bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Milko-Tester Minor for Determining Fat in Milk
Authors: Shipe Frank W , Senyk Gary F
Published: February 2020

The Milko-Tester Minor was tested to determine if it conformed to recommended AOAC performance specifications. Results were compared with those from the Babcock method and other approved instruments. Results indicated that the MT Minor conformed to the specifications for transfer errors, linear response, and homogenizer efficiency. In addition, 3 MT Minors, 1 Milko-Tester Automatic, 2 Model 300 Milk-Scans, and the Babcock method were used to determine 15 individual cow milks and 15 bulk milks in triplicate. Standard deviations of triplicates were 0.035 and 0.024 (av. for MT Minors), 0.015 and 0.013 (Automatic), 0.030 and 0.012 (av. for Milko-Scans), and 0.039 and 0.038% (Babcock) for individual and bulk milks, respectively. Standard deviations of differences between instrument and Babcock results were within recommended limits with the 3 MT Minors, averaging 0.070 and 0.042% on individual and bulk milks, respectively. Analysts and MT Minors instrumental variations were studied by having 3 analysts operate each of 3 MT Minors independently to test 12 samples. Range of average fat content was 4.290–4.312% for analysts and 4.292–4.311% for instruments.
Improved Ammonium Molybdate Method for Thin Layer Chromatographic Detection of Organophosphate Residues
Authors: Murty A Satyanarayana , Rajabhushanam B Roosevelt , Christopher K , Ramani A Venkata
Published: February 2020

An improved ammonium molybdate method for detecting organophosphate residues on thin layer chromatographic (TLC) plates is described. After development, the plates are heated at 110°C for 2 h and the resultant inorganic phosphate is reacted with ammonium molybdate to form phosphomolybdate which is then reduced to a blue complex by ascorbic acid. Quantities as low as 0.1–0.2 μg residues could be detected on TLC plates by this method.
Automated Analysis of Soil Extracts for Phosphorus, Potassium, Calcium, and Magnesium
Authors: Flannery Roy L , Markus Denes K
Published: February 2020

An automated method is described for determining P in double acid (0.05N HCI + 0.025N H2SO4) and Bray P1 (0.025N HCI + 0.03N NH4F) soil extracts and K, Ca, and Mg in double acid and 1N ammonium acetate soil extracts. Comparisons are made between double acid and Bray P1 soil extraction methods for removal of P from a Freehold sandy loam soil that had been differentially fertilized with P fertilizers. Comparisons are also made between the double acid and ammonium acetate soil extraction methods for removal of K, Ca, and Mg from the same soil that had been differentially fertilized and limed with K fertilizers and pulverized–dolomitic limestone, respectively. Comparisons are made between automated and atomic absorption determinations of K, Ca, and Mg in standard solutions and double acid and ammonium acetate soil extracts. Bray P1 soil extractant removed 30–73% more P than did the double acid soil extractant from Freehold sandy loam soil. Ammonium acetate extractant removed about 25% more K from soil than did the double acid extractant. Double acid soil extractant removed more Ca from the soil than did ammonium acetate extractant, particularly at high soil Ca levels. Greater amounts of Ca were found in both types of soil extracts by the automated than by atomic absorption techniques. Double acid extractant removed more Mg from soil than did ammonium acetate extractant. The 2 instrumentation methods produced similar results for Mg and K analyses of both soil extract types.
Nitrogen Specific Ion Electrodes for Soil, Plant, and Water Analysis
Authors: Mills Harry A
Published: February 2020

The nitrate specific ion electrode and the ammonia and nitrogen dioxide gas-sensing combination electrodes offer simple methods of analyses of plants, soils, and water. The nitrate electrode measures activity of the nitrate ion in solution and is susceptible to interfering ions, particularly Cl. Considerable discrepancies exist in the literature concerning nitrate extracting solutions and buffering solutions used to eliminate interferences with the nitrate electrode. An evaluation of ionic strength adjusters, used to alleviate fluctuating ionic background interferences, indicates (NH4)2SO4 produces consistent results without adversely affecting life of the nitrate electrode. Ammonia electrode determination of total nitrogen in soil, plant, and water samples is a rapid method that eliminates the time-consuming distillation-titration step. The nitrogen dioxide electrode is relatively new and little information is available concerning methodology and its potential problems.
Automated Turbidimetric Determination of Sulfate Sulfur in Soils and Fertilizers and Total Sulfur in Plant Tissues
Authors: Wall Larry L , Gehrke Charles W , Suzuki Jun
Published: February 2020

An automated turbidimetric method has been developed for the rapid and accurate determination of sulfate. The method is practical and useful for accurately measuring total sulfur in plant tissues, and extractable sulfate in soils and fertilizers. The principle of intermittent reagent addition is used, which eliminates drift and sensitivity changes caused by coating of BaSO4 on tubing and cell walls. Also, the appropriate chemistry is used to minimize coating and interactions of the wash with the sample at a sampling rate of 30/h. The sensitivity of the method is excellent with a working range of 0–15 ppm sulfur for soils. For plant and fertilizer digests, the sample solutions are diluted to 0–35 ppm S. The precision as determined by repeated analysis of a soil sample extract was 0.58% relative standard deviation (RSD) with a mean of 9.26 μg extractable sulfate sulfur. On another soil sample, using a different extractant and extraction procedure, the RSD was 0.64%, mean of 9.29 μg/g. Multiple automated sulfur analyses on a plant tissue digest resulted in an RSD of 0.41% for a sample containing 0.21% S. The average recovery of sulfate sulfur on 5 Magruder Fertilizer Check Samples by the automated turbidimetric method was 100.6%, range of 99.8 to 101.4%, as compared to gravimetric analysis. The automated turbidimetric method for sulfate has excellent precision and sensitivity in plant tissue and soil analyses where gravimetric BaSO4 assays are not practical. The method is rapid, precise, and accurate for analysis of sulfate sulfur in fertilizers.
Rapid Method for Analysis of Aflatoxin M1 in Dairy Products
Authors: Fukayama Mark , Winterlin Wray , Hsieh Dennis P H
Published: February 2020

Four methods for determining aflatoxin M1 levels in fluid milk were compared in a search for a simple, routine analytical procedure. Each method was tested with samples spiked at levels of 0, 0.1, 0.5, and 1.0 ppb. The 3 quantitative methods were comparable in sensitivity (0.1 ng/mL) and recoveries (80–90%). A new method, a commercially available extraction column that contains an inert hydrophilic matrix to permit extraction of dairy products, is described. The milk is adsorbed on the column and aflatoxin M1 is eluted with chloroform-acetone (9 + 1). The extract is further purified on a small silica gel collumn and aflatoxin M1 is determined by TLC. This method was simpler and shorter, and was equally sensitive and reproducible in determining aflatoxin M1 in spiked and naturally contaminated fluid milk samples and in spiked nonfat powdered, condensed, and evaporated milk.
Thin Layer Chromatographic Determination of Aflatoxins in Dry Ginger Root and Ginger Oleoresin
Authors: Trucksess Mary W , Stoloff Leonard
Published: February 2020

A method for determining aflatoxins in dry ginger root and ginger oleoresin, using 1-dimensional thin layer chromatography (TLC) for the determinative step, has been developed. The key cleanup steps that permit this change from the 2-dimensional TLC previously required are partitioning of the extract with carbon tetrachloride and use of an improved eluting system for the silica gel adsorption column. Recoveries of aflatoxins B1, B2, G1, and G2 added to samples of ground ginger were 82, 101, 106, and 110%, respectively; recoveries of these aflatoxins added to ginger oleoresin were 75, 100, 93, and 125%, respectively. The method is applicable to fish meal and a number of mixed feeds.
Rapid HPLC Determination of Hydroxymethylfurfural in Tomato Paste
Authors: Allen Bradford H , Chin Henry B
Published: February 2020

A procedure is presented for the rapid determination of hydroxymethylfurfural in tomato paste. The clear serum obtained from the ultracentrifugation of tomato paste is analyzed by high pressure liquid chromatography using a reverse phase LiChrosorb C8 column, an ultraviolet detector operated at 284 nm, and isocratic elution with water.
High Pressure Liquid Chromatographic Determination of Vitamin D3 in Mineral Feed Premixes
Authors: Lein Dennis G , Campbell Harold M , Cohen Huguette
Published: February 2020

A simple and rapid quantitative method is described for determining the presence and amount of vitamin D3 (cholecalciferol) in mineral feed premixes by high pressure liquid chromatography. The samples were extracted with dichloromethane–pentane–methanol (46+46+8) after treatment with ammonium hydroxide, cleaned up by silica Sep-pak, and analyzed by normal phase high pressure liquid chromatography: 10 μm LiChrosorb NH2 column, hexane-isopropanol (98+2) mobile phase, ultraviolet detection at 254 nm. Recoveries were better than 95% in the range 25 000–100 000 IU/kg.
Spectrophotometric Determination of Urea in Urine Stains on Foods and Containers
Authors: Goo Reginald K S , Kanai Hiromitsu , Inouye Veronica , Wakatsuki Helen
Published: February 2020

Urea is extracted from rodent urine-contaminated material with hot acetone. After the extract is evaporated to dryness, aqueous urease solution is added to produce ammonia and carbon dioxide. A blue product, indophenol, is formed by the reaction of ammonia with phenol in the presence of hypochlorite. Absorbance is maximum at 625 nm. Presence of urea is easily detected at 4 μg. Detection of urine contamination in various materials is compared with detection by the AOAC urease– H2PtCL6 test.
High Performance Liquid Chromatographic Determination of Phenothiazine Residues in Sheep Tissues
Authors: Blackman Graeme L , Ho Ah Chai , Jozsa Alex , Kelly John D
Published: February 2020

A high performance liquid chromatographic (HPLC) technique is described for the determination of residue levels of the anthelmintic drug phenothiazine in sheep tissues. Phenothiazine was administered to sheep which were slaughtered after withholding periods of 24, 48, and 72 h. Residues of phenothiazine were then extracted from tissue samples by homogenization in methanol. The HPLC analysis of the extracts involved separation on a 10 μm silica column using a mobile phase of 0.3% n-propanol in cyclohexane. The lower limit of detection by ultraviolet absorption at 254 nm was 0.05 ppm
Some Parameters Affecting Hydride Generation From Arsenic(V) for Atomic Absorption Spectrophotometry
Authors: Liddle John R , Brooks Robert R , Reeves Roger D
Published: February 2020

The atomic absorption signals obtained from the reduction of arsenic(V) by sodium borohydride solution are strongly dependent on a number of parameters which are examined in this paper. If the arsine produced by sodium borohydride reduction is condensed in a cold trap and then released suddenly, the atomic absorption peak is larger and more reproducible. The procedure is more satisfactory if the borohydride solution is added to the reaction mixture in small aliquots. Peak height depends on the total volume of the reaction mixture and on the carrier gas flow rate. Peak height is also a function of the time elapsed after addition of the final aliquot of borohydride, and increases as the interval between successive aliquots is increased. Optimum conditions established were: initial volume of reaction mixture, 30 mL; 12 mL 3% NaBH4 solution added in 2 mL aliquots at 30 s intervals; carrier gas flow 1.25 L/ min; 60 s time lapse from last addition of borohydride until removal of the cold trap. Under these conditions, linear absorbance-concentration curves were obtained for 0.05–3.0 μg arsenic, with a relative standard deviation of 4.2% at the 2 %g level.
Simple Colorimetric Method for Determination of Acetaminophen
Authors: Sane Ramesh T , Kamat Sudhir S
Published: February 2020

A simple colorimetric method for the determination of acetaminophen is described. The method is based on the measurement of a crimson complex formed when acetaminophen is treated with 10% sodium hydroxide solution at elevated temperature. Compounds such as phenacetin, aspirin, caffeine, oxyphenbutazone, barbiturates, hydantoins, and dextropropoxyphen which are present in various formulations containing acetaminophen do not interfere. The method is sensitive to concentrations as low as 25 μg acetaminophen/mL.
Spectrophotometric Estimation of Cinnamic and Benzoic Acids in Balsam Tolu and Benzoin
Authors: Saleh Mohamed R I , Habib Abdel-Azim M , El-Shaer Nagwa
Published: February 2020

In a previous work, a difference spectrophotometric method was developed for quantitating benzoic and cinnamic acids, in the presence of resin acids. In the present work, the technique was adapted for estimating the individual balsamic acids in balsam tolu and benzoin. A procedure for determining purity of the balsamic acids fraction, recovered after alternative purification steps, was studied. Thus we developed an assay procedure relevant to both balsams. Results by the proposed method, the BPC method, and a literature spectrophotometric method are compared.
Analysis of Potato Glycoalkaloids by Gas-Liquid Chromatography of Alkaloid Components
Authors: King Russell R
Published: February 2020

A gas-liquid chromatographic (GLC) method has been developed for the analysis of potato glycoalkaloids by direct determination of the alkaloid components isolated by hydrolysis with IN ethanolic HCl. Recoveries of solanidine from potato tubers and foliage fortified with solanine over a range approximately 0.5 to 5 times the glycoalkaloid originally present averaged greater than 95%, and the lower limit of sensitivity was 0.25 mg/100 g using a nitrogen-phosphorus detector. A means of distinguishing solanidine and demissidine by formation of their respective 3β-trifluoroacetates with trifluoroacetic anhydride (TFAA) is demonstrated.
Argon Plasma Emission Spectrometric Determination of Molybdenum in Mixed Fertilizer
Authors: Woodis Terry C , Holmes John H , Ardis Jimmie D , Johnson Frank J
Published: February 2020

A method is described for the determination of molybdenum in fertilizers by argon plasma emission spectrometry. The sample is acid digested, potassium is added to standards to prevent enhancement, and emission intensities at 313.26 nm are compared. Results compared to a dithiol colorimetric procedure show no difference at the 95% confidence level.
Determination of Ammoniacal Nitirogen in the Presence of Urea
Authors: Viswanathan T S , Nagarajan M , Haribabu B
Published: February 2020

There is no approved AOAC procedure for determining ammoniacal nitrogen in the presence of urea, which is required for the quality control of urea-ammonium phosphate-based fertilizers. A comparative study has been made of various methods available for this estimation. We found that the automated spectrophotometric method, the ion selective electrode method, and the reduced pressure distillation method all furnish results of comparable precision and accuracy. The MgO distillation method, even though not recommended for the above type of sample, still yields results of satisfactory accuracy when certain precautions are taken.
Extraction Efficiencies for Pesticides in Crops: 14C-Benomyl Extraction from Mustard Greens and Radishes
Authors: Wheeler Willis B , Thompson Neal P , Andrade Pio , Krause Richard T
Published: February 2020

14C-labeled benomyl [methyl l-(butylcarbamoyl)-2-benzimidazolecarbamate] suspended in a commercial benomyl formulation was sprayed on mustard greens and radishes. At 3 intervals after application, the crops were extracted with methanol, acetonitrile, or acetone. Crops were either blended and leached or repetitively blended followed by Soxhlet extraction. Essentially all olF the extractable radioactivity was removed by blending. The 14C was more difficult to extract from radishes than from mustard greens as time increased. Respective percentages of 14C extracted at 1, 7, and 14 days were 99, 98, and 97 jFrom mustard greens and 96, 88, and 79 from radishes. Methanol exhibited the highest extraction efficiency, and the blend-Soxhlet process was better than the blend-leach process. Thin layer ihromatography of the organic-soluble extracts indicated that the majority of 14C was recovered as methyl 2-benzimidazole carbamate (MBC), a breakdown product of benomyl. Acid hydrolysis of the extracted tissues released 30–50% of the residual 14C.
Gas Chromatographic Determination of Fluridone Aquatic Herbicide and Its Major Metabolite in Fish
Authors: West Sheldon D , Burger Robert O
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for determining residues of the aquatic herbicide fluridone (l-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(lH)-pyridinone) and its major metabolite (l-methyl-3-(4-hydroxypherayl)-5-[3-(trifluoromethyl)phenyl]-4(lH)-pyridinone) in fish. Both compounds are extracted from fish tissue with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. After purification by liquid-liquid partitioning, sample extracts are reacted with methyl iodide to methylate the metabolite, and then both fluridone and the metabolite are brominated with phosphorus tribromide. After purification by Florisil column chromatography, the derivatives are separated and measured by electron capture GLC. The method is capable of determining approximately 0.01 ppm of both compounds in fish, and recoveries have averaged 84±14.7% for fluridone and 83±13.4% far the metabolite.
Analytical Methods for Sulfonamides in Foods and Feeds. I. Review of Methodology
Authors: Horwitz William
Published: February 2020

Sulfonamides are an important class of antibacterial compounds used in veterinary practice and animal production. A number of specific compounds are approved for use in certain species under limitations requiring withdrawal long enough to eliminate the residues from edible tissues. In most cases, the legal tolerance is 0.1 ppm. This residue is measured in regulatory laboratories by a modified Bratton-Marshall procedure of solvent extraction, transfer to an acid solution, removal of potentially interfering amines by extraction from basic solution, diazotization of the sulfonamide in a reacidified solution, and spectrophotometric measurement of the developed color. The tissue metabolites of the sulfonamides are usually the parent compound and the N4-acetyl derivative, which is hydrolyzed to the parent compound by evaporation of the extracting solvent in the presence of acid.

The only collaborative studies which have been performed on methods for veterinary sulfonamides involve their determination as additives to feeds at levels of the order of magnitude of 100 ppm. Recoveries (94-103%) are satisfactory for the collaborative studies available. The reproducibility coefficient of variation of 5% is satisfactory for sulfaquinoxaline, sulfaguanidine, sulfanitran, and sulfamethazine; the 13% coefficient of variation for sulfadimethoxine is not satisfactory, indicating that the method for this compound needs improvement.

No collaborative studies have been performed on tissue residue methods. Therefore the between-laboratory variability and the susceptibility to outliers of the method used to enforce residue tolerances are unknown. Based upon within-laboratory studies, however, it appears that all of the diazotization-based methods are being operated close to their limit of reliable determination, a poor analytical practice.

Current methodological approaches utilize gas chromatography, high pressure liquid chromatography, and even gas chromatography-mass spectrometry with an isotopically labeled internal standard. None of these proposed methods have yet reached the stage of collaborative studies for either feeds or tissues.

In this discussion of analytical methods for sulfonamides, an introductory section covering the regulatory aspects and chemical properties of sulfonamides is followed by three main sections: first, general problems, including sampling and sample preparation, extraction, protein precipitation, cleanup, emulsions, color reactions, confirmation of identity, interferences, and sulfonamide metabolites; second, collaboratively studied methods of analysis, including methods for feeds, concentrates and premixes, and tissues, and statistical parameters; and last, other available analytical methods, including methods in the Food Additives Analytical Manual, validation studies for New Animal Drug Applications, the Tishler method, methods for sulfonamides as contaminants in feeds, methods involving chromatography, polarography, and automation, and prospective methods.
Improved Method for Confirmation of Identity of Aflatoxins B1 and M1 in Dairy Products and Animal Tissue Extracts
Authors: Egmond Hans P Van , Stubblefield Robert D
Published: February 2020

A method is described for confirming the identity of aflatoxins B1 and M1 in dairy products and liver extracts on a thin layer plate. Extracts and standards containing aflatoxins B1 and M1 are spotted on 10 × 10 cm plates, which are developed 2-dimensionally in mixtures of isopropanol-acetone-chloroform. After the first development, trifluoroacetic acidhexane (1 + 4) is sprayed on that part of the plate containing the separated extract components and the undeveloped standard spots of B1 and M1, and the plate is heated 6-8 min at 75°C. Then the plate is developed in a second direction, and the reaction products of B1 and M1 with trifluoroacetic acid from the extract are compared with the same derivatives of the respective standards. The method has been used successfully on extracts of milk, cheese, and liver containing 0.1 ng B1 or M1/g and can be completed in 35-45 min.
Radioimmunoassay of T-2 Toxin in Corn and Wheat
Authors: Lee Sungsoo , Chu Fun S
Published: February 2020

A radioimmunoassay (RIA) for the determination of T-2 toxin in corn and wheat was developed. The toxin was first extracted with methanol, and the methanolic extract was washed with hexane and passed through a Sep-Pak C18 reverse phase cartridge. The extract was then evaporated to remove the organic solvent, diluted with 0.1M sodium phosphate buffer (pH 7.2), and subjected to RIA using an ammonium sulfate precipitation method to separate the free T-2 toxin from the antigen-antibody complex. The recovery of T-2 toxin after the extraction and cleanup steps was 78-85% for corn and 90-95% for wheat. Sep-Pak cleanup removed a considerable amount of interfering substances from the sample, thus enabling the detection of 1 and 2.5 ppb of T-2 toxin in the wheat and corn samples, respectively. The recovery by RIA methods of T-2 toxin added to the corn and wheat samples was between 84 and 103% in the ranges of 1-20 ppb (for wheat) and 2.5-20 ppb (for corn). The new RIA proved to be a sensitive, accurate, reproducible, and relatively simple method for determining T-2 toxin.
Confirmation of Penicillic Acid by High Pressure Liquid and Gas-Liquid Chromatography
Authors: Phillips Timothy D , Ivie G Wayne , Heidelbaugh Norman D , Kubena Leon F , Cysewski Sigmund J , Hayes A Wallace , Witzel Don A
Published: February 2020

A pyrazoline (Py) derivative of the mycotoxin penicillic acid (PA), resulting from its reaction with diazomethane, was analyzed by high pressure liquid chromatography (HPLC) and gas-liquid chromatography (GLC). Both PA and Py-PA were chromatographed using reverse phase HPLC with a mobile phase of acetonitrile-water (60+40). An approximately 2.5-fold increase in absorbance at 254 nm and an increase in retention time of 32 s was observed with Py-PA. As an alternative means of confirmation, Py-PA could also be analyzed by GLC using flame ionization detection. This dual method should prove useful for rapid and efficient detection, quantitation, and coupled HPLC-GLC identity confirmation of low levels of PA.
Identification of Cephalosporins. II. Color Reactions and Thin Layer Chromatography
Authors: Hoogmarten Josh , Roets Eugéne E , Vanderhaeghe Hubert J
Published: February 2020

Some color reactions obtained with 16 commercially available cephalosporins are described. Thin layer chromatography of these cephalosporins in 17 different mobile phases is examined. Combining 2 or 3 TLC systems allows identification of all products.
High Pressure Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080) in Canine Gastric Content
Authors: Ray Allen G , Post Lynn O , Reagor John C
Published: February 2020

A sensitive high pressure liquid chromatographic method was developed for the determination of sodium fluoroacetate (compound 1080) in canine gastric content. The procedure involves extraction of 1080 with water, methyl ethyl ketone, and dilute base, followed by sample cleanup using octadecylsilane bonded phase cartridges and derivatization in ethyl acetate solution with O-p-nitrobenzyl-N-N’-diisopropylisourea (PNBDI). The compound was chromatographed on a 10 μm silica column, and ultraviolet absorbance at 254 and 280 nm was measured. Recovery was greater than 95% for standard 1080 and in the 70-90% range for spiked samples (1-50 ppm).
Determination of Trace Amounts of Nitrites in Fabricated Nonmeat Products
Authors: Desiena Anthony , Jacobs Emma , Romagnoli Ronald
Published: February 2020

Low levels of nitrite (1-5 ppm) contributed by raw materials in new fabricated food products were successfully determined by a modification of an AOAC method for processed meats. Recoveries were greater than 90% for composite samples to which 5-10 ppm nitrite had been added. This method allows analyses of fabricated food products containing hydrogenated vegetable oils, soy proteins, and dried egg whites for low levels of nitrite.
Survey of North Dakota Sunflower Seeds for Aflatoxin
Authors: Casper Howard H , Backer Leslie F , Kunerth Wallace
Published: February 2020

In a survey of oil-type sunflower seeds, 89 samples were collected from 32 storage bins in 10 counties of North Dakota in 1979. None of these survey samples exceeded the 20 ppb Food and Drug Administration aflatoxin guideline. Four research samples, from 2 grossly spoiled storages, contained 100-1100 ppb aflatoxin B1. This research is believed to be the first to document natural aflatoxin contamination in sunflower seeds.
Metal Content of Shark Muscle Powder Biological Reference Material
Authors: Taguchi Masashi , Takagi Hiroyuki , Iwashima Kiyoshi , Yamagata Noboru
Published: February 2020

Powdered dried shark muscle (Cephaloscyllium umbratile) is a promising biological reference material for metal analysis. Homogeneity indices (CV%) for Na, K, Zn, As, Ca, and Hg of the shark powder were within 5%. Mercury and arsenic concentrations (total Hg, 9.1 ppm dry wt, As, 99 ppm dry wt) in shark powder are relatively high. Muscle can be obtained inexpensively, and the powder can be preserved indefinitely if kept cold.
Paper Chromatographic Determination of Total Capsaicinoids in Capsicums and Their Oleoresins with Precision, Reproducibility, and Validation Through Correlation with Pungency in Scoville Units
Authors: Rajpoot Nagin C , Govindarajan Venkatesa S
Published: February 2020

Total capsaicinoids is an important quality index of capsicums. It has been recommended that this index can be reliably estimated by a simple and rapid paper chromatographic method. Details of the method have been critically studied to establish the precision and reproducibility. The repeatability and reproducibility of the method were ±3.12% and ±6.63% (relative to mean), respectively. In addition, the values by this method for samples of capsicums and their oleoresins, varying over a wide range of capsaicinoids content, were validated by a high correlation (r ≃ 1) to pungency values by the standardized threshold dilution method. In light of the results presented, it is suggested that the total capsaicinoids be accepted as an index of pungency.
Automated Thermal Conductivity Determination of Carbon Dioxide in Wine
Authors: Mitchell J Dale , Benjamin Christian R
Published: February 2020

Determination of CO2 in Lambrusco, using an automatic analyzer, has proven to be both fast and precise. The analyzer uses a thermal conductivity detector to measure CO2 gas liberated from the sample. Good accuracy was obtained when the method was compared to the enzymatic method. Ten samples gave an average difference of 1.4% from the accepted method.
Gas Chromatographic – Mass Spectrometric Determination of Volatile Organic Compounds in Fish
Authors: Easley Diane M , Kleopfer Robert D , Carasea Angelo M
Published: February 2020

A technique has been developed for the determination of volatile organic compounds in fish. The methodology is based on procedures used to determine purgeable organic compounds in water and wastewater. Fish tissue is added to reagent water, cooled in an ice bath, and homogenized with cell disruption using ultrasonic energy. The processed sample is then analyzed by a purge and trap procedure using an impinger-type device at 70°C, with determination of the purged compounds by computerized gas chromatography-mass spectrometry. Both ground fish and cored fish specimens were successfully analyzed by this technique. The overall average recovery for 39 volatile compounds studied was 77% with an average standard deviation of 20%.
High Performance Liquid Chromatographic Determination of Intermediates/Side Reaction Products in FD&C Yellow No. 5
Authors: Calvey Robert J , Goldberg Allen L , Madigan Elizabeth A
Published: February 2020

A rapid, sensitive, reproducible method that uses a strong anion exchange column and high performance liquid chromatography is described for determining intermediates/side reaction products in FD&C Yellow No. 5. With this method, 3 intermediates (sulfanilic acid, pyrazolone-T, and phenylhydrazinep- sulfonic acid) and 2 side reaction products (ethyl ester of pyrazolone-T and 4,4′-(diazoamino)dibenzenesulfonic acid) are eluted in a reproducible pattern by increasing the ionic strength of a buffered mobile phase. The intermediates sulfanilic acid and pyrazolone- T and the 2 side reaction products are quantitated; the intermediate phenylhydrazine-p-sulf onic acid is detected but not quantitated. Average recoveries for intermediates/side reaction products quantitatively determined in FD&C Yellow No. 5 samples were 99-104%. The amounts of intermediates/ side reaction products recovered were 0.005-0.18% by weight of the total sample.
Radioimmunoassay of T-2 Toxin in Biological Fluids
Authors: Lee Sungsoo , Chu Fun S
Published: February 2020

A simple radioimmunoassay (RIA) for detection of T-2 toxin in biological fluids was developed. The method, which involves a Sep-Pak C18 reverse phase column cleanup step before RIA, can detect 0.5 ppb T-2 toxin in serum and 2.5 ppb T-2 toxin in urine and milk. Recoveries for toxin added to serum and urine or milk samples were 87-106% in the 0.5-20 ppb range and 88-117% in the 2.5-20 ppb range, respectively. If samples were not cleaned up, false positive results prevented positive detection at concentrations less than 2.5 ppb in urine and milk.
Comparison of Methods for Determining Sodium in Fertilizers
Authors: Corominas Luis F , Boy Víctor M , Rojas Pedro
Published: February 2020

The AOAC official first action method, 2.147-2.150, for flame emission spectrophotometry (FES) determination of sodium in fertilizers was compared with the atomic absorption spectrophotometric (AAS) method and the sodium selective electrode (SSE) method. Ammonium oxalate, which was previously compared with water, H2SO4, HC1, and HNO3, was used to extract the sample for all 3 methods. Three synthetic NPK samples, 3 commercial samples (urea, normal superphosphate, and neutrophos), 1 phosphate rock, and 2 Magruder check samples were used for the study. Statistically significant differences were obtained in averages for most of the samples, but few differences were found in standard deviations. The AAS method showed the best accuracy and precision. Accuracy of the AOAC method is acceptable. The SSE method showed the highest deviations from the theoretical values. A collaborative study is recommended to compare the AOAC with the AAS method.
Use of Closed-System Vacuum Distillation for Isolation of Moderately Volatile Compounds
Authors: Daniels Daniel H , Warner Charles R , Birkel Thomas J
Published: February 2020

A rapid, efficient vacuum distillation method has been used to quantitatively determine moderately volatile compounds in food-related samples. The following components and matrices were studied: 1,4-dioxane in polysorbate 65 and choline chloride; ethylene chlorohydrin in choline chloride, choline bitartrate, and cumin; and epichlorohydrin, 1,3-dichloro-2-propanol, and l-chloro-2-propanol in cornstarch. The matrix is slurried with water or aqueous methanol, frozen, and subjected to vacuum distillation. The distillate, which is free of salts and nonvolatile matrix components, is chromatographed on a gas chromatographic column and quantitated using a flame ionization detector. Foaming, which is a problem with purge and trap and azeotropic distillation procedures, does not occur. Recoveries of the components ranged from 85 to 101% at levels of 0.5-600 ppm
Rapid Check on Proof of Rums
Authors: Alvarez-Nazario Fabián
Published: February 2020

The apparent proof of undistilled rum is determined by alcohol hydrometer and by refractometer, and correlated with the true proof and solids content.
Analytical Methods for Sulfonamides in Foods and Feeds. II. Performance Characteristics of Sulfonamide Methods
Authors: Horwitz William
Published: February 2020

Important factors in interpretation of methods for sulfonamides in tissues are value of the blank, use or omission of recovery factors, and precision of the methods. For determining sulfonamide in tissues, no interlaboratory collaborative studies have been performed to provide reproducibility parameters. By assuming comparability with other tissue residue methods at equivalent concentrations, it may be anticipated that the coefficient of variation withinlaboratories of the Bratton-Marshall method is about 15% at concentrations of a fraction of a part per million. It is estimated that the limit of reliable measurement of the Bratton-Marshall method is about 0.2 ppm, varying with the individual laboratory. This value is higher than the tolerance it is intended to enforce. Obviously, the method in this case has been stretched beyond its original claimed capabilities. This method also has high blanks and low recoveries. Assignment of sufficient resources to the solution of the problem by regulatory agencies has resulted in methods capable of handling the sulfonamide residue problem at 0.1 ppm.
Application of Chiral Lanthanide Nuclear Magnetic Resonance Shift Reagents to Pharmaceutical Analysis. II. Determination of Dextroand Levoamphetamine Mixtures
Authors: Wainer Irving W , Schneider Lynda C , Weber John D
Published: February 2020

Optically pure d- and l-amphetamine sulfate, as well as various mixtures of the 2 enantiomers, were analyzed using a europium chiral nuclear magnetic resonance shift reagent. The enantiomeric shift difference (ΔΔδ) exhibited by the doublet associated with the α-methyl protons was large enough to differentiate between the levo- and dextro-isomers. The α-methyl protons were decoupled and the enantiomeric composition was determined by using the peak heights of the resulting singlets. As little as 5% of the levo-isomer in the presence of the dextro-isomer can be determined using this method. The method is applicable to the analysis of bulk drug and pharmaceutical preparations.
Gas-Liquid Chromatographic-Thermal Energy Analyzer Determination of N-Nitrosodimethylamine in Beer at Low Parts per Billion Level
Authors: Sen Nrisinha P , Seaman Stephen
Published: February 2020

A gas-liquid chromatographic (GLC) procedure is described for the determination of low ppb levels of N-nitrosodimethylamine (NDMA) in beer. The sample is treated with sulfamic acid under acidic conditions followed by alkalinization with dilute KOH, distillation at atmospheric pressure, extraction of NDMA from alkaline aqueous distillate with dichloromethane, concentration of dichloromethane extract by Kuderna-Danish concentrator, and, finally determination by a GLC-thermal energy analyzer technique with N-nitrosodipropylamine (NDPA) as an internal standard. The method gave results comparable with 2 other well established methods. Recoveries of added NDMA, N-nitrosodiethylamine, and NDPA at levels ranging from 0.08 to 10 ppb were 75-112, 86-115, and 85-109%, respectively. Five replicate analyses of a beer sample gave a mean NDMA concentration (corrected for recovery) of 2.21 ± 0.08 ppb (± SD). Minimum detection limit of the method is about 0.1 ppb.
Bacitracin Determination in Feeds: Evaluation of Methods
Authors: Ragheb Hussein S
Published: February 2020

Assay of bacitracin activity in feeds is subject to many sources of variation. Bacitracin standards are complex mixtures and may contain various amounts of less active forms of bacitracin. Test organisms may respond differently to these mixtures. Collaborative studies should involve the use of one standard, perhaps USP zinc bacitracin. The use of different types of bacitracin standards (regular or zinc) in a laboratory may contribute to variation in sample potency. The pyridine extraction method is subject to serious operational difficulties. Among the contributing factors are incomplete evaporation of pyridine (causing positive bias), allowing the temperature to increase too much during evaporation (causing negative bias), and the numerous manipulative steps in the technique (causing large variability). Because of these factors and the toxic properties of pyridine, the method finds little use. Methanol extraction offers a better substitute for determining zinc or methylene disalicylate bacitracin in premixes and complete feeds by the plate method.
Determination of Aflatoxin B1 in Corn, Wheat, and Peanut Butter by Enzyme-linked Immunosorbent Assay and Solid Phase Radioimmunoassay
Authors: El-Nakib Ossama , Pestka James J , Chu Fun S
Published: February 2020

Determinations of aflatoxin B1 in corn, wheat, and peanut butter by an enzyme-linked immunoassay (ELISA) and a solid-phase radioimmunoassay (RIA) were compared. Samples spiked with 2.9-43.2 ppb B1 were subjected to AOAC extraction procedure 26.017 or 26.023. The extracts were concentrated, redissolved in methanol, diluted in phosphate-buffered saline with Tween 20, and directly analyzed for B1 by either ELISA or RIA. At 5.8 ppb or greater, recoveries for B1 in corn, wheat, and peanut butter samples were 80.0,86.6, and 94.8% by ELISA and 61.0, 93.3, and 110.0% by RIA, respectively. Recoveries greater than 120% were obtained for the wheat and peanut butter samples spiked with 2.9 ppb aflatoxin B1 by the RIA method but not by ELISA. Overall results indicated that ELISA gave more consistent data, relatively lower standard deviations, and lower coefficients of variation than did RIA. Analysis of 3 samples naturally contaminated with aflatoxins revealed that the ELISA data were comparable to those obtained by other established chemical methods.
Stable Isotope Ratio Determination of the Origin of Vanillin in Vanilla Extracts and Its Relationship to Vanillin/Potassium Ratios
Authors: Martin Glenn E , Alfonso Felipe C , Figert Donald M , Burggraff James M
Published: February 2020

A method is described for isolating vanillin from vanilla extract, followed by stable isotope ratio analysis to determine the amount of natural vanillin contained in adulterated vanilla extracts. After the potassium content is determined, the percent Madagascar and/or Java vanilla beans incorporated into the extract may then be approximated from the vanillin/ potassium ratio.
Nuclear Magnetic Resonance Spectroscopic Determination of Methoxyflurane
Authors: Henry Kermit W
Published: February 2020

A simple, rapid nuclear magnetic resonance (NMR) spectroscopic method for quantitatively determining methoxyflurane was developed. The proton NMR spectrum of methoxyflurane in carbon tetrachloride exhibited a well defined triplet at 5.67 ppm and a sharp singlet at 3.68 ppm. Using dimethyl sulfoxide (DMSO) as an internal standard, methoxyflurane was quantitated by comparing the integral for the singlet of methoxyflurane with the integral for the singlet of DMSO at 2.60 ppm. The method was accurate to concentrations as low as 1‑2%, and results agreed with those obtained by the NF XIV method
Ethylene Dibromide Residues in Biscuits and Commercial Flour
Authors: Rains Diane M , Holder James W
Published: February 2020

Flour and biscuit samples from a school lunch program were analyzed for ethylene dibromide (EDB). Flour samples were extracted with hexane at room temperature with maximum extraction of EDB in 4 days. Biscuits were extracted by steam distillation with hexane; optimum recoveries were obtained by a triple extraction of the sample. Recoveries of EDB from flour and biscuits ranged from 85 to 103% as determined by gas-liquid chromatography on a 15% OV-17 column and a 63Ni electron capture detector. Random samples were confirmed by gas chromatography- mass spectrometry. From <8 ppb to 4 ppm EDB were determined in flour and <0.5 ppb to 260 ppb in biscuits. Possible sources for the higher values are discussed.
Jack Bean Meal as Source of Urease in Determination of Urea
Authors: Hoover William L , Melton James R
Published: February 2020

Ground jack bean was added to feed samples as a source of urease in urea determinations. Jack bean meal is much less expensive and is more stable in the presence of soluble salts than is refined urease powder. Percent recoveries in terms of protein equivalent for 3 types of feed ranged from 96.1 to 98.9, using the proposed method. Jack bean meal was equal or superior to refined urease powder in converting urea to ammonia in all samples analyzed.
Template for Marking Thin Layer Chromatographic Plates for Two-Dimensional Development
Authors: Gardner Albert M
Published: February 2020

A compact template for marking 200 × 200 mm thin layer chromatographic (TLC) plates for 2-dimensional TLC is described. Directions are provided for use of the easily fabricated apparatus. The template permits rapid, accurate, and reproducible marking of plates for application of samples and standards
High Performance Liquid Chromatographic Method for Pyrantel Tartrate in Swine Feeds and Supplements
Authors: Goras John T
Published: February 2020

A new method for the determination of pyrantel tartrate in swine feed and supplements has been developed because the current official AOAC method is not applicable to feeds co-medicated with tylosin. The new method involves: (a) leaching of drug from feed with methanolic NaCl solution, (b) removal of interfering substances by ion pair liquid-liquid extraction and high performance liquid chromatography, and (c) quantitation of pyrantel tartrate by monitoring the ultraviolet absorption of the effluent stream at 313 nm. The method of standard addition is used to compensate for the effect of the feed matrix on drug recovery. No interference is encountered from tylosin, carbadox, lincomycin, non-drug components of feeds and supplements, or potential degradation products of pyrantel tartrate, i.e., cis isomer of pyrantel tartrate and (E)-N(3-methylaminopropyl)-2-thiopheneacrylamide. Results for the assay of 3 lots each of feeds and supplements containing 0.0106 and 0.106% pyrantel tartrate, respectively, were within ±4% of label claim. Coefficients of variation ranged from 1.6 to 1.8% for feeds and from 1.9 to 3.9% for supplements.
Determination of 2,4-D Butoxyethanol Ether Ester and Its Degradation Products 2,4-Dichlorophenoxyacetic Acid and 2,4-Dichlorophenol in Sediment
Authors: Kan Gordon Y P , Mah Fred T S , Wade Norman L , Bothwell Max L
Published: February 2020

2,4-D butoxyethanol ether ester (2,4-D BEE) was isolated from sediment by extraction with acetonehexane at neutral conditions; from the same sediment sample, 2,4-dichlorophenoxyacetic acid (2,4-D) was isolated with methanol after the sediment had been acidified to < pH 2. 2,4-Dichlorophenol in the sediment was extracted with isooctane by steam distillation. Mean recoveries from 4 spiked samples ranged from 99 to 108%, 94 to 102%, and 74 to 76% for 2,4-D BEE, 2,4-D, and 2,4-dichlorophenol, respectively. These procedures were developed for routine analyses of lake sediments in the Okanagan region of British Columbia.
Chromatographic Separation of Polar and Nonpolar Components of Frying Fats
Authors: Waltking Arthur E , Wessels H
Published: February 2020

A method is proposed to assess deterioration of frying fats by measuring polar and nonpolar components separated on a silica gel column. Means for polar components measured in duplicate samples by 19 collaborators ranged from 8.0 ± 0.34 to 25.8 ± 0.90%. Coefficients of variation ranged from 3.5 to 4.9%. The method has been adopted as official first action.
Comparison of Dietary Fiber Methods for Foods
Authors: Heckman Mary M , Lane Susan A
Published: February 2020

In order to evaluate several proposed dietary fiber methods, 12 food samples, representing different food classes, were analyzed by (1) neutral and acid detergent fiber methods (NDF, ADF); (2) NDF with enzyme modification (ENDF); (3) a 2-fraction enzyme method for soluble, insoluble, and total dietary fiber, proposed by Furda (SDF, IDF, TDF); (4) a 1-fraction enzyme method for total dietary fiber proposed by Hellendoorn (TDF). Foods included cereals, fruits, vegetables, pectin, locust bean gum, and soybean polysaccharides. Results show that TDF by Furda and Hellendoorn methods agree reasonably well with literature values by the Southgate method, but ENDF is consistently lower; that ENDF and IDF (Furda method) agree reasonably well; that except for corn bran fiber (insoluble) and pectin and locust bean fiber (soluble), all materials have significant fractions of both soluble and insoluble fiber. The Furda method was used on numerous food and ingredient samples and was found to be practical and informative and to have acceptable precision (RSD values of 2.65–7.05%). It is suggested that the Furda (or similar) method be given consideration for the analysis of foods for dietary fiber.
High Pressure Liquid Chromatographic Determination of Ethoxyquin in Paprika and Chili Powder
Authors: Perfetti Gracia A , Warner Charles R , Fazio Thomas
Published: February 2020

A method is described for the determination of ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) in paprika and chili powder. Ethoxyquin is extracted from the spice with hexane and partitioned into 0.3N HCl. After adjusting the solution to pH 13-14, ethoxyquin is extracted into hexane, and the hexane layer is evaporated to dryness. An acetonitrile solution of the residue is then analyzed by reverse phase high pressure liquid chromatography with detection at 254 nm. The mobile phase is water-acetonitrile with ammonium acetate buffer. Recoveries from samples fortified at 50, 100, and 200 ppm averaged 92% with a coefficient of variation of 2.3%. The method was applied to a number of commercial samples of paprika and chili powder. Ethoxyquin was found in paprika samples at levels up to 63 ppm and in chili powder samples at levels up to 20 ppm