bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Liquid Chromatographic Determination of Fenitrothion in Fish, Water, and Sediment
Authors: Grift Norbert , Lockhart W Lyle
Published: February 2020

A procedure is described for the determination of fenitrothion (O,O-dimethyl O-4-nitro-3- methylphenyl thiophosphate) residues in fish tissue, water, and sediment. Fish and sediment samples are extracted with ethyl acetate and cleaned up by partitioning with hexane and passing through Florisil columns. Extracts are analyzed by gas-liquid chromatography, using a flame photometric detector to determine phosphorus and sulfur. Mean recoveries of triplicate analyses of fish muscle samples spiked with 0.1-5.0 μg fenitrothion/g were 94舓110%.
Confirmation of Six Organothiophosphorus Pesticides by Chemical Derivatization at Nanogram Levels
Authors: Singh Joginder , Lapointe Michel R
Published: February 2020

A confirmatory procedure is described in which organothiophosphorus compounds are oxidized by neutralized sodium hypochlorite solution and the oxidation products are subjected to gas-liquid chromatography, using a flame photometric detector. Six pesticides, diazinon, ronnel, malathion, parathion, methyl parathion, and fenitrothion, were studied in 4 different substrates, peaches, blueberries, apples, and lettuce, at fortification levels of 0.25-0.5 ppm. These pesticides can be confirmed when present individually or in combination. Three pesticides, parathion, malathion, and diazinon, were shown to produce the corresponding oxons or oxygen analogs with retention times identical with the corresponding oxon reference standards.
Determination of EPN, Its Oxygen Analog, and p-Nitrophenol in Aqueous Suspensions and Enzymic Digests
Authors: Bhagwat Vasanti M , Ramachandran Bhikshander V
Published: February 2020

O-Ethyl O-p-nitrophenyl phenylphosphonothioate (EPN), its oxygen analog O-ethyl O-p-nitrophenyl phenylphosphonate (EPNO), and p-nitrophenol (PNP) are completely extractable from slightly acidic aqueous suspensions or enzymic digests by a mixture of equal volumes of benzene and isobutanol. In shaking the extract with 0.05N NaOH, PNP is quantitatively partitioned into the aqueous phase and can be determined spectrophotometrically at 410 nm. Aliquots of the solvent phase which now contains EPN and EPNO are evaporated to dryness at 120°C. One portion of the residue is treated with ethanol and alkaline hydroxylamine. The PNP liberated is equivalent to the total EPN -f EPNO. Another portion of the residue is dissolved in cyclohexane and shaken with alkaline hydroxylamine. EPNO, which has a greater reactivity and is more soluble in water, is rapidly decomposed to PNP and can be measured as above. EPN remains unaffected in the cyclohexane phase under these conditions. The value for EPN is calculated either by difference or, when necessary, by evaporating the cyclohexane and decomposing the residue with ethanol and hydroxylamine. The method is sensitive to 0.1 μmole EPN, EPNO, or PNP and can be used in the study of enzyme systems converting EPN and EPNO to PNP or EPN to EPNO. It can also be used in monitoring the preparation of EPNO from EPN by bromine water.
Evaluation of an Automated Dual-Channel Hydroxylamine Assay Procedure for Formulated Penicillin Products. II. Intact Solid Dosage Formulations
Authors: Lane Jonathan R
Published: February 2020

The dual-channel hydroxylamine method of Stevenson, Bechtel, and Coursen for the potency determination of formulated penicillins has been evaluated for use as an official Food and Drug Administration (FDA) alternative assay method for solid dosage formulations. A modified Technicon SOLIDprep Sampler I was used to assay a wide range of penicillin capsules and compressed tablets. In some instances, as many as 10 tablets/sample cup were tested. Results by this method and the official FDA manual method are compared. Some of the problems encountered in the analysis of ampicillin trihydrate capsule formulations and with compressed, film-coated tablets are also described. Based on the performance of the automated system and the data obtained, recommendations have been made to make the dual-channel hydroxylamine procedure an official FDA alternative assay technique for penicillin formulations.
Spectroanalytical Parameters of Fungal Metabolites. IV. Moniliformin
Authors: Lansden J A , Clarkson R J , Neely W C , Cole R J , Kirksey J W
Published: February 2020

The spectral data for a novel fungal metabolite, moniliformin (potassium salt of 1-hydroxycyclobut- 1-ene-3,4-dione), are reported. The corrected ambient temperature fluorescence excitation and emission spectra are given and the quantum efficiency is calculated to be 5.32 × 10舓3. The uncorrected low temperature phosphorescence emission spectrum and lifetime are also reported. Other physical data are given to support spectral evidence that the molecule exists as a dimer in aqueous solutions.
Two-Dimensional Thin Layer Chromatography of Aflatoxins in Figs
Authors: Allen Lewis
Published: February 2020

A method is described for the identification and analysis of aflatoxins in figs. This method is based on 2-dimensional thin layer chromatography, using an antidiagonal spotting technique after sample cleanup in accordance with AOAC official first action Method I for nuts and nut products, 26.015-26.020. Plates were developed in the first direction with toluene-ethyl acetate-90% formic acid (5 + 4 + 1) and in the second direction with acetone-chloroform (1 + 9). Results obtained by this method and those obtained by conventional thin layer methods are comparable. The advantage of the described method, however, is that a fluorescent artifact present in figs no longer interferes in the B2-G1 region.
Stability of Salmonella Biochemical and Serological Characteristics After Long-Term Refrigerated Storage
Authors: Wilson Clyde R , Poelma Paul L , Romero Aida , Andrews Wallace H
Published: February 2020

Viable Salmonella were found in 3 of 4 Salmonella cell suspensions after 6舓8 years of storage in physiological saline at 4°C. Biochemical and serological reactions of the surviving microorganisms remained typical.
Determination of Altosid Insect Growth Regulator in Waters, Soils, Plants, and Animals by Gas-Liquid Chromatography
Authors: Miller Wayne W , Wilkins James S , Dunham Loren L
Published: February 2020

Residues of isopropyl (2E,4E)-ll-methoxy-3, 7,1 l-trimethyl-2,4-dodecadienoate (Altosid®) insect growth regulator are determined in waters, soils, plants, milk, eggs, fish, shellfish, poultry and cattle tissues, blood, urine, and feces. Acetonitrile is the primary extraction solvent for all samples. Residues are extracted by high-speed blending followed by vacuum filtration. Fatty extracts are subjected to cold-temperature precipitation and filtration. Samples are cleaned up by petroleum ether partitioning and Florisil and neutral alumina chromatography. The concentrated eluants are analyzed by gas-liquid chromatography (GLC) on columns of differing polarity, using hydrogen flame ionization detectors. The identity of suspected residues is confirmed by additional GLC and by mass fragmentography. The lower limits of detection were: water samples, 0.0004–0.001 ppm; soils, blood, and urine, 0.001 ppm; forage grasses, forage legumes, and rice foliage, 0.005 ppm; and milk, eggs, fish, shellfish, poultry and cattle tissues, and feces, 0.010 ppm.
Modification of the Official Fluorometric Method for Selenium in Plants
Authors: Olson Oscar E , Palmer Ivan S , Cary Earle E
Published: February 2020

The official first action AOAC fluorometric method for selenium in plants, 3.074–3.078, has been modified to simplify the method and to make it more accurate. The digestion time has been increased from 15 to 30 min past the appearance of perchloric acid fumes to better assure complete oxidation of all forms of selenium to selenite. Preparation of the 2,3-diaminonaphthalene solution, the reagent used for fluorometric analysis, has been changed so that the reagent is stable for several weeks; in the previous writeup, this solution had to be prepared daily. Special equipment (micro-Kjeldahl flasks with ground glass joints) has been eliminated and cyclohexane has been substituted for decahydronaphthalene. The modified method is convenient and applicable to a wide range of materials; it yields results comparable to those from the official method.
Comparison of Virus Recovery Techniques for Assessing the Virucidal Activity of Disinfectant Spray Products
Authors: Chen John H S
Published: February 2020

A comparison was made of virus recovery from inoculated glass surfaces by 3 different viral recovery techniques used in spray test methods. On a total of 7, 5, and 5 observations, for the cover glass crushing, cotton swab rubbing, and microscopic slide shaking techniques, respectively, the log reduction of the median tissue culture infective dose (log TCID50/ml) averaged 1.48, 2.57, and 2.22, the mean percentage recovery was 77.98, 61.55, and 66.94%, and the coefficient of variation was 4.37, 10.01, and 7.42%. The cover glass technique was found to be the least variable and the most effective and precise of the 3 methods.
Gravimetric Determination of Carbon Dioxide in Wines
Authors: Castillo Graham A
Published: February 2020

A gravimetric determination of CO2 in wines was both accurate and relatively fast when compared with the titrimetric method. When 21 samples of lightly carbonated wine were analyzed by both methods the average results agreed within 0.2 mg (range of agreement from 0.1 to 5.0 mg CO2/100 ml wine). In the gravimetric procedure, the CO2 contained in the wines is converted into the carbonate by adding 50% NaOH to the previously chilled sample. An aliquot is introduced into a closed vacuum system. The CO2 is evolved by adding HCl and shaking and warming the reaction flask. The generated gases are pulled through the system by a vacuum pump. Along the path, the gases are dried and purified, and finally the CO2 is absorbed by Indicarb reagent between layers of anhydrous magnesium perchlorate. The absorption bulb is weighed before and after absorption of CO2.
Collaborative Study of Microchemical Sulfur Determination, Using Oxygen Flask Combustion: THQ Indicator
Authors: Scroggins Laverne H
Published: February 2020

A collaborative study was conducted on microchemical sulfur determination by oxygen flask combustion. Seven collaborators performed duplicate determinations on 5 samples: sulf anilamide, benzylisothiourea hydrochloride, cystine, potassium sulfate, and a mixture of potassium sulfate and phosphate. Following oxygen flask combustion, the resultant gases were absorbed in a solution containing 0.1/V NaOH and 30% H2O2. The acidified sample was shaken 30 min and evaporated to dryness on the steam bath; the sulfate was titrated with standard barium chloride solution. The indicator used in this study was tetrahydroxyquinone. Its reliability has been previously proved and adopted by AOAC for use with the Carius-type combustion. Evaluation of the statistical data and overall consideration indicate satisfactory results for all types of compounds studied, with the exception of phosphorus-contaminated samples. Both systematic and random errors for the pure compounds were low. The method has been adopted as official first action.
Formation of Aflatoxin Derivatives on Thin Layer Chromatographic Plates
Authors: Przybylski W
Published: February 2020

Rapid confirmation of the presence of aflatoxing B1 and G1 in foods is provided by reaction with trifluoroacetic acid at the origin of a thin layer chromatographic plate. The procedure has been used successfully with various nuts, grains, coffee and cocoa beans, and other foods.
Determination of Fat in Body Tissues and in Food Mixtures
Authors: Conway Emily S , Adams Mildred
Published: February 2020

The official final action acid hydrolysis method, 14.019, for the determination of fat in foods was successfully applied, with slight modifications, to the analysis of homogenates of food, feces, and animal tissues as well as dry samples of mixed foods. In samples containing sucrose or fructose, it was necessary to carry out a fermentation procedure before acid hydrolysis to avoid problems encountered when these sugars were present.
Carbaryl Insecticide: Extraction from Dust and Powder Formulations
Authors: Mcdermott William H
Published: February 2020

Some 10% and lower guarantee carbaryl dusts cannot be quantitatively extracted by shaking with chloroform as specified in the official first action infrared method for carbaryl formulations, 6.206–6.208. A repeatability extraction study has been made, using a different extraction technique with both chloroform and 10% methanol in chloroform. The results indicate that the new extraction technique and the mixed solvent are suitable for all solid carbaryl formulations. It is recommended that a collaborative study be conducted on the new solvent system and extraction technique.
The Purity of Sulfanilic Acid
Authors: Marmion Daniel M
Published: February 2020

Thirteen samples of sulfanilic acid from various sources were evaluated for purity, using a variety of instrumental and chemical methods. The properties considered include strength, moisture, insoluble materials, iron, sodium, aniline sulfate, orthanilic acid, nictanilic acid, aniline- 2,4-disulfonic acid, and absorptivity. In general, the samples were found to be organically pure and reasonably consistent in quality.
Collaborative Study of a Semiautomated Method for the Analysis of Acenocoumarol, Phenprocoumon, and Potassium Warfarin Tablets
Authors: Kolinski Richard E
Published: February 2020

This collaborative study was undertaken to determine if the anticoagulants acenocoumarol, phenprocoumon, and potassium warfarin could be analyzed by the automated analysis system described in the collaborative study for the analysis of sodium warfarin and dicumarol. Collaborators were supplied with a composited tablet sample of each anticoagulant. Results agreed well with the National Formulary methods for phenprocoumon and potassium warfarin, and an unpublished method for acenocoumarol. For acenocoumarol, coefficients of variation on individual sets of data ranged from 0.30 to 1.94% For phenprocoumon, coefficients of variation ranged from 0.52 to 1.20%. For potassium warfarin, coefficients of variation ranged from 0.54 to 1.79%. The results of this study show that acenocoumarol, phenprocoumon, and potassium warfarin can be analyzed by the official AOAC method for the analysis of sodium warfarin and dicumarol tablets.
Determination of Potassium Guaiacolsulf onate by Ion-Pairing Partition Chromatography
Authors: Doyle Thomas D , Proctor Joseph B
Published: February 2020

Potassium guaiacolsulfonate, a highly polar, acidic substance, is readily eluted by chloroform from a pH 4.5 Celite column in the form of its ion-pair with trihexylamine, thereby effecting facile separation from other pharmaceuticals. The sulfonic acid is then back-extracted into aqueous alkali and determined spectrophotometrically. Assay of standard solutions by this procedure averaged 100.44±0.81%. The method was applied successfully to 4 commercial cough preparations containing a variety of other drugs.
Gas Chromatographic Resolution of Organochlorine Insecticides on OV-l/OV-17, OV-210/OV-17, and OV-225/OV-17 Mixed Phase Systems
Authors: Suzuki Manabu , Yamato Yasuhiro , Watanabe Tadao
Published: February 2020

The resolution of organochlorine insecticides and their related compounds on OV-l/OV-17, OV-210/OV-17, and OV-225/OV-17 mixed phase column systems was investigated. Four BHC isomers and p,p'-DDT, its isomer, and their metabolites (except p,p'-DDE and o,p'-DDE) were resolved on the OV-210/OV-17 system. Heptachlor and heptachlor epoxide were separated on 5% OV-1/2% OV-17 or 5% OV-225/2% OV-17. Resolution of aldrin, dieldrin, and endrin was obtained on 5% OV-210/2% OV-17. p,p'-DDE and o,p'-DDE could not be separated by any of the systems studied.
Report of Ad Hoc Committee on Vitamin D Methodology, AOAC
Authors: Quackenbush Forrest W , Banes Daniel , Derse Philip H
Published: February 2020

In a collaborative study 6 samples of vitamin D3 resins were analyzed chemically by 9 laboratories and tested biologically by 3 laboratories to determine whether there exists a discrepancy between chemical and biological methods of measuring potency of these materials. The chemical methods employed saponification with and without subsequent maleic anhydride treatment. The biological method was the AOAC official final action rat assay, 39.149–39.162. The results showed good agreement between laboratories in the chemical analysis and relatively poor agreement in the biological tests. However, based upon the mean values as reported by the different laboratories, the chemical method employing saponification alone consistently overestimated biopotency, whereas the chemical method including maleic anhydride treatment gave results which averaged much closer to the mean biopotency values. There was no evidence that maleic anhydride treatment reduced values significantly below biopotency values.
Collaborative Study of a Method for the Extraction of Light Filth from Crushed Red Peppers
Authors: Thrasher Joel J
Published: February 2020

A new method was developed for the extraction of light filth from crushed red peppers. The method utilizes an isopropanol defatting of the product followed by separation of light filth elements with mineral oil and n-heptane (85+15) in a 2 L trap flask. Collaborative studies resulted in good recoveries of light filth spike elements and clean extraction papers. The method has been adopted as official first action.
Collaborative Study of a Method for the Extraction of Light Filth from Whole, Cracked, or Flaked and Ground Spices
Authors: Glaze Larry E
Published: February 2020

An improved method has been developed for the extraction of light filth from whole, cracked, or flaked spices (basil, bay leaves, celery leaves, chervil, chives, dill weed, mint flakes, parsley, rosemary, sage, tarragon, thyme, and vegetable flakes) and from ground spices (cloves, cumin, marjoram, mustard seed, oregano, sage, and thyme). The method involves a chloroform or isopropanol defatting, followed by a direct flotation from 40% isopropanol with Tween 80-EDTA (1+1) and mineral oil-heptane (85+15). Collaborative results show that the proposed method is more rapid to perform and yields better filth recoveries than the official first action methods for ground spices, 44.116, and whole, cracked, or flaked spices, 44.129. The method has been adopted as official first action.
Collaborative Study of a Method for the Extraction of Light Filth from Ground Turmeric
Authors: Glaze Larry E
Published: February 2020

An improved method has been developed for the extraction of light filth from ground turmeric. The method involves an isopropanol defatting followed by a direct flotation from 40% isopropanol with Tween 80-EDTA (1+1) and hot mineral oil. Collaborative results show that the method is rapid and yields better filth recoveries than the official first action method, 44.118. The method has been adopted as official first action to replace 44.118.
Multiple Automated Analyses for Orange Juice Content: Determination of Total Sugars, Reducing Sugars, Total Acidity, Total Amino Acids, and Phenolics
Authors: Vandercook Carl E , Price Ruth L , Harrington Christina A
Published: February 2020

Developing methods for determining orange juice content in orange products requires the analyses of many samples. To speed up and simplify the acquisition of data, an automated analytical system was devised whereby 5 constituents were measured on a single manifold. Sample preparation involves diluting to single strength, if necessary, and removing any large pulp particles by filtering or centrifuging. Converting from one analysis to another requires only a change in the colorimeter filter, reagents, and 1 or 2 tubes. The automated procedures were tested on 150 samples of California, Florida, and foreign orange juices. Averages and standard deviations for all samples were 10.2±0.9 g/100 ml, 6.1±0.7 g/100 ml, 12.2±2.8 mequiv./lOO ml, 2.52±0.89 mequiv./lOO ml, and 109±31 mg phenol equiv./lOO ml, for total sugars, reducing sugars, total acidity, total amino acids, and phenolics, respectively. Ratios of the data were calculated for the various juice types and sources.
Gas-Liquid Chromatographic Determination of Docosenoic Acid in Fats and Oils: Collaborative Study
Authors: Conacher Henry B S
Published: February 2020

A gas-liquid chromatographic method for the determination of docosenoic acid in fats and oils was studied collaboratively, using 2 corn oil mixtures spiked with 3.73 and 5.59% methyl erucate, respectively, and 10 oil mixtures containing docosenoic acid at levels between 2 and 30%. Average recoveries from the 2 spiked corn oil samples were 96.5 and 98.7% with coefficients of variation of 4.0 and 3.1%, respectively. With the 10 oil mixtures coefficients of variation ranged from 1.9% at 28.1% docosenoic acid level to 11.1% at 2.7% docosenoic acid level. The method has been adopted as official first action.
Collaborative Study of a Gas-Liquid Chromatographic Method for the Analysis of Chlorobenzilate and Chloropropylate
Authors: Hofberg Arthur H , Heinrichs Lee C , Gentry Gene A
Published: February 2020

A gas-liquid chromatographic method for the determination of chlorobenzilate and chloropropylate in liquid formulations containing about 46 and 26% active ingredient, respectively, was collaboratively studied, using a matched pair scheme. The samples were dissolved in acetone containing dibenzyl succinate as an internal standard and chromatographed on Carbowax 20M, using a flame ionization detector. Analyses of 4 samples by 13 collaborators using peak height measurements showed the following results: chlorobenzilate—2.5% overall coefficient of variation, 1.0% coefficient of variation for the random error; and 0.7% systematic error; chloropropylate—2.0, 1.4, and 0.4%, respectively. The method has been adopted as official first action.
Rapid Method for Extracting Aldrin, Dieldrin, and Endrin from Visceral Material
Authors: Kurhekar Madhao P , D’Souza Francis C , Meghal Sharadchandra K
Published: February 2020

A simple method is described for purifying aldrin, dieldrin, and endrin from visceral material by using a Celite column. Celite retains all interfering materials including lipids whereas the chlorinated insecticides are eluted from the column with n-hexane. This extract can be used directly for gas chromatographic analysis.
Determination of Residues from the Herbicide 2,4-Dichloro-l-(4-nitrophenoxy)-benzene in Rice and Wheat by Electron Capture Gas-Liquid Chromatography
Authors: Adler Irving L , Wargo Joseph P
Published: February 2020

A residue method has been developed which is capable of determining not only 2,4-dichloro-1-(4-nitrophenoxy)-benzene but a majority of the known metabolites of this compound. The residues are reduced to a common amine intermediate which is further derivatized and quantitatively measured by electron capture gasliquid chromatography. The method is sensitive to 0.01 ppm and is readily suited to routine use. The method has been used on rice and wheat samples.
Determination of Hexachlorobenzene and Mirex in Fatty Products
Authors: Bong Rodney L
Published: February 2020

A procedure is described for the isolation and cleanup of hexachlorobenzene (HCB) and mirex in fats and oils for gas-liquid chromatographic (GLC) analysis. The fat or oil is distributed on unactivated Florisil, and the HCB and mirex are eluted with acetonitrile. The pesticides are then partitioned into petroleum ether. Elution through activated Florisil with methylene chloride-hexane (20+80) is used for the final cleanup. HCB and mirex are then measured by GLC, using the appropriate electron capture conditions with a 15% OV-210 column for HCB and a 3% OV-101 column for mirex. The method demonstrates recoveries greater than 90% for HCB and mirex and allows screening at or below the 0.1 ppm level in fats with a 3 mg fat injection.
New Confirmatory Test for Aflatoxins B1 and B2
Authors: Ashoor Samy H , Chu Fun Sun
Published: February 2020

A new confirmatory test for anatoxins B1 and B2 is described. The test involves treatment of aflatoxins with excess sodium borohydride for 10 min at room temperature, to yield a fluorescent trihydroxy derivative of each aflatoxin. The test is sensitive and simple and gives no side reactions. The test is also applicable to aflatoxins G1 and G2.
Indirect Method for the Determination of Density of Solutions at Various Temperatures
Authors: Basker Dov
Published: February 2020

For solutions of solutes other than strong electrolytes, the density at temperature t2 may be derived from the density at t1, the refractive index at t1 and t2, and the refractive index of the solvent at t1, and t2. Good agreement was obtained between direct and indirect determinations of the density of sucrose solutions.
Metabolic Alterations in Organ Function
Authors: Plaa Gabriel L
Published: February 2020

When the standardization of procedures is envisioned, problems arise regarding the selection of the test procedure and its ability to detect changes in organ function. Dose-response curves can be derived for the parameters used for assessing dysfunction. These curves can be useful for selecting equitoxic doses of substances to be compared with each other. They can also be useful for estimating relative safety as well as absolute toxic potency. Enzyme inducers can be used to determine whether metabolic transformations are involved in toxic reactions. However, all enzyme inducers do not produce the same effect. It is necessary to clearly define the enzyme inducers that have to be employed. Interactions leading to enhanced toxic effects can occur by pathways other than enzyme induction. It is necessary to determine if the toxic interaction is the result of a change in the sensitivity of the organ to the presence of the toxic moiety. The experimental environment can also affect toxicity. The presence of pathology in laboratory animals may alter the response. Body temperature can also markedly alter the response to a toxic agent.
Toxicology Experimental Design and Conduct as Measured by Interlaboratory Collaborative Studies
Authors: Weil Carrol S
Published: February 2020

Interlaboratory variability in certain acute, toxicological procedures was discussed. Three collaborative studies have been performed. One study concerned a determination of acute peroral toxicity and 2 collaborative studies have involved eye and/or skin irritation. All have indicated that, while the majority of the laboratories produced relatively consistent results, some were definitely outliers and others were quite variable. Recommendations were made to counteract and correct this interlaboratory variability; it was suggested that these be accomplished before standardization of techniques be promulgated. A brief discussion was presented on the faulty conclusions that can result from improperly planned and executed repeated-dose toxicological studies. Furthermore, the estimation of risk at the low-response end of a doseresponse curve was discussed. The relative variability of the measurement of the slope of such a curve was compared to the variability of the measurement of the midpoint. The danger of extrapolation of animal dose-response results, using a constant slope, was deprecated.
Isobutane Chemical Ionization Mass Spectrographic Examination of Explosives
Authors: Saferstein Richard , Chao Jew-Ming , Manura John J
Published: February 2020

The detection of explosive residues in debris is difficult because of the thermal instability of many explosives along with the high sensitivity requirements of the analyses. The isobutane chemical ionization (CI) mass spectra of common civilian and military explosives were obtained under different instrumental parameters. The intent of the study was to determine the feasibility of applying CI to residue detection. The CI spectra of the explosives 1,3,5-trinitro-1,3,5-triazocydohexane, 1,3,5,7-tetraazocyclooctane, and pentaerythritol tetranitrate were shown to be particularly sensitive to the conditions of source temperature and reagent gas pressure. These parameters were adjusted to yield the least complex CI spectra for the explosives studied. The simplicity of the CI spectra obtained makes it a feasible technique for detecting explosive residues in the presence of extraneous materials found in the acetone extracts of debris material. Placement of the extract into the direct probe of the CI mass spectrometer eliminates the need for prior chromatographic treatment of the extract and would optimize the high sensitivity of the CI technique.
Collaborative Study of a Rapid Method for Determining Aflatoxins in Cottonseed Products
Authors: Pons Walter A
Published: February 2020

Eleven laboratories collaboratively studied a modification of the official final action AOAC method, 26.048–26.056, for determining aflatoxins in cottonseed products. An aflatoxinnegative meal, 6 contaminated meals, 4 contaminated meats (kernels) samples, and 2 ammonia-inactivated meals were used. Mean a (latoxin values, μg/kg, ranged from 6 to 223 (B1), 2 to 44 (B2), and 7 to 266 (total: B1 + B2). Only one laboratory reported a false-positive for the negative meal. The mean coefficients of variation for B1, B2, and total were 28, 56, and 29%, respectively, for meals; 35, 54, and 37%, respectively, for meats; and 35, 58, and 38%, respectively, for ammoniated meals. Statistical treatment of data from triplicate sets of meals and meats showed evidence for systematic error between laboratories. Since the modified method is considerably faster than the official method and yields precision estimates consistent with previous AOAC collaborative studies on determining aflatoxins, the method has been adopted as official first action.
Gas-Liquid Chromatographic Determination of Diethylstilbestrol in Molasses-Based Liquid Feed Supplements
Authors: Jain Anant V , Schall Elwyn D
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for the determination of diethylstilbestrol (DES) in molasses-based liquid feed supplements, using dienestrol diacetate as the internal standard. A sample equivalent to 110 μg DES was diluted, acidified with dilute sulfuric acid, extracted with chloroform, and subjected to basic sodium acetate cleanup. The bis-(trimethylsilyl) acetamide derivative was prepared and determined by GLC. Interfering peaks and/or low recoveries were found to be related to emulsions and the procedure incorporates centrifugation to minimize these.
Fluorescent Antibody Method for the Detection of Salmonella: Development, Evaluation, and Collaborative Study
Authors: Fantasia Leonard D , Schrade John P , Yager James F , Debler Diane
Published: February 2020

In preliminary studies, several commercial polyvalent fluorescent antibody (FA) preparations were evaluated for specificity and crossreactivity and an FA method was developed for the screening of Salmonella in products. Approximately 4000 product samples were tested by the FA method and the results were compared to those from the official final action AOAC method, 46.013–46.026. Only 4 FA falsenegatives were found for a total of 619 confirmed positive Salmonella samples. The FA false-positive rate was 7%. The method was then subjected to a 2-phase collaborative study. In Phase I, 22 analysts tested 5 inoculated and 5 uninoculated samples of dried milk. In Phase II, 5 naturally contaminated and 5 presumably uncontaminated foods were analyzed. The study was designed to compare results from 11 analysts experienced in FA methodology with those from 11 analysts with little or no experience. Selenite cystine (SC) and tetrathionate (TT) broths were used for enrichment and both were inoculated into SC for post-enrichment. All 4 combinations (SC, TT, SC-SC, and TT-SC) were used with the FA method to determine the best technique. Results were compared to the analysis with TT and SC by the AOAC culture method. In all studies, FA analysis with SC-SC gave the highest correlation with the AOAC method. In a total of 200 samples, the experienced group found 125 AOAC positives and 127 FA positives ; no FA false-negatives and only 2 falsepositives were reported. The inexperienced group reported 9 FA false-negatives and 5 FA false-positives. All false-negatives occurred in only 3 of the inexperienced laboratories. These studies showed that enrichment and post-enrichment in SC gave the best FA results and that training in FA methodology is required for correlation with existing AOAC methodology. The FA method for the detection of Salmonella has been adopted as official first action.
Collaborative Study of an On-Column Periodate Reaction Method for the Determination of Ephedrine Sulfate in Sirups
Authors: Clark Charles C
Published: February 2020

Fifteen laboratories collaboratively studied a method for the quantitative ultraviolet determination of ephedrine sulfate in sirups. Ephedrine is separated from water-soluble impurities and strong acids by elution from a weakly basic Celite column. Further cleanup is accomplished by retention of the ephedrine on a weakly acidic column while the weak acids, weak bases, and organic-soluble neutral compounds 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 2 commercial ephedrine-containing sirups and 2 commercial non-ephedrine-containing sirups to which ephedrine was added. Recoveries for the spiked sirups averaged 100.7 and 100.3% for mixtures containing 2.5 and 5.0 mg ephedrine sulfate/ml, respectively. The means and standard deviations for the commercial preparations were 4.088 ± 0.068 and 2.375 ± 0.053 mg/ml. The method has been adopted as official first action and has been incorporated into the official method for phenylpropanolamine hydrochloride, 38.199–38.203.
Quantitative Determination of Relative Isomeric Ratios of IH- and 2H-Tetrazole-l-Acetic Acids and Their Ester Analogs by Nuclear Magnetic Resonance Spectroscopy
Authors: Staiger David B , Warren Richard J , Zarembo John E , Post Alex
Published: February 2020

A fast and accurate nuclear magnetic resonance spectroscopic method for the quantitative determination of IH- and 2H-tetrazole acetic acid isomeric mixtures is presented. The method takes advantage of the significant difference in chemical shift of the methylene groups or the ring protons in the 1- and 2-tetrazole acetic acid analogs. The relative ratio of the isomers is determined from the measured intensities of the methylene groups.
Gas-Liquid Chromatographic Determination of Technical Chlordane Residues in Food Crops: Interpretation of Analytical Data
Authors: Cochrane William P , Lawrence James F , Lee Young W , Maybury Ronald B , Wilson Brian P
Published: February 2020

An interlaboratory investigation of technical chlordane residues in food crops was carried out to determine the most practical and consistent method of reporting results. Using a technical chlordane reference standard, 8 gas chromatographic stationary phases were studied for their resolution capabilities. The best separations were obtained with SE-30 and its OV-1 equivalent. Using these columns and electron capture detection, potatoes and carrots from supervised field experiments were analyzed in duplicate and quantitated by using 4 methods of calculation. The data were statistically treated to determine the precision and bias for each method. Also, 1 sample was analyzed in duplicate on 2 different occasions by 6 laboratories to substantiate the initial conclusions. Based on the criterion of high precision it is suggested that a comparison of total area under the chromatogram of the sample with total area of a standard technical chlordane be the method of quantitation. Only peaks which are common to both standard and sample have any significance in this type of calculation.
Estimation of the Bioavailability of Iron
Authors: Fritz James C , Pla Gwendolyn W , Harrison Bertha N , Clark Geneva A
Published: February 2020

Eight laboratories conducted a test for the estimation of the bioavailability of iron from 4 sources, using depleted male albino rats. Ferrous sulfate was used as the reference standard. Ferric orthophosphate was found to have a relative biological value of 11 (range 6–22), an old sample of hydrogen-reduced iron 27 (range 15–41), and ferric citrate 96 (range 75–125). Good results were obtained with a simplified basal diet prepared without ingredients that had previously contributed variable quantities of iron. There was no apparent advantage in using the change in hemoglobin during the repletion period instead of the final homoglobin value as the criterion of response to iron supplements. Several statistical treatments of the data yielded similar conclusions regarding relative biological values of the iron sources.
Methods for the Detection of Trichothecenes
Authors: Eppley Robert M
Published: February 2020

The trichothecenes are a group of fungal metabolites with a tetracyclic, sesquiterpenoid ring system and include a number of compounds which are highly toxic. These compounds are produced by various species of the imperfect fungi including members of the following genera: Calonectria, Fusarium, Myrothecium, Stachybotrys, Trichoderma, and Trichothecium. Both biological and chemical methods for detection of various trichothecenes are reviewed. Some of the bioassay techniques in use for the detection of the various trichothecenes include the rabbit dermal toxicity test, cytotoxicity, and inhibition of protein synthesis tests; these are highly sensitive but lack specificity. The sensitivity of these tests for the T-2 toxin are 0.005 μg for rabbit skin toxicity, 0.03 μg/ml for inhibition of protein synthesis in rabbit reticulocytes, and <1 μg/ml for cytotoxicity to human karyoblast cells. In the present state of development of the chemical assay methods, thin layer and gas-liquid chromatography are specific for various trichothecenes but lack sensitivity. The lower detection limit of the trichothecenes on thin layer plates varies from 0.2 to 2–3 μg/spot while gas-liquid chromatography has a reported sensitivity of approximately 0.05 μg/injection.
Patulin Production in Apples Stored in a Controlled Atmosphere
Authors: Lovett Joseph , Thompson Ruben G , Boutin Brenda K
Published: February 2020

Red Delicious apples were inoculated with Penicillium expansum NRRL 973 or P. expansutn 1071 (fresh apple isolate), and incubated in air at 33°F and in a controlled atmosphere of 1% carbon dioxide, 3% oxygen, and 96% nitrogen at 33°F. Both fungal strains produced the carcinogen, patulin, in the air-incubated lots, but only the freshly isolated strain (1071) produced detectable patulin in controlled atmosphere lots. Thin layer chromatography was used to assay ethyl acetate extracts of juice pressed from blended apple tissue. We conclude that naturally occurring P. expansum strains are capable of producing significant levels of patulin in apples stored from 3 to 6 months under controlled atmospheric conditions.
High-Performance Liquid Chromatographic Determination of Strychnine in Grain Baits
Authors: Bushway Rodney J , Cramer Christine W , Hanks Alan R , Colvin Billy M
Published: February 2020

A simple and rapid high-performance liquid chromatographic procedure is described for the determination of strychnine. Grain baits containing strychnine alkaloid are ground, mixed, and extracted by shaking with chloroform. Without further cleanup, extract nitrates are injected directly into a liquid chromatograph. Chromatography is complete within 7 min and peak heights are used for quantitation. Separations were made on a 30 cm × 4 mm id stainless steel column packed with μ Porasil (8–12 μm silica). The eluting solvent was methanolchloroform (10+90) at a flow rate of 2.0 ml/ min. Recovery of spiked samples ranged from 91.5 to 95.2%. Confirmation of strychnine from a commercial sample was made by high resolution mass spectrometry with mass agreement to 1.2 ppm.
Gas-Liquid Chromatographic Determination of Strychnine in Grain Baits
Authors: Hanks Alan R , Engdahl Barbara S , Colvin Billy M
Published: February 2020

A simple and rapid gas-liquid chromatographic procedure, using a 6’ × ¼“ glass column packed with 5% SE-30 on Chromosorb W (DMCS) and a flame ionization detector, is described. Grain baits containing strychnine alkaloid are ground, mixed, and extracted by shaking with chloroform containing an internal standard, 1,3,5-triphenylbenzene. Without further cleanup, extract nitrates are injected directly into a gas chromatograph. Peak height ratios are used for quantitation of strychnine. The analysis of commercial samples shows that the method compares well with a commonly employed ultraviolet spectrophotometric method; good precision, with recoveries ranging from 89.9 to 91.7%, is obtained in the analysis of prepared samples. The method is sensitive to 2 μg strychnine.
Separation of Rotenoids and the Determination of Rotenone in Pesticide Formulations by High-Perf ormance Liquid Chromatography
Authors: Bushway Rodney J , Engdahl Barbara S , Colvin Billy M , Hanks Alan R
Published: February 2020

The rotenoids deguelin, B-dihydrorotenone, dehydrorotenone, rotenone, 6αβ,12-rotenolone, and tephrosin were chromatogaphed on 8–12 μm silica. A mobile phase of chloroformisooctane (35+65) pumped at a flow rate of 1 ml/min through a 30 cm column was used and the absorbance of the eluate was monitored at 294 nm. Rotenone, B-dihydrorotenone, deguelin, and dehydrorotenone are completely resolved while 6αβ,12αβ-rotenolone and tephrosin chromatograph as one peak. This method has potential as a preparative separation technique for rotenoids. Also described is a procedure to quantitatively measure rotenone in pesticide formulations. Samples were extracted with chloroform and chromatographed at a flow of 2.5 ml/min. The method is rapid (rotenone is eluted in 12 min) and reproducible.
Measurement of Thiabendazole, Benomyl, and Folcidin Fungicides in Aqueous Suspensions
Authors: Miller Vernon L , Gould Charles J , Csonka Elizabeth
Published: February 2020

An improved procedure is described for the estimation of benomyl (methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate), folcidin (methyl [l-([(5-cyanopentyl) amino] carbonyl)-1H-benzimidazole-2-yI] carbamate), and thiabendazole ( 2-(4’-thiazolyl)-benzimidazole) in the concentration range of 0.1–1.0 mg/ml. Representative samples of the fungicides in aqueous suspension are shaken with a chloroform solution of cupric acetate and l-dimethylamino- 2-propanol (sodium hydroxide is added in the case of thiabendazole) to produce a green color in the chloroform phase. The analysis may be completed by spectrophotometric measurement or by comparison with described artificial standards.
Determination of Ammonia Inhibition in Fabric Impregnated with Antimicrobials
Authors: Wilson Frederic H , Ball William
Published: February 2020

A new method is described for determining the presence or absence of ammonia produced by urealytic microorganisms, using fabric which has been treated with an antimicrobial. Circular disks of fabric treated with various concentrations of an antimicrobial are placed in the bottoms of snap-on lid petri dishes. Nutrient medium containing urea, an indicator, and a dilution of an overnight culture of Proteus mirabilis is applied to the fabric disks. The lids are snapped on and the dishes are incubated at 37°C. By examination of the fabric disks at regular intervals of time for a color change from white to red, one may determine whether the concentration of antimicrobial in the fabric is sufficient to inhibit the production of ammonia by a urealytic microorganism.
Direct Plating Method for Enumeration of Staphylococcus aureus: Collaborative Study
Authors: Baer Edward F , Messer James W , Leslie James E , Peeler James T
Published: February 2020

Considerable evidence has been published regarding the adverse effect of sodium chloride on physiologically impaired cells of Staphylococcus aureus, such as are to be expected in processed foods. A direct plating method for enumeration of S. aureus eliminating the use of sodium chloride was devised and subjected to collaborative study by 16 analysts. Results obtained by the direct plating method were compared to those obtained by the AOAC official first action method (46.036–46.040). Participating analysts examined duplicate samples at population levels of 91, 34, and 20 S. aureus/g. Coefficients of variation among analysts were considerably lower for the direct plating method (31, 81, and 48%, respectively) than for method 46.040 (59, 156, and 150%, respectively) at all 3 population levels. High coefficients of variation for the direct plating method at 2 of the 3 levels were due principally to low populations of S. aureus. The direct plating method has been adopted as official first action for general purpose use and use of method 46.036–46.040 has been restricted to raw food ingredients and nonprocessed foods.
Microwave Oven Method for Rapid Determination of Moisture in Meat
Authors: Pettinati Julio D
Published: February 2020

A new, rapid procedure was developed for moisture determination in meat. Results with the method were evaluated by comparative analysis with AOAC method 24.003(b). The new method is accurate, precise, and simple. Samples were prepared for drying by admixture with ferrous oxide and sodium chloride in glass weighing bottles and heating 2.5 mill in a domestic-type 1000 watt microwave oven. After heating, the residues were exposed 1 min in the stream of the oven chamber air blower, then covered and weighed. From comparative determinations on 67 meat samples containing from 3.5 to 77.9% moisture, meat type and moisture level were not significant (P = 0.05) sources of variation as determined by t-tests. Mean moisture content was 0.05% higher by the microwave oven method than by the AOAC method. Repeatability between duplicates was ± 0.47% moisture by microwave oven and ±0.45% by the AOAC method. Precision between paired determinations by the 2 methods was ±0.57% moisture. Both the t-test for significance (P = 0.05) and linear regression analysis of the comparative determinations indicated that the 2 methods were equivalent for determining moisture. Continued study of the method is recommended.
An Automated Total Protein Nitrogen Method
Authors: Wall Larry L , Gehrke Charles W
Published: February 2020

A rapid automated method for total protein nitrogen has been developed, using the Technicon AutoAnalyzer with block digestor. Ammonia is determined by the automated ammoniasalicylate reaction at a rate of 40 samples/hr. A number of variations in digestion parameters have been evaluated. Hydrogen peroxide was used as a digestion accelerator. A salt-acid ratio of 1:1 and a block temperature of 425°C were chosen. The catalysts evaluated included HgO, CuS04, Se02, and Ti02/CuS04. Maximum nitrogen recovery in the shortest time (30 mill) was achieved with HgO as the catalyst. The results from multiple analyses of 10 experimental samples of different refractoriness with the block digestor method, using HgO or CuS04 as a catalyst, compared well with the results by the official AOAC Kjeldahl method. The accuracy, precision, economy, and saving of space offered by the Missouri-Technicon block digestor method make this an attractive alternative to classical Kjeldahl analysis for large numbers of total protein determinations in samples of different refractoriness. The AutoAnalyzer cartridge manifold is simple and reproducible in its performance, and a large dilution of the sample is made on dialysis which eliminates the matrix effects from the sample digests. At least 250 samples can be analyzed in 9 hr with 1 instrumentation setup.