, and 18.1%. The method has been adopted official first action.
Determination of Proof of Alcoholic Beverages Using Oscillating U-Tube Density Meter
Authors: Mark Frances G , Vaughn Troy E
Published: February 2020

The density meter provides a rapid and reliable means for determining proof of alcoholic beverages. The instrument measures the oscillation period of a U-shaped tube filled with sample and, when calibrated in specific gravity units, computes the specific gravity of the sample and presents the result as a digital display. Proof is obtained from specific gravity by use of conversion tables. Air and water are used as calibration standards. Specific gravity values are reproducible to ±0.000 01 which corresponds to an error of no more than ±0.02° proof. Proof values are within ±0.1° proof when compared to results obtained using pycnometer and hydrometer. Proof measurements are reported for ethanol–water solutions from 20 to 100° proof and for various distilled beverages, cordials, and speciality products.
Extraction and Separation of Staphylococcal Enterotoxin in Foods: Collaborative Study
Authors: Bennett Reginald W , Mcclure Foster ,   Collaborators:, Bryant J , Bryant R , Campbell W , Clarke J , Cleveland J , Grahn M , Lancette G , Mageau R , McCall W , Reese B , Rivas M , Ruby R , Tatini S , Zaika L
Published: February 2020

A study was performed by 15 collaborators on a method for the extraction and chromatographic separation of Staphylococcus aureus enterotoxins from foods. Enterotoxin types A–E were added to crabmeat, milk, ground beef, and potato. Evaluation of the method was based on solubility of food eluates after extraction and separation of the enterotoxin; efficiency of recovery of enterotoxins A–E from foods; and serological categorizing of foods, as determined by the presence or absence of enterotoxins in the 8 food samples studied. The collaborative results on sample solubility, detection and identification of enterotoxin in foods, and differentiation of toxic from nontoxic samples showed overall positive rates of 94.79, 72.69, and 99.23%, respectively. The method, which has been substantiated by statistical evaluation, appears to be effective for the separation of staphylococcal enterotoxins from foods. The Association has adopted the method as official first action and no adverse comments have been received.
Determination of Vitamin E in Animal Feeds by Normal Phase High Pressure Liquid Chromatography
Authors: Cohen Huguette , Lapointe Michel R
Published: February 2020

A simple and rapid quantitative method for the determination of vitamin E in animal feeds is described. The method involves direct extraction with a mixture of isooctane–l,4-dioxane (80 + 20) followed by saponification. Additional purification was achieved by using a silica gel Sep-Pak. Elution time for vitamin E alcohol was 7.98 min (standard deviation (SD) 0.06) using a Partisil-10 PAC column and an isocratic mobile phase of hexane–dichloromethane–isopropanol (70 + 30 + 0.2) with a flow rate of 1 mL/min, and detection at 292 nm and 0.01 AUFS by a variable UV monitor. The average recovery of vitamin E was 96.64% (SD 5.19) in 4 different animal feeds. The method compared favorably with the official AOAC method. The minimum detectable amount of vitamin E in an animal feed is 10 IU/kg.
Extraction of Light Filth from Ground Allspice: Collaborative Study
Authors: Dent Russell G ,   Collaborators:, Eye J G , Freeman C C , Hall E , Karpus J T , Palmer W , Senff W A
Published: February 2020

The present official AOAC method (44.120(a)(b), 13th Ed.) for extracting light filth from ground allspice uses flammable solvents and gives poor filth recoveries. An improved method has been developed which uses a single pretreatment with 40% isopropanol and hydrochloric acid, followed by wet sieving. After deaeration by boiling, the light filth is extracted from 40% isopropanol-Tween 80-tetrasodium EDTA with light mineral oil. Reports from all 6 collaborators showed that the proposed method resulted in 90 and 89% average recoveries of rodent hairs and insect fragments, respectively. The proposed method is recommended for adoption as official first action to replace AOAC (44.120(a)(b)) for allspice.
High Performance Liquid Chromatographic Method for Simultaneous Determination of Residual Benomyl and Methyl 2-BenzimidazoIe Carbamate on Apple Foliage Without Cleanup
Authors: Chiba Mikio , Veres D F
Published: February 2020

A simple HPLC method has been developed to individually determine residues of benomyl and MBC on apple leaves without cleanup. Sample leaves in a Mason jar are freeze-dried and tumbled for extraction in CHC13 containing 5000 μg n-propyl isocyanate/mL at 1°C. n-Butyl isocyanate is added to the extract at 5000 μg/mL, and 20 μL of the mixture is injected into the HPLC system. A Brownlee LiChrosorb silica gel column with a guard column is operated with a mixed mobile phase of chloroform-hexane (4+1) saturated with water. MBC, present as a degradation compound of benomyl, is identified as methyl 1 – (n – propylcarbamoyl) – 2 – benzimidazole carbamate (MBC-n-PIC derivative). At 280 nm, both benomyl and MBC-n-PIC can be detected with a UV detector at a level of 0.2 ppm in apple leaves.
Visible and Ultraviolet Absorption and Fluorescence Excitation and Emission Characteristics of Florida Orange Juice and Orange Pulpwash: Detection of Adulteration
Authors: Petrus Donald R , Attaway John A
Published: February 2020

Visible and ultraviolet absorption and room temperature fluorescence excitation and emission spectra, obtained from alcoholic solutions of Florida orange juice and pulpwash, were investigated to characterize citrus products, and thereby detect adulteration and approximate orange juice content. Absorption shoulders and maxima were observed at 465, 443, and 425 nm of the visible spectrum and at 325, 280, and 245 nm of the ultraviolet spectrum. The spectral curves for orange juice and pulpwash were similar. However, orange pulpwash had weaker visible and stronger ultraviolet absorption than did orange juice. It was determined (416 frozen concentrated orange juice and 206 orange pulpwash samples obtained from Florida commercial processors) that the average sum and standard deviation of absorbance at 443, 325, and 280 nm was 2.410 ± 0.164 for orange juice and 3.781 ± 0.473 for orange pulpwash (based on reconstituted 12.8° Brix products). Average absorbance 443/325 nm ratio was 0.144 ± 0.026 for orange juice and 0.048 ± 0.020 for orange pulpwash. Simple dilutions of orange juice with water and/or sugar solutions resulted in a linear decrease in absorbance sum while the absorbance ratio remained essentially the same. Orange juice and pulpwash systems resulted in a linear increase in absorbance sum and a decrease in absorbance ratio (natural log function). The investigation enabled the derivation of equations, using absorption data, to approximate orange juice and/or pulpwash contents and/or dilution of a sample. The constants used in the equations were based on results obtained from commercially produced Florida citrus products and may vary with other citrus-producing regions. Fluorescence excitation and emission spectra complemented the absorption spectra. Fluorescence excitation for orange juice was maximum at 283 nm with a shoulder at 291 and inflections at 270 and 302 nm with maximum emission at 333 nm. Excitation was also maximum at 291 nm with a shoulder at 283 and inflections at 270 and 302 with maximum emission at 343 nm. Pulpwash excitation was maximum at 270 and 302 nm with a minimum at 283 nm and emission at 353 nm. Peaks or pronounced shoulders at 270 and 302 nm have been indicative of the presence of orange pulpwash.
Ultraviolet Spectrophotometric Determination of Sorbic Acid in Dry Fermented Sausage
Authors: Holley Richard A , Millard George E
Published: February 2020

A rapid and reliable method is described for determining sorbic acid in dry fermented Italian salami (moisture <50%, fat >25%). Sorbic acid was extracted from the homogenized sample with metaphosphoric acid and partitioned into isooctane. The absorbance of the extract was read at 255 nm. Background UV-absorbing materials were determined by their absorbance at 255 nm after permanganate oxidation of sorbic acid. Unexpectedly, spice components contributed to the UV absorbance of permanganate-labile substances, and sorbic acid was at first overestimated. Interference caused by spice components was calculated by measuring the difference in absorbance before and after permanganate treatment of a sample extract from a salami which had not been treated with sorbic acid. Recovery of added sorbic acid (50 –600 ppm) was between 92 and 98.7%.
Commentary on AOAC Method for Paralytic Shellfish Poisoning
Authors: Adams Willard N , Miescier John J
Published: February 2020

Paralytic shellfish poisoning (PSP) is caused by ingesting bivalve molluscan shellfish which have fed on the toxigenic marine dinoflagellates Conyaulax catanella or G. tamarensis. The toxins from these organisms are neurotoxic alkaloids which interfere with nerve conduction and block muscleaction potential. The U.S. Food and Drug Administration cooperates with state shellfish control officials in the National Shellfish Sanitation Program to prevent marketing of toxin-contaminated shellfish. The toxins are quantitated by the standard mouse bioassay method, as found in Official Methods of Analysis of the AOAC. This paper discusses the procedure followed in the standard bioassay method in an attempt to clarify for the PSP analyst the rather complex official methodology and, thus, promote more uniform results among laboratories.
Simplified Method for Estimation of DDT and Hexachlorocyclohexane Residues in Milk
Authors: Kapoor Sudesh K , Chawla Ram P , Kalra Rajinder L
Published: February 2020

A procedure that combines acetone-hexane extraction and cleanup by treatment with concentrated sulfuric acid is described for determining DDT and 1,2,3,4,5,6-hexachlorocyclohexane (HCH) residues in milk. Recoveries from samples fortified with 0.004-0.008 ppm of different HCH isomers and 0.01-0.02 ppm DDT and its metabolites ranged from 83.4 to 99.8%. The proposed method is simple and rapid, and does not require the use of costly adsorbents.
Comparison of Automated Method and Improved AOAC Kjeldahl Method for Determination of Protein in Meat and Meat Products
Authors: McGill Debra L
Published: February 2020

The Kjel-Foss automated method for protein determination in meat and meat products was compared with the improved AOAC Kjeldahl method. Meat samples were separated into 3 categories based on fat content and analyzed in duplicate by both methods. No significant difference was found in a paired comparison of the 2 methods in each of the 3 meat categories, using Student’s t-test at the 99% confidence level. A number of additional meat samples analyzed 6-9 times by the automated method showed an overall average range of 0.55% protein and average standard deviation of 0.20. The Kjel-Foss automated method was applicable for total protein determination in a wide variety of meat and meat products.
Rapid Fish Species Identification by Agarose Gel Isoelectric Focusing of Sarcoplasmic Proteins
Authors: Lundstrom Ronald C
Published: February 2020

A rapid method is described for fish species identification by agarose gel isoelectric focusing (AGIEF). The AGIEF method can be completed in less than 2 h and gives reproducible species-specific sarcoplasmic protein patterns. Protein patterns are similar using either centrifuged tissue fluid or muscle tissue as the sample. One species, monkfish (Lophius americanus), has a polymorphic protein pattern. A predominant pattern was found in 66.7% of the individuals; 2 variant patterns were equally distributed among the remaining 33.3%. AGIEF offers a more rapid, less expensive alternative to the current AOAC official first action method for fish species identification based on polyacrylamide gel isoelectric focusing.
Atomic Absorption Spectrophotometric Method for Determination of Water-Soluble Copper in Water-Insoluble Copper Fungicides: CIPAC Collaborative Study. Comparison with Bathocuproine Method
Authors: Rasero F Sánchez ,   Collaborators:, Balayannis P G , Beyers H P , Celma E , Hays E H , Magallanes M , Meier J , Roofayel R L
Published: February 2020

An atomic absorption spectrophotometric (AAS) method was collaboratively studied by 8 laboratories from Africa, the United States, Australia, and Europe. The samples were dispersed in deionized water. After centrifuging and filtering, the water-soluble copper in the filtrate was acidified and measured by atomic absorption spectrophotometry, in an airacetylene flame, at 324.7 nm. The results from 7 laboratories were satisfactory and no unfavorable comments were received. Repeatability standard deviations ranged from 0.005 to 0.023, and reproducibility standard deviations ranged from 0.012 to 0.062. When compared with the bathocuproine method, the difference in bias between both methods is not significant. They were both adopted as full CIPAC methods, with the bathocuproine method as the referee method. Both methods have been adopted official first action.
Detection of High Fructose Corn Syrup in Apple Juice by Mass Spectrometric 13C/12C Analysis: Collaborative Study
Authors: Doner Landis W , Phillips John G ,   Collaborators:, Gearing J N , Hillaire-Marcel C , Parker P L , Reeseman R M , Smith B N , Ziegler H
Published: February 2020

The addition of high fructose corn syrups (HFCSs) to apple juice can be detected by mass spectrometric determination of 13C/12C ratios. Forty-one pure apple juice samples, representing 18 varieties, gave a mean value for δ13C of −25.3‰ (parts per thousand), while 4 HFCSs averaged −9.7‰. In a collaborative study, 1 pure apple juice and 4 apple juice-HFCS mixtures containing from 25 to 70% apple juice were properly classified by 6 laboratories. Samples with δ13C values less negative than −20.2‰, 4 standard deviations from the mean of pure juices, can, with a high degree of confidence, be classified as adulterated. Because of the range of values for pure apple juices, other interpretations of δ13C data on suspect samples are meaningless (i.e., samples with values more negative than −20.2‰ must be considered unadulterated with HFCS). The 13C/12C mass spectrometric method for corn syrup products, 31.150-31.153, has been adopted official first action for detecting HFCS in apple juice.
Free Sugars and Sorbitol in Fruits — A Compilation from the Literature
Authors: Wrolstad Ronald E , Shallenberger Robert S
Published: February 2020

The glucose, fructose, sucrose, and sorbitol content of apple, pear, plum, cherry, grape, strawberry, raspberry, blackberry, and peach fruit was compiled from the literature; their range, mean, standard deviation, and percent coefficient of variance were calculated. The individual fruits have characteristic patterns relating to their sorbitol content, glucose: fructose ratio, and sucrose content which are influenced to only a small degree by variety, season, or geographic origin. Processing in many cases has a marked effect on sucrose content
High Performance Liquid Chromatographic Determination of Intermediates and Two Reaction By-Products in FD&C Red No. 40: Collaborative Study
Authors: Cox Elizabeth A , Reed George F ,   Collaborators:, Bille L , Bischof R , Gasper G , Gunn M , King J , Penta F , Richfield-Fratz N , Seager J , Sharpies W , Young R
Published: February 2020

Nine laboratories participated in a collaborative study of an ion exchange high performance liquid chromatographic procedure for determining the intermediates and 2 reaction by-products in FD&C Red No. 40: cresidine sulfonic acid (CSA), Schaeffer’s Salt (SS), 4,4’-(diazoamino)bis(5-methoxy-2-methylbenzenesulfonic acid) (DMMA), and 6,6’-oxybis(2- naphthalenesulfonic acid) (DONS), respectively. The repeatability and reproducibility standard deviations (absolute) found in the study were 0.012 and 0.019 for CSA at the 0.2% level, 0.004 and 0.006 for DMMA at the 0.1% level, 0.067 and 0.087 for DONS at the 1% level, and 0.015 and 0.020 for SS at the 0.3% level, respectively. The method has been adopted official first action.
Density Meter Determination of Proof of Alcoholic Beverages: Collaborative Study
Authors: Strunk Duane H , Hamman Jack W , Aicken John C , Andreasen Arthur A ,   Collaborators:, Aicken J C , Eichner J M , Feeny F , Hamman J W , Hoehn H J , Mark F G , Martin G E , Morano D E , O’Bryan W C , Perreault A W , Piet M , Reh B W , Strunk D H , Timmel B M
Published: February 2020

A procedure using the Mettler/Paar density meter to measure the concentration of ethanol in aqueous solutions has been collaboratively studied. This instrument measures specific gravity to ±0.00001, which corresponds to ±0.02° proof. Fourteen collaborators determined the ethanol concentration in 7 different samples varying in proof from 1 to 190°. The density meter values for these samples are 0.00 to 0.17° lower than true proof as determined by a pycnometer. This is the result of nonlinearity which occurs when the specific gravity of ethanol solutions is plotted vs concentration. A graph or programmed calculator can be used to correct for this difference.
Particle Size and Concentration Adjustments of Tomato Products for Howard Mold Count
Authors: Bandler Ruth , Cichowicz Stanley M ,   Collaborators:, Cichowicz S , Floyd D , Kaminski J , Russell G , Senff W , Trauba R
Published: February 2020

The present AOAC method for mold counts of tomato products (44.096) provides no inter-product standardization of concentration among juice, sauce, paste, puree, and catsup; no intra-product standardization of concentration for juice, sauce, and catsup; and no adjustment for degree of comminution. Use of the official method, therefore, could result in an artificially increased mold count for products which have undergone extreme comminution. A new method was developed to adjust all products to the same concentration and grind them to a uniform particle size, thereby ensuring comparable mold counts on products produced by different processes. Collaborative study results showed equal repeatability for both the official and the proposed methods and a lower coefficient of variation for the proposed method.
Calibration and the Straight Line: Current Statistical Practices
Authors: Hunter J Stuart
Published: February 2020

A recent article used data involving high pressure liquid chromatographic (HPLC) analyses of known concentrations of FD&C Red No. 2 (and other colors) and statistical methods to determine prediction intervals and an estimate of the limit of detection. Using data from this article, the present paper expands on these uses of statistics. Described are the various confidence interval estimates associated with a fitted straight line that use Student′s t statistic, the construction and use of a confidence region for the slope and intercept of the line using Snedecor′s F, the construction of the Working-Hotelling-Scheffé bounds for the true line, and limits appropriate to the repeated use of the fitted line. The inverse use of the fitted line (the calibration problem) is next discussed, and an interval estimate is constructed for the true amount of Red No. 2, given future HPLC readings. The statistical methods described are of general applicability and should be in wider use.
High Pressure Liquid Chromatographic Method for Indole in Shrimp: Development of Method and Collaborative Study
Authors: Chambers Theodore L , Staruszkiewicz Walter F ,   Collaborators:, Bohm G , Bond J F , Carr R , Edge D J , Everett R L , Illuminati J C , Rose J La , Mcmurtrey K , Miller G , Panaro K W , Smith B H
Published: February 2020

A collaborative study on the determination of indole in shrimp was conducted in which a high pressure liquid chromatographic (HPLC) method and a spectrofluorometric method were compared with the AOAC gas-liquid chromatographic (GLC) method (18.075–18.078,13th ed.). In the HPLC method, 10 g shrimp was blended with methanol, an internal standard was added, and the extract was filtered. Indole was separated on an octadecylsilane reverse phase column, using 60% MeOH-H2O, and quantitated with a fluorescence detector (excitation 280 nm, emission 330 nm) by comparing the indole peak height with that of an internal standard, 2-methylindole. Recoveries at a 25 μg/100 g level averaged 104% with a range of 90–127%, and at a level of 35 μg/100 g averaged 102% with a range of 93–112%. In the spectrofluorometric method, 25 g shrimp was extracted with 2% EtOAc-hexane. After several washes, indole was partitioned into a saturated NaCl-MeOH solution and its fluorescence was measured (excitation 280 nm, emission 332 nm). Recoveries at a 25 μg/100 g level averaged 93% with a range of 0–255% and at a level of 35 μg/100 g averaged 64% with a range of 0–107%. Recoveries obtained by the AOAC-GLC method at a level of 25 μg/100 g averaged 96% with a range of 81–116% and at a level of 35 μg/100 g averaged 101% with a range of 81–119%. The coefficients of variation were 20,10, and 64% at a 25 μg/100 g level for the GLC method, the HPLC method, and the spectrofluorometric method, respectively. The HPLC method was adopted as official first action for indole levels in shrimp exceeding 1 μg/100 g.
Comparison of Modified A-1 Method with Standard EC Test for Recovery of Fecal Coliform Bacteria for Shellfish
Authors: Hunt Daniel A , Lucas John P , Mcclure Foster D , Springer Janet , Newell Richard
Published: February 2020

This study is one of a series in which variations of the A-1 method for the detection and enumeration of (ecal coliforms and Escherichia coli in seawater and foods were evaluated. The tests were conducted jointly by the Food and Drug Administration and state and provincial laboratories that support shellfish control programs in the United States and Canada as part of the National Shellfish Sanitation Program’s Microbiology Task Force activities. Results showed significantly higher recovery of fecal coliforms from naturally contaminated shellfish by the AOAC official A-l-M method than by the American Public Health Association standard method. There was no significant difference in recovery of E coii by the 2 methods.
Identification of Trialkyl and Triaryl Phosphates in Distilled and Super-Q Water
Authors: Williams David T , Lebel Guy L , Benoit Frank M
Published: February 2020

An unknown compound detected in an extract from water purified through a Millipore Super-Q system has been identified as tributoxyethyl phosphate by gas chromatographic retention times and by gas chromatography/mass spectrometry. Purified water from distillation systems also contained trialkyl/aryl phosphate plasticizers/flame retardant additives: Tris(l,3-dichloropropyl) phosphate and triphenyl phosphate were formally identified and isopropylphenyl diphenyl phosphate was tentatively identified from mass spectra interpretation and from GC retention times on 2 chromatographic columns.
Minicolumn Detection Methods for Aflatoxin in Raw Peanuts: Collaborative Study
Authors: Shotwell Odette L , Holaday Charles E ,   Collaborators:, Athnasios A K , Ayres J L , Baxley J R , Bean G A , Chisholm T , Edds G T , Erickson R , Holaday C E , Johnson H S , Lowie D M , Minyard J P , Nesheim S , Rashmawi K J , Romer T R , Shannon G M , Soloman W , Teague R T , Wilson D M
Published: February 2020

The Holaday-Velasco method and a modified Holaday method have been compared. The former method combines the speed and simplicity of the Holaday extraction and cleanup with the sensitivity of the minicolumn originally described by Velasco. The combination method has been approved by the AOAC and the AACC for determining aflatoxin in corn. The Holaday method was modified by substituting toluene for benzene in the solvent partition, and methylene chloride for chloroform in the minicolumn development to eliminate use of hazardous solvents. The neutral alumina in the Holaday minicolumn was changed from activity V to activity III to provide a more stable column. At aflatoxin levels in raw peanuts of 13-20 ng/g, the presence of aflatoxin was missed by the modified Holaday method in 4 analyses (3 laboratories) of 42 reported. There were no misses in this contamination range by the Holaday-Velasco method. There were no misses by either method with samples containing >20 ng total anatoxins/g. Analysis of uncontaminated raw peanuts by the modified Holaday method resulted in 2 false positives of 14 reports; the Holaday-Velasco method produced no false positive reports from 15 analyses of uncontaminated peanuts. The Holaday-Velasco method was adopted official first action for peanuts.
Spectrophotometric Determination of Dicumarol in Sweet Clover
Authors: Casper Howard H , Benson Margaret E , Kunerth Wallace
Published: February 2020

A procedure is described for the purification and quantitation of dicumarol in sweet clover. The toxin is extracted by refluxing the sweet clover with 1,2-dichloroethane and 1M NaH2PO4, and partially purifying the extract by base partitioning. The extract is examined by thin layer chromatography, and then the dicumarol band is eluted and quantitated by ultraviolet spectrometry. All interferences are removed when the procedure is applied to moldy and nonmoldy sweet clover. The estimated limit of detection is 1 mg dicumarol/kg sweet clover. At the 10 mg/kg level the procedure standard recovery is 91 ± 1%. The recovery of a dicumarol standard addition (10mg/kg) from a moldy (15 mg dicumarol/kg) sweet clover pool was 95 ± 1%.