bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of Two-Dimensional Thin Layer Chromatographic Analysis of Aflatoxin B1 in Peanut Butter Extracts, Using the Antidiagonal Spot Application Technique
Authors: Beljaars Paul R , Verhülsdonk Cornelius A H , Paulsch Walter E , LIEM DHIAM H 
Published: February 2020

Abstract
A collaborative study has been carried out among 20 laboratories in The Netherlands, representing governmental and industrial institutes, on the determination of aflatoxin B1 in peanut butter extracts. Blank peanut butter extracts prepared according to the proposed official Dutch method were spiked with aflatoxin B1, representing contamination levels of 0, 3, 6, and 12 μg B1/kg. Samples and standards were spotted on silica gel G TLC plates by the antidiagonal spot application technique described herein. Spotted plates were developed by 2-dimensional TLC with diethyl ether-methanol-water (94+4.5+1.5; lined tank) in the first direction and chloroform-acetone (90+10; unlined tank) in the second direction. Separated B1 spots from sample and standards developed in both directions were free from background interference. The quantity of aflatoxin B1 present in the sample was established by visual comparison of the fluorescent intensities of sample and standard B1 spots. For this procedure the variability of measurements within and between laboratories was statistically investigated: 80–90% of the complete results given by the participants were correct for the hlank and spiked extracts (contamination level of 12 μg B1/kg). For contamination levels of 3 and 6 μg B1/kg an approximate coefficient of variation of 35% was calculated for within- and between-laboratory results. Results obtained in this investigation were compared with those found by previous investigators who used the one-dimensional TLC technique. It is concluded that, with the antidiagonal procedure, small amounts of aflatoxin B1 (lowest level tested, 3 ppb) may be detected.
Determination of Isonicotinic Acid Hydrazide by Direct Bromimetric Titration
Authors: Urbanyi Tibor , Winchurch Robert 
Published: February 2020

Abstract
Isonicotinic acid hydrazide alone and in tablet formulations was determined by a bromimetric titration. This titration gave more accurate and reproducible results and was more rapid than the iodometric method. The end point of the titration was detected visually or electrometrically. Electrometric titrations were used only for formulations in which an ingredient obscured the visual end point detection because of its strong color. Oxidizable compounds such as carbohydrates, which are common excipients in formulations and which gave high assay results with the iodometric method, do not interfere. The proposed method can be employed for formulations without any time-consuming preparations.
Determination of Sulfaquinoxaline, Sulfathiazole, Sulfamerazine, and Sulfamethazine in Feed Concentrates or Premixes
Authors: Cieri Ugo R 
Published: February 2020

Abstract
Sulfaquinoxaline is determined by its UV absorbance at about 358 nm, where the other 3 sulfonamides do not absorb. Sulfathiazole, sulfamerazine, and sulfamethazine are determined by a quantitative TLC procedure, based on the separation of the compounds on silica gel plates; the spots are extracted and the centrifuged extracts are analyzed spectro-photometrically. A method of calculating the total sulfonamide content, independent of the individual components, is also introduced.
Formation of Pentafluorobenzyl Derivatives for the Identification and Quantitation of Acid and Phenol Pesticide Residues
Authors: Johnson Lauren G 
Published: February 2020

Abstract
A procedure is described for the preparation and electron capture GLC determination of pentafluorobenzyl ester and ether derivatives of 2,4-D, p,p′-DDA, 1-naphthol, p-nitrophenol, and sec.-amyl phenols. A column cleanup procedure quantitatively isolates the derivatives from excess reagents and other interferences. The method can be used as an aid in the confirmation of the identity of pesticide residues and for the quantitative determination of extracted residues.
Modified Procedure for Determining Mercury in Coal by Cold Vapor Atomic Absorption Spectrophotometry
Authors: Lo Fa-Chun , Bush Brian 
Published: February 2020

Abstract
The combustion procedure previously described for the determination of mercury in coal by cold vapor atomic absorption spectrophotometry has been modified to permit samples to be analyzed more rapidly and with better precision. A coefficient of 8.3% was obtained for the analysis of 7 samples containing 0.1 ppm mercury. In addition a greater variety of types and particle sizes of coal can be analyzed by the modified procedure.
Column Chromatographic Cleanup and Gas-Liquid Chromatographic Determination of Hydroxybenzoic Esters in Food
Authors: Daenens Paul , Laruelle Leander 
Published: February 2020

Abstract
Hydroxybenzoic acid esters are isolated on a column of silica gel while interferences are removed with petroleum ether. The preservatives are then eluted with petroleum ether-diethyl ether (8+2), derivatives are formed by reaction with bis(trimethylsilyl)acetamide, and the concentrations are determined by gas-liquid chromatography.
Microbiological Determination of Thiram
Authors: Rappe Andre , Mauquoy Guy , Baur Serge 
Published: February 2020

Abstract
A rapid and simple agar plate method has been developed for the microbiological determination of thiram, using Saccharomyces carlsbergensis ATCC 9080 as the test organism. With this organism, as little as 25 ng thiram/ well or 200 ng/disk can be detected, well below the levels that can be detected with either Bacillus licheniformis or Flavobacterium as the test strain. The assay has been applied to a dietetic food preparation.
Rapid Determination of γ-Aminobutyric Acid and Arginine in Orange Juice: Application to Detecting Adulteration
Authors: Vandercook Carl E , Price Ruth L 
Published: February 2020

Abstract
A rapid, semiautomated liquid chromatographic method has been developed for the determination of γ-aminobutyric acid and arginine in orange juice. Data have been gathered on these amino acids, total amino acids, titratable acidity, total phenolics, and soluble solids for several seasons of commercial California, Florida, Arizona, and foreign orange juice concentrates. Possible applications of the data for detecting adulterations were suggested but, for statistical significance, data from at least one additional season should be gathered.
Gas-Solid Chromatographic Determination of Volatile Denaturants in Ethanol Solution
Authors: Martin Glenn E , Figert Donald M 
Published: February 2020

Abstract
A gas-solid chromatographic determination of volatile denaturants in non-beverage alcohol samples was studied by 10 collaborators representing 6 laboratories. The mean values obtained by 10 collaborators for a concentration of 2.00% each in ethanol solution were: acetone 2.14, ethyl acetate 1.95, ethylene glycol monomethyJ ether 1.90, toluene 1.89, methanol 2.08, chloroform 1.89, n-butanol 1.95, ethylene glycol monoethyl ether 1.88, methyl isobutyl ketone 1.83, isopropanol 2.18, sec.-butanol 2.01, and benzene 2.03. The mean values obtained by the 10 collaborators for a concentration of 4.00% each were: 4.08, 3.94, 3.91, 3.94, 4.07, 4.04, 4.01, 3.99, 3.99, 4.12, 4.05, and 4.06%, respectively. Likewise, at a concentration of 8.00%, each of the results by these same collaborators were: 7.89, 7.94, 8.07, 8.03, 8.04, 8.19, 7.98, 7.97, 8.10, 7.99, 8.10, and 8.07%, respectively. As a general rule, as the precision improved so did the accuracy.
Gas-Liquid Chromatographic Determination of Residues of Chlorpyriphos and Leptophos, Including their Major Metabolites, in Vegetable Tissue
Authors: Braun Heinz E 
Published: February 2020

Abstract
A method is described for the determination of residual chlorpyriphos (O, O-diethyl 0-3,5,6- trichloro- 2 - pyridyl phosphorothioate) and leptophos (O-(4-bromo-2,5-dichlorophenyl) O-methyl phosphonothioate), and their respective oxygen analogs and hydrolytic metabolites, in field-treated vegetables. Samples are extracted by blending with acetonitrile followed by liquid-liquid partitioning between benzene and aqueous sodium carbonate to separate the parent compounds and oxygen analogs from the hydrolytic metabolites. Both fractions are individually cleaned up on silica gel which also serves to fractionate the parent compounds from their oxygen analogs as the result of oncolumn hydrolysis of the oxygen analogs. Chlorpyriphos and leptophos are determined by flame photometric gas-liquid chromatography (GLC); the residual and derived hydrolysis products are derivatized with trimethylsilyl acetamide and determined by electron capture GLC. Overall recoveries from fortified samples averaged 95% for the parent compounds and 85% for the oxygen analogs and hydrolytic metabolites. Detection limits approximated 0.005 ppm for chlorpyriphos and leptophos, 0.002 ppm for the oxygen analogs, and 0.001 ppm for the hydrolytic metabolites.
Collaborative Study of the Microanalytical Oxygen Flask Sulfur Determination with Dimethylsulfonazo III as Indicator
Authors: Scroggins Laverne H 
Published: February 2020

Abstract
The volumetric, microchemical oxygen flask sulfur determination using dimethylsulfonazo III as the sulfate indicator and standard barium perchlorate as the titrant was tested by 21 collaborators. The samples studied were sulfanilamide, benzyl-isothiourea hydrochloride, cystine, potassium sulfate, and potassium sulfate with a phosphate additive. Only 5 collaborators reported good results for the potassium sulfate when it was contaminated with phosphate. Overall statistical evaluation of the data for the 4 pure compounds gave satisfactory values—average standard deviation 0.10, overall average deviation of the mean from theoretical value 0.16, and average bias 0.10. However, a statistical analysis of the reproducibility among analysts showed 10 of the 21 laboratories had an overall average deviation of the mean from the theoretical value greater than 0.20. A critical factor was the necessity for vigorous, efficient stirring during the titration to overcome indicator lag-time by hastening the fading of the pseudo-end point color. Thus, many collaborators reported the titration to be slow and tedious. It is recommended that the study of the microanalytical oxygen flask sulfur determination be continued.
Rapid Screening Method, Including Automated Colorimetry, for Low Residue Levels of Linuron and/or Chlorpropham in Vegetables
Authors: Friestad HÅkon O 
Published: February 2020

Abstract
Linuron and/or chlorpropham are extracted from crop material with acetonitrile and the extracts are given preliminary cleanup with a slightly modified Mills-Onley-Caither method. The herbicides are hydrolyzed to aromatic amines which, after automatic diazotization and coupling, are determined by colorimetry. The use of manual rapid and efficient cleanup and hydrolysis steps have made it possible to establish lower limits of detection of about 0.01 mg/kg, equivalent to those commonly obtainable by GLC, for the 4 crops tested. Recoveries from carrots and potatoes, when corrected for predetermined consistent procedural losses, averaged 95% with satisfactory precision.
Collaborative Study of the Microanalytical Determination of Bromine and Chlorine by Oxygen Flask Combustion
Authors: Lalancette Roger A , Steyermark Al 
Published: February 2020

Abstract
Twenty collaborators studied a specific method for bromine and chlorine, using oxygen flask combustion followed by mercurimetric titration. The method was previously adopted as official first action for iodine in organic compounds. Eighty-four determinations were performed on p-bromoacetanilide for which the statistical evaluation of the data gave x = 37.30%, x—theory = —0.03%, s = 0.13, and sm = 0.18. With the exception of one collaborator (x—theory = —0.55%), all obtained acceptable accuracy and precision and only his accuracy was not acceptable. Statistical evaluation of the data for 85 determinations on p-chloroacetanilide gave x = 20.86%, x—theory = −0.04%, s = 0.11, and sm = 0.11. All collaborators obtained acceptable accuracy and precision. The official first action method for iodine has been adopted as official first action for bromine and chlorine as an alternative to the Carius method.
Ion Exchange Determination of Strontium-89 and Strontium-90 in Milk: Collaborative Study
Authors: Baratta Edmond J 
Published: February 2020

Abstract
Eleven collaborators performed a second collaborative study of an ion exchange method for determining strontium-89 and -90. For milk containing 29.0 and 197 pCi/L of strontium- 89, the results at 2 levels were: average 31.0, 199.6; range 26-36, 164-290; standard deviation 2.9, 7.2; and per cent error 10.0, 3.4. For milk containing 32.4 and 151.2 pCi/L of strontium-90, the results were: average 32.5, 149.9; range 27.2-38.0, 125.3-170.3, standard deviation 0.32, 4.17; and per cent error 0.9, 2.8. The method has been adopted as official first action.
Collaborative Study of the Gas Chromatographic Determination of Six Thiocarbamate Herbicides in Formulations
Authors: Barney James E 
Published: February 2020

Abstract
Eptam, Ordram, Ro-Neet, Sutan, Tillam, and Vernam thiocarbamate herbicides are determined in emulsifiable and granular formulations by gas chromatography on an OV-1, SE-30, or OV-17 column with a flame ionization detector. Another thiocarbamate is used as an internal standard. The method was tested collaboratively by 19 laboratories, 18 of which tested the method on all 6 thiocarbamates. The coefficient of variation for 12 formulations was 3.10%. A significant amount of systematic error was detected, particularly in the analysis of emulsifiable formulations. The method has been adopted as official first action, and it is recommended that additional studies be conducted.
Quantitative Determination of Polysorbate 60 in Shortening: Collaborative Study
Authors: Smullin Charles F 
Published: February 2020

Abstract
Six samples of shortening, containing from 0.38 to 1.02% polysorbate 60, were submitted to 7 collaborators. The shortening is saponified and, after acidification, the acids are removed. The aqueous polyol solution is desalted and the polyoxyethylated polyols are precipitated as a highly insoluble heteropoly acid complex, using barium hydroxide as the precipitant. The polysorbate 60 content is calculated from the weight of the precipitate, using a gravimetric factor. Average recoveries from the collaborative samples ranged from 97.7 to 103.2%, with standard deviations from 0.019 to 0.061. The method has been adopted as official first action.
Evaluation of Malonate Dulcitol Lysine Iron Agar for Presumptive Identification of Salmonellae
Authors: Stroup John R 
Published: February 2020

Abstract
Malonate dulcitol lysine iron agar (MDLI) was evaluated, using 173 Salmonella subgenus I (19 serotypes) from 129 samples and 140 Salmonella subgenus III (Arizona hinshatcii) from 17 samples. Sixty-four stock cultures were tested including 3 Salmonella subgenus II, 5 Salmonella subgenus IV, and 5 Edwardsiella tarda. Three hundred thirty-five non-Salmonellae from 81 samples were also studied. Only the Edwardsiella cultures and 1 other non- Salmonellae gave aberrant results in MDLI. Five of the known Salmonella serotypes tested and 2 serotypes isolated from samples gave atypical results. If MDLI is used to differentiate the subgenera, and lysine iron agar is used to confirm lysine decarboxylase for subgenera II, III, and IV, as well as act as a source of cells for "O" group serology, then the results of this study indicate that 305 (97.4%) of the 313 Salmonellae isolated from samples gave typical reactions within 30 hr. Biochemical and serological tests should be used to confirm cultures that give positive reactions.
Gas-Liquid Chromatographic Quantitative Determination of Vanillin and Ethyl Vanillin in Foods
Authors: Schlack Janis E , Dicecco Joseph J 
Published: February 2020

Abstract
A gas-liquid chromatographic method for vanillin and ethyl vanillin in foods has been devised. Vanillin and ethyl vanillin are extracted into methylene chloride, and the extract is purified, concentrated, and then chromatographed on an EGSS-X column. Recovery of vanillin and ethyl vanillin averaged 99.54 and 98.05%, respectively.
Gas-Liquid Chromatographic Determination of Choline in Low and High Potency Multiple Vitamin Tablets and Liver Preparations
Authors: Garavelli Caesar B 
Published: February 2020

Abstract
A procedure is described for the quantitative determination of 0.020—6.0 mg choline in low and high potency reference multiple vitamin tablets and standard liver preparations. The trimethylamine quantitatively produced in a sealed tube by treatment with aqueous 5 0% alkali is simultaneously extracted with 0.200—0.500 ml of an isobutanol-ethanol (1+1) mixture and determined by gas-liquid chromatography. An average recovery of 100 ± 3 % was obtained.
Scale-up of AOAC Method III for Quantitation and Isolation of Aflatoxins in Nuts and Nut Products for Chemical and Biological Confirmation
Authors: Diprossimo Vincent P 
Published: February 2020

Abstract
The official AOAC Method III for aflatoxins in peanuts and peanut products (Best Foods or BF method) has been adapted to a larger sample size (500 g), approaching the sample handling capacity of the 1 kg official AOAC Method I (FDA Contaminants Branch or CB method). The modified procedure (NY method) was used in place of the 1 kg CB method for obtaining quantitative assay results and for isolation of pure aflatoxin B1 for derivatization and bioassay. Two samples of naturally contaminated unshelled pistachio nuts and 4 peanut product samples were analyzed using the modified NY method and the results were compared with quantitative assays using official methods. Results were in excellent agreement with the official methods. The thin layer chromatographically pure aflatoxin B1 recovered using the modified procedure on various products was 39 to 57% of that calculated to be present in the samples, a favorable recovery compared to the 1 kg CB method (usually about 50%). All derivatizations carried out were successful (3 samples) and all biological confirmations were successful (2 samples were tested by the chick embryo bioassay for aflatoxin B1 toxicity).
Automatic Potentiometric Titration of Sodium Sulfate in Certifiable Water-Soluble Colors
Authors: Bailey John E , Graichen Charles 
Published: February 2020

Abstract
A method has been developed for the automatic potentiometric titration of sulfate in water-soluble colors, which has the advantage of requiring little sample preparation and attention. A platinum indicating electrode is used with a coated silver reference electrode. The colors are dissolved in 75% alcohol. The sulfate is titrated with lead nitrate solution, using a Hiranuma recording automatic titrator. The method is applicable to the determination of sulfate in all sulfonated certifiable water-soluble colors except External D&C Green No. 1. It is not applicable to the determination of sulfate in the certifiable water-soluble fluorescein colors, namely, FD&C Red No. 3, D&C Orange No. 11, D&C Red No. 22, D&C Red No. 28, and D&C Yellow No. 8. The method is also not applicable to D&C Red No. 19. The
Determination of Uncombined Intermediates in FD&C Yellow No. 6 by High-Pressure Liquid Chromatography
Authors: Singh Manjeet 
Published: February 2020

Abstract
A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates in FD&C Yellow No. 6 (sunset yellow FCF, CI. No. 15895). Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid, 0.1-0.4% 6-hydroxy-2-naphthalenesulfonic acid, and 0.3— 1.0% 6,6'-oxybis(2-naphthalenesulfonic acid) were prepared and analyzed using this method. Recoveries ranged between 94 and 101%. Twenty-two samples of FD&C Yellow No. 6 were analyzed by the conventional column elution chromatographic method as well as by the high-pressure liquid chromatographic method. Good agreement was obtained between the 2 methods.
Fluorometric Determination of Selenium in Foods
Authors: Ihnat Milan 
Published: February 2020

Abstract
A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.
Atomic Absorption Spectroscopic Determination of Cadmium in Fungicide Formulations
Authors: Jung Paul D , Clarke David 
Published: February 2020

Abstract
A rapid and accurate method for the determination of cadmium in fungicidal materials using the secondary absorption at 326.1 nm has been developed. Analyses of several fungicide formulations containing cadmium, as well as synthetically prepared samples, are reported and discussed. The range of recovery of cadmium from synthetic samples was 100—105%.
Total Sugars as Invert in Animal Feed Products: Collaborative Study
Authors: Moore Howard P , Berg Dorothy 
Published: February 2020

Abstract
An expressed need for a method of analyzing for total sugars as invert in animal feed products led to a modification of the volumetric sugar method. Twenty collaborators, analyzing 3 pairs of samples of molasses products, plus a known concentration of sucrose and a sample of dried whey, produced results with standard deviations ranging from 1.25 to 1.86 and coefficients of variation ranging from 3.6 to 5.1. The average recovery of the known sucrose solution was 98 % with a standard deviation of 1.22 and a coefficient of variation of 2.9. The method has been adopted as official first action to replace sec. 7.058.
Gas-Liquid Chromatographic Determination of 3-Trifluormethyl-4-nitrophenol Residues in Fish
Authors: Allen John L , Sills Joe B 
Published: February 2020

Abstract
A procedure for the determination of 3-trifluormethyl-4-nitrophenol (TFM) in fish tissues is described. Homogenized tissues are extracted with hexane-ethyl ether; the extract is cleaned up by partitioning the TFM from the extracting solvent into 0.1N NaOH, acidifying the aqueous solution, and partitioning again with hexaneethyl ether. The TFM is methylated with diazomethane and analyzed by gas-liquid chromatography, using electron capture detection. Recoveries ranged from 75 to 100% from fish muscles that were spiked with 0.01—2.00 μg TFM/g.