bluuebunny/crossref_metadata_2025 huggingface dataset:
Chromatographic Separation of Malathion Prior to Infrared Spectrophotometry Estimation
Authors: Double R C
Published: February 2020

Column chromatography was used to separate malathion from other pesticide formulations prior to spectrophotometric measurement. Malathion is separated by a petroleum ether-acetone system on a Florisil column. The chromatographic procedure is applicable to technical preparations, emulsifiable concentrates, dusts, and water-based fruit fly bait.
Hydrolysis of Proteins for Amino Acid Analysis. II. Acid Hydrolysis in Sealed Tubes of Mixtures of β-Lactoglobulin and Starch
Authors: Gordon William G , Basch Jay J
Published: February 2020

Experiments with a mixture of β-Iactoglobulin and starch, simulating the composition of carbohydrate-rich foods and feeds, have been carried out to determine conditions for acid hydrolysis that will permit maximal recovery of amino acids in hydrolysates of such materials. When a large excess of 6N HC1 is used for hydrolysis, good recoveries of most amino acids are obtained. However, about one-quarter of the tyrosine present is destroyed under the conditions investigated. Some destruction of methionine and cystine may also be attributed to the presence of carbohydrate, but a special method for the determination of these amino acids is available.
Potentiometric Determination of Vitamin C in Highly Colored Products
Authors: Hardesty William S
Published: February 2020

The method of Barakat and co-workers for determination of vitamin C in colored products has been modified for potentiometric use. The procedure is simple and rapid: An aliquot of sample containing 1—3 nig of ascorbic acid is titrated in a 3% acetic acid medium in the presence of KI with previously standardized 0.01% N-bromosuccinimide. The potentiometric titration uses two Pt electrodes with a polarizing current. Results were compared with the USP XVI method and the AOAC 2,6-dichlorophenol indophenol method. Recoveries, obtained from seven commercial products, four of which were vitamin C-enriched, ranged from 96 to 101%. The method also works well on drug mixtures containing ascorbic acid. It is recommended that the method be studied collaboratively.
Assay of Oil-Soluble Vitamins. Part II. Vitamin A and Vitamin D Assays from a Common Saponification and Extraction
Authors: Deutsch M J , Duffy D , Weeks C E
Published: February 2020

Combining the assays of vitamin A and vitamin D facilitates the completion of analyses of products containing both vitamins. Methods are given for typical pharmaceuticals, feeds, and oils. Samples not containing vitamin A or similar compounds may be assayed for vitamin D without chromatography.
Chemical Assay of Chick Edema Factor in Fats and Fatty Acids
Authors: Higginbotham G R
Published: February 2020

A microcoulometric gas chromatographic method for detecting chick edema factor in fats was studied collaboratively by six laboratories. The method involved extracting unsaponifiable material from fat and fractionating it on an activated alumina column, then examining the third alumina fraction by microcoulometric gas chromatography. Results did not warrant adoption of the method. Initial studies with electron capture gas chromatography for this determination showed promise. A better cleanup procedure needs to be developed. It is planned to continue the study, and to combine acetonitrile extraction and cleanup on an acid- Celite column with electron capture determination.
Aluminum and Iron in Plants
Authors: Lixden Elizabeth I
Published: February 2020

A review of literature discloses nun erous methods applicable to determination of Al and Fe in plants. A comparison of results for Fe by a colorimetric method using 2,2’-bipyridine as chelating agent with those by the colorimetric o-phenanthroline and the TiCl3 titrimetric methods in Official Methods of Analysis showed that the 2,2’-bipyridine was simpler, less time-consuming, and equally as accurate as the o-phenanthroline procedure, and free of the Cu interference encountered in the TiCl3 method. Further study is recommended for accurate and efficient methods for Al and Fe.
Confirmatory Tests for Aflatoxin B1
Authors: Andrellos Peter John , Reid George R
Published: February 2020

Three confirmatory tests have been devised to identify aflatoxin B±. Portions of the isolated toxin are treated with formic acid-thionyl chloride, acetic acid-thionyl chloride, and trifluoroacetic acid, respectively, and aliquots of the three fluorescent reaction products are spotted on thin-layer chromatography plates. Standards treated with each of the three reagents, plus an untreated standard, are spotted on the same plate, and after development the spots are compared under ultraviolet light.
Pyridoxine Determined Fluorometrically as Pyridoxal Cyanide Compound
Authors: Polansky Marilyn Macarthur , Camarra Ricpiard T , Toepfer Edward W
Published: February 2020

Pyridoxine was oxidized with manganese dioxide to pyridoxal, which was converted to pyridoxal cyanohydrin by a reaction with potassium cyanide. Fluorescence readings were linearly related over a range of 0.005 to 0.5 μg of pyridoxine/ml. Recoveries of pyridoxine as pyridoxal were good and offered a method for the fluorometric determination of pyridoxine in aqueous solution.
Gas Chromatographic Analysis of Insect Attractants: Trimedlure, Medlure, Siglure, Butyl Sorbate, Cue-lure, Methyleugenol
Authors: Beroza Morton , Sarmiento Rafael
Published: February 2020

Means of analyzing trimedlure, medlure, siglure, butyl sorbate, cue-lure, and methyleugenol by gas chromatography have been devised to ensure the procurement of high quality attractants needed for the detection of insect pests, especially those invading noninfested areas. The methods permit the estimation of the 4 trans isomers present in commercially produced trimedlure and medlure, and of the cis and trans isomers of siglure. Commercially available butyl sorbate gives a single sharp peak and is supposed to be the trans, trans isomer. Cue-lure and methyleugenol each give a single peak.
Cleanup Processes for Pesticide Residue Analysis
Authors: Mckinley W P , Coffin D E , Mccully K A
Published: February 2020

At least six cleanup procedures developed for the isolation of chlorinated hydrocarbon pesticides are described. Four procedures for organophosphate pesticide cleanup in plant extracts are also given. A combination of methods is suggested for a broad scope organophosphate pesticide cleanup technique.
Application of Thin-Layer Chromatography to the Quantitative Estimation of Antioxidants: BHA, BHT, PG, and NDGA
Authors: Sahasrabudhe Madhu R
Published: February 2020

A procedure is described for the quantitative estimation of BHA, BHT, PG, and NDGA in lard. The antioxidants are extracted from n-hexane solutions of the fat with 80% ethyl alcohol and acetonitrile, separated by two-dimensional thin-layer chromatography using benzene and acetonitrile, and estimated quantitatively by colorimetric methods after extraction of the spots. A special flask for concentration and a suction tube assembly for spot pickup are described. Recoveries of the antioxidants from lard were in the following ranges: BHA, 98-101%; BHT, 96-101%; PG, 90-101%; NDGA, 82-98%. The advantages of the method over others in use are that (I) all four antioxidants can be estimated in one aliquot of fat, (2) PG and NDGA can be estimated when present together in mixtures, and (3) the isomers of BHA can be effectively separated.
Filth in Fruit Paste
Authors: Wheeler Helen H
Published: February 2020

A two-step procedure for examining fig paste for light filth and heavy filth has been investigated. The first step is a modification of method 36.052, using a kerosene-water flotation treatment to separate light filth elements. The second step consists of treating the residual material from flotation with Na4EDTA and screening on a No. 140 sieve to recover heavy filth elements, along with light filth not separated by flotation. Studies indicate that the proposed kerosene- water flotation gives superior recovery of light filth and heavy filth, and the method is recommended for adoption as official, first action.
A Method for the Routine Determination of Corn Sirup in Prepared Meat Products
Authors: Hankin Lester , Wickroski Alphonse F
Published: February 2020

A method has been devised for the determination of corn sirup added to processed meat products. The method is based on the quantitative determination of dextrin added to corn sirup. The dextrins are enzymatically hydrolyzed by α-amylase and β-amylase, and maltose is calculated as the difference in CuO2 found by copper reduction between a treated and an untreated aliquot. A correction factor was devised to determine the average amount of dextrin in corn sirup by testing a number of commercial sirups for their dextrin content and subjecting the data to statistical analysis. With this equation the method is applicable to a wide range of sirups. The method also permits the estimation of dextrose added to meats in excess of that included as one of the components of corn sirup.
An Improved Alkaline Citrate Method for Evaluation of Phosphorus in Fertilizers
Authors: Brabson J A , Burch W G
Published: February 2020

The Netherlands alkaline ammonium citrate extraction method for the determination of available P2O5 was modified for routine use. The water-insoluble portion of the sample is extracted with the alkaline citrate solution for 2 hours in a shaking apparatus at 65°C. Dicalcium phosphate dissolves, but apatite, whether formed in processing (as in the ammoniation of superphosphate) or present as unreacted phosphate rock, does not dissolve. The results of the extraction method correlate well with those of field tests of the fertilizers.
Residues in Milk of Cows Fed Rations Containing Low Concentrations of Five Chlorinated Hydrocarbon Pesticides
Authors: Williams S , Mills P A , Mcdowell R E
Published: February 2020

A feeding study involving 16 lactating dairy cows was carried out in which mixtures of 5 pesticides (heptachlor epoxide, dieldrin, endrin, lindane, and DDT) were fed at levels of approximately 0.05, 0.15, and 0.30 ppm of each pesticide based on total feed consumption. Analyses showed that heptachlor epoxide and dieldrin transferred to the milk in much higher concentrations than did the other pesticides. Next in order of concentration were endrin and lindane. Small but definite increases of DDT and TDE in the milk were noted with increased feeding levels of DDT, but the DDE concentration was apparently not affected by the feeding of DDT at these levels.
Metabolites: Reductive Dechlorination of DDT to DDD and Isomeric Transformation of o,p’-DDT to p,p’-DDT In Vivo
Authors: Klein A K , Laug E P , Datta P R , Watts J O , Chen J T
Published: February 2020

Feeding p,p’-DDT and o,p’-DDT separately at a level of 50 ppm in the diet of rats causes reductive dechlorination of DDT to DDD in the liver. No DDD was found in the fat. DDE is not involved in the metabolic pathway. Feeding o,p’-DDT yields evidence of isomeric conversion to p,p’-DDT in the fat stores. The proportion of the p,p’-DDT found to the o,p’-isomer observed is approximately 7:1.
A Comparison of Assay Procedures for Aflatoxin in Peanut Products
Authors: Tracer W T , Stoloff L , Campbell A D
Published: February 2020

A number of analytical procedures for aflatoxin assays, which were used in the autumn of 1963 by government and industry laboratories, were compared for their efficacy in the detection and quantitative estimation of aflatoxin in peanut meal and peanut butter. All but one of these procedures employed aluminum oxide thin-layer chromatography in the determinative step, but the method employing silica gel thinlayer chromatography was shown to be superior to the aluminum oxide technique. When silica gel was used as the determinative step in each of the procedures, all but one were found to be approximately equal. The other procedure did not effectively extract the aflatoxin.
An Ultraviolet Absorption Criterion For Total Polynuclear Aromatic Hydrocarbon Content of Petroleum Waxes in Food Additive Use
Authors: Howard John W , Haenni Edward O , Joe Frank L
Published: February 2020

An ultraviolet absorption test to limit the total polycyclic aromatic hydrocarbon content in petroleum waxes has been developed. The procedure consists of extraction of a solution of melted wax in an aliphatic solvent with a dimethyl sulfoxide-phosphoric acid mixture, followed, if necessary, by chromatography on a magnesia-Celite column.

Recoveries of representative polycyclic aromatic hydrocarbons, added at a level of 12.5 μg to 25 g samples (0.5 ppm) of wax, ranged from 64 to 93% after the extraction part of the procedure, and from 44 to 85% after the column chromatographic part of the method. The variations in the recoveries may be attributed to the differences in the partition coefficients of the hydrocarbons between the aliphatic solvent and the dimethyl sulfoxide-phosphoric acid extraction mixture, plus the tendency of some of the compounds to be oxidized during the chromatographic part of the test.

The procedure has been applied to the analysis of commercial, refined petroleum waxes, and specifications have been developed to limit the total polycyclic aromatic content of such waxes for food additive use.
Rapid Colorimetric Determination of Microgram Amounts of Selenium in Soils and Biological Samples, Using Millipore Filters
Authors: Newberry Carvel L , Christian Gary D
Published: February 2020

A method is described for the determination of selenium in biological samples or soil samples, following acid digestion or distillation as the tetrabromide, respectively. The selenium is reduced to the element by ascorbic acid. The element is filtered and collected on a white Millipore filter. The intensity of the coloration of the filter is used as a measure of the selenium content. The range of the method is from 0.2 μg selenium to > 0.1 mg selenium. Complete analysis time for a single biological sample is about 60 minutes, while that for a soil sample is less than 2 hours. Control of variables is not critical.
Isolation of Microquantities of Pesticides by Gas Chromatography for Infrared Analysis
Authors: Giuffrida Laura
Published: February 2020

A dual column gas chromatography system using a fraction collector has been developed to isolate one or more components in a mixture for infrared analysis. Interferences from solvents and other contaminants are virtually eliminated because of the separation qualities of the GLC column. Compounds in the vapor state from the GLC column are condensed directly on KBr powder to obtain infrared spectra of microquantities of pesticides.
Separation and Micro Quantitative Determination of Dipterex and DDVP by Gas-Liquid Chromatography
Authors: El-Refai Abdel Rahman (Ali) , Giuffrida Laura
Published: February 2020

A simple, rapid, and sensitive method was required for the determination of Dipterex and DDVP in water and insecticidal formulations. Existing methods were found to he unsatisfactory. This paper describes a rapid method for the gas chromatographic separation and estimation of Dipterex and DDVP in macro and micro amounts. The sodium thermionic detector (STD) was used, and the GLC conditions are described. A general method for extraction of the two compounds from water solutions was developed and applied in studying the rate of hydrolysis of Dipterex and DDVP in river water. A simple procedure has been developed for analysis of formulations of Dipterex and DDVP. Several commercial formulations have been analyzed by this method with a precision of 1–2% obtained under experimental conditions.
Micro KBr Technique of Infrared Spectrophotometry
Authors: Chen Jo-Yun T
Published: February 2020

A combined metal funnel and packing device are used to prepare 4 mg of KBr powder for pressing in a 2 mm diameter hole punched into folded aluminum foil. With the sample added and the KBr pressed between metal blocks a clear transparent disc is obtained which yields a well denned infrared spectrum. A Beckman IR-5A spectrophotometer equipped with a beam condenser, scale expander, and auxiliary recorder is used for the examination. As little as 1 μg of sample has been used successfully for recording spectra of pure pesticides. The same order of sensitivity has been attained by using gas chromatographic fractions separated from pesticide mixtures.
Studies on the Biodegradability of Water-Insoluble Nitrogen Sources in Fertilizers
Authors: Katz Stanley E
Published: February 2020

A method was developed for water-insoluble nitrogen in fertilizers, based upon the principles of biodegradability used to determine the biological oxygen demand of wastes. By making the nitrogen content the limiting factor in the growth medium, the biodegradation of water-insoluble nitrogen sources could be studied. A relationship between oxygen utilization and nitrogen content allowed for fairly accurate measurement by means of a Warburg Respirometer. The per cent biodegradability of nine water-insoluble nitrogen materials was determined within 2 weeks. A comparison of the per cent ureaform biodegradability with some recently published agronomic studies was made.
Determination of Sodium in Fertilizers by Flame Photometer
Authors: Gersten Bertram
Published: February 2020

A collaborative study was conducted on a flame photometric method for sodium in fertilizers. The method is an “outgrowth” of the AOAC flame potash method, with simple modifications. Data show that the method is precise, and it is recommended for adoption as official, first action.
Determination of Total Nitrogen in Fertilizers
Authors: Davis H A , Urban W E
Published: February 2020

Five methods, AOAC 2.037, 2.039, modified reduced iron, chromium powder, and Raney nickel catalyst powder for the determination of total nitrogen in fertilizers, were submitted to collaborators for study. Twelve laboratories participated and completed the work. No one method was “best.” The modified reduced iron, chromium powder, and Raney nickel catalyst powder methods gave essentially equal results, but the chromium powder method is favored for case of operation and time required. However, if considerable organic matter and nitrate are present in a sample, satisfactory results may not be obtained. The analyst should select the official method best suited to the makeup of the sample. It is recommended that the chromium powder method he adopted as official, first action, and that study be continued with the modified reduced iron and Raney nickel catalyst methods, including helpful proposals in developing a method that may be applicable to all fertilizers.
Determination of Isolated Trans Isomers by Infrared Spectrophotometry
Authors: Firestone David , LaBouliere Pauline
Published: February 2020

A study was made of the AOCS Tentative Method for Determining Isolated Trans Isomers by Infrared Spectrophotometry. Triglycerides with zero or low trans content produced isolated trans values which were about 2–3% high, whereas derived methyl esters produced values which were about 1.5–3% low. Corrections are suggested for analysis of samples of low isolated trans content. It is recommended that the AOCS Tentative Method be adopted as official, first action by the AOAC, applicable to margarines and shortenings.
Temperature Corrections for Dilutions in the Refractometer Method for Determining Alcohol
Authors: Reeves Paul A
Published: February 2020

A table of factors is provided for computing the alcoholic contents of distilled liquors from the alcoholic contents of distillates in the immersion refractometer method when the samples and distillates are measured at 20, 25, 30, or 35°C.
How Rugged Are Our Nitrogen Methods?
Authors: Burgh W G , Brabson J A
Published: February 2020

Youden’s ruggedness test was made of two official methods and four more recent methods for the determination of total nitrogen in fertilizers containing nitrates. Among the variables tested were amounts of nitrogen and reductant, effect of chloride, and time of reaction of reductant.

Official method 2.039 (reduced-iron) failed the test. In order of increasing standard deviation, the five methods that passed the test were the chromous reduction method, Raney-catalyst-powder method, official method 2.037 (salicylic acid), improved reduced-iron method, and the chromiumpowder method.
Gradient Elution Chromatography of the Acids in Concord and Other Grape Juices and Jellies
Authors: Jorysch David , Marcus Seymour
Published: February 2020

The gradient elution technique was used to determine the acid profiles of grape juices and jellies prepared from their juices. Acids were separated by placing predetermined volumes of grape juices containing equal milliequivalents of free acid on columns of Dowex 1-X10 anion exchange resin in the formate form and eluting with formic acid in gradually increasing concentration. The eluates were collected in a fraction collector and evaporated to dryness on a waterbath, and the residues were titrated with standard alkali solution. The gradient elution chromatograms of the acids in Concord grape juice samples pressed in the laboratory differed only slightly from similar commercial samples. Grape juices other than Concord have similar acid patterns but show another acid peak. Grape jellies were liquefied and their acids determined by the method; the presence of added citric acid in these jellies is shown to affect the acidity patterns.
Extraneous Materials in Flour
Authors: Reed Garland L
Published: February 2020

Collaborative studies are planned on the AACC acid hydrolysis method for extraneous materials in flour. This proposed method appears equal to AOAC method 36.025 (a) and provides some advantages over it.
Revision of the AOAC Sediment Test for Milk
Authors: Joiner Curtis R
Published: February 2020

The revised method for preparing 1⅛″ diameter sediment standards and the new method for preparing 0.40″ diameter standards (presented last year) were studied collaboratively. Four collaborators prepared acceptable standards of both sizes. Study showed that vacuum nitration was superior to filtration by increased pressure above the liquid being filtered. New photographic standards of both sizes are now available from the U.S. Department of Agriculture. It is recommended that the revisions given in this paper be incorporated into 36.009–36.012, and that the revised method be adopted as official, final action.
Polarographic Determination of Organomercury Drugs
Authors: Hopes Ted M
Published: February 2020

Official NF, USP, and AOAC methods for organomercury drugs are long and determine only total mercury. Initial studies were made of the polarographic behavior of merbromin NF, on a Polarotrace Model K-1000. The peak current of a reduction peak that was found to be specific for the carbon-mercury bond was not directly proportional to concentration in pH 7.5 Britton-Robinson buffer-KCl solution. A much stronger peak, derived from another group in the molecule, exhibited a linear relationship between peak current and concentration in the 10–100 μg/ml range. Column and thin-layer chromatography of commercial merbromin indicates the presence of a number of compounds. Further work on the polarographic determination of merbromin will require the preparation of an adequate standard and a judgment of the therapeutic efficacy of the compounds present in merbromin preparations.
Hexestrol in Tablets
Authors: Matherne Mederic J
Published: February 2020

The phenolic properties of hexestrol are utilized to extract it from tablet excipients. This method is applicable to hexestrol alone in tablets. Hexestrol is extracted with chloroform from an acid medium; then iso-octane is added to the chloroform to reduce the polarity so that the hexestrol may be removed by NaOH extraction. The basic extracts are acidified and the hexestrol is finally extracted with chloroform and evaporated to dryness. An ethanolic solution of the hexestrol residue is scanned in the UV between 240 and 320 mμ hexestrol is measured quantitatively at 280 mμ
Isopropyl Alcohol Extraction of Free Sugars from Plant Materials
Authors: Potter Earl F
Published: February 2020

At present the free sugars of plant material are extracted with ethyl alcohol. Experimental data show that isopropyl alcohol will work as well.
Determination of Dibrom and DDVP Residues in Some Fruit and Vegetable Crops by Microcoulometric Gas Chromatography
Authors: Boone George H
Published: February 2020

A rapid procedure has been developed for quantitative detection of Dibrom (dimethyl- l,2-dibromo-2,2-dichloroethyI phosphate) and DDVP (dimethyI-2,2-dichIorovinyl phosphate) in apples, cabbage, and carrots. Dibrom and DDVP are extracted from plant material with benzene, and interfering plant substances are removed from the extract by column chromatography. Microcoulometric gas chromatography is used for the determinative step. Recoveries of Dibrom at the 5.18 ppm level averaged 84.2% for apples, 86.2% for cabbage, and 86.9% for carrots. Recoveries of DDVP at the 5.06 and 3.75 ppm level averaged 89.0% for apples; at 5.00 and 5.06 ppm they averaged 87.9 and 83.7% for cabbage and carrots, respectively.
Increased Specificity in the Determination of Maleic Hydrazide
Authors: Hoffman I , Gordon A D , Parups E V
Published: February 2020

A study was condvicted to determine the effects of certain chemicals, either alone or with maleic hydrazide (MH), on the validity and applicability of the present colorimetric method for the determination of MH residues. This report presents the findings, together with procedure modifications, which should further increase the specificity of the analytical method.
Determination of Carbaryl Residues in Honey Bees
Authors: Johnson D P , Stansbury H A
Published: February 2020

A method has been developed for detecting residues of carbaryl (1-naphthyl methylcarbamate) as well as its hydrolysis product, 1-naphthol, in dead bees. The method is based on extraction of the bees with benzene, followed by a cleanup involving liquid partitioning and chromatography on Florisil. The quantitative determination involves hydrolysis of carbaryl to 1-naphthol and coupling of the latter with p-nitrobenzenediazonium fluoborate in acetic acid to form a yellow substance. For separate analysis, free 1-naphthol is separated from methylene chloride into a basic aqueous solution. The sensitivity of the method is about 0.1 ppm; recoveries averaged 85.6 ± 6.6% for 1- naphthol and 83.8 ± 2.7% for carbaryl.
Composition of Oil-Soluble Annatto Food Colors. III. Structure of the Yellow Pigment Formed by the Thermal Degradation of Bixin
Authors: Mckeown G G
Published: February 2020

The stereochemical structure of bixin is demonstrated in this paper by isolating the yellow hexaene pigment as the free acid, preparing its ethyl ester, and degrading it to its aromatic fragments, which were identified by gas chromatography. Results indicate that the described structure is correct.
Identification and Determination of Dichlone Residues in Treated Tobaccos
Authors: Hoffman I , Parups E V , Morley H V
Published: February 2020

Dichlone as a residue in tobacco was determined quantitatively by a spectrophotometric procedure following cleanup on a column of Florisil that had been slightly deactivated with water. Recoveries ranged from 93 to 100%. In a parallel study, dichlone was identified by thin layer chromatography. Results indicate TLC is suitable for screening.
Detection of Peanuts in Adulterated Tehina and Halva
Authors: Letan Arieh , Turzynski Berta , Raveh Ariela
Published: February 2020

A proposed method for detection and approximate estimation of peanut admixtures in adulterated tehina and halva (local sesame products) at a minimum level of 3–7% is presented which is based on the difference in behenic acid content of oils extracted from peanuts and sesame seeds. Long-chain saturated fatty acid esters from the analyzed mixture of methyl esters were isolated through urea complexing, and the gas chromatographic technique of analysis was used. Behenic acid was found to be present not only in peanut oil (as reported in the literature) but also in sesame oil in amounts not exceeding 0.3%.
Use of Thin Layer Chromatography and Phosphorimetry for Rapid Quantitative Determination of Biphenyl in Oranges
Authors: Mccarthy W J , Winefordner J D
Published: February 2020

Biphenyl, a widely used fungicide in citrus fruits, is quantitatively determined by initial extraction of the orange juice and pulp or peel, thin layer chromatographic separation of the biphenyl, and phosphorimetric measurement of the separated biphenyl. The ether extraction is quantitative and reproducible, and it requires less time than the lengthy steam distillations previously used. By the ether extraction method, the relative average deviation is only ± 0.2 ppm for orange juice and pulp containing 3.8–8.9 ppm biphenyl, and only ± 2 ppm for orange peel containing 39–65 ppm biphenyl. Thin layer chromatography quantitatively separates biphenyl from the orange essential oils, waxes, and other ether extractives in 15 minutes. Phosphorimetry provides an extremely sensitive and accurate final step in the analysis. Because the limit of detection of biphenyl by phosphorimetry is very low (4 × 10-3 µg biphenyl/ml solvent), an analysis can be carried out easily and accurately on an orange sample containing as little as 5 µg of biphenyl. The total time for the analysis of the biphenyl content in fovir different samples with four replicate determinations for each sample is approximately 2 hours.
Analysis of Imidan Colorimetrically and by Electron-Affinity Gas Chromatography
Authors: Bowman Malcolm C , Beroza Morton
Published: February 2020

A procedure for analyzing Imidan® colorimetrically is based on the acid hydrolytic cleavage of formaldehyde from the molecule and the determination of the liberated formaldehyde with chromotropic acid by the Eegriwe reaction. Recoveries of the pesticide from milk ranged from 75 to 88% in the 0.5–5.0 ppm range.

A gas chromatographic method, also devised, required less cleanup and was faster, more accurate, more sensitive, and more specific than the colorimetric procedure. Recoveries of Imidan from milk at levels of 0.01–5 ppm ranged from 93 to 101% ; from whole sweet corn plants recoveries at levels of 0.05–10.0 ppm were from 94 to 106%.
A Specific Bioassay Method for Determining Bidrin® Insecticide Residues
Authors: Sun Yun-Pei , Lau S C , Johnson Elmer R
Published: February 2020

A specific bioassay method based on the application of physico-chemical and biological techniques has been developed for the determination of Bidrin® (3-hydroxy-iV,Ardimethyl-cis-crotonamide dimethyl phosphate) residues. The experimental design, procedure, and evaluation of bioassay results are essentially the same as in a residue-film bioassay.

Interferences of most insecticides tested were less than 0.1% ; however, water-miscible insecticides, such as dimethoate and phosphamidon, gave relatively high interferences (1–6%). Mixtures containing 100-150 ppm of "less toxic" insecticides gave interferences of 0.6 to < 0.03% of apparent Bidrin.

When several crops were fortified with 0.1–22 ppm of Bidrin, either before or after extraction, recoveries were satisfactory. About 0.05 ppm of Bidrin can be detected. The reproducibility of this method is comparable to that of a residue-film bioassay. The overall coefficient of variation is 8.8%. A comparison of results for several Bidrin-treated materials, obtained by a cholinesterase-inhibition method and the specific bioassay method, shows good agreement.
An Improved Raney Catalyst Powder Method for Determination of Nitrogen in Fertilizers
Authors: Burch W G , Brabson J A
Published: February 2020

With a Raney catalyst powder containing 10% Co, 40%; Ni, and 50% Al, nitrates are reduced to ammonia in 8N sulfuric acid in 10 minutes. Neither chlorides nor organic nitrogen compounds interfere with the reduction, and the reduction passed Youden’s ruggedness test. Results of analyses of fertilizers for total nitrogen that included reduction with the powder were in good agreement with those of accepted methods.
Thin Layer Chromatographic Determination of Ehtyl 0,0-Dimethyldithiophosphoryl-1-phenyl Acetate in Both Technical Cidial and Its 50% Liquid Formulation
Authors: Bazzi B , Santi R , Radice M , Fabbrini R
Published: February 2020

A method based on the phosphorus determination, including thin layer chromatographic separation, has been developed for determining ethyl 0,0,-dimethyldithiophosphoryl- 1 -phenyl acetate in both technical products and its 50% liquid formulation. The insecticide or a convenient amount of an insecticidal preparation is dissolved in benzene, and the solution is spotted on a thin layer chromatographic plate. After development and spraying with the chromogenic reagent, the surface containing Cidial is detached and eluted. The quantity of the active ingredient in the eluate is obtained by estimation of phosphorus as ammonium phosphomolybdate. The concentration of Cidial in the original sample can be derived by calculation.
Determination of Microgram Quantities of Atropine Sulfate and Hyoscyamine in the Presence of Methylene Blue
Authors: Woodson Albert L
Published: February 2020

Tablets with microgram quantities of atropine sulfate and hyoscyamine, containing approximately 90 times as much methylene blue as total alkaloids, may be assayed successfully. The total alkaloids are separated from methylene blue by partition chromatography. The isolated alkaloids are determined by nitrating, reducing to the aromatic amine, diazotizing the amine, and coupling with the Bratton-Marshall reagent to form a stable red solution. Five assays of a commercial tablet gave values that averaged 96.4% of the label declaration. Recoveries at a level of 37–112 μg/tablet averaged 109%.
A Sweep Co-distillation Cleanup Method for Organophosphate Pesticides.
Authors: Storherr R W , Watts R R
Published: February 2020

A simple sweep co-distillation method which uses the Storherr tube was developed for cleanup of 2 g or less of crude crop extracts which contain organophosphate pesticide residues. Five crops (kale, carrots, apples, strawberries, and potatoes) were fortified at levels of 1.0, 0.5, and 0.1 ppm with a mixture containing Trithion, diazinon, malathion, methyl parathion, and parathion. The sweep co-distillation method was compared with the adsorption column method by use of this mixture. The range of average per cent recoveries were 89–101% and 83–96%, respectively. The cleanup required approximately 20 minutes per sample and was as good as, and in many cases better than, adsorption column chromatography. Detection of the organophosphate pesticides was performed by GLC with the thermionic detector.
Analysis of Dicamba in Crops and Milk, Including a Rapid Cleanup Method
Authors: Smith M , Suzuki H , Malina M
Published: February 2020

A fast, sensitive, and specific method has been developed for determining residues of 2-methoxy-3,6-dichlorobenzoic acid (Dicamba, Banvel-D*) in agricultural crops. Interferences affecting electron capture gas chromatography detection are removed by column partition chromatography. This method has been tested on a wide variety of crops; its sensitivity is 0.05 ppm.
Detection and Estimation of Animal Fats in Vegetable Oils by Gas Chromatography
Authors: Ettinger Charles L , Malanoski Anthony J , Kirschenbaum Herbert
Published: February 2020

The total unsaponifiable matter of various mixtures of animal fat in vegetable oils was extracted with ether following saponification, and this ether extract was subjected to gas chromatographic analysis. The presence of adulterating animal fats was confirmed by chromatography of their sterol acetates on the same column under the same conditions. The presence of 2.5% animal fats in vegetable oils can be detected, and recoveries range from 83 to 116%.
Authentic Vanilla Extracts: Comparison of Analyses of Commercial Samples with Their Laboratory-Prepared Analogs
Authors: Blomquist V H , Kovach E I , Johnson A R
Published: February 2020

Analytical indexes and profiles for 13 commercial and laboratory-made vanilla extracts were compared in a collaborative study. Experimental data are presented and discussed, indicating limits of comparability for the two types of extracts. Agreement in analytical values for corresponding commercial and laboratory-prepared extracts was satisfactory.
Modification of the USP Chemical Method for Determining Vitamin D in Evaporated Milk
Authors: Jones S W , Wilkie J B , Libby D A
Published: February 2020

The USP XVI chemical method for vitamin D in USP products has been substantially modified and applied to evaporated milk containing approximately 30 units of vitamin D per fluid ounce. A major modification is a 15 second reading at 500 mμ which most nearly represents the vitamin D content of the sample. An improved sample preparation eliminates much of the background interference, which also produces a color reaction. This method, when applied to a variety of samples, will show a relative standard deviation of 10%. Statistical data are presented to compare the modified method with the rat bioassay method for assaying vitamin D in evaporated milk.
Collaborative Study of the Infrared Method for DDVP in Pesticide Formulations
Authors: Mitchell L E , O’dowd A C , Patterson D R
Published: February 2020

A collaborative study, begun in 1963, to evaluate an infrared method for determining the DDVP content of four commercially available formulations, was continvied in 1964. Formulations assayed in 1964 were as follows: 0.5% sugar bait, 4 lb/gallon emulsible concentrate, 0.5% spray solution, and 1.0% cattle spray. Special emphasis was placed on refining the procedure applicable to the low-concentration hydrocarbon solutions. A statistical analysis of the data indicates that results of the test program were satisfactory, and the method is recommended for adoption as official, first action.
Collaborative Study of Spectrophotometric Determination of Hexachlorocyclopentadiene in Technical Chlordane
Authors: Malina Marshall
Published: February 2020

Hexachlorocyclopentadiene exhibits strong ultraviolet absorption at 324 mμ, while technical chlordane exhibits only small absorption at this wavelength. The intensity of this absorption is a quantitative measure of the hexachlorocyclopentadiene content. Eight laboratories cooperated in a collaborative study of two alternative procedures on six samples. Results show that one procedure exhibits a positive bias and that the other procedure does not. The precision of both procedures is excellent. The methods are recommended for adoption as official, first action.
Microbiological Methods for Examination of Frozen and/or Prepared Foods
Authors: Surkiewicz Bernard F
Published: February 2020

A method for the microbiological examination of frozen and/or prepared foods as an index to the sanitary conditions under which the food was produced and/or stored was subjected to collaborative study. The method encompasses four determinations: aerobic plate count, the MPN (most probable number) of coliforms, the MPN of E. coli, and the numbers of S. aureus. Subdivisions of custard pie filling, some inoculated with E. coli, A. aerogenes, or S. aureus, were examined by four laboratories. Statistical evaluation of the results indicated that the method gives essentially equivalent results from laboratory to laboratory. It is recommended that the method be adopted as official, first action.
EDTA Titration of Calcium and Magnesium
Authors: Steagall Edward F
Published: February 2020

A revised method for the EDTA titration of calcium and/or magnesium in pharmaceutical preparations was resubmitted for collaborative study this year. The method was also adapted for calcium analysis in tomato products as a check for standards compliance. Three simulated pharmaceutical mixtures and a sample of tomato juice were analyzed collaboratively by 10 analysts in 9 laboratories. The results were easily reproducible, and agreement between laboratories was good. It also appears that the problems of turbidity and fading end points have been resolved. The revised method was recommended for adoption as official, first action.
Preparation of Plant Material for Analysis
Authors: Grier John D
Published: February 2020

A survey was made of the problems, practices, and apparatus involved in the preparation of plant material for analysis. This report summarizes the replies to a questionnaire sent to 200 investigators concerned with plant analysis.
Raceophenidol in Feed
Authors: Pratt Edward L , Auerbach Morris E
Published: February 2020

Raceophenidol in feed can be estimated by an ultraviolet spectrophotometric measurement of the derived p-methylsulfonylbenzaldehyde. The method, effective for measurement of raceophenidol in feed at medication levels greater than 0.002%, is based on amide hydrolysis and subsequent periodate oxidation. Collaborative studies were conducted on the method; average value was 98.5 ± 7.8%. The method is recommended for adoption as official, first action.
Microcoulometric Gas Chromatographic Determination of Trichloroacetic Acid (TCA) Residues in Wheat Grain
Authors: Chiba M , Morley H V
Published: February 2020

TCA residues in wheat grain may be determined directly without extraction or cleanup. The chloroform formed by decomposition of TCA is collected in xylene and determined by microcoulometric gas chromatography. Two varieties of wheat grown in two different soil types and treated with TCA applied at the 1–4 lb per acre level were analyzed by this direct technique. By using the direct procedure as an arbitrary standard for 100% recovery, comparisons were made among three extraction techniques. Extraction of spiked wheat samples gave recoveries comparable to the direct method. Field-treated samples, however, gave poor recoveries. The results indicated that TCA is not readily extracted from fieldtreated samples, possibly because of combination with basic cell constituents.
Quantitative Determination of Benzaldehyde in Flavors and Cordials by Ultraviolet Spectrophotometry, 2,4-Dinitrophenylhydrazine Precipitation, and the Official AOAC Procedure
Authors: Brunelle Richard L
Published: February 2020

The present official AOAC method was compared with other gravimetric and spectrophotometric procedures for the determination of benzaldelvyde in flavors, cordials, and other distilled spirits products. Collaborative results indicate that the ultraviolet spectrophotometric and the 2,4-dinitrophenylhydrazine gravimetric methods are superior to the present official AOAC procedure, and it is recommended that both be adopted as official, first action as alternative methods.
Nonnutritive Residues: A System of Analysis for the Replacement of Crude Fiber
Authors: Van Soest P J
Published: February 2020

A literature review of the use of crude fiber for the estimation of the poorly digestible part of feedstuffs, together with a discussion of the factors that affect nutritive availability of different chemical entities in feeds, shows that crude fiber may be unsuitable for the evaluation of feeds. The new system described, utilizing detergents, divides dry matter of feeds along lines consistent with modern views in nutrition and emphasizes the cell-wall and lignin contents in feeding materials of plant origin and the acid-detergent insoluble fraction in high protein feeds of plant and animal origin.
Sorting Procedure for the Determination of Vanillin in Vanilla Extracts by Ultraviolet Absorption
Authors: Feeny Frank J
Published: February 2020

Further collaborative study was conducted on the ultraviolet absorption method for vanillin, 19.008. Results indicated that the method should be adopted as official, final action as a sorting procedure for vanillin.
Analysis by Microcoulometric Gas Chromatography
Authors: Burchfield H P , Wheeler R J
Published: February 2020

Microcoulometry provides an absolute and stoichiometric measure of chlorine, sulfur, and phosphorus in pesticides. The practical limit of detection of most pesticides containing these ions is 0.01–0.1 µg with the Dohrmann Model C-100; with the Model C-200, 0.001 µg chlorine can be detected. When the coulometer is used in the reducing mode, phosphorus is detected as PH3; when it is used in the oxidizing mode, chlorine is detected as HC1, and sulfur is detected as SO2. Temperature-compatible polar and nonpolar columns can be housed in the same oven, so that relative retention times, as well as elemental compositions, can be crosschecked by using either the oxidation or reduction modes.

Microcoulometric detection eliminates interfering peaks; reduces enhanced baselines; minimizes tailing from the solvent peak; allows programming without column bleed; and permits use of more volatile and less stable liquid phases than is possible with ionization detectors.
Ethoxyquin (Santonin®) in Eggs, Chicken Muscle, and Chicken Liver
Authors: Vanderen John M , Jaworski E G
Published: February 2020

A method, based on the fluorescence of ethoxyquin in iso-octane following a purification procedure, has been developed for the determination of ethoxyquin in egg yolk, chicken muscle, and chicken liver. Ethoxyquin is extracted from tissue with iso-octane and then transferred to dilute sulfuric acid by extraction. The acid is neutralized with sodium hydroxide, and the ethoxyquin is re-extracted by iso-octane. The fluorescence of this solution is then measured. This method gave recoveries of ethoxyquin from egg yolks, muscle, and liver ranging from 60 to 90%, depending upon the tissue and ethoxyquin concentration. The precision of the method is good, with an average standard deviation of 0.04 ppm for samples containing 0.50–2.50 ppm ethoxyquin.
Sulfur Dioxide Determination by Modified Monier-Williams Method
Authors: Thrasher Joel J
Published: February 2020

An alternative trapping system for the two U-tubes now incorporated in the modified Monier-Williams method for total sulfurous acid, 27.079, is recommended. This system is easy to use, permits the titration of distilled SO2 during the determination, and is cheaper and more durable than the U-tube system. The nonapplicability of 27.079 to dried onions, leeks, and cabbage is also discussed.
Halogenated Hydrocarbons in Drugs: Chlorobutanol
Authors: Healton Donald C , Davidson Arthur W
Published: February 2020

An infrared spectrophotometric and gasliquid chromatographic method for chlorobutanol in drugs was studied collaboratively. The method consists of carbon disulfide elution of a Celite column and determination by infrared and/or GLC Recoveries for solutions containing 0.475% chlorobutanol were 91.1 ± 3.6 and 92.2 ± 4.5 for infrared and GLC methods, respectively. Recoveries for solutions containing 0.237% chlorobutanol were 91.0 ± 3.7 and 95.0 ± 4.9 for infrared and GLC methods, respectively. Collaborative results revealed the need for modification of preparation of the standard solution.
The Mass Spectra of Some Organophosphorus Pesticide Compounds
Authors: Damico Joseph N
Published: February 2020

The mass spectra of 23 pentavalent organophosphorus pesticide esters were investigated. Rearrangements and fragmentation by simple cleavage are postulated from analogy with similar compounds, from the presence of chlorine atoms with their readily-recognizable isotopic distribution when applicable, from elemental compositions determined by accurate mass measurements, and, in a few cases, from model compounds. The compounds are divided into four groups: phosphorodithioates, phosphorothionates, phosphorothiolates, and phosphates. The base peaks are formed by rearrangements and simple cleavage. Rearrangement ions are formed by (I) hydrogen migration from the alkyl ester group to the thiophosphite-oxygen skeleton; (2) migration of hydrogen from the Z moiety (aryl or alkyl group) to the phosphorus-oxygen skeleton; (3) migration of hydrogen from the Z moiety to the thiophosphite-oxygen skeleton; (4) migration of hydrogen from the ester group bonded to phosphorus to the Z moiety; and (5) alkyl migration to the Z moiety. The base peak does not characterize the different groups or compounds within a group. However, beta-cleavage (relative to the Z moiety) producing relatively intense peaks (with the charge on the Z moiety) is characteristic of a given group. These data may be useful in identifying metabolites isolated from crops field sprayed with an individual parent organophosphorus pesticide.