bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Liquid Chromatographic Method for the Determination of Dimethoate and Dimethoxon Residues in Plant and Animal Tissues, Milk, and Eggs
Authors: Steller W A , Pasarela N R
Published: February 2020

Residues of both dimethoate and dimethoxon are extracted from finely chopped plant or animal tissues with methylene chloride. The resulting extract is concentrated and cleaned up by silica gel chromatography, if necessary. The concentrate is injected into a gas chromatograph equipped with either a flame photometric or an alkali flame ionization detector and a column containing 11% DC-200 on 60–80 mesh Gas-Chrom Q/0.01% Versamid 900. Recovery values for dimethoate and dimethoxon added a t 0.002–1.0 p pm ranged from 56 to 112% with an overall average of 89.2% for dimethoate and from 60 to 127% with an overall average of 81.9% for dimethoxon. The lower limit at which recovery values were obtained for both compounds was 0.05 p pm for plant tissues, 0.02 for animal tissues and eggs, and 0.002 for milk. Residue values obtained for animal tissues involving both exposure and feeding studies a n d for field-treated plant samples are also presented.
A Simplified Halphen Procedure for Cyclopropene Fatty Acids
Authors: Coleman Eugene C , Firestone David
Published: February 2020

A simplified Halphen procedure was developed for the quantitative determination of cyclopropene fatty acids in fats and oils. Butanol, dimethyl sulfoxide (DMSO), and mixtures of butanol and DMSO were used as reaction media in a closed system. Higher sample absorbances were produced in butanol than in mixtures of butanol and DMSO. Butanol was superior to the other solvent systems for both quantitative and qualitative analyses. The lower limit of sensitivity for the tube-butanol system for quantitative and qualitative analyses was 18 and 15 μg cyclopropene fatty acids/g oil, respectively.
Gas-Liquid Chromatographic Detection of Palm Kernel and Coconut Oils in Cacao Butter
Authors: Iverson John L
Published: February 2020

A gas-liquid chromatographic method for the detection of palm kernel and coconut oils in cacao butter is presented. Detection of adulteration is based on the programmed-temperature gas chromatographic analysis of lauric acid. Cacao butter naturally contains approximately 0.01% lauric acid, while coconut and palm kernel oils contain approximately 50% lauric acid. The 95% confidence interval indicated that it was possible to reliably detect 0.25% lauric acid, which corresponds to 0.5% adulteration.
Recovery of Shigella Under Acidic Conditions
Authors: Fishbein Morris , Mehlman Ira J , Wentz Barry
Published: February 2020

The rationale for an investigative approach in the recovery of small numbers of Shigella in the presence of large numbers of the competitive Enterobacteriaceae is discussed. On this basis, the acid production of the Enterobacteriaceae in common enrichment media is explored. The inhibition of Shigella growth initiation from small inocula (10–50 organisms/ml) by particular acid metabolites, such as formic and acetic acids, is shown. Finally, the ability of small Shigella inocula to grow in the fermented acidic media in which the Enterobacteriaceae have previously grown was studied in detail. It is recommended that the competitive factors affecting Shigella be studied further.
An Improved Screening Method for Chlorodibenzo-p-dioxins
Authors: Williams D T , Blanchfield B J
Published: February 2020

2,3,7,8-Tetrachlorodibenzo-p-dioxin is detected at a level as low as 0.05 ppm in corn oil by conversion to octachlorodibenzo-p-dioxin and measurement of the latter compound by electron capture gas-liquid chromatography. The method presented is based on a previously reported screening method, which has been modified to include different chlorination conditions and a subsequent alumina column cleanup.
Modified Ferric Gel Method for Determining Aflatoxin in Cottonseed Meals
Authors: Velasco James
Published: February 2020

The ferric gel method for determining anatoxin in cottonseed has been adapted for cottonseed meals. A change in solvent system and an additional purification step required by some meals have been incorporated into the method. Purification of these meals is accomplished by filtration rather than by chromatographic fractionation on columns of silica gel. The time of analysis as compared to the AOAC method is reduced by more than one half with this new method and total recoveries are comparable to or higher than those obtained with the AOAC method. Consideration should be given to cleanup of seed or plant extracts with ferric gel rather than with lead acetate not only because it removes plant pigments more effectively but also because it avoids the disposal of hazardous lead salts into water effluent systems.
Chromatographic Determination of Mineral Oil in Pesticide Formulations
Authors: Trombetti Giuseppe , Gordini Tullio
Published: February 2020

A simple method is described for the determination of mineral oil in emulsified concentrates, based on the separation of the oil from the emulsifiers by column chromatography. The emulsifiers are not eluted and the oil is determined gravimetrically after the solvent is evaporated. This method is also applicable to emulsifiable concentrates that do not contain solvents as co-formulants.
On-Line Computer System for Automatic Analyzers
Authors: Overton Mack W , Alber Larry L , Smith Donald E
Published: February 2020

A computer system for AutoAnalyzer data acquisition and reduction has been written for a minicomputer, using an easily constructed interface. The FOCAL-12 program and interface circuit diagram are included.
Direct Determination of Potash in Fertilizers by Atomic Absorption Spectrophotometry
Authors: Thorpe Virginia A
Published: February 2020

A rapid atomic absorption method is presented for the direct determination of potash in fertilizers, using the extract prepared for available phosphorus without dilution. By using the secondary potassium line and scale expansion, sensitive linear curves were obtained for 100–1000 ppm, covering K2O guarantees in all fertilizers.
Gravimetric Determination of Saccharin in Cider
Authors: Markus John R
Published: February 2020

Samples of spiked and unspiked cider were analyzed for saccharin by 18 laboratories, using the official final action gravimetric method, 20.145(a)-20.146. Recoveries for 30.5 mg saccharin added/100 g cider ranged from 25.6 to 32.9 mg/100 g (83.9 to 107.9%, respectively). The mean recovery was 28.1 mg/100 g (92.8%), with a standard deviation of ±1.95 mg/100 g.
Simplified Method for the Determination of Ethoxyquin in Alfalfa Products and Mixed Feeds
Authors: Witt S C , Bickoff E M , Kohler G O
Published: February 2020

A simplified improved method for the determination of ethoxyquin in alfalfa products has been developed. It is based on the official AOAC photofluorometric method for ethoxyquin in animal feeds but eliminates some of the tedious steps encountered when that method is applied to ethoxyquin-treated alfalfa products. The extraction and phasic distribution steps are modified to simplify and make the method more reliable. A single total volume extraction with methanol and a single phasic distribution step with hexane are employed rather than successive partial volume extractions and partitioning steps. The increment technique is used in the fluorometric step to reduce possible errors caused by impurities which sometimes remain after phasic distribution in both methods. Results by the simplified method compare favorably with those by the official method and by a column chromatographic method for ethoxyquin. The method is also applicable to the determination of ethoxyquin in mixed feeds.
Colorimetric Method for Monensin
Authors: Golab Tomasz , Barton Steven J , Scroggs Robert E
Published: February 2020

A colorimetric method has been developed for the analysis of monensin, an anticoccidial agent. The principle of the method is adaptable to feeds, premixes, fermentation broth, and crystalline samples. A solution of 3% vanillin in 0.5% sulfuric acid in methanol was used as the color reagent for monensin. The method is simple, fast, sensitive (1 μg/ml), and reproducible. No interference was found with 15 other poultry feed additives.
Gas Chromatographic Determination of Low Levels of Di-(2-ethylh exyl)phthalate in Soy Oil
Authors: Williams D T
Published: February 2020

Di-(2-ethylhexyl)phthalate can be determined by gas chromatography at a level of 0.3 ppm in soy oil. A cleanup procedure involving epoxidation of soy oil residues with m-chloroperbenzoic acid allows confirmation of the phthalate ester by thin layer chromatography-mass spectrometry or gas chromatography-mass spectrometry.
Microbiological Assay of Oxytetracycline in Feed: Manual Turbidimetric Assay and Plate Assay
Authors: Ragheb Hussein S , Cummings Anne M , Browning Barbara M
Published: February 2020

The useful range for manual turbidimetric analysis of Oxytetracycline (OTC), using K. pneumoniae, was between 0.04 and 0.08 μg/ml in the assay tubes. Laboratory-prepared feeds containing 43.5 and 86.5 g OTC.HCl/ton gave 90–98% recovery by the turbidimetric method and 104–116% by the AOAC method, 38.211–38.213. The coefficients of variation were 9.2–13.0 and 10.2–12.8%, respectively. Feeds containing 50 and 100 g OTC.HCl and neomyein sulfate/ton gave 77% of theory when analyzed turbidimetrically and 95% of theory by the plate method. The coefficient of variation for the turbidimetric method was about 16%, indicating unsatisfactory precision. At 200 g/ton theoretical concentration of each antibiotic, both methods agreed. Commercial premixes and finished feed samples gave almost the same results by both methods. The main advantage of the turbidimetric method over the plate assay is that results can be obtained the same day of analysis.
Evaluation of Chemical Confirmatory Tests for Analysis of Dieldrin Residues
Authors: Maybury Ronald B , Cochrane William P
Published: February 2020

Eight of the more commonly used reagents for the confirmation of dieldrin at the residue level were compared for several substrates. In some instances derivatives were isolated and identified. The reactions were evaluated, using pure dieldrin and spiked sample extracts of grass, animal feeds, and butterfat. Two reagents, aqueous HBr solution and BCl3/2-chloroethanol, were especially useful because of their application and sensitivity, i.e., 0.003 ppm for a 10 g dry sample and 0.001 ppm for a 25 g wet sample. The ZnCl2/HCl reagent was a practical alternative to the BCl3/2-chloroethanol reagent. The TIBr/Ac2O reagent gave a more positive confirmation at a lower sensitivity.
Comparison of Three Extraction and Cleanup Methods for Determining Carbon-14-Labeled Residues from Wheat Plants Grown in Soil Treated with Dyfonate-Ring-14C
Authors: Saha Maitreyi , Sumner Arthur K , Saha Jadu G
Published: February 2020

Three methods for determining organophosphorus insecticide residues in plant tissues were compared for efficiency of extraction and cleanup of 14C-labeled residues from wheat plants grown in soil treated with Dyfonatering-14C. Blending with ethyl acetate recovered 70.5% of the radioactivity present in the plant tissues and cleanup of the extract by sweep codistillation recovered 99% of the radioactivity. Blending of plants with benzene recovered about 58% of the radioactivity and subsequent cleanup of the extract on a silica gel column recovered about 78% of the activity. Although blending with acetonitrile recovered 59% of the radioactivity present in the plant tissue, partitioning of the extract between water and petroleum ether or chloroform retained only about 14 and 30% of the activity in the organic layer, respectively. Thus, the overall efficiency of this procedure was only between 8 and 18% as compared to 45 and 70% in the other 2 methods.
Antigenic Properties of Some Insects Involved in Food Contamination
Authors: Johnson Howard M , Bukovic Joann A , Eisenberg William V , Vazquez Alberto W
Published: February 2020

Six common insect contaminants of food were studied antigenically for possible development of an immunoassay test for the detection of soluble insect constituents in food. Phosphate-buffered saline (pH 7.2) extracts of the insects yielded material suitable for immunization of rabbits. The extracts contained multiple antigens. Cross-reactions between antisera and antigens tended to occur between phylogenetically related insects. The data suggest that detection of insect contaminants of food by immunoassay is feasible.
Collaborative Study of the Gas-Liquid Chromatographic Determination of Sorbitol in Bakery Products
Authors: Hundley Harvey K
Published: February 2020

A GLC method for the determination of sorbitol has been collaboratively studied. Sugar and sugar alcohols are extracted from the bakery products by methanol and the solvent is evaporated. Acetate derivatives are then formed by addition of acetic anhydride in pyridine, and the derivatives are extracted from an aqueous solution with chloroform and analyzed by flame ionization GLC. Collaborative results show a recovery ranging from 90 to 102% sorbitol from bakery products containing 1.5 to 7% sorbitol. The method has been adopted as official first action.
Gas Chromatography of Organonitrogen Pesticides, Using a Nitrogen-Specific Detection System
Authors: Laski Ronald R , Watts Randall R
Published: February 2020

A gas-liquid chromatographic system with a nitrogen-specific detector was investigated for the determination of 95 organonitrogen pesticides. Each compound was chromatographed, using DC-200 liquid phase on a solid support of 80–100 mesh Chromosorb W (HP). Retention times and response data are given for these pesticides.
Differentiation of Geographic Origin of Spices. III. Lampong and Sarawak Black Pepper by Emission Spectroscopy
Authors: Kahan Gerald , Stahl William H
Published: February 2020

Statistical techniques applied to the data obtained for the amount of strontium, barium, and calcium found in Sarawak and Lampong black pepper are used for differentiating between the 2 varieties of pepper. Also, a regression analysis applied to the data obtained for strontium is used as a means of determining the amount of Sarawak black pepper used to adulterate pure Lampong black pepper.
Direct Titrimetric Microdetermination of Fluorodifen, Linuron, Faneron, and Pebulate
Authors: Abbas Syed L , Ghosh Asoke K , Rizvi Saiyid A I , Saxena Om C
Published: February 2020

The herbicides fluorodifen, linuron, faneron, and pebulate have been determined in individual standard solutions by direct titration against gallium chloride solution, using different indicators. The same technique is applied to estimation of these herbicides in treated soils. The complex between gallium chloride and fluordifen or linuron is formed in a 1:3 ratio, whereas the complex with faneron or pebulate is in a 1:1 ratio. Recoveries for fluorodifen, linuron, faneron, and pebulate were 99.9–101.5, 99.0–102.4, 97.1–101.3, and 98.3–101.2%, respectively. Treatment with herbicide lowered the pH of the soil.
Collaborative Study of the Quantitative Determination of Titanium Dioxide in Cheese
Authors: Leone Joseph L
Published: February 2020

A quantitative, colorimetric procedure for the determination of titanium dioxide has been subjected to collaborative study. The method incorporates ashing, dissolution of the ash in sulfuric acid, and color development using hydrogen peroxide. The Spectrophotometric response is compared to a standard prepared similarly. The yellow-to-orange color is quite stable in the absence of Fe. Other interferences are Ni, Cu, Co, Mb, Vd, and Cr. A collaborative study of cheese containing 0.05, 0.10, and 0.4% titanium dioxide gave favorable results. The method has been adopted as official first action.
Collaborative Study of a Test to Determine Whether Shucked Oysters Have Been Frozen and Thawed
Authors: Gould Edith
Published: February 2020

Six laboratories have collaboratively tested a method to determine whether shucked oysters have been frozen and thawed at any time. The method utilizes the differing electrophoretic migration rates of various forms of malic enzyme activity, some of which are not present in the tissue fluid until after the tissue has been frozen and thawed. The technique is enzymography, which combines electrophoresis and a specific histochemical medium. Five laboratories tested Crassostrea virginica, obtaining markedly different patterns for the unfrozen oysters compared with the frozen and thawed oysters. The sixth laboratory tested C. gigas, and was similarly successful in distinguishing between the storage treatments. In shucked oysters stored up to 3 weeks at 4°C, neither autolysis nor bacterial activity altered the enzymographic patterns. The method has been adopted as official first action.
Moisture and Fat Analysis of Meat and Meat Products: A Review and Comparison of Methods
Authors: Pettinati Julio D , Swift Clifton E , Cohen Edward H
Published: February 2020

Published analytical methods for moisture and fat analysis of meat and meat products and reviews of the methodology are surveyed. The methods are briefly described and characteristics such as time required for an analysis, accuracy, and precision are given. The discussion of instrumental methods includes methods which have not been fully developed for meat but which may become useful. Several of the considerations and limitations that are involved in moisture and fat analysis of meat are discussed. From the large number of moisture, fat, and combined methods available, the most promising were selected for a close inspection and compiled in two tables of data. The most useful rapid methods for meat industry quality control are the following: For moisture determination, high temperature mechanical convection oven drying, hot plate drying, moisture balance, and azeotropic distillation methods have the most advantages. For fat content determination, the modified Babcock procedures, X-ray transmission, specific gravity of heptane extracts, and determination of fat in the extract from azeotropic moisture analysis (a combined method) offer the most advantages.
Gas Chromatographic Determination of Brominated Sesame Oil in Orange Drinks: Collaborative Study
Authors: Conacher H B S
Published: February 2020

A gas-liquid chromatographic method for the determination of brominated vegetable oils in soft drinks was collaboratively studied, using a commercial orange drink spiked with known amounts of brominated sesame oil. Initial results based on calculations involving total peak area measurement were considered erroneously high, since drink components coeluted with the C16 and C18 methyl esters, especially at low levels of brominated oil. A modified calculation, based only on brominated ester content, showed recovery values (6 collaborators) of 94.6, 95.3, and 96.0% for drinks containing 3.10, 5.22, and 10.66 mg/10 fluid oz., respectively, with corresponding standard deviation values of 0.40, 0.46, and 0.64. The method with the modified calculation incorporated has been adopted as official first action.
Nitrate, Nitrite, and Dimethylnitrosamine in Cured Meat Products
Authors: Panalaks Thayil , Iyengar Jagannath R , Sen Nrisinha P
Published: February 2020

Nitrate, nitrite, and dimethylnitrosamine (DMN) were determined in 197 samples of various kinds of meat products. Nitrate and nitrite were determined by the method of Kamm et al. (1965), and DMN was estimated semiquantitatively by a GLC method using a Coulson electrolytic conductivity detector (pyrolytic mode). The average levels of nitrate and nitrite were 181 ppm (range, 0–3467 ppm) and 28 ppm (range, 0–252 ppm), respectively. Trace amounts (2–12 ppb) of DMN were present in 57 samples; others were negative. As no mass spectrometric confirmation of the identity of DMN was carried out, the results should be considered as only tentative and not as an absolute proof of the presence of DMN. Except in a few types of meat products, the concentrations of nitrate or nitrite did not correlate with that of DMN detected in the samples.
Collaborative Study of a Method for the Extraction of Light Filth from Prepared Horseradish
Authors: Gecan John S , Brickey Paris M
Published: February 2020

A method has been developed for the extraction of light filth from prepared horseradish. The method involves a direct flotation from 40% isopropanol with a mineral oil-n-heptane mixture. Collaborative study showed the method to be rapid and easy to perform, and to yield good recoveries and clean extraction papers. The method has been adopted as official first action.
Collaborative Study of the Extraction of Light Filth from Canned Whole and Cream Style Corn
Authors: Dent Russell G
Published: February 2020

An improved method has been developed for canned whole and cream style corn to replace 40.104. The proposed method is unique because the microscopic and macroscopic examinations can be conducted almost concurrently; in the official method the macroscopic examination is dependent upon completion of the microscopic examination. The proposed method is shorter and it eliminates the use of viscous castor oil by specifying extraction in a percolator with paraffin oil from hot 40% isopropanol. Glassware is easily cleaned up after percolator cycles with isopropanol and water rinses. The proposed method yielded improved recoveries of insect and rodent filth spike elements. The method has been adopted as official first action.
Method for Determining Direction of Insect Boring Through Food Packaging Materials
Authors: Brickey Paris M , Gecan John S , Rothschild Albert
Published: February 2020

Insect chewing on food packaging materials has been characterized in order to differentiate between entrance and exit bore holes. The characteristics specific to various types of packaging are presented as a method in the form of a descriptive “key” that permits determination of the direction of boring. A collaborative study of the method resulted in 92% correct determinations of boring direction. The method has been adopted as official first action.
Differentiating Nonaqueous Titration of Mixtures Containing Acetaminophen and Salicylamide
Authors: Blake Martin I , Shumaker Linda B
Published: February 2020

A differentiating nonaqueous titration procedure is described for the determination of mixtures of acetaminophen and salicylamide. Tetrabutylammonium hydroxide is the titrant and a Fisher titrimeter equipped with a calomel-glass electrode system is used. The technique is applied to the individual components, synthetic mixtures, and complex dosage forms.
Nuclear Magnetic Resonance Analysis of Pharmaceuticals. IX. Methenamine and Methenamine Mandelate in Tablets
Authors: Turczan John W , Goldwitz Bruce A
Published: February 2020

An NMR procedure is described by which methenamine and mandelic acid are simultaneously determined in methenamine and methenamine mandelate tablets. Maleic acid was chosen as the internal standard and dimethylformamide-acetone-acetonitrile (10+25+65) as the solvent. The solvent system was selected to resolve the problems of solubility of methenamine and its salt with mandelic acid, overlapping of the resonance signals of the components, and potential decomposition of methenamine. Known standard and commercial preparations were analyzed and the results were compared to those of official USP and NF procedures. The NMR technique, when applied to the determination of methenamine and methenamine mandelate in tablets, is rapid, simple, and specific and can provide an assay with an accuracy of 1–2%.
Collaborative Study of a Semiautomated Method for the Analysis of Sodium Warfarin and Dicumarol Tablets
Authors: Kolinski Richard E
Published: February 2020

A semiautomated extraction and UV determination for sodium warfarin and dicumarol tablets was collaboratively studied by 7 laboratories. Collaborators were supplied with 4 composites of tablets of different dosage levels (3 sodium warfarin composites and 1 dicumarol composite). Results agreed well with the USP method. For sodium warfarin, coefficients of variation ranged from 0.35 to 2.10%. For dicumarol, coefficients of variation ranged from 0.39 to 2.19%. The method has been adopted as official first action.
Collaborative Study of the Quantitative Determination of Ethanol by Gas-Solid Chromatography
Authors: Martin Glenn E , Figert Donald M
Published: February 2020

The determination of ethanol by gas-solid chromatography was collaboratively studied for nonbeverage alcohol samples by 10 collaborators representing 6 laboratories. In one sample, the alcohol was determined by pycnometer, hydrometer, fluid densitometer, and gas-solid chromatography and the results obtained by these procedures compare favorably. The standard deviation for the 7 samples range between 0.133 and 1.311. This method is simple and fast, and the interference from other compounds is essentially eliminated. The proposed procedure for the quantitative determination of ethanol has been adopted as official first action.
Analytical Constituents of Strawberry and Raspberry and Their Change in Jam Production
Authors: Ryan John J , Dupont Jo Anne
Published: February 2020

The constituents of strawberry and raspberry have been studied in order to regulate the fruit content of jams made from these fruits. Four constituents, potassium, insoluble solids, amino acids, and phosphorus, were examined to ascertain the variation, means, and minimum acceptable values. From data taken after about 1950 from these laboratories and from the literature, the variation of the first 3 constituents was less than 30% and acceptable, while that of phosphorus was too large and rejected. Strawberry and raspberry fruit samples of known constituent content were processed into jams and the amount of fruit in jam was estimated by using the constituent values. There was little or no difference between the per cent fruit in jams found by using potassium and insoluble solids and the true values determined by weighing. The percentage of fruit using total amino acid values was unreliable and could not be used. Minimum and mean values determined for strawberry jam containing 52% fruit are, for potassium, 45 and 77 mg/100 g and, for insoluble solids, 0.49 and 0.87 g/100 g.
Determination of Sulfaquinoxaline in Feeds: Collaborative Study
Authors: Szalkowski Chester R
Published: February 2020

In the method developed, sulfaquinoxaline is extracted from the feed sample with dimethylformamide and separated from interfering substances by chromatography on alumina. The isolated sulfaquinoxaline is diazotized and coupled in the presence of zirconium. The color complex is then extracted with butanol and measured at 550 nm. Recoveries of sulfaquinoxaline from feeds reported by 13 collaborators ranged from 96 to 101%, with a coefficient of variation of 5%. This assay method is suitable for determining sulfaquinoxaline at all levels and has been adopted as official first action, to replace methods 38.139 and 38.140–38.141.
Polychlorinated Terphenyls as Potential Contaminants of Animal Products
Authors: Fries George F , Marrow George S
Published: February 2020

The polychlorinated terphenyl (PCT) Aroclor 5460 has been used in a sealant for concrete stave silos. PCT residues were found in samples of wall scrapings, silage, and milk from farms known to have affected silos. The PCTs are complex mixtures, making identification and quantitation difficult. The samples were allowed to react with SbCl5 to form the 3 tetradecachloroterphenyl derivatives. Formation of the derivatives facilitated identification of PCT residues by gas-liquid chromatography. It also appears to be the most promising approach to a quantitative method.
Versatile Combustion-Amalgamation Technique for the Photometric Determination of Mercury in Fish and Environmental Samples
Authors: Willford Wayne A , Hesselberg Robert J , Bergman Harold L
Published: February 2020

Total mercury in a variety of substances is determined rapidly and precisely by direct sample combustion, collection of released mercury by amalgamation, and photometric measurement of mercury volatilized from the heated amalgam. Up to 0.2 g fish tissue is heated in a stream of O2 (1.2 L/min) for 3.5 min in 1 tube of a 2-tube induction furnace. The released mercury vapor and combustion products are carried by the stream of O2 through a series of traps (6% NaOH scrubber, water condenser, and Mg(ClO4)2 drying tube) and the mercury is collected in a 10 mm diameter column of 24 gauge gold wire (8 g) cut into 3 mm lengths. The resulting amalgam is heated in the second tube of the induction furnace and the volatilized mercury is measured with a mercury vapor meter equipped with a recorder-integrator. Total analysis time is approximately 8 min/sample. The detection limit is less than 0.002 μg and the system is easily converted for use with other biological materials, water, and sediments.
Determination of Moisture in Molasses by the Karl Fischer Method
Authors: Kviesitis Boris
Published: February 2020

The AOAC method for the determination of the moisture content of molasses, 31.074–31.076, has been modified so that it is applicable to a variety of molasses products and not only to feed grade molasses (diluted to 79.5° Brix).
Determination of Fluoride in Household Products by Ion-Selective Electrode and Gran’s Plot
Authors: Schick Ann L
Published: February 2020

In the method presented, variants from mixed electrolyte systems and interferences from complexing cations are avoided. Concentration rather than ionic activity is determined by the simplified combination of several techniques. Millivolt readings are taken as standard NaF is added to products diluted in a buffer background ; the initial fluoride concentration is then extrapolated according to Gran’s theory from a volume-corrected, semi-antilogarithmic plot. The method was applied to 12 reagents of various fluoride salts and to 10 products, including concrete etchers, stain removers, metal fluxes, metal cleaners, and oven cleaners. It could also be applied to wood preservatives and insecticides which contain fluorides. Product concentrations of fluoride ranged from 0 to 30%. Results agreed favorably with those from distillation and thorium nitrate titration methods. The standard deviation was 0.52, relative standard deviation, 2%, and standard recoveries, 98–104%. Sample preparation is adequate only for products containing inorganic fluorides. Products containing organically bound fluoride must be ashed. Eight laboratories analyzed 3 reagents and 5 products by the proposed method with excellent results. The amount of fluoride present ranged from 0 to 30%, w/v. The standard error from collaborative results ranged from 0.046 to 0.930. The method has been adopted as official first action.
Analysis of Ochratoxins A and B and Their Esters in Barley, Using Partition and Thin Layer Chromatography. II. Collaborative Study
Authors: Nesheim Stanley
Published: February 2020

To test the method of Nesheim et al., 6 samples wert; analyzed in 13 laboratories. The samples encompassed a blank and 5 samples containing one or more ochratoxins in the range 50–200 μg/kg. Two samples were spiked with the 4 ochratoxin standards and 3 were spiked with barley naturally contaminated with ochratoxin A. The confirmation of identity of ochratoxins A and B by preparation of their ethyl ester derivatives was also tested. The average recovery of standard ochratoxin A was 112% at levels of 45 and 90 μg/kg, with a 27.1% coefficient of variation calculated from analysis of variance, one analyst, one replicate. Similar satisfactory results were obtained for the ethyl esters of A and B at a level of 120 μg/kg. The results were unsatisfactory for ochratoxin B and for the esters of A and B at the 60 μg/kg level. The chemical confirmation test was satisfactory for both ochratoxins A and B. The method, including chemical confirmation, has been adopted as official first action as quantitative for ochratoxin A and qualitative for the other toxins.
Application of High-Speed Liquid Chromatography to the Analysis of Aflatoxins
Authors: Seiber James N , Hsieh Dennis P H
Published: February 2020

Partial resolution of aflatoxins B1, B2, G1, G2, and P1 was achieved by high-speed liquid chromatography (HSLC) on a porous layer silica adsorbent, using chloroform-isooctane as the eluting solvent and a 254 nm UV monitor for detection. The resolution was somewhat less than, although comparable with, that obtained by thin layer chromatography, using Adsorbosil-1 adsorbent and fluorodensitometric detection. The HSLC response to B1 and G1 was linear in the 400–3000 ng range, allowing application of the technique to the quantitative analysis of B1 and G1 in crude extracts of Aspergillus parasiticus cultures. The coefficients of variation (precision) were 4.2% for B1 and 23.2% for G1 in a series of 4 replicate injections. The advantages and limitations of the technique for quantitative analysis and isolation are compared with those of more conventional chromatographic methods.
Determination of Diuron in Wheat
Authors: Parouchais Constantin
Published: February 2020

A simplified analytical procedure is described for the determination of diuron residues in a large number of wheat grain samples. The sample is subjected to Soxhlet extraction with acetone, the extract is dissolved in an acetone-aqueous phase (1+5) and then extracted with petroleum ether, and diuron is extracted into methylene chloride and carbon tetrachloride. Electron capture GLC is the determinative step, with ultraviolet spectrophotometry as an alternative technique.
Proposed Modification of the Manometric Method for the Determination of Carbon Dioxide in Wine
Authors: Caputi Arthur
Published: February 2020

In the course of a comparative study of various methods for the determination of CO2 in wine, an anomaly was encountered in the manometric method. Results obtained from several apple wines were consistently 15–30 mg/100 ml higher with the manometric method than with the other methods under study. The problem was traced to the formation of CO2 from components of these particular wines due to addition of the H2O2 used in the method to oxidize SO2, which was deemed to be a potential source of interference. Elimination of the H2O2 from the procedure avoided the problem. No measurable effect on results was found with the addition of up to 400 mg SO2/L, even in the absence of H2O2. Either deletion of the H2O2 from the procedure or subtraction of a degassed blank eliminated the problem. It is recommended that method 11.053–11.057 be revised by the addition of a blank to be prepared by degassing a duplicate wine sample at room temperature under about 27″ vacuum for 1–2 min and subjecting it to the same analysis.
Collaborative Study of the Flame Photometric Method for Sodium in Fertilizers
Authors: Corominas Luis F
Published: February 2020

Both methods for determination of sodium in fertilizers, 2.117 (10th edition) and 2.132–2.135 (11th edition), were studied, as well as the influence of resin treatment on the accuracy of results. Four samples containing 4–14% sodium were analyzed. The best accuracy was found for method 2.132–2.135 with the resin treatment omitted. The Sb values increased with greater sodium content; however, accuracy was not affected. The resin treatment in method 2.135 has been repealed, official first action, and an additional standard curve in the 0–10 ppm sodium range has been added for sodium concentrations lower than 1%.
Nitrogen in Feed and Fertilizer
Authors: Rexroad Paul R
Published: February 2020

Low values by Raney powder method 2.056 have been obtained on a few samples from one manufacturer. The values ranged from 0.2 to 5.0% nitrogen low. In relation to pollution, further work is reported in investigating digestion conditions and use of copper as a catalyst in Kjeldahl digestions. Data show that certain digestion conditions that are rugged for 0.5 g nicotinic acid lead to solidification on cooling after digestion. Further study is indicated. Deletion of paragraph (c) from 2.061 is recommended.
Collaborative Study of the Microanalytical Determination of Iodine by Oxygen Flask Combustion
Authors: Lalancette Roger A , Steyermark Al , Lukaszewski Donna M , Kostrzewski Patti L
Published: February 2020

Twenty-two collaborators participated in the study of a specific method using oxygen flask combustion followed by mercurimetric titration of the resulting iodide. With the exception of 2 collaborators, all obtained acceptable results on m-iodobenzoic acid. Statistical evaluation of the data from all collaborators gave: x̿ = 51.07%, x̿ – theory = –0.10%, s̄ = 0.28, and sm = 0.94. When the results of 2 collaborators are omitted, the corresponding values are: 51.07%, –0.10%, 0.15, and 0.19, respectively. Similar results were obtained on p-nitroiodobenzene. The results from all collaborators gave: x̿ = 50.82%, x̿ – theory = – 0.14%, s̄ = 0.19, and sm = 0.43. When the results of 3 collaborators are omitted, the values are: 50.87%, –0.09%, 0.14, and 0.23, respectively. The method has been adopted as official first action, as an alternative to the Carius method, for the determination of iodine in organic compounds.
Color-Specific Reagent for Identification and Semiquantitation of Pyrethrins and Piperonyl Butoxide by Thin Layer Chromatography
Authors: Olive Boyce M
Published: February 2020

A color-specific reagent, a mixture of phosphoric, tannic, and acetic acids and acetone, has been adapted for the thin layer chromatographic identification and quantitation of pyrethrins and piperonyl butoxide in pesticide formulations. Approximately 1 μg of either pyrethrin or piperonyl butoxide can be detected as pink and blue spots, respectively, in aerosol and solid formulations.
Critical Evaluation of the AOAC Method of Analysis for Nitrite in Meat
Authors: Nicholas Rosemary A , Fox Jay B
Published: February 2020

Results of studies on the effects of 5 alternative procedures of sample preparation are presented. The standard deviations for the methods were 0.00505, 0.00142, 0.00307, 0.00265, and 0.00243, with the AOAC method giving the highest values for nitrite. The effects of some variables on the determination of the nitrite content of meat by the official method were also studied. These variables include the addition of mercuric chloride, duration of heating, rate of color reaction, and reagent preparation. The nitrite concentration as measured by the AOAC method varied with the initial dilution of meat sample. A number of compounds were added to the Griess reagent and nitrite solution to see whether they would affect the reaction. Reductants were found to interfere consistently. Suggestions for simplifying and improving the official method are made. These include omitting mercuric chloride, recrystallizing 1-naphthylamine before using, and allowing only 25 min for the completion of the color reaction, using a higher concentration of Griess reagent.
Lower Sulfonated Subsidiary Colors in FD&C Blue No. 1
Authors: Bell Sandra
Published: February 2020

Two postulated lower sulfonated dyes were prepared and purified, and analytical data were obtained. Two subsidiary dyes were isolated from commercial samples of FD&C Blue No. 1 by column and thin layer chromatography. The visible and infrared spectra of these compounds were obtained and found to be identical to those for the prepared lower sulfonated dyes.
Collaborative Study of an Automated Optical Somatic Cell Counting Method for Raw Milk
Authors: Kelley Wesley N
Published: February 2020

A collaborative study was conducted to compare tbe automated optical somatic cell counting method (OSCC) with the direct microscopic somatic cell counting method (DMSCC) for raw milk. Samples were prefixed with formaldehyde and introduced into an Auto-Analyzer system. Dilution, clarification, and cell counting were performed automatically. Eight collaborators participated in the study, analyzing 48 samples in duplicate, using 2 different sampling rates. The results were compared with DMSCC counts reported by 3 different analysts. Statistical results show that the standard deviation for the DMSCC method was 0.1086 and for the OSCC method, at a sampling rate of 30/hr, 0.0911. From comparison of results it appears that the OSCC method is as accurate as, and more precise than, the DMSCC method. The faster sampling rate of the OSCC method (60/hr) has some effect on precision but little effect on accuracy. The method has been adopted as official first action.
Toxic Heavy Metals in Vegetables and Forage Grasses in Missouri’s Lead Belt
Authors: Hemphill Delbert D , Marienfeld Carl J , Reddy Ravula S , Heidlage Walter D , Pierce James O
Published: February 2020

Missouri supplies approximately 75% of the U.S. production of lead. Lead poisoning of horses in the vicinity of one smelter alarmed local residents about the possible hazards of consuming their fruits and vegetables. County Extension Directors selected cooperators in 7 counties in the lead mining and smelting area and 3 “control” counties in N.C. Missouri to grow lettuce, radishes, and greenbeans for toxic metal analysis. Seed and cultural instructions were furnished all cooperators. All samples were washed in distilled water. Atomic absorption analyses detected the following maximum levels of Pb in μg/g dry weight: lettuce leaf 1324, radish root 518, and greenbean pods 136. Cd levels in μg/g dry weight were as follows: lettuce leaf 34.5, radish root 13.7, and greenbean pods 8.5. Vegetables from control counties contained markedly lower levels of Pb and Cd. Only one smelter is located in the new mining area and considerable Pb ore (essentially powdered PbS) is transported by rail or truck to smelters in older mining areas of S.E. Missouri. Forage grasses (Festuca arundinacea and Tridens flavus) were collected along ore truck and control routes. Maximum levels of Pb (4350 μg/g dry weight, unwashed) and Cd (4.32 μg/g) were detected in samples along highway rights-of-way of ore truck routes. Considerably lower levels were detected along control routes.
Polychlorinated Biphenyls and Polychlorinated Terphenyls in Canadian Food Packaging Materials
Authors: Villeneuve David C , Reynolds Lincoln M , Thomas Gordon H , Phillips William E J
Published: February 2020

A survey has been carried out to determine the extent of PCB and PCT content of Canadian food packaging materials. Samples were obtained from 120 manufacturers in early 1972, representing 19 food categories. A total of 569 samples were submitted for PCB analysis and the total number of components analyzed was 911. Of these 81.7% contained less than 1.0 ppm PCB, 14.9% contained 1–10 ppm PCB, and 3.4% contained in excess of 10 ppm PCB. A total of 445 samples were submitted for PCT analysis and the total number of components analyzed was 731. Of these, 84.5% contained less than 1.0 ppm, 11.4% contained 1–10 ppm, and 4.1% contained in excess of 10 ppm PCT. A total of 77 foods were analyzed for PCB of which only 2 contained in excess of 1 ppm PCB. A total of 73 foods were analyzed for PCT and none of these contained in excess of 0.05 ppm PCT.
High Resolution Infrared Spectra of Fragrance and Flavor Compounds
Authors: Morris Walter W
Published: February 2020

High resolution infrared spectra in the region from 4000 to 300 cm−1 (2.5–33 μm) are presented for 99 fragrance and flavor compounds. These compounds were isolated from commercial and natural sources and were purified by preparative gas-liquid chromatography. Nuclear magnetic resonance analysis was utilized in many cases for verification of structure. The 4 strongest infrared bands in the 1100–300 cm−1 region are also tabulated.
Improvement of Dissolution in the SOLIDprep Sampler by Ultrasonics
Authors: Urbányi Tibor , Brunskill William T , Lin Maria
Published: February 2020

This paper describes a novel device which is capable of disintegrating and homogenizing tablets within a very short time and with a minimum of investment. The modification on the existing SOLIDprep Sampler I can be performed in-house. An increase of assay efficiency of at least 50% was observed when these modifications were made. The advantages as well as the disadvantages of the modification are discussed in detail.
Collaborative Study of an Automated Method for the Determination of Total and Direct Available P2O5 in Fertilizers
Authors: Johnson Frank J
Published: February 2020

In a collaborative study, an automated method for the determination of total and direct available P2O5 was compared with the official gravimetric quinolinium molybdophosphate method, 2.023–2.025. Nine laboratories participated in the analysis of the 12 sample solutions, and the results were evaluated by the technique of closely matched pairs. The t-test showed no difference in the means of the results of the 2 methods. The estimates of the random, systematic, and total errors of the automated method all differed significantly from those of the official method when evaluated by the F-test. Further study of the automated method for P2O5 in fertilizers is not recommended.
Collaborative Study of the Quantitative Determination and Chemical Confirmation of Sterigmatocystin in Grains
Authors: Stack Michael E , Rodricks Joseph V
Published: February 2020

A quantitative method of analysis for sterigmatocystin in grains was studied collaboratively by 17 participants. The results show that 7 analysts had difficulty with the corn and oat samples because of an oily residue in the sample extracts which interfered with sterigmatocystin on TLC plates. Barley and wheat samples were analyzed without difficulty. All of the quantitative results show the type of random error expected for visual analyses of TLC plates. Confirmative tests for sterigmatocystin were carried out without difficulty. The methods for the quantitative determination of sterigmatocystin in barley and wheat and the chemical confirmation of sterigmatocystin have been adopted as official first action.
Collaborative Study of Modified AOAC Moisture Method and Other Rapid Moisture Methods for Analysis of Meat and Meat Products
Authors: Pettinati Julio D , Metzger Virginia G , Van Horn David , Cohen Edward II
Published: February 2020

Three new methods for determining moisture content of ground beef, frankfurters, and fresh pork sausage were tested collaboratively by 10 laboratories. Results were compared with those obtained by AOAC official methods. The new methods involved: 1) use of a gravity oven at 125°C in place of a mechanical convection oven, 2) exposure of samples to IR radiation for 40 min, and 3) azeotropic distillation for 30 min, using either cumene, m-xylene, or 2-octanol. Determinations of moisture content by the use of a gravity oven and IR radiation were in agreement with the official methods, but azeotropic distillation with any of the 3 solvents gave lower values for all 3 types of meat product. The expected standard deviation, se, averaged for the 3 types of meat product in per cent moisture was as follows: gravity oven, ±0.65; IR radiation, ±1.18; and azeotropic distillation, ±0.79, ±0.86, and ±0.98, using cumene, m-xylene, and 2-octanol, respectively. For the official methods, ±0.64% moisture was obtained for se. An amendment to the official final action method for the determination of moisture in meat and meat products, 24.003(b), was adopted as official first action to provide for the optional use of an air oven.
Colorimetric Determination of Pyrimethamine in Feeds
Authors: Garber John B , Fink David W , Szalkowski Chester R
Published: February 2020

A method, based upon an acid dye ion-pair extraction colorimetric measurement with bromcresol green reagent, has been developed for the determination of pyrimethamine at the 5 ppm level in feeds. Pyrimethamine is extracted from the feed into benzene and separated from interferences by solvent partition and chromatography on alumina. Amprolium, ethopabate, and sulfaquinoxaline do not interfere with pyrimethamine determinations by this method.