bluuebunny/crossref_metadata_2025 huggingface dataset:
N-1-Naphthylphthalamic Acid Residues on Food Crops
Authors: Johnson Raymond H
Published: February 2020

The method of Lane, et al. for N-l-naphtliylphthalamic acid was modified as follows: The distillation of the freed l-naphthylamine was changed to provide for a true steam distillation that lessened decomposition losses of the amine in the strong alkali; the color development conditions were modified to yield a more stable solution for measurement. With the modified method, recoveries of 80–100% were obtained on cabbage, asparagus, and alfalfa meal fortified with 0.10–1.1 ppm N-1-naphthylphthalamic acid.
Determination of Chlorine in DDT by the Use of Dispersed Sodium
Authors: Berges Herman H
Published: February 2020

An accurate method for the determination of chlorine in DDT employs dispersed sodium to convert the organic chlorine to inorganic chlorine; this reduces the reaction time to 2–3 minutes, compared to 1–1½ hours for the official method. Otherwise this procedure is identical to the official procedure. No special equipment is needed.
Determination of Phosphatase in Dairy Products by Dialysis
Authors: Perlmutter Sam H , Lewis Lossie M
Published: February 2020

A method for determination of phosphatase, the enzyme naturally present in raw milk, hascd on a dialysis technique, was evaluated by a collahorative test among seven laboratories. Results indicate that the method is accurate and reproducible, and it was adopted as official, first action.
Direct Micro determination of Mercury in Color Additives by the Photometric-Mercury Vapor Procedure
Authors: Wenninger John A
Published: February 2020

A direct method has been developed for the determination of submicrogram amounts of mercury in inorganic and organic color additives. Samples are pyrolyzed at 650°C, generating mercury vapor from the mercury compounds present in the sample. The pyrolysate is passed over heated copper oxide and swept through a series of traps that remove interfering substances. The mercury content of the gas stream is determined with a commercially available mercury vapor meter. The method requires no pretreatment of the sample, such as digestion and isolation of mercury. Amounts of mercury as low as 0.01 μg can be detected. Samples as large as 25 mg (organic colors) or 250 mg (inorganic colors) may be used. Mercury at a concentration of 0.50 ppm in organic colors and 0.05 ppm in inorganic colors can be determined to within ± 2 0 % . About 5 minutes is required per analysis. The method is not suitable for the determination of mercury in samples containing organically bound iodine.
Total Diet Study: Content of Ten Minerals—Aluminum, Calcium, Phosphorus, Sodium, Potassium, Boron, Copper, Iron, Manganese, and Magnesium
Authors: Zook Elizabeth G , Lehmann Joanna
Published: February 2020

Ten mineral elements were determined by emission spectroscopy in 20 subsamples of the Food and Drug Administration “total diet” described in earlier publications. Radioactivity residues from fallout, proximate composition, selected vitamins, pesticide residues, and carbohydrate fractions were previously determined on these samples. On a dry, fat-free basis, aluminum content of these diets varied considerably (14-fold). In view of the normal range of mineral content in individual foods, minerals other than aluminum were remarkably uniform (2-fold variation). Minerals and their ranges per 100 g dry, fat-free solids were as follows: aluminum, 0.54–7.40 mg; calcium, 223–323 mg; phosphorus, 296–398 mg; sodium, 968–1147 m g ; potassium, 686–899 mg; boron, 0.290–0.593 mg; copper, 0.330–0.733 mg; iron, 3.80–6.18 mg; manganese, 0.54–1.30 mg; and magnesium, 60.4–102.8 mg. Data on a 4200 calorie daily intake are also presented.
Determination of Available Lysine in Food Materials
Authors: Lyman Carl M , Thomas M C
Published: February 2020

The major problems in the determination of available lysine in samples of high carbohydrate content are: (1) the destruction of e-dinitrophenyl lysine by carbohydrate decomposition products, and (2) the formation of interfering colored materials during hydrolysis of the samples. A procedure based on a modification of the Sanger reaction is described. Since this procedure is too involved and too intricate to be generally useful, collaborative study has been delayed and our efforts have been directed toward development of a simpler method.
Application of Chemical Kinetics to Assay of Phenobarbital and Pentobarbital Mixtures
Authors: Chafetz Lester , Robinson J Rocky , Petrick Robert J
Published: February 2020

An assay of mixtures of phenobarbital and pentobarbital is described which exploits the difference in rate of degradation of the drugs in alkali. The procedure entails measurement of peak absorbance of dilutions (pH 10) of phenobarbital and a mixture of the drugs before and after heating them in 0.1M trisodium phosphate for 15 minutes. In four trials of the procedure on replicated samples, the average recovery of the phenobarbital was 97.3% (range 89.5–105.2%) and of the pentobarbital 98.1% (range 94.0–101.0%). Synthetic tablet mixtures containing phenobarbital-pentobarbital combinations were assayed with satisfactory results after chromatographic separation of the barbiturates from the mixture.
Analysis of Vanilla Powders
Authors: Fitelson J
Published: February 2020

A number of the official methods for vanilla extracts have been adapted for use with vanilla powders, including lead number, vanillin, ethyl vanillin, organic acids by paper chromatography, and resins. Results on authentic samples compared well with results for extracts or concentrates. The direct paper chromatographic method for foreign plant material was not adaptable to powders.
Extraction p-Values of Pesticides and Related Compounds in Six Binary Solvent Systems
Authors: Bowman Malcolm C , Beroza Morton
Published: February 2020

The extraction p-values (fraction of solute partitioning into upper phase of an equivolume two-phase system) of 131 pesticides and related compounds in six solvent systems have been determined to aid in pesticide analysis and identification. The 85 compounds whose p-values were determined by electron-capture gas chromatography have been tabulated in order of increasing retention times alongside their p-values to allow the best choice of the six solvent systems to be made for identification purposes. Remaining p-values were determined gravimetrically. Mathematical formulas are given for calculating from the p-value the fractional amount extracted after repeated extractions. Graphs are presented which allow the specificity of a given p-value in a given system to be determined readily.
Determination of Carbaryl in Crops by Oscillographic Polarography
Authors: Gajan Raymond J , Benson Walter R , Finocchiaro Josephine M
Published: February 2020

The insecticide carbaryl can be determined quantitatively in the presence of a-naphthol by means of oscillographic polarography. A characteristic peak for the hydrolysis product of nitrosated carbaryl is obtained which has a peak potential of –0.45 ± .05 v vs. a mercury pool reference electrode. Using a modified cleanup method, as little as 0.2 ppm of carbaryl residues on certain fruils and vegetables has been determined. Recoveries from fortified crops averaged 95.3% ± 9 . 0% at the 0.2, 5.0, and 10.0 ppm levels. Among those pesticides tested, only o-phenylphenol interfered.
Gas-Liquid Chromatographic Method for Determination of Fat-Soluble Vitamins. III. Evaluation of a Vacuum Distillation Procedure for Vitamin E Isolation, Using C-14 Labelled Alpha-Tocopheryl Acetate
Authors: Sheppard A J , Ford L A , Boehne J W , Libby D A
Published: February 2020

Alpha-tocopheryl acetate, carbon-14 labelled in the methyl group at the two position, was used to determine the stability and recovery of the vitamin during vacuum distillation (140–160°C, and 0.020 mm Hg pressure, 60 minutes). Evaluation was based on measurements of radioactivity with a liquid scintillation spectrometer and a lowbackground Geiger counter. Recoveries of 20 mg of the pure compound were nearly quantitative (97%). Recoveries of the tocopheryl ester added to lard, “stripped” of vitamin E, at 0.5 mg/g or less and to butter at 0.1 mg/g were 98 and 82%, respectively. Results of the differential counting technique suggest that the ester is increasingly unstable at temperatures exceeding 160° and that a molecular rearrangement probably takes place.
Human Bioassay Techniques for Determining Availability of Vitamins from Preparations Resistant to In Vitro Disintegration
Authors: Libby David A , Schertel Max E , Loy Henry W
Published: February 2020

The human bioassay method has been utilized to determine the availability of certain vitamins from preparations which did not pass the official USP disintegration test. Urinary riboflavin recoveries from the test preparation were compared to urinary recoveries from equivalent quantities of a riboflavin reference standard. Tablets which traversed the entire digestive tract and were recovered intact were assayed for specific vitamins. Multiple vitamin dosage forms which did not disintegrate during the USP in vitro disintegration test were found to be also significantly resistant to human digestive action. Vitamin availabilities from these forms as determined by urinary excretion were seriously impaired. Extreme individual variations were noted in tests of the same product. Several preparations were found to be totally unavailable to certain individuals.
Wick Trough and Thin Layer Chromatography Developments
Authors: Wilkie John B
Published: February 2020

A wick trough system was developed which permits chromatographing in the horizontal, ascending, or descending position. This system will chromatograph large samples with good resolution in approximately 30 minutes. It was applied to a nonsaponifiable fraction of a feed extract containing vitamin A. The system satisfactorily separated xanthophyll, vitamin A, carotene, and the extraneous material.

Micro thin layer plates were adapted to the wick system. Trial runs with a dye mixture gave promising results.
Determination of DDVP in DDVP-Dipterex Formulations by Gas Chromatography
Authors: Ellis John , Bates John
Published: February 2020

In the analyses of commercial fly-bait samples for DDVP (0,0-dimethyI-2,2-dichloro vinyl phosphate), containing Dipterex (0,0-dimethyl-2,2,2-trichloro - 1 - hydroxyethyl phosphonate) as a guaranteed ingredient, interferences were observed at 9.9– 10.4/t with the current spectrophotometric methods. These samples were analyzed by an electron capture gas chromatographic method, and the results showed no interference from Dipterex or other substances. A selected group of samples was analyzed by gas chromatography and spectrophotometry, and the results were compared.
Applicability of an Isotope Exchange Method for the Determination of Milligram and Microgram Quantities of Organic Mercurials. I. Pharmaceutical and Agricultural Mercurials
Authors: Davis Sidney , Arnold Alphonso
Published: February 2020

The isotope exchange technique was applied to the analysis of milligram and microgram quantities of organic mercurials, with emphasis on pharmaceuticals and fungicides of an agricultural nature. Average recovery was 98.48 ± 1.12% for Hg-203 in equilibrium with chemical mercury. In comparison studies, the isotope exchange procedure showed essential agreement with standard techniques for mercury determination. At low levels, traces of mercury via glassware contamination were observed to interfere. The digestion system was found to be applicable to most organic mercurials studied except ethyl mercuric phosphate and three commercial fungicides.
II. Rapid Extraction Method for Crops
Authors: Watts Randall R , Storherr Robert W
Published: February 2020

An ethyl acetate extraction method for organophosphate pesticide residues on crop samples requires about 40 minutes for extraction and preparation of sample. This procedure eliminates the lengthy acetonitrile concentration and reduces the volume of solvent used in the acetonitrile procedure. Dimethoate, diazinon, Trithion, Guthion, Phosdrin, and parathion were easily extracted from field-sprayed kale by the ethyl acetate extraction method.
4-(p-Nitrobenzyl) pyridine, A New Chromogenic Spray Reagent for the Organophosphate Pesticides
Authors: Watts Randall R
Published: February 2020

This paper describes p-nitrobenzyl pyridine as a chromogenic spray reagent for detection of organophosphate pesticides on paper and thin layer chromatograms. The chromogenic spray is equally sensitive for thio and nonthio organophosphate pesticides. All 20 organophosphate pesticides tested on paper and thin layer chromatograms gave distinct and persistent spots with the spray procedure. The lower sensitivity limit is 0.5 μg of pesticide on paper chromatograms and 0.5–2.0 μg of pesticide on thin layer chromatograms.
Rapid Visual Technique for Recovery of Mold from Beverages and Therapeutic Liquids
Authors: Miller Bob J
Published: February 2020

A visual method is presented that enables the analyst to isolate clumps of mold from dark solutions and from colored and irregular bottles and to examine the material microscopically. The solutions to be examined are passed through a glass tube for visual examination, and any observed extraneous material is deposited directly onto a slide. Physical characteristics are not altered, and all visible mold clumps can be accurately counted and measured.
A Rapid Method of Carbon Analysis for Biological Materials
Authors: Smith L W , Flatt W P , Barnes K A , Soest P J Van
Published: February 2020

An induction furnace and a gasometric analyzer have been adapted for the analysis of carbon in biological materials. Samples for analysis must not exceed 70 mg carbon. The number of analyses which can be routinely performed for carbon in an eight-hour day has been increased from 8, by wet combustion, to 50, by the induction furnace method. Hay, concentrate, dried feces, wet feces, milk, and urine have been analyzed by this method with iron, cupric oxide, molybdenum trioxide, and silicic acid used as reagents. Silver phosphate and vanadium pentoxide were required to obtain satisfactory analyses of dried milk. Liquid urine was analyzed successfully by the same methods employed for dried samples except for minor modifications of the combustion tube and catalysts. Analyses on sodium carbonate, glucose, and potassium hydrogen phthalate yielded carbon recoveries of essentially 100%.
Rapid Method for the Determination of Insect Fragments from Cocoa
Authors: Stein Richard , Ferrera Robert S , Brown Robert F
Published: February 2020

A rapid screening method for determining insect fragments in cocoa uses a 5 g sample of cocoa and requires only 10 minutes for extraction, as compared with the 50 g samples in the official method. The new method shows approximately eqvial recoveries and good agreement between determinations and analysts.
Effects of Neutral Salts on the Activity of Iodine, Bromine, and Chlorine as Swimming Pool Water Disinfectants
Authors: Koski T A , Beloian A , Stuart L S
Published: February 2020

Potassium iodide, potassium bromide, and potassium chloride materially slow down the bacteria killing rates of iodine, bromine, and chlorine, respectively, in distilled water. The germicidal activity of elemental iodine in water does not increase as the pH is increased from pH 5.8 (the mean value fovind in unbuffered water containing 2.0 ppni free iodine) to 8.0 as might be expected if the germicidal activity of iodine could be attributed to hypoiodous acid. Chlorine is considerably less effective as a disinfectant for sea water than for fresh water when judged by activity against the gram-positive test organism S. faecalis. While this can be attributed, in part, to interference by the neutral chloride salts present in sea water, the presence of an initial high chlorine demand and difficulties encountered in maintaining available chlorine residuals after this demand has apparently been satisfied make it impossible to conclude that this is the only factor involved.
Efficiency of Several Selective Media for Isolating Coagulase-Positive Staphylococci From Food Products
Authors: Baer Edward F , Franklin Marquitta K , Gilden Mildred M
Published: February 2020

The relative efficiency of several selective media recommended for detecting coagulasepositive staphylococci was determined during the course of random food sample examination. Media compared were: cooked meat broth containing 10% NaCl, Trypticase soy broth containing 10% NaCl, sorbic acid broth, staphylococcus medium No. 110, polymyxin-B agar, Vogel and Johnson agar, tellurite glycine agar, and mannitol egg agar. Results indicate that Trypticase soy broth containing 10% NaCl combined with Vogel and Johnson agar as the plating medium was the most efficient media system.
Thiabendazole in Feeds
Authors: Szalkowski C R
Published: February 2020

Two methods for thiabendazole, 2-(4′-thiazoyl)-benzimidazole, in feeds were studied collaboratively. Method I is applicable to all feeds. Method II is applicable to cattle supplements and premixes containing > 1% thiabendazole. Thiabendazole is extracted from the feed with 0.1N HCl; any interferences are removed with sodium citrate and chloroform extraction. The thiabendazole is re-extracted with 0.1N HCl and treated with a zinc slurry in 30% glycerol containing p-phenylenediamine. Oxidation with ferric sulfate yields a blue complex which is extracted with n-butanol and measured at 605 mμ. The methods are recommended for adoption as official, first action.
Rapid Detection of Chlorinated Pesticide Residues by an Improved TLC Technique: 3¼ × 4″ Micro Slides
Authors: Kovacs Martin F
Published: February 2020

Submicrogram quantities of as many as 26 chlorinated pesticides can be resolved in 5–10 minutes and identified on 3¼ × 4″ micro slides coated with either aluminum oxide G or MN-silica gel G-HR. Plates are developed in 800 ml beakers with one of three solvent systems: n-heptane + 1% acetone; n-heptane; or iso-octane with 25% dimethylformamide. Rf values are presented. A 3¼ × 4″ micro plate combines the speed and economy of a 1 × 3″ microscope slide with the capacity and efficiency of an 8 × 8″ plate for TLC analysis.
Determination of Tranid Residues in Fresh Fruits, Vegetables, and Cottonseed
Authors: Johnson D P , Stansbury H A
Published: February 2020

Tranid, 3-exo-chloro-6-endo-cyano-2-norbornanone O-(methylcarbamoyl)oxime, is an acaricide effective against both resistant and nonresistant strains of red and citrvis mites. Residvies of Tranid are determined in fresh frviit and vegetables as well as cottonseed by a combination of base- and acid-catalyzed hydrolysis to form hydroxylamine. The latter is then oxidized to nitrous acid which is determined colorimetrically. The compound is extracted from the crop with benzene and cleaned up by liquid partitioning. The method is sensitive to abovit 0.03 ppm of Tranid, and recoveries from all crops tested averaged 91.5 ± 4.4% over the range 0.05–3 ppm.
Determination of the Substituted Urea Herbicides Linuron, Monuron, Diuron, Neburon, and Fenuron in Surface Waters
Authors: Katz Stanley E
Published: February 2020

A quantitative method has been developed for the substituted urea herbicides in surface waters. The herbicide is extracted from water with chloroform and hydrolyzed under reflux conditions with 6N HCl. The resulting aniline is diazotized and condensed with N-(l-naphthyl) ethylenediamine to form a magenta dye, which is extracted with n-butanol and measured colorimetrically at 555 μ. Qualitative determination is made by thin layer chromatography. The herbicide is extracted from water with chloroform, and the volume is reduced. After development, the chromatograms are sprayed with ninhydrin and visualized.
Analytical Methodology of Oxytetracycline in Feed
Authors: Billman D C
Published: February 2020

Preliminary evaluations have been conducted of the AOAC method for the assay of oxytetracycline in feed at the level of 10 g/ton. With careful techniques, nonmineral feeds containing 10 g/ton oxytetracycline can be assayed. Mineral feeds containing 10 g/ton oxytetracycline gave erratic results; further studies are planned with the use of compensating standard curves.
Collaborative Study of an Ultraviolet Spectrophotometric Method for Griseofulvin in Animal Feed
Authors: Kabasakalian Peter
Published: February 2020

Collaborative studies were made of an ultraviolet spectrophotometric method for determining griseofulvin in animal feed. Prior to measurement, the antibiotic is isolated from the feed by extraction with chloroform and separated from ultravioletabsorbing interferences in the extract by column chromatographic fractionation. The average recovery of griseofulvin by 9 collaborators was 103 ± 8.7% from fortified meal and 102 ± 9.7% from fortified pellets. The method is recommended for adoption as official, first action.
Malt Beverages and Brewing Materials
Authors: Stone Irwin
Published: February 2020

One new method, Total Haze of Beer After Chilling, is recommended for adoption as official, first action. Other new methods of the American Society of Brewing Chemists, which will be eventually submitted to the AOAC, are Diacetyl in Beer, Microbiological Controls, Aphids in Hops, and Physical Stability of Beer. The ASBC now has nine technical subcommittees investigating various analytical methods which may be of eventual interest to the AOAC.
Cryoscopy of Milk: Effect of Variations in the Method
Authors: Henningson R W
Published: February 2020

Bath level, sample temperature, rate of stirring, degree of supercooling, sample size, sample isolation, and refreezing of the sample were the variables in the thermistor cryoscopic method for the determination of the freezing point value of milk chosen for study. Freezing point values were determined for two samples of milk and two secondary salt standards utilizing eight combinations of the seven variables in two test patterns. The freezing point value of the salt standards ranged from –0.413 to –0.433°C and from –0.431 to –0.642°C. The freezing point values of the milk samples ranged from –0.502 to –0.544°C and from –0.518 to –0.550°C. Statistical analysis of the data showed that sample isolation was a poor procedure and that other variables produced changes in the freezing point value ranging from 0.001 to 0.011°C. It is recommended that specific directions be instituted for the thermistor cryoscopic method, 15.040–15.041, and that the method be subjected to a collaborative study.
Comparison of the FAO Schmid-Bondzynski-Ratzloff and Official AOAC Methods for Determining the Fat Content of Cheese
Authors: Weik R W , Horwitz William
Published: February 2020

The official AOAC method, 15.164, for determining the fat content of cheese was compared in six laboratories with the Schmid - Bondzynski - Ratzloff method, as adopted by the Food and Agriculture Organization of the United Nations. The results of analysis by the two methods are not significantly different; thus, the two methods can be used interchangeably.
Determination of Oven Moisture in Tobacco
Authors: Bortner C E , Ogg C L
Published: February 2020

A comparison of mechanical convection and gravity convection oven-drying of tobacco was made on 12 tobacco samples, six with high and six with low moisture content. Data show that better interlaboratory precision was obtained by drying in a mechanical convection oven. The term “apparent moisture” is vised becavise oven drying also causes loss of volatile organic material. The magnitude of this loss is shown to be from 0.25 to 1.5%, depending on the type and treatment of the tobacco. The forced draft oven method is recommended for adoption as official, first action.
Dessert Gel Strength Testing
Authors: Borker Emanuel , Stefanucci Arthur , Lewis Alfred A
Published: February 2020

The history of gelatin and gelatin dessert strength testing is reviewed. The current AOAC method for dessert gels using the Bloom Gelometer was found too variable for control of gelatin dessert production in a multi-plant operation. Variability can be reduced with a lower shot flow rate, rigid control of sample preparation, and frequent maintenance in gelometer alignment and adjustment. Detailed instructions for dessert gel strength testing are given.
A Rapid Method for the Quantitative Determination of Antihistamines and Some Related Compounds by Gas Chromatography
Authors: Celeste Anthony C , Polito Michael V
Published: February 2020

Laboratory-prepared and commercial samples of antihistamine mixtures are analyzed by gas chromatography with a Carbowax 20M-SE 30 phase on Anakrom ABS column. Recoveries for the simulated tablet preparations range from 96.9 to 102.5%. Recoveries from commercial preparations range from 90.7 to 113.2% of label declarations. Retention times for 12 antihistamines, dextromethorphan HBr, and phenylpropanolamine HC1 relative to diphenylpyraline HCI, the internal standard, are given.
Collaborative Studies of Methods for Determining Vanillin and Ethyl Vanillin in Flavoring Material
Authors: Fitelson J
Published: February 2020

Collaborative study was conducted on two ultraviolet absorption methods for vanillin and one paper chromatographic method for vanillin and ethyl vanillin. The official, first action screening method for vanillin was compared with another ultraviolet absorption method which determines p-hydroxybenzaldehyde. Results were more accurate by the ultraviolet absorption method than by the official method, when the estimation of p-hydroxybenzaldehyde was eliminated. The method is recommended for adoption as official, first action. Improvements have been incorporated into the paper chromatographic method to prevent tailing of spots, and the revised method is recommended for adoption as official, first action.
Extraneous Materials in Flour
Authors: Reed Garland L
Published: February 2020

Collaborative results are presented comparing method 36.02S(a) for extraneous materials in flour with method 36.029. Last fall method 36.029 was adopted as official, first action based on a collaborative study by the AACC. The present study was conducted to obtain additional data and to clarify the exact wording to be used in 36.029. The data, although limited, tend to show that the two methods are equal.
Improved Method for the Determination of Maggots in Canned Mushrooms
Authors: Brown Robert F , Aho Arthur C
Published: February 2020

Collaborative studies were conducted on a new sieving method, using both a nested combination of Nos. 20, 40, and 140 sieves and a crystal violet stain, for determining maggots and other arthropod filth in canned mushrooms. The method greatly improves the yield, accuracy, speed, and facility with which this determination can be accomplished. It is recommended for adoption as official, first action.
Rapid Flame Photometric Method for Sodium in Fruits
Authors: Boland Feederick E
Published: February 2020

The flame photometric method of Pro and Mathers for sodium in wines and distilled spirits has been adapted to the analysis of sample solutions of fruit and subjected to collaborative testing. A sample solution of fruit is aspirated directly into the flame photometer, which eliminates the need for ashing the sample and thus effects a saving of time. Six Food and Drug Administration District Laboratories, two State laboratories, and the Associate Referee participated in the collaborative study. The results indicate that the method is sufficiently accurate for the determination of sodium in fruit, and the method is recommended for adoption as official, first action.
Investigations of the Gas-Liquid Chromatography of Fruit Acids
Authors: Hautala Earl
Published: February 2020

Present analytical methods for the determination of fruit acids are long, since most require a separate determination for each individual acid. Gas-liquid chromatography offers a method capable of determining many acids by one procedure. Citric and l-malic acid esters were successfully prepared and chromatographed. Tartaric acid esterification and chromatography were attempted without satisfactory results. It is recommended that other stationary liquids and derivatives be studied.
Study of Extraction Procedures for Chlorinated Organic Pesticides in Fresh Eggs
Authors: Sawyer Allen D
Published: February 2020

The Johnson procedure was modified to provide a quicker and more satisfactory method for cleanup of fresh egg samples for chlorinated pesticide residue analysis. Acetonitrile extraction of the sample was followed by centrifugation of the extract and chromatography on a “layered” Florisil sodium sulfate column. The use of the “layered” column yielded 15% eluates suitable for direct analysis by microcoulometric gas chromatography. Unfortified egg samples were analyzed for DDD, DDE, DDT, heptachlor epoxide, and dieldrin by both this procedure and the Onley-Mills technique, and the results were compared.
Coliform and Total Bacterial Counts in Spices, Seasonings, and Condiments
Authors: Warmbrod Fred , Fry Linda
Published: February 2020

The regulatory program of the Tennessee Food and Drug Division has been extended to include microbiological contaminants in spices, seasonings, and condiments. Samples were examined for aerobic plate count, coliform count, and acid tolerant bacteria and mold counts. Some samples gave high coliform counts which may possibly indicate contamination. A regulatory program is more meaningful if microbacteriological examinations are made on food products.
Collaborative Study of Improved Sporicidal Test
Authors: Ortenzio L F
Published: February 2020

Collaborative data indicate that changes are needed in the present official sporicide test to avoid serious errors caused by carryover of the germicidal chemical into subculture tubes, slow germination time with exposed surviving spores, and failure of such spores to germinate in ordinary subculture and re-subculture tubes withovit a heat-shock treatment. Changes also appear desirable to reduce variations due to irregular drying of spores prior to exposure to sporicidal chemicals. A proposed revised text is recommended for adoption as official, first action.
Moisture in Dried Vegetables and Spices
Authors: Eader Bobby R
Published: February 2020

A collaborative study was conducted to compare the near-infrared spectrophotometric method and a Karl Fischer volumetric method with a vacuum oven method for the determination of moisture. Results by the near-infrared method were as accurate as and more rapid and specific than the vacuum oven method. Results by the Karl Fischer method were not as satisfactory; more study is needed to improve the precision of the method.
Rapid Procedure for Aflatoxin Analysis in Cottonseed Products
Authors: Stoloff Leonard , Graff Alan , Rich Harold
Published: February 2020

A new method for the determination of aflatoxins in cottonseed is presented and compared with two other procedures. This procedure yields good recovery for added aflatoxin, is relatively simple and rapid, and produces relatively clean extracts for TLC. A 75 g sample of ground cottonseed or cottonseed meal is extracted with aqueous acetone, centrifuged to remove solids, treated with lead acetate and acetic acid to precipitate interfering substances, and recentrifuged. An aliquot of the supernatant is mixed with powdered cellulose and packed into a chromatographic column for liquid-liquid partition chromatography. Hexane elutes the lipid materials; the aflatoxins are eluted with a hexane-chloroform mixture. After solvent evaporation, the aflatoxin-containing residue is dissolved in chloroform and chromatographed by TLC. Silica gel is the adsorbent; a benzeneethanol-water mixture is the developing solvent. The aflatoxin content is estimated by comparison with standard aflatoxins.
Determination of Molecular Weight
Authors: Ogg C L
Published: February 2020

An initial study, in which 23 collaborators participated, was conducted on the determination of molecular weight by the isothermal distillation (vapor pressure osmometry) method. Each used his own method and apparatus to analyze four samples in duplicate; the molecular weight ranged from 123 to 891. Results show that the chief problem is the choice of the correct solvent and reference standard and that the use of bare thermistors is questionable.
Determination of Chlorinated Pesticide Residues in Wheat by Electron Capture Gas Chromatography
Authors: Saha J G
Published: February 2020

Electron capture gas chromatography has been used to measure the efficiency of an extraction and cleanup procedure for chlorinated pesticide residues in wheat. Soxhlet extraction of ground wheat with acetonitrile, followed by partition into petroleum ether and cleanup on a magnesia-Celite column has been found adequate for the determination of heptachlor, aldrin, dieldrin, and endrin in concentrations as low as 5 ppb. Recoveries of aldrin, dieldrin, and endrin ranged from 98 to 104%, while those of heptachlor were 84–92%.
Gas Chromatography of Dinitro Herbicides
Authors: Boggs Hugh M
Published: February 2020

Dinitrophenolic pesticides tail badly when gas chromatography is attempted. Tailing can be eliminated by converting these pesticides to their methyl ethers with diazomethane and detecting these methylated compounds with electron capture gas chromatography, using either radium or tritium as the source. These compounds give symmetrical peaks on a 4′ × 4 mm i.d. column packed with 10% DC-200 on 90/100 mesh Anakrom ABS and operated at 150 or 200°.
Phenylmercuric Compounds: A Review of Analytical Methods and a Proposed Polarographic Assay
Authors: Hopes Ted M
Published: February 2020

A polarographic method, using pH 10 borate buffer and 0.1M KCl as the base solution, has been applied to phenylmercuric compounds. The second reduction wave given by phenylmercuric compounds is easy to measure. The limiting current is controlled by the diffusion and is directly proportional to concentration between 8 and 40 μg/ml. A sensitive test for free Hg++ will detect 3.7 μg/ml in the final test solution. The polarographic method is more specific, sensitive, and accurate than existing methods which are reviewed here. It is recommended that the method be applied to various pharmaceuticals.
Coulometric Determination of Kjeldahl Nitrogen
Authors: Christian Gary D , Jung Paul D
Published: February 2020

After digestion by official methods, samples were analyzed for nitrogen. The pH of an aliquot of the acid digest was adjusted to 8.6, and the ammonia was titrated with coulometrically-generated hypobromite. Distillation and preparation of standard solutions were eliminated, and the results agreed closely with those obtained by standard procedures.
A Flow Cell and Chart Ratchet for Repetitive Infrared Analysis
Authors: Ellis John H
Published: February 2020

A system for minimizing the recycling time between samples in an infrared quantitative analytical routine is described. This system utilizes flow-through attachments that allow changing samples without removing the cell from the spectrophotometer. A chart ratching device permits the instrument to scan automatically and repeatedly a portion of the spectrum and record each sample in sequence.
Hydrochloric Acid, Sulfuric Acid, and Sodium Hydroxide Standard Solutions
Authors: Hall Martha J
Published: February 2020

Official Methods of Analysis was reviewed for these three standard solutions to eliminate all vinnecessary duplication of instructions and to provide additional, alternative methods of standardization. Additions and deletions are recommended for several methods and for Chapter 42.
Determination of Nitrite and Nitrate in Meat Products
Authors: Landmann Wendell A
Published: February 2020

A study was initiated on a method for the simultaneous determination of nitrate and nitrite in meat products. Nitrate and nitrite are determined by difference before and after the reduction of nitrate with metallic cadmium. Nitrate is diazotized, coupled with sulfanilic acid and 1-naphthol, and measured. From 93 to 95% of nitrate and nitrite added to meat can be recovered, and nitrate and nitrite do not interfere with each other in the determination. Ruggedness tests were satisfactory, and the method should be studied collaboratively.
Chemical Identification of Meat
Authors: Cook H R , Sturgeon John D
Published: February 2020

Horse, pork, and beef fat are identified by gas chromatography of the unsaponifiable matter which is first fractionated by column chromatography. Fractions two and three give peaks which identify the fats.
Oxidative Metabolism and Persistence of Parathion and Malathion on Field-Sprayed Lettuce
Authors: Coffin D E
Published: February 2020

Parathion and malathion, at a rate of 400 g active ingredient/acre, were applied individually to field plots of lettuce. Samples were taken at various intervals after spraying and analyzed by paper chromatography for residues of these compounds and their metabolites. Parathion residues decreased from 1.9 to 0.1 ppm in 4 days; detectable quantities were present up to 15 days. Small quantities of paraoxon and two unidentified metabolites of parathion were detected, at times, up to 2 days after application of parathion. Malathion residues decreased from 11.5 ppm at 4 hours to less than 0.1 ppm at 10 days. Malaoxon and three unidentified metabolites of malathion were detected, at times, up to 2 days after application of malathion.
Determination of Trace Levels of Copper in Soil Solutions With 1,5-Diphenylcarbazone
Authors: Geering H R , Hodgson J F
Published: February 2020

Soil solutions containing 3 to 14 ppb copper were analyzed colorimetrically with 1,5-diphenylcarbazone (DCO) as reagent. In this method, a 50 ml sample of soil solution is adjusted to about pH 1 with HCl (1 + 1) and copper is extracted from the solution with 0.025% dithizone/CCl4 solution. The dithizone extract is digested with 70% HClO4, redissolved in 5 ml 0.01M HCl, and diluted to 25 ml with water. A 20 ml aliquot of this solution is neutralized with 0.2M aqueous NH3 and buffered at pH 4.7 with 5 ml lM KH2PO4. Up to 3 μg copper is then determined by extracting the element from the aqueous solution into 5 ml benzene containing 0.0036% DCO. The color developed in the benzene layer follows Beer’s law at 550 mμ. As little as 0.1μg can be estimated with a precision of ± 10%.
Identification of Supplemental d- and dl-α-Tocopheryl Acetate in Premixes, Feed Concentrates, and Feeds
Authors: Tinkler F Howard , Passero Frank V , Ames Stanley R , Nelan Donald R
Published: February 2020

A procedure has been developed to distinguish between supplemental d- and dl-atocopheryl acetate in premixes, feed concentrates, and feeds. Tocopheryl acetate in a crude extract is partially purified by oxidative adsorption, de-esterified by saponification, and further purified by chromatography. Identification of the form of tocopheryl acetate is based on the change in optical rotation of the purified tocopherol measured before and after oxidation by potassium ferricyanide. In eight experiments the procedure was used on a poultry feed containing 4.5% fat and supplemented at levels of 10 and 20 IU vitamin E/lb with d- and dl-α-tocopheryl acetate. The form of supplemented tocopheryl acetate was readily identified in each case.
Determination of Lipids in Fish Meal
Authors: Lee C F , Ambrose M E , Smith P
Published: February 2020

Lipids were extracted from a series of twelve menhaden meals by six methods, and results were compared. The chloroformmethanol extraction method developed by Smith, et al., extracts approximately the same amount of lipids as the official AOAC method, 22.037. The Torry-TNO method with chloroform-methanol extraction, and acid and alkaline hydrolysis methods extract lesser amounts of lipids, but all methods extract more than the ethyl ether method, 22.032. The Smith-Ambrose-Knobl method, rather than AOAC method 22.037, is recommended for extraction of total lipids from fish meal because of its simplicity and efficiency.
Metabolism and Storage of DDT in Beef Cattle
Authors: McCully K A , Villeneuve D C , McKinley W P , Phillips W E J , Hidiroglou M
Published: February 2020

Beef steers were fed forage contaminated with technical DDT for 83 days. Fat samples were removed by omentectomy at various intervals after feeding of the contaminated forage had ceased. Residues of p,p′-DDE, DDD, and p,p′-DDT were found. DDD residues declined at the greatest rate, p,p′-DDT declined at an intermediate rate, while p,p′-DDE declined at the slowest rate.

In a second experiment technical DDT was administered orally, intraperitoneally, and intravenously to beef steers. Fat samples were removed by omentectomy 3 days after dosing. The steers that received technical DDT intraperitoneally and intravenously stored DDD and p,p′-DDT in the fat at a much lower ratio than the orally treated animals.

p,p′-DDT was administered by the oral, intraperitoneal, and intravenous routes in another experiment. Three and 8 days after dosing, the residues in the omental fat of the orally treated animals showed increased DDD to p,p′-DDT ratios when compared to these ratios for the other 2 groups which had declined from pre-treatment levels.

The data suggest that p,p′-DDT is dechlorinated to DDD in the rumen of the bovine.
Determination of Dichlobenil and Its Metabolite, 2,6-Dichlorobenzoic Acid, in Agricultural Crops, Fish, Soil, and Water
Authors: Meulemans Kenneth J , Upton Edwin T
Published: February 2020

A rapid and sensitive analytical method has been developed for the detection of residues of the selective herbicide, 2,6-dichlorobenzonitrile, and its possible metabolite, 2,6-dichlorobenzoic acid, in agricultural crops, fish, soil, and water. Plant extractives, which interfere with the electron capture gas chromatographic detection of these compounds, are removed by special column absorption chromatography. A limit of detectability of 0.05 ppm is obtained.
An Improved Method for the Analysis of DDT and Its Metabolites in Eggs
Authors: Beckman Herman , Bevenue Arthur , Carroll Kenneth , Erro Felix
Published: February 2020

A rapid method has been developed in which DDT residues are extracted from egg samples by blending with acetone and filtering, and then cleaned up on a Florisil column. An overall average recovery of 94.4% was obtained on samples fortified at levels of 0.05 to 1.0 ppm. The determinative step was electron capture gas chromatography; confirmation of the analysis could be obtained with microcoulometric gas, paper, or thin layer chromatography.
A Study of the Effectiveness of Some Extraction Procedures for Pesticide Residues in Vegetables
Authors: Burke Jerry A , Porter Mildred L
Published: February 2020

Nine blending-type extraction procedures were compared for effectiveness in removal of field-applied p,p’-TDE from kale. Extraction efficiencies were based on the amount removed by an exhaustive extraction. Acetonitrile, as used in the Mills, et al. rapid method for nonfatty foods, produced the highest result for this chlorinated pesticide, i.e., 99% of that removed by the exhaustive technique. Extraction efficiencies as low as 65% were obtained by some procedures. Higher results for field-applied diazinon and parathion were obtained by the Mills, et al. procedure than by the Watts and Storherr method.
Use of Thin Layer Chromatography for Detection of Contaminating Pesticides in Commercial Pesticide Formulations
Authors: Bontoyan Warren
Published: February 2020

A rapid and specific procedure has been devised for detecting chlorinated hydrocarbons, organophosphorus compounds, and other contaminating pesticides in commercial pesticide formulations. Samples were extracted with chloroform, spotted on thin layer plates, and compared to standards. Spots showing evidence of contamination are identified by gas chromatography and infrared techniques. Silver nitrate mixed with aluminum oxide and silica gel G are used as the immobile phases. Spraying is not necessary with the silver nitrate-aluminum oxide immobile phase.
A Rapid Method for Determination of Microgram Amounts of Aluminum in Deodorants and Antiperspirants by Fluorometry
Authors: Hozdic Charles
Published: February 2020

A procedure has been developed for the determination of micro amounts of aluminum (5–100 μg) in solution or in samples that can be decomposed to provide aqueous solutions of aluminum salts. In this method, aluminum is measured by the fluorescence of the aluminum salt of 8-hydroxyquinoline formed in the breakdown of the complex aluminum chlorhydroxide contained in deodorants and antiperspirants. Samples were analyzed by the proposed method and also by the gravimetric method by precipitating and determining the aluminum as the oxide in the commercial sample. One synthetic sample containing aluminum chlorhydroxide was determined as the phosphate. A known amount of aluminum was added to two other samples before fluorometric analysis was performed. This fluorometric method is faster and just as accurate as the gravimetric method.
Automation of the AOAC Photometric Phosphomolybdovanadate Method for Direct Available P2O5
Authors: Gehrke Charles W , Baumgartner James H , Ussary James P
Published: February 2020

An automatic photometric method utilizing the Technicon AutoAnalyzer has been developed to determine phosphorus in all forms of fertilizer phosphorus in the range of 2.0–4.5 mg P2O5/100 ml at a sampling rate of 40 analyses/hr. Multiple analyses of KH2PO4, 9 Magruder check samples, and numerous commercial fertilizers were made and compared with results obtained by the official quinolinium phosphomolybdate method, 2.025(b). Average range for five independent determinations was 0.22% P2O5 for the automated method and 0.26% P2O5 for the gravimetric method; average relative standard deviations were 0.44 and 0.60%, respectively. The average recovery of P2O5 from KH2PO4 was 99.8% with the photometric method and 100.3% with the quinolinium method. Results on 69 commercial fertilizers containing 5–54% P2O5 by the automatic method were only 0.02%% lower than those by the gravimetric quinolinium method. Results show that the automated phosphomolybdovanadate method for direct available phosphorus in fertilizers is accurate, precise, and less time consuming for routine control and industrial laboratories.
A Modified Babcock Procedure for Rapid Determination of Fat in Meats Using Dimethyl Sulfoxide
Authors: Whalen Francis
Published: February 2020

A rapid method of determining fat in a wide variety of meat products has been developed. The meat is digested with hot HO and the products of the hydrolysis are dissolved in dimethyl sulfoxide; neutral triglycerides are insoluble in this solvent. The solubility of starches, sugars, and the usual curing inorganics in dimethyl sulfoxide and its miscibility with water prevent interference by these substances. Digestions are rapid, and phase separation and demarcation are excellent. One analysis (exclusive of sample preparation time) takes approximately 10 minutes. Only two reagents must be purchased, and no special equipment other than the usual Babcock apparatus is needed. Results by the sulfoxide procedure approximate results by the Mojonnier method. Its speed and simplicity should make it valuable for process monitoring and formulation adjustment in the manufacture of meat products.
Gas-Liquid Chromatographic Analysis of Piperazine as Diacetylpiperazine in Animal Feed
Authors: Fricke Fred L , Walters Stephen M
Published: February 2020

A gas-liquid chromatographic method is presented for the analysis of piperazine in feeds. The feed, containing levels of either 0.11 or 0.25% piperazine, is extracted with water, acetylated, and gas chromatographed, using phenothiazine as an internal standard. Recoveries of piperazine base added to a blank feed ranged from 97.6 to 100.2% with a mean of 99.1%. Results on two commercial feeds compared favorably with the quinone colorimetric method. The procedure is specific, accurate, and not subject to the interferences which cause difficulties in other methods.