bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Glucose in Corn Sirup and Sugars
Authors: Rohwer Arthur G , Henschel Erwin R , Engel C E
Published: February 2020

The Glucostat method, a simple, rapid, and accurate procedure for the quantitative determination of glucose, was adapted to the determination of glucose in starch hydrolysates, corn sirups, and sugar solutions. Dilute solutions of the hydrolysates were reacted with the duo-enzyme preparation “Glucostat Special,” the enzymes inactivated, and the light absorbances of the solutions determined at 396 mμ. The absorbance was directly proportional to the glucose concentration. In analyzing hydrolysates having a range in glucose content from 10 to 87% dry basis, the method exhibited a standard error in precision of ± 0.54%. Agreement with results obtained by chromatographic analysis was good.
Examination of Calculations and Colorimetric Procedures in the Chemical Evaluation of Vitamin D
Authors: Shue Glen M
Published: February 2020

Examination of data obtained from the 1963 collaborative study of a proposed chemical assay of vitamin D shows the following: the vitamin D content of the sample may be calculated by vising a reading at 550 mμ as the blank, with an accuracy and precision equal to or better than that of the proposed calculation; an internal standard is not necessary.

These findings suggest a simplified colorimetric procedure which requires less than 5 μg (200 units). Data demonstrate a marked improvement in the color reagent resulting from reduction of the concentration of antimony trichloride.

Preliminary data indicate that the method can be applied to high potency irradiated yeast.
Spectrophotometric Method for the Direct Determination of Available Phosphorus in Fertilizers: Use of Dry Ashing to Destroy Citrate
Authors: Brammell Wallace S
Published: February 2020

A simple, rapid spectrophotometry method has been developed for direct determination of available phosphorus in fertilizers. Citrate and other organic materials are destroyed by dry ashing. The combined water and citrate extracts are diluted, a 5 ml aliquot is pipetted into a 25 ml Erlenmeyer flask, and 2 ml of ashing reagent (dilute HNO3, sucrose, and MgO) is added. During evaporation to dryness on a hot plate, nonorthophosphates are hydrolyzed to orthophosphates which react with Mg to form heat-stable compounds. During the subsequent ashing, phosphorus remains in the ortho form. Due to sucrose, the dry residue has a very porous structure and can be converted to a white ash in about 30 minutes in a pre-heated 550°C muffle. Color is developed with vanadomolybdic acid reagent. Absorbance is read on a spectrophotometer at 400 mμ.
Automation of the Flame Photometric Method for Potassium in Fertilizer Grade Potassium Salts
Authors: Ussary James P , Gehrke Charles W
Published: February 2020

Five selected commercial salts and two reagent grade salts were analyzed for potassium at least 10 times independently by both the automatic flame photometric method and the AOAC official STPB method. The flame photometric results were as precise and accurate as the official STPB results. The relative standard deviations were 0.36% K2O for the automated flame method and 0.32% K2O for the STPB method. The averages of the results (100.1%) on the reagent grade salts were very close to the theoretical values. The automatic flame photometric method for potassium in fertilizer grade potassium salts is accurate and precise, and results in a considerable saving in analytical time, especially for laboratories routinely analyzing large numbers of samples.
Symposium on Unit Processes in Residue Analysis
Authors: Kiigemagi Ulo
Published: February 2020

The increasing public concern over possible hazards associated with pesticide residues and the laws enacted to protect public health have forced a rapid development of analytical methods for pesticide residues. One of the most widely used methods for the determination of pesticide residues is light absorption spectrometry. The physical laws governing the absorption of radiant energy by a sample at some specific wavelength are explained. The advantages of such a method for pesticide residue determination may include lower equipment costs, adequate sensitivity in many cases, and a reasonable degree of specificity. On the other hand, disadvantages may include destruction of sample, susceptibility to interferences, and in many cases lack of specificity. Since pesticide molecules are not colored per se, one or more chemical reactions have to be performed to produce colored compounds. Any of these reactions can be the limiting factor for sensitivity or reproducibility. The choice of color developing reagent providing maximum sensitivity and minimum interferences is discussed. The factors that influence absorption characteristics include among others, pH, temperature, and solvent. Several methods of eliminating or compensating for interferences by background absorption are presented.
Preparation and Extraction of Samples Prior to Pesticide Residue Analysis
Authors: Thornburg W W
Published: February 2020

Prior to the analysis of pesticide residue on a crop, the pesticide must be extracted and the extract purified. Several solvent extraction systems are discussed. A procedure for estimating the percentage recovery of pesticides from crops using a “weathered residue study” is outlined. Results of solvents partitions as a purification step using hexane and four polar solvents are tabulated.
Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects
Authors: Burke Jerry A
Published: February 2020

The operations necessary for the application of gas chromatography to multiple detection of pesticide residues are described and discussed. Gas chromatography with specific or selective detectors provides qualitative and quantitative analysis of a number of pesticide residues present simultaneously in a single sample. Gas chromatography has been applied successfully to chlorinated pesticide residues; it shows promise as an analytical tool for organophosphorus pesticide residue determination. When the gas chromatography system is operating efficiently, accuracy and precision are good at the nanogram to microgram level. Rules are given to achieve reliable results by gas chromatography.
Characterization of Wheat Components by Infrared Spectroscopy
Authors: Lin Fang Ming , Pomeranz Y
Published: February 2020

Infrared spectra of major wheat flour components have been obtained for the range 4000–700 cm-1 (2–15µ). Starch shows three prominent hydrogen stretching spectra around 3200 cm-1, a number of double bond stretching spectra in the range 1875 to 1475 cm-1, and the typical type I ring stretching and type HI breathing vibrations at 920 and 770 cm-1, respectively. Flour proteins were characterized by amide I, II, III, and V spectra around 1650, 1550, 1270, and 675 cm-1, respectively, and by CH stretching and CH2 and CH3 deformation bands. In Iipids, strong absorption bands were found around 3333 cm-1 (O—H stretching), 3000 cm-1 (C=H stretching), and 1750 cm-1 (C=O stretching). The specific bands of the major wheat flour components were identified in whole flours, but there were no consistent qualitative differences found in spectra of flours varying widely in bread-making quality or in various protein fractions isolated from the flour. Fractionation of flour Iipids by thin layer or silicic acid column chromatography permitted differentiation between mono- and triglycerides according to absorption at 3333 and 1111 cm-1, and between polar and nonpolar lipids depending on the presence of P—O and P—O—C bands at 1270 and 1065 cm-1, respectively.
Gas-Liquid Chromatographic Method for the Determination of Fat-Soluble Vitamins. II. Application to Menadione
Authors: Libby David A , Sheppard Alan J
Published: February 2020

The parameters for the gas-liquid chromatographic detection of menadione have been developed. Five immobile phases were tested. Neopentyl glycol succinate as the immobile phase gives most promise for a quantitative method for menadione. The gas-liquid chromatographic method for the detection of menadione is very sensitive; as little as 4 nanograms has been detected with the hydrogen flame ionization detector. The argon ionization detector under the same conditions will detect 20—40 nanograms. Watersoluble derivatives of menadione must be converted to menadione before they can be chromatographed. Calibration studies show that the response to increasing quantities of menadione is linear.
Dichrornate Method for Iron in Fertilizers
Authors: Ingram William J
Published: February 2020

Details are given of a dichromate method for iron, which is now under collaborative study.
Methods of Analysis for Water-Insoluble and Slow-Release Nitrogen in Fertilizers
Authors: Holt Kenneth E
Published: February 2020

Method 2.047 for determination of waterinsoluble organic nitrogen has been revised to include slow-release nitrogen in coatedtype fertilizers. Also, the procedure has been changed to analyze for leached N in the nitrate rather than insoluble N in the residue. A collaborative study and a ruggedness test were conducted on the revised method. It is recommended that the revised method be adopted as official, first action.
Analysis of Salicylic Acid and Benzoic Acid
Authors: Weber J D
Published: February 2020

Salicylic and benzoic acids can be separated on a ferric chloride-urea column. Salicylic acid is retained; benzoic acid is trapped on a Celite:1N sodium bicarbonate column; other phenolic compounds are eluted from both columns. Benzoic and salicylic acids are eluted from their respective columns with acetic acid in ether and chloroform.
Fatty Acid Composition of Olive Oil by Urea Fractionation and Gas-Liquid Chromatography
Authors: Iverson J L , Eisner J , Firestone D
Published: February 2020

The fatty acid composition of California and imported (France, Greece, Italy, Spain, and Tunisia) olive oils is reported. The entire series of fatty acids of odd and even chain lengths from C12 to C28 is present as well as the even chain length monounsaturates from C16 to C22. Branched (iso and/or anteiso) C18 and C22 to C30 acids were tentatively identified in certain olive oils. Tunisian olive oil is characteristically high in palmitic acid (17%) and low in oleic acid (57%) compared with the levels of palmitic acid (12%) and oleic acid (72%) in the other olive oils.
Ascorbic Acid Assay: A Modified Procedure to Overcome Difficulties in the Determination of Ascorbic Acid in Non-USP Products
Authors: Hall Wallace L , Deutsch Mike J
Published: February 2020

The official methods for ascorbic acid are not applicable to many pharmaceutical preparations. Alternative methods which use acidified extractants are presented for tablets or capsules which contain various quantities of basic and/or interfering reducing substances. A procedure has been developed by which the sample is directly introduced into the extracting solution during the titration.
Deposition of Individual Carotenoids in Avian Skin
Authors: Quackenbush F W , Kvakovszky Sheena , Hoover Theresia , Rogler J C
Published: February 2020

In a comparison of the skin-pigmenting efficiency of isolated carotenoids during a five week feeding period with male chicks, the carotenediols, lutein and zeaxanthin, were superior to all other materials tested. While lutein was deposited to the same extent as zeaxanthin, the depth of color produced was slightly less intense. Neolutein was nearly as effective as trans-lutein. Yellow corn selections in which either lutein or zeaxanthin was preponderant produced deposits similar to those of the purified pigments. Dietary fat (2% or 10% lard) improved pigmenting efficiency. In a comparison of mono-carotenols, cryptoxanthin was deposited about twice as efficiently as was zeinoxanthin. β-Carotene was ineffective. Synthetic β-apo-8′-carotenal was nearly half as effective as the carotenediols and produced a normal color; canthaxanthin was more efficient but produced an unnatural color. The carotenols deposited in the skin were found to be largely in the ester form. The carotenol fed was in each case the predominant pigment found in the skin.
Microfluorometry Assay for Vitamin C
Authors: Deutsch Mike J , Weeks Cora E
Published: February 2020

The reaction of dehydroascorbic acid with o-phenylenediamine to give a fluorescent quinoxaline has been used as the basis of an assay to determine microgram quantities of ascorbic plus dehydroascorbic acids. The development of the fluorescent derivative of the vitamin is prevented by forming a boric acid-dehydroascorbic acid complex prior to addition of the diamine solution. This provides a means of differentiating between the fluorescence from the vitamin and that from possible interfering substances. When applied to pharmaceutical preparations, beverages, and special dietary foods, the method shows a high degree of specificity. No substances tested have been found to interfere. Comparison of results with those obtained by using other methods showed excellent agreement.
Gas Chromatography of Pesticides—Improvements in the Use of Special Ionization Detection Systems
Authors: Giuffrida L , Ives N F , Bostwick D C
Published: February 2020

The operating parameters for electron capture and flame ionization detectors are discussed, and the effects of varying each are described. Investigation of the detection of organophosphorus pesticides by a hydrogen flame burning in an atmosphere of alkali metal salts has resulted in increased sensitivity and complete specificity. With the use of potassium salts, sensitivity for phosphorus compounds equals that of the electron capture detector for chlorinated hydrocarbon pesticides. A detection system using both detectors to obtain a dual analysis simultaneously is described. Specificity is achieved with certain halogen salts (KCl, KBr, RbCl) which suppress the minor enhanced response by the modified flame detector to organohalogen compounds.
Proposed Method for Isolating Coagulase-Positive Staphylococci from Food Products: Report of a Collaborative Study
Authors: Baer Edward F
Published: February 2020

Eleven collaborators studied the reproducibility of the method, proposed in 1965, for the isolation of coagulase-positive staphylococci. Samples studied were milk, beef and turkey samples, and fresh, headless shrimp. Based upon statistical analysis of collaborative results, the laboratory means did not vary significantly. The method is recommended for adoption as official, first action.
Ultraviolet Spectrophotometric Method for Ronnel in Feeds
Authors: Gehrt Albert J
Published: February 2020

The ultraviolet spectrophotometric method for ronnel in feeds, adopted as official, first action at the 78th Annual Meeting (1964), was studied at levels of 0.015–5.5% ronnel by 9 collaborators on 4 feed samples. The study was to confirm the 1964 work and to test the accuracy and reproducibility of a Dowex 2-X8 ion exchange resin separation of ronnel from its decomposition product, 2,4,5-trichlorophenol. When an aliquot of the extract was passed through the Dowex column, 2,4,5-TCP remained, while ronnel passed through. Collaborators obtained satisfactory results; therefore, the Associate Referee recommends adoption of the new method and repeal of the earlier method.
Quantitative Estimation of Lactylated Glycerides and Polyglycerol Esters in Shortenings Containing Mono-and Diglycerides
Authors: Sahasrabudhe M R , Legari J J , McKinley W P
Published: February 2020

A column chromatographic method has been developed for the quantitative estimation of lactylated glycerides and polyglycerol esters in shortenings. The components are eluted successively with benzene, benzene with 10% ethyl ether, ethyl ether, and ethyl alcohol. Lactylated glycerides eluted along with the corresponding mono- and diglycerides are estimated as lacto-palmitates from their lactic acid content. Polyglycerol esters are quantitatively eluted with ethyl alcohol. Results of analyses of several combinations of emulsifiers in lard and a vegetable shortening yielded recoveries of 94 to 102%.
Column Chromatographic Cleanup Procedure for the Isolation of Chlorinated Pesticides in Oil
Authors: Tolbert Claude E
Published: February 2020

A column chromatographic procedure is described which will clean up five chlorinated pesticides that may be present in oil. The oil is dissolved in ethyl ether and transferred to a chromatographic column containing a support mixture of sand, magnesium oxide, and Celite. After the ethyl ether is eliminated from the column, the pesticides are eluted with 80% acetonitrilewater solution, extracted into petroleum ether, concentrated to an appropriate volume, and determined by electron capture gas chromatography. Recoveries by this procedure of DDT, BHC, aldrin, endrin, and dieldrin added to oleomargarine fat at levels of 0.1–2.0 ppm ranged between 58–108%.
Determination of Diethylstilbestrol in Feeds
Authors: Ponder Carl
Published: February 2020

Experimental extractions of diethylstilbestrol from animal feed, containing alfalfa meal and other rich sources of chlorophyll, indicated that a reaction may occur between the drug and a component of the vegetable material. Recovery data, obtained by a new 1.5 hour acid-acetone-chloroform extraction, indicate that an acid-base reaction occurs with the magnesium ion in chlorophyll. Phosphoric acid frees the diethylstilbestrol and permits complete recovery with organic solvents. The drug is separated from the vegetable extracts by elution with ethyl ether from a barium hydroxide column. The final determination is made by a modification of the AOAC irradiation method. Recoveries are comparable to those of the longer AOAC method.
Chromatographic Separation and Spectrophotometry Determination of Phenylephrine Hydrochloride, Codeine Phosphate, and Some Other Pharmaceuticals in a Mixture
Authors: Smith Donald J
Published: February 2020

Codeine phosphate, chlorpheniramine maleate, pyrilamine maleate, phenylpropanolamine hydrochloride, and hydrocortisone acetate were analyzed in samples containing phenylephrine hydrochloride. A series of four columns is used to separate the various pharmaceutical components prior to analysis. Assays of commercial samples ranged from 87.2 to 118% of declared content.
Collaborative Study of the Determination of l-Malic Acid in Lemon Juice
Authors: Yokoyama Henry
Published: February 2020

Additional collaborative studies were conducted on the l-malic acid content of lemon juice. Results were accurate and precise; the method is recommended for adoption as official, first action.
Examination of Three Concentrated Black Raspberry Juices for Authenticity
Authors: Jorysch David , Marcus S
Published: February 2020

Gradient elution, paper, and thin layer chromatography were used to detect adulteration in black raspberry juice concentrates. Results show that a combination of gradient elution chromatography plus thin layer chromatography of the anthocyanin isolates provide definite indications of the purity of concentrated fruit juices.
Cleanup and Screening of Citrus Extracts for Residues of Benzo(a)pyrene and Two Other Polynuclear Hydrocarbons
Authors: Craft C C , Norman Shirley
Published: February 2020

A method has been developed for the cleanup and screening of extracts from citrus fruit for residues of benzo(a)pyrene, 3-methylcholanthrene, and dibenz(a,h) anthracene. Whole fruits were stripped with pentane, the pentane solution was partitioned with dimethyl sulfoxide, the extract was adsorbed on a magnesia column, and the residue from the eluate was chromatographed on thin layer plates beside spots of standard polynuclear hydrocarbons. The addition of 4.1 μg of either benzo(a)-pyrene or 3-methylcholanthrene to the surface of individual fruits was detected, after cleanup, in extracts stripped from samples of 10–15 oranges or 15–20 lemons. Dibenz-(a,h) anthracene added at levels of 0.1 fig per fruit was detected in only occasional samples. With this procedure, no residues of benzo(a)pyrene, 3-methylcholanthrene, or dibenz(a,h) anthracene were detected in more than 40 paired samples of nonwaxed and commercially waxed citrus fruits. With the proposed cleanup procedures, recoveries of the polynuclear hydrocarbons ranged from 50 to 80% as determined by ultraviolet spectral analysis.
Iodine in Iodized Salt
Authors: Kleks Abraham I , Davidson Arthur W
Published: February 2020

The official method for iodine in iodized salt, 31.064–31.067, was studied to determine interference from sodium thiosulfate added as a stabilizing agent; no interference was found. The present official method for iodine in iodized salt is reliable, and study of methods should be discontinued.
Collaborative Study of the Determination of Zoalene and ANOT in Chicken Tissue
Authors: Thiegs B J
Published: February 2020

Zoalene (3,5-dinitro-o-toIuamide) and a metabolite, ANOT (3-amino-5-nitro-o-toluamide), are both present in chickens when the former compound is fed as a coccidiostat. The colorimctric methods for zoalene and ANOT in chicken tissue were studied collaboratively, and results indicate that the methods are reasonably accurate and reproducible for both compounds. It is recommended that the methods be adopted as official, first action.
Determination of Water and Ethyl Alcohol in Cosmetics by Gas Chromatography
Authors: Gross Frederick C
Published: February 2020

A gas chromatographic technique for determining water and/or ethyl alcohol in cosmetics utilizes a relatively inert perfluorocarbon solid support coated with a high molecular weight polyethylene glycol. Methyl Cellosolve, used as solvent, is suitable for most cosmetic preparations and serves as an internal standard. Although semi-emperical, this procedure yields satisfactory results for the usual amounts of water and/or ethyl alcohol found in cosmetics. The method is recommended for adoption as official, first action.
Collaborative Study on the Analysis of Aflatoxins in Peanut Butter
Authors: Campbell A D , Funkhouser J T
Published: February 2020

A second collaborative study has been carried out on the determination of aflatoxin in peanut butter under the sponsorship of the Aflatoxin Methodology Working Group. Thirteen collaborators, representing industrial, independent, and government laboratories, analyzed twelve peanut butter samples containing known amounts of aflatoxin at levels of 10 and 110 μg/kg of peanut butter. Two samples of naturally contaminated peanut butter containing aflatoxins B1 and B2 were also analyzed. The study was designed to estimate the accuracy and precision of the method, both within laboratories and between laboratories. Some samples and collaborators were common to both this study and an international study sponsored by the IUPAC Results of the two studies have been compared. The method was recommended for adoption as official, first action.
Classification of Contents of Self-Pressurized Containers by Flammability Hazards
Authors: FM mcxerney C , Keppel George E
Published: February 2020

Studies were conducted to classify the flammability hazards of products marketed in self-pressurized containers for household use, and results indicate that these products can be classified as extremely flammable and flammable by flame extension and cloth ignition tests. It is recommended that the study be continvied.
Oscillopolarographic Analysis of Morestan® Residues in Valencia Orange Rind Following Thin Layer Chromatography
Authors: Hearth Fred E , Ott Daniel E , Gunther Francis A
Published: February 2020

A new method combining oscillopolarography and thin layer chromatography is described for the microdetermination of residual Morestan in Valencia orange rind; 0.5 ppm is readily detectable, but accurate quantitation is difficult below 1.0 ppm. Data obtained by this method are comparable to those from a colorimetric method.
Determination of Ascorbic Acid in the Presence of Ferrous and Stannous Salts
Authors: Pelletier O , Morrison A B
Published: February 2020

Ferrous and stannous ions in the presence of traces of the oxalic acid found in canned fruit juices and drinks interfere with 2,6-dichlorophenol - itidophenol titration of ascorbic acid in various media. A method is presented in which these ions, in buffered solution, are oxidized by air and chelated with EDTA before ascorbic acid is determined by titration. The method has given accurate results in samples containing ferrous and stannous ions.
Extraction, Cleanup, and Gas Chromatographic Determination of BHA and BHT in Fats and Oils
Authors: Schwien William G , Miller Bob J , Conroy Harry W
Published: February 2020

In preparing samples for analysis of antioxidants in fats and oils, melted fat and/or oil is mixed with Celite, blended with acetonitrile, and the acetonitrile is extracted with mixed ethers. The mixed ethers are evaporated, and the oily residue is incorporated with alumina acid. The alumina mixture is placed in a chromatographic column and eluted with aqueous methanol, and the methanolic eluate is extracted into mixed ethers. The ether extract is clean enough for TLC as well as GLC determinations. Recoveries from tallow, lard, and corn oil spiked at 16.7 and 66.7 ppm with BHA and BHT ranged from 80 to 95% for BHA and 91 to 115% for BHT.
Determination of Phenothiazine and Several of its Derivatives by Gas-Liquid Chromatography
Authors: Bramlett C L
Published: February 2020

Phenothiazine, promethazine.HCl, chlorpromazine. HCl, promazine.HCl, and levomepromazine. HCl were chromatographed satisfactorily on a column containing 5% Apiezon L coated on Anakrom ABS, 100/110 mesh, using a hydrogen-flame ionization detector. This gas chromatographic technique is rapid and more specific than existing official methods. The use of an internal standard to improve precision will be investigated.
Gas Chromatographic Determination of Trace Amounts of the Insect Chemosterilants Tepa, Metepa, Methiotepa, Hempa, and Apholate and the Analysis of Tepa in Insect Tissue
Authors: Bowman Malcolm C , Beroza Morton
Published: February 2020

A gas chromatographic method, sensitive to as little as 0.1 nanogram, was devised for analysis of the insect chemosterilants tepa, metepa, methiotepa, hempa, and apholate. The method is needed to monitor amounts and persistence of chemosterilant in treated insects. The procedure uses a flame-photometric detector. Response is linear (phosphorus analysis) between 0.1 and at least 200 ng. The procedure was shown to be directly applicable to analysis of methanol extracts of insects fed tepa. Concurrent gas chromatographic and radiometric analyses indicated that the radiometric method would not give satisfactory results without a suitable cleanup, whereas virtually no cleanup was required for the gas chromatographic analysis. The gas chromatographic method is rapid and easily carried out.
Infrared Spectra of Amino Acids in the 700-400 cm−1 Region
Authors: Warren R J , Thompson W E , Zarembo J E , Eisdorfer I B
Published: February 2020

The spectra of 49 amino acids and closely related metabolites of varying structure have been studied and analyzed in the region 700–400 cm−1; these amino acids have four characteristic bands in this region. Spectra-structure correlations and assignments of the absorption bands are presented and discussed. This compilation of data is an important supplement to existing infrared data in the 4000–650 cm−1 range. It should provide spectral data for ready identification of a large number of amino acids and make it possible to verify spectral data which is either inconclusive or ambiguous.
Air-Agitation Modification of the AOAC Method for Fly Egg Detection in Tomato Products
Authors: Riley Robert C , Prostak Donald J
Published: February 2020

The present official, first action method for fly eggs and maggots in tomato products, 36.064, was modified by using airagitation in place of hand-rotary shaking. Air-agitation is more efficient than hand swirling both in the number of fly eggs recovered and in the time necessary for analysis.
Colorimetric Determination of Calcium in Rice and Wheat
Authors: Potter Earl F , Long Marion C
Published: February 2020

Micro amounts of calcium in cereals have been determined colorimetrically with glyoxal-bis(2-hydroxyaniI) reagent. Interfering heavy metals are removed by extraction with sodium diethyldithiocarbamate.
Assay Methodology Studies of Carbohydrate Fractions of Wheat Products
Authors: Eheart James F , Mason Blanche S
Published: February 2020

Statistically planned assay methodology studies are described for reducing and nonreducing sugars, starch, lactose, and pentosans in 10 different wheat products from the consumer market. The assay method for starch resulted in the least variation, those for reducing and nonreducing sugars were next, while those for lactose and pentosans varied the most. Duplicate run, aliquot size, and sample differences were, in some cases, considered of analytical significance, while duplicate tube and fermentation flask and quintuplicate polarimeter reading differences were negligible. Assay methods, modifications, and recommendations are given.
Determination of Imidan and Imidoxon in Sweet Corn by Gas Chromatography with Flame Photometric Detection
Authors: Bowman Malcolm C , Beroza Morton
Published: February 2020

A rapid procedure to quantitatively determine Imidan® and Imidoxon with a minimum detection level of 0.002 and 0.004 ppm, respectively, has been devised. The compounds, first separated on a silica gel column, were individually gas chromatographed on a glass column containing 10% DC-200 (w/w) on 80/100 mesh Gas Chrom Q at 200°C. An important requirement of the gas chromatographic procedure was the conditioning of the column. The flame photometric detector used in these analyses was very sensitive and, unlike the electron capture detector, was not contaminated by unclean extracts. Two methods
Alkalimetric Quimociac Method for Phosphorus— A Re-evaluation with Needed Modifications
Authors: Duncan R D , Brabson J A
Published: February 2020

The alkalimetric quimociac method for phosphorus has been studied by AOAC, but it was abandoned because of the difficulty of dissolving the precipitate with alkali. The formation of the hard-to-dissolve precipitate resulted from slow heating during precipitation and from agglomeration of the finely divided precipitate into lumps during filtration. Use of additional citric acid in the precipitation medium, however, forms larger crystals that do not agglomerate during filtration and are readily soluble in alkali. The solubility of the precipitate is negligible in the presence of additional citrate in the precipitation medium, but excessive washing results in significant loss of precipitate. The modified method is rugged, and compares favorably in precision and accuracy with the official gravimetric quimociac method.
Determination of Sulfamethazine in Mixed Feeds Containing Procaine Penicillin
Authors: Hill V B , Martin E E
Published: February 2020

Sulfamethazine in combination with procaine penicillin is used as a medicament in swine feeds. Interference from procaine must be eliminated to determine sulfamethazine by the Bratton-Marshall color reaction. In the method, sulfamethazine is extracted with hot methanol, the protein is precipitated with zinc sulfate and filtered, and the azo dyes of sulfamethazine and procaine are formed by the Bratton-Marshall color reaction. The mixed dye solution is shaken with chloroform to separate the procaine dye, made alkaline, and reshaken. An aliquot of the aqueous phase which contains the sulfamethazine dye is removed, re-acidified, and measured at 540 mμ.i against a standard curve. Procaine penicillin added at 25 times the formulation level does not interfere. Swine feeds at sulfamethazine levels of 0.011 and 0.044% give average recoveries of 95 and 99%, respectively, with a coefficient of variation of less than 6% under routine laboratory conditions.
Colorimetric Determination of Urea in Feeds (Report of AOAC Committee)
Authors: Potts T J
Published: February 2020

The colorimetric DMAB method for urea in feeds was improved with regard to sampling, color reading, and calibration, and the revised method was again studied collaboratively in comparison with the official enzymatic method. Validity of the data was tested by Youden's ranking method. It is recommended that the DMAB method be adopted as official, first action.
Investigation of Volatile Compounds in Cod Fish by Gas Chromatography and Mass Spectrometry
Authors: Wong N P , Damico J N , Salwin Harold
Published: February 2020

Eighteen volatile compounds in cod fish have heen identified hy their mass spectra and gas chromatographic retention times. Volatile compounds were vacuum distilled at 35°C from fresh cod fish and from samples stored for 7 and 14 days. Fractions collected in traps immersed in ethyl alcohol- Dry Ice or liquid nitrogen were separated on aββoxydipropionitrile column by programmed cryogenic temperature gas chromatography. The eflluent from the column was split to a flame ionization detector and to a molecular separator leading to a fastscanning mass spectrometer; this arrangement permitted simultaneous recording of gas chromatograms and mass spectra. The following compounds have not been previously reported in the literature for cod fish: carbon disulfide, methylene chloride, chloroform, benzene, toluene, methyl propyl ketone, diethyl ketone, and methyl vinyl ketone. Compounds which were identified only in stored samples were triinethylamine, propionaldehyde, butyraldehyde, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, and methyl vinyl ketone. No attempt has yet been made to determine the significance of these compounds to decomposition.
Determination of Buquinolate in Chicken Feeds by Thin Layer
Chromatography and Fluorometry
Authors: Borfitz H , Para J , Stickles J V , Ginther G B , Southworth B C
Published: February 2020

A procedure has been developed for determining buquinolate (ethyl 4-hydroxy- 6,7- diisobutoxy - 3 - quinolinecarboxylate) in finished chicken feeds. In the procedure, a chloroform extract of the feed is concentrated to a small known volume, separated from background substances by thin layer chromatography on silica gel (two solvent systems), eluted from the plate, and compared fluorometrically with reference standard buquinolate. No background interference was found from 157 feed samples investigated or from 11 common feed additives. Recovery experiments on 31 samples at levels ranging from 0.0044 to 0.0143% buquinolate averaged 99.7% with a standard deviation of 3.3. The method is equally applicable to both fresh and aged feeds. This method was studied collaboratively, results were good, and the method is recommended for adoption as official, first action
Drained Weight of Frozen Shrimp
Authors: Werren J C , Weik R W
Published: February 2020

Collaborative studies were conducted on a modified U.S. Fish and Wildlife procedure for determining the drained weight of frozen shrimp. Results indicate good precision or within-laboratory repeatability. A water flow rate of 1—3 gallons/minute was as accurate as the prescribed rate of 6 gallons/ minute. It is recommended that the method, with the suggested change in flow rate of water, be adopted as official, first action
Photochemical Changes of Aflatoxin B1
Authors: Andrellos P J , Beckwith A C , Eppley R M
Published: February 2020

Irradiation of aflatoxins B1 and G1 with UV light (principal wavelength 𝀈365 mμ) converts both compounds to new fluorescent photoproducts which have much lower R1 values than aflatoxin B1 and G1 when chromatographed on silica gel thin layer plates. Photoproducts of aflatoxin B1 form much faster on a silica gel surface than in methanol solution. Photoconversion of aflatoxin B1 is shown to alter fluorescence comparison assays and identification tests. Studies show that the principal photoproduct developed from aflatoxin B1 is significantly less toxic than the parent aflatoxin.
Sampling Bulk Fertilizers
Authors: Gehrke C W , Baker W L , Krause G F , Russell C H
Published: February 2020

A sampling study was designed to investigate the sampling of bulk loads of semigranular, granular, pulverized, and blended fertilizers. The study was designed to obtain information on appropriate instruments and methods for sampling bulk fertilizers. An accurate fertilizer sample can be secured by passing a stream sampling cup through the entire flow of material at equally timespaced intervals during the loading of a truck; this "stream" sample is used as a reference point. The AOAC triers did not secure accurate samples of bulk loads. Two compartmented triers and t h e stream sampler were recommended as official sampling instruments. A concentric sampling pattern for taking bulk samples was recommended. Studies on bulk sampling will continue.
An Automatic Electromagnetically Operated Multiple Pipet
Authors: Ellis John H , Midkiff V C
Published: February 2020

An improved electromagnetically-operated automatic pipet, specifically designed for taking aliquots, is described. It may be used singly or several may be mounted in parallel for multiple pipetting operations. Pipetting is 6 times faster with a six-unit pipet in battery arrangement than with the conventional manual method. Aliquots delivered are accurate and precise.
Development of an Assay for Neomycin in Feeds
Authors: Barbiers A R , Neff A W
Published: February 2020

A systematic study of the assay of neomycin in finished feeds has been completed. Neomycin gave sharper zones and less varying results because Tris buffer was used instead of phosphate buffer. The addition of MgCl2 or CaCl2 to Tris buffer enhanced neomycin activity. When these salts were added to the agar, "flatter" curves resulted; CaCl2 was the more effective salt. However, MgCl2 more effectively improved the sensitivity of neomycin. Although very water-soluble, neomycin was shown to be bound to certain feeds. Extraction with 2 0 % NaCI improved recoveries to 90—100%. Standard curves of neomycin in buffer systems differed from those obtained on a feed extract. To avoid this unknown bias, neomycin activity in a feed extract can be inactivated with sodium hypochlorite to prepare standard curves. It is proposed that this procedure be submitted for collaborative study.
Extraneous Materials in Dairy Products: Cheese
Authors: Stephens Robert L
Published: February 2020

A microanalytical method has been developed for extraneous material in cheese. The method is applicable to very hard, hard, semi-soft, and soft cheese, but not to cheese containing spices, herbs, or mold throughout. In the method, the cheese is dispersed in an aqueous basic medium by treatment with the tetrasodium salt of EDTA, the dispersion is digested with pancrcatin, and the extraneous material is isolated by filtration. Results of two collaborative studies are reported. Results of the second study are considered satisfactory, and the method is recommended for adoption as official, first action
Rapid Method for Separation of Extraneous Materials from
Whole and Degerminated Corn Meal, Prepared Mustard, and
Soy Flour
Authors: Miller Mary T
Published: February 2020

A rapid method, based on acid hydrolysis in the presence of mineral oil, has been developed to separate extraneous materials from whole and degerminated corn meal, prepared mustard, and soy flour. Corn meal may be first examined for rodent excreta by method 36.032 and then examined for light filth, or it may be analyzed directly for light filth by the acid hydrolysis method. Soy flour is prepared for analysis by solubilizing the protein in dilute sodium chloride solution in the presence of mineral oil. The Kilborn separatory funnel is used with all 3 products. The proposed method improves recoveries of insect fragments by 13—34% and rodent hair recoveries hy 25—54%. Analyst time required for actual assay is reduced by at least onethird. The method will be subjected to collaborative study
Dilution Method for Mold Count of Catsup
Authors: Wildman John W
Published: February 2020

Studies indicate that mold counting is simpler and easier when catsup samples are diluted with an equal volume of stabilizer solution before applying the official method. However, the amount of reduction in mold count is variable and unpredictable; some mold may be obscured by tomatoinsoluble solids. This effect has also been encountered in a cyclone juice sample. It is recommended that the method be studied further and that it be applied to tomato products other than catsup
New Substrate for Alkaline Phosphatase in Milk
Authors: Babson Arthur L , Greeley Sharon J
Published: February 2020

Phcnolphthalein monophosphale is used as a new substrate for the determination of residual alkaline phosphatase in pasteurized milk. Hydrolysis of this compound yields phcnolphthalein and thus a red solution which can be compared visually with a standard prepared from the same milk. The three reagents required are stable and can be delivered directly from plastic dropping bottles. No extraction into organic solvents is necessary, and this method eliminates the chances for false positive reactions
Comparison of the Reproducibilities of the Kjeldahl and Dye
Binding Methods for Measuring Protein in Milk
Authors: Sherbon J W , Hemphill Bobbie
Published: February 2020

Protein in milk samples was measured by both the Kjeldahl and Orange G binding methods. Ten samples of pooled raw milk were tested with ten replications of each method. Coefficients of variation were 0.352-3.089% protein for the Kjeldahl method and 0.098-0.661% protein for the dye binding method. The overall means of the two methods were significantly different, but not more than the expected agreement between duplicate Kjeldahl analyses. The position of the reaction flask in the manifold during digestion and distillation affected the Kjeldahl results. One sample of pasteurized-homogenized milk was tested on four successive days. The variation in dye binding results was less than in the Kjeldahl results. The dye binding response decreased each day and the mean values on the first and last days were significantly different
Collaborative Testing of the Dye Binding Method for
Milk Protein
Authors: Luke H Alan
Published: February 2020

Seven Market Administrators' laboratories, with two years of experience in collaborative testing of dairy products, analyzed 10 samples of milk in quadruplicate. Eight of the samples were fresh, raw milk taken from farm bulk tanks and represented four breeds of dairy cattle; two samples were pasteurized skim milk. All samples were preserved with HgCl2. The protein content was measured by the Udy dye binding procedure. Analysis of variance showed a significant betweenlaboratory variation. The within-laboratory variation was slight. Laboratory means were between 98.56 and 101.53% of the overall mean for each sample. Between-laboratory coefficients of variation were 0.52—1.13%. Thus the dye binding method is highly reproducible within laboratories; between-laboratory reproducibility is acceptable
Programmed Temperature Gas Chromatography of
Pesticides, Using Electron Capture and Thermionic Detectors
Authors: Bostwick David C , Giuffrida Laura
Published: February 2020

Operating parameters for temperature programming with a single column system are given for electron capture and thermionic detection of pesticides with widely varying isothermal retention times. For the electron capture detector, rise in baseline was limited to about 10% or less of full scale deflection over a 60 °C program by using a differential flow controller and stainless steel tubing to connect the column and detector. With the thermionic detector, a differential flow controller alone produced an even smaller baseline rise over this program range. A temperature programmed dual analysis with both detectors was also possible with a single column
Infrared Absorption Spectra and Polymeric Structures of
Three s-Triazine Herbicides and Their Metabolites
Authors: Chen J-Y T
Published: February 2020

The infrared spectra of three 2-chloro- 4,6-bis (alkylamino) s-triazincs and their metabolites in solid (KBr) phase are described, and the characteristic infrared absorption frequencies are given. These compounds may -exist as dimers in the solid state when hydrogen bonding occurs through one or both of the amino groups. In addition, the metabolic products, 2-hydroxy derivatives, may also exist as dimers by hydrogen bonding of the enol (OH) to the keto tautomers in equilibrium. Evidently the weak NH hydrogen bonding of the cis cyclic lactam dimer is partially depolymerized when the compound is ground in an adequate amount of Nujol, and the equilibrium shifts to yield the dimer resulting from strong hydrogen bonding of the enol (OH) to the keto form of the tautomers
Determination of the Herbicide Tordon (4-Amino-3,5,6- trichloropicolinic Acid) in Soil by Electron Capture Gas Chromatography
Authors: Saha J G , Gadallah L A
Published: February 2020

A method is presented for determining the herbicide tordon (4-amino-3,5,6-trichIoropicolinic acid) in soil. It involves extraction of tordon as the free acid with acetone and phosphoric acid, followed by esterification with diazomethane and estimation of the methyl ester by electron capture gas chromatography. Recoveries of tordon added to soil samples at 0.05—1.0 ppm were between 83 and 92%. The minimum amount detectable by this method was 0.01 ppm. The difficulties of developing an analytical method for this compound are discussed in the light of its structure and solubility
Separation and Spectrophotometric Determination of Acetylcarbromal and Bromisovalum
Authors: Look James M
Published: February 2020

The only official methods for the brominated acylurea group of sedative and hypnotic drugs are nonspecific determinations of total bromine. In the proposed method, acetylcarbromal and bromisovalum are separated on a Celite:HCl (2 + 1) column. Acetylcarbromal is eluted with heptane-carbon tetrachloride (1 + 1), and bromisovalum is eluted with chloroform. After evaporation, the residues are dissolved in carbon tetrachloride and chloroform, respectively, and quantitatively measured by infrared spectrophotometry. Recoveries of simple mixtures by this procedure were acetylcarbromal, 95.8 ± 1.1%, and bromisovalum, 97.0, ± 0.02%. It is recommended that the method be studied collaboratively
Collaborative Study of a Gas Chromatographic Method for Phenothiazine in Drugs
Authors: Bramlett C L
Published: February 2020

A rapid and specific gas chromatographic method for phenothiazine in microgram amounts has been developed and studied collaboralively. The phenothiazine is extracted from a ground sample with chloroform. An internal standard, promethazine hydrochloridc, is added to the extract and to a chloroform solution of phenothiazine standard. Both solutions are diluted and aliquots are chromatographed on a 4' column of Gas Chrom Q with a 5% coating of Apiezon L. Collaborative results, based on 18 separate analyses of each sample, were 38.2 ± 1.2% (38.2% added), and 42.2 ± 1.2% (43.1% added)
Relation Between Refractive Index, Specific Gravity, and Total Solids of Tomato Juice, Puree, and Paste
Authors: Lamb Frank C
Published: February 2020

Total solids by drying, refractive index, and specific gravity were determined on about 375 commercial samples of tomato juice, puree, and paste. Refractive index was determined with and without dilution of tomato paste; pectic enzymes were used to aid filtration and centrifugation. A new specific gravity bottle was used. The new AOAC method for total solids was compared with the former AOAC method on 115 samples. Variations from previous tables relating refractive index and total solids were of little significance up to 20% solids but were increasingly greater as solids increased above 20%. Data obtained in these studies showed lower values for total solids than the old tables in most instances. Separate regression equations had to be calculated for the solids content of the diluted and undiluted samples. Total solids by the official AOAC method was the most precise of the methods used. However, specific gravity and refractive index were both found to have satisfactory degrees of precision