bluuebunny/crossref_metadata_2025 huggingface dataset:
Anion-Exchange Method for Determination of Phytate in Foods: Collaborative Study
Authors: Harland Barbara F , Oberleas Donald ,   Collaborators:, Ellis R , Gelroth J , Gordon D , Phillips K , Ranhotra G , Shah B G , Stoecker B , Trick K D , Zymonas J
Published: February 2020

Phytate, a naturally occurring organic compound found in plant seeds, roots, and tubers, was determined in a collaborative study using a modified anion-exchange method. Seven samples (peanut flour, oats, rice, isolated soybean protein, a vegetarian diet composite, wheat bran, and whole wheat bread), supplied as blind duplicate samples, were analyzed in triplicate by 7 collaborators. Phytate concentrations in the samples ranged from 2.38 to 46.70 mg/g. Relative standard deviations (RSD = CV) for repeatability ranged from 2.5 to 10.1%, and for reproducibility, from 4.5 to 11.0%. The method has been adopted official first action.
Effects of Superglue, Other Fingerprint Developing Agents, and Luminol on Bloodstain Analysis
Authors: Duncan George T , Seiden Howard , Vallee Laura , Ferraro Donna
Published: February 2020

The stability of bloodstains exposed to various fingerprint developing agents (superglue, ninhydrin, and black powder) and luminol, which indicate the presence of blood via luminescence, was examined. Parameters used to characterize the stability were those common to forensic serology, and included any anomolies in ABO grouping, enzyme electrophoresis, species origin tests, and crystal and peroxidase examinations for the presence of hemoglobin in blood. Blood samples were collected from laboratory personnel and placed on absorbent and nonabsorbent substrates. These samples were then exposed to the developing agents and were characterized by using serological methods. Superglue, luminol, and black powder did not interfere with catalytic (peroxidase) examinations, crystal testing for hemoglobin, species origin testing, or ABO blood grouping. It was noted, however, that ninhydrin may adversely affect species origin, hemoglobin tests, and typing of “O” blood groups. All materials except black powder destroyed or weakened various enzymes of forensic interest. These results strongly suggest that before any fingerprint development, blood samples should be collected for serological examination by qualified personnel except when the black powder fingerprint method is used.
Spectrophotometric and Liquid Chromatographic Identification of 3,4-Methylenedioxyphenylisopropylamine and Its N-Methyl and N-Ethyl Homologs
Authors: Noggle F Taylor , DeRuiter Jack , Long Melinda J
Published: February 2020

3,4-Methylenedioxyphenylisopropylamine (MDA) is an hallucinogenic drug that somewhat resembles lysergic acid diethylamide (LSD) in its effects. Recently, widespread abuse of the N-methyl homolog (MDMA) of MDA has led to federal control. This article reports on the synthesis of the N-ethyl homolog (MDEA) of MDA as well as spectrophotometric and chromatographic methods for identification of the 3 homologs.
Liquid Chromatographic Determination of Ergot Alkaloids in Wheat
Authors: Ware George M , Carman Allen S , Francis Octave J , Kuan Shia S
Published: February 2020

A method is described for the determination of individual ergot alkaloids in wheat. The sample is extracted with ethyl acetate-4% ammonium hydroxide (100 + 10), and the extract is cleaned up by liquidliquid partition. The ergot alkaloids are resolved by liquid chromatography (LC), using a porous cross-linked polystyrene-divinylbenzene resin column and a mobile phase consisting of acetonitrile-0.05M dibasic ammonium phosphate (55 + 45) buffered at pH 10.0. The ergot alkaloids ergonovine, ergonovinine, ergotamine, ergotaminine, α-ergocryptine, α-ergocryptinine, ergocristine, and ergocristinine are separated by LC and detected with a fluorescence detector. Recovery of ergot alkaloids added to wheat at levels of 16-760 ng/g averaged 85.6% with a coefficient of variation of 11.1%.
Improved Method for Extraction of Filth from Cheese
Authors: Gardiner Mary-Ann , Peace Diane McClymont
Published: February 2020

An official AOAC method for detection of total filth in hard and soft cheese was modified to (a) achieve digestion of cheese at lower cost, (b) improve filtration rates, and (c) facilitate microscopic examination of the filth collected. The modifications involve a wet-sieving step, a reduction in the amounts of liquid filtered and pancreatin used, a detergent defatting step, and an acid boil step, if required. Average recoveries ranged from 85 to 100%. The method modifications should be collaboratively studied so changes in the official method can be recommended
Introduction to Microcomputers
Authors: Wagstaff D Jesse
Published: February 2020

Use of microcomputers in integrating different types of scientific information is a natural extension in the development of means to store and communicate observations and ideas. These means include human language, writing, printing, and now electronic storage and communications. Those who are faced with decisions about buying and using microcomputers'and their programs should base their decisions on a clear picture of what observations and ideas are to be stored and what objectives are to be met in communication. General functions and principles of information storage and communication should be considered more than the details of particular models of computer equipment.
The Personal Computer as an Analytical Workstation: Integrating Standard Software Products
Authors: Cawley Jeffery L
Published: February 2020

The personal computer is a powerful scientific and administrative analytical tool. Commercial computer programs can be effectively combined to meet most data-handling and report-writing needs. The selection of specific computer equipment (hardware) and computer programs (software) should be based on a careful assessment of the flow of work in the data-handling, statistical analysis, and reportwriting phases of analytical projects and on an assessment of the time and training required of the users of the computer system. In most projects, data must be transferred between different hardware and software. The use of standard ASCII text files is recommended for data transfer.
Use of Computer-Aided Design in the Preparation of Technical Manuscripts
Authors: Roach John A G , Roach Nancy M
Published: February 2020

Decreased computing costs and constantly improving capability are transforming microcomputers into general rather than specialized productivity tools. This has made it possible to increase personal productivity in ways that were not previously cost-effective. We are using computer-aided design (CAD) to prepare technical illustrations for chemical and geochemical manuscripts. CAD offers several advantages over hand-drawn illustrations. Chemical structures are stored in a library of shapes and may be combined or modified to form other structures in subsequent drawings. An original drawing only has to be drawn once with a computer. The drawing may then be scaled to any size and placed in a draft of a manuscript. Revisions require a fraction of the time needed to revise a drawing by hand. All or part of the drawing may be plotted to provide a sequence of drawings without changing the original drawing.
Computer Assistance in Food Analysis
Authors: Dusold Laurence R , Roach John A G
Published: February 2020

Laboratory computer links are a key part of acquisition, movement, and interpretation of certain types of data. Remote information retrieval from databases such as the Chemical Information System provides the analyst with structural and toxicologicai information via a laboratory terminal. Remote processing of laboratory data by large computers permits the application of pattern recognition techniques to the solution of complex multivariate problems such as the detection of food adulteration.
Determination of Ampicillin in Serum by Using Simple Ultrafiltration Technique and Liquid Chromatographic Analysis
Authors: Hutchins James E , Tyczkowska Krystyna , Aronson Arthur L
Published: February 2020

A new liquid chromatographic method for determination of ampicillin in canine and equine serum has been developed. The serum sample (500 μL) is vortex-mixed with 20% ethanol (500 μL) and filtered using a 30 000 molecular weight cutoff microseparation tube to separate high molecular weight solutes following low-speed centrifugation. Ampicillin is then separated from other serum components by reverse phase ion-pair liquid chromatography (LC). The ultraviolet (UV) absorbance of the column effluent is monitored at 230 nm. Recoveries of ampicillin from canine serum spiked at concentrations of 10, 40, and 60 μg/mL were 93.1,100.9, and 87.8%, respectively, with coefficients of variation (CVs) of 2.91, 3.08, and 4.08%, respectively. Recoveries of ampicillin from equine serum spiked at the same concentrations were 91.6, 90.1, and 88.7%, respectively, with CVs of 3.03, 2.61, and 3.35%, respectively. The limit of detection for ampicillin by this method is less than 0.5 μg/mL serum.
Computerized Semiautomated Microbiological Assay of Folacin
Authors: Keagy Pamela M
Published: February 2020

A semiautomated microbiological folacin assay system is described. microcomputer A controls sample dilutions, medium addition, turbidity determination, and data acquisition. Assay capacity is 600 tubes per day, approximately twice that of comparable manual assays. Using the automated equipment, more samples can be compared within one assay, eliminating many sources of between-assay variation in large studies. Additional advantages of this sytem are reduced human errors, flexibility of assay design, and multifunctional component equipment. Folacin results from chicken liver, spinach, and breakfast cereal samples show equivalent precision for manual and automated assays.
Methods of Analysis for Infant Formula: Food and Drug Administration and Infant Formula Council Collaborative Study, Phase III
Authors: Tanner James T , Barnett Stephen A ,   Collaborators:, Barnett S A , Beare-Rogers J L , Bueno M P , Chaudhari R , Eisenhardt W , Ellefson W , Ponto K , Reynolds S , Richards P , Soliman A G , Tanner J T
Published: February 2020

Phase III of the collaborative study of methods of assay for nutrients in infant formulas was conducted. The study included assay of chloride, phosphorus, proxiraates (ash, fat, protein, total solids, and carbohydrates), thiamine, total pantothenates, and vitamins A, Bu, and E. Most of the methods were those in Official Methods of Analysis, 13th edition, with slight modifications, or methods of the Infant Formula Council. On the basis of the results obtained by the collaborators, the methods for chloride, phosphorus, proximates, thiamine, and vitamin Bu have been adopted official first action. Methods for total pantothenates, vitamin A, and vitamin E were not recommended for adoption at this time because of anticipated improvements in methodology in the foreseeable future.
Enzyme Immunoassay for Detection of Salmonella in Foods: Collaborative Study
Authors: Flowers Russell S , Eckner Karl , Gabis Damien A , Robison Barbara J , Mattingly Jerome A , Silliker John H ,   Collaborators:, Bailey J , Bednar A , Chen K , Cirigliano M , Coschigano M , Deibel K , DonLevy T , Eckner K , Elliott P , Erickson J , Feldsworth M , Fenlon M , Finn S , Fischer G , Gaugert A , Givich K , Graham C , Guarino P , Hall P , Humber J , Jogan M , Jones W , Jost K , Koenig E , Lenovich L , Loudermilk L , Lynn T , Magno E , Miklovic G , Nemeth B , Nolan D , Posey D , Rasilewicz C , Risty N , Roberts B , Rogers J , Romick T , Clair V St , Sakai H , Schwenger K , Smittle D , Smoeger D , Sparks D , Sveum W , Tong M , Tremont D , Trailer J , Arman T Van , Way J Van , Wagner C , Wagner D , Walsh K , Worley N , Zari C
Published: February 2020

A collaborative study was performed in 25 laboratories to validate an enzyme immunoassay (EIA) procedure utilizing 2 specific monoclonal antibodies for rapid detection of Salmonella in foods. The EIA was compared with the standard culture procedure for detection of Salmonella in 6 food types: ground black pepper, soy isolate, dried whole eggs, milk chocolate, nonfat dry milk, and raw deboned turkey, Uninoculated and inoculated samples were included in each food group analyzed, with the exception of poultry which was naturally contaminated. There was no significant difference in the productivity of the EIA and culture procedures at the 5% level for any of the 6 foods. The enzyme immunoassay screening method has been adopted official first action.
Thin Layer Chromatographic Detection and Liquid Chromatographic Determination of Stevioside and Rebaudioside A in Beverages and Foods Following Reverse Phase Column Chromatography
Authors: Fujinuma Kenji , Saito Kazuo , Nakazato Mitsuo , Kikuchi Yoko , Ibe Akihiro , Nishima Taichiro
Published: February 2020

A method for the detection and determination of stevioside and rebaudioside A in beverages and foods by thin layer chromatography (TLC) and liquid chromatography (LC) is presented. Stevioside and rebaudioside A are extracted with water from a sample and purified by a reverse phase column chromatographic procedure using a silica gel 60 silanized column. The eluate from the column is concentrated to dryness, and the resulting residue is dissolved in 80% ethanol. For the detection, TLC is used, and spots of stevioside and rebaudioside A are visualized with anisaldehyde sulfuric acid reagent. Stevioside and rebaudioside A detected in samples are determined by LC with a Finepak SIL NH2 column and a mobile phase of acetonitrile-water (200 + 45) containing tetrabutylammonium phosphate, which is added to achieve the separation from some interfering compounds. Recoveries from samples spiked at 10 and 100 ppm ranged from 97.8 to 100.3% (stevioside) and 96.3 to 99.7% (rebaudioside A).
Liquid Chromatographic Determination of Carbofuran in Technical and Formulated Products: Collaborative Study
Authors: Kikta Edward J ,   Collaborators:, Bane E , Burns A , Christensen A , Cohen C J , Forrette J E , Glinski R , Hageman L R , Hitas P , Lonn P , McDevitt J B , Meinen V J , Moya H , Owen M E , Pavel K , Polli R , Roth M K , Schreiber M L , Skelly N E , Vaysse M
Published: February 2020

A liquid chromatographic (LC) method for the analysis of technical and formulated carbofuran samples was evaluated in a collaborative study. Carbofuran is determined by reverse phase LC, using a water-methanol mobile phase and acetophenone as internal standard, and detected at 280 nm. Twelve samples, 5 formulations and technical matched pairs, were analyzed by 17 collaborating laboratories. Accuracy and variability of results are typical of large LC data sets. The method has been adopted official first action.
Quantitative Aqueous Ammonium Ion Analysis by Transmission Infrared Spectroscopy
Authors: Voort Frederick R Van De , Mills Bernice L , Paquette Guy A , Grunfeld Eva
Published: February 2020

An investigation was undertaken to determine whether ammonium ion could be quantitated in aqueous solution by using commercially available infrared filter instruments such as the Multispec M1 analyzer. Ammonium salt solutions were scanned using an infrared spectrophotometer modified specifically to facilitate the study of aqueous systems and were shown to have 2 main absorption bands at 3.49 μm (2865 cm-1) and 6.89 μm (1451 cm-1). The 3.49 μm band did not correspond to any individual band noted in the literature and was concluded to be a composite of fundamental bands and Fermi resonances due to hydrogen bonding affecting the ion in solution. The response of the 6.89 μm band to NH4+ concentration was approximately twice that of the 3.49 μm band, and quantitation of the ammonium ion was assessed by the dual wavelength method as employed in filter-based commercial infrared analyzers. Good quantitation was obtained using 5.56 μm as a reference wavelength, and the slope of the standard curve of ammonium sulfate was not significantly affected by pH in the pH 3-8 region. A 6.86 μm sample filter and a 5.56 μm reference filter were installed in a Multispec M1 analyzer and a linear response was obtained for concentrations of up to 0.6% ammonium sulfate. Accurately weighed samples of ammonium sulfate were converted to ammonia by using the micro-Kjeldahl procedure and then distilled into standard acid, diluted to volume, and assessed by titration and transmission infrared analysis. The infrared method was more accurate than the titration method in replicating the initial weights. The measurement of ammonium ion in Kjeldahl distillates may be feasible as a method of protein determination if an inexpensive, simple, and dedicated instrument designed for this purpose were available.
Radioimmunoassay of Deoxynivalenol in Wheat and Corn
Authors: Xu Yi-Chun , Zhang Guang-Shi , Chu Fun Sun
Published: February 2020

With the availability of antibody against deoxynivalenol triacetate (DONtriacetate), a radioimmunoassay (RIA) for DON in wheat was developed. DON is extracted from the sample with acetonitrile-water (84 + 16), defatted with hexane, and then reacted with acetic anhydride to form DON-triacetate. The reaction mixture is loaded onto a C-18 cartridge to remove excess reagents and impurities. Acetylated DON is eluted from the cartridge with 50% methanol in water, and then analyzed by radioimmunoassay utilizing antiserum against DON-triacetate and tritiated DON-triacetate. Overall recovery for DON added to wheat between 50 and 5000 ppb was 86% with a standard deviation of 7% and coefficient of variation of 8%. The limit of detection for DON was about 20 ppb. Analysis of 12 naturally contaminated wheat, corn, and mixed feed samples for DON revealed that RIA results agreed well with thin layer chromatographic analyses performed by other laboratories.
Acid Hydrolysis of Proteins for Chromatographic Analysis of Amino Acids
Authors: Zumwalt Robert W , Absheer Joseph S , Kaiser Floyd E , Gehrke Charles W
Published: February 2020

The conditions used to hydrolyze proteins are vital in determining amino acid compositions because they necessarily represent a compromise aimed at yielding the best estimate of amino acid composition. Variations in ease of peptide bond cleavage, differences in amino acid stabilities, and matrix effects from nonproteinaceous components all militate against a single set of hydrolysis conditions that quantitatively hydrolyze every peptide bond and concurrently cause no destruction of any amino acid. This presentation summarizes and reviews an extensive study which evaluated a number of variations in the techniques and procedures of the classical 6N HC1, 110°C, 24 h hydrolysis of protein. The objectives of the recent investigation were: (/) to compare hydrolysis at 145°C, 4 h with 110°C, 24 h for proteins in a wide range of different sample matrixes; (2) to compare protein hydrolysis at 110°C, 24 h conducted in sealed glass ampoules after vacuum removal of air with hydrolysis in glass tubes with Teflon-lined screw caps after removal of air by vacuum, nitrogen purge, and sonication; (3) to evaluate a performic acid oxidation procedure before hydrolysis for the analysis of cystine and methionine in the different sample matrixes; (4) to evaluate multiple hydrolysis times at 145°C; (5) to evaluate the variation of interlaboratory hydrolysates prepared at 145°C, 4 h in 2 different laboratories on the amino acid analysis of an array of protein-containing matrixes. The major sources of inaccuracy and lack of precision arising from the application of ion-exchange or gas chromatography, both of which provide excellent accuracy and precision, are prechromatographic sample handling and the method used for hydrolysis of the protein sample itself. Hydrolysate preparation is the area that requires the most attention to solve problems of variability of amino acid analyses.
Determination of Sodium Dioctylsulfosuccinate in Dry Beverage Bases by Liquid Chromatography with Post-Column Ion-Pair Extraction and Absorbance Detection
Authors: Lawrence James F
Published: February 2020

Sodium dioctylsulfosuccinate (DSS) is extracted as an ion pair with methylene blue from finished drinks prepared from dry beverage bases. The complex is quantitatively determined colorimetrically in chloroform-acetone solution by a standard procedure. DSS is specifically identified by analyzing an aliquot of the extract by reverse phase liquid chromatography (LC). The compound is detected by using a simple post-column dynamic extraction system in which DSS is extracted from the aqueous mobile phase into chloroform as a methylene blue ion pair. The chloroform phase passes through the absorbance detector for measurement at 546 nm (filter detector). The absolute detection limit was 5-10 ng DSS, while in beverage bases as low as 0.1 μg/g was detected. Extraction of the beverage bases with mobile phase followed by filtration and direct LC analysis with the described system was also successful, although not evaluated on a routine basis.
Effects of Freezing on Nitrite Stability in Aqueous Solutions
Authors: Muneta Paul , Jasman Richard , Reid Luanne M
Published: February 2020

The effects of freezing on nitrite stability in microbial cultures and in other liquid media were examined. Nitrite (12-13 mg (NO2)N/ 100 mL, pH 5.7) in culture and aqueous media was very unstable during frozen storage. Freezing resulted in the degradation of nitrite to other products including nitrate. Losses of 38-57% of the nitrite occurred after 15 days of frozen storage. Neither addition of chloroform nor a 5 min boiling treatment before freezing prevented nitrite destruction. However, nitrite concentration in the unfrozen portion of aqueous media increased during the freezing process. Nitrite can be stabilized during frozen storage by increasing the pH to near 11.0. For aqueous solutions, nitrite can be preserved by the use of chloroform or by increasing the pH to 11.0 and storing at 5°C.
Ultraviolet Spectrophotometric Determination of Hydralazine Hydrochloride in Tablets Following Derivatization with Nitrite
Authors: Mopper Barry
Published: February 2020

Routine use of the USP XXI spectrophotometric method for the content uniformity determination of hydralazine hydrochloride tablets has shown that tablet excipients can significantly alter the spectral characteristics of the drug and thus cause inaccurate assay values to be obtained. Because of this problem, a simple and reliable alternative spectrophotometric assay method, based on the conversion of hydralazine to tetrazolo [5,l-α]phthalazine with nitrite ions under acidic conditions, was developed. The derivative showed an absorption maximum at about 274 nm and obeyed Beer's law over the concentration range 4-40 μg/mL. Mean recoveries of hydralazine hydrochloride added to commercial coated and uncoated tablets were 101.0% (n = 10) and 100.8% (n = 8), respectively. The proposed method was found suitable for the assay not only of individual tablets but also of tablet composites
Phosphorus in Wine: Comparison of Atomic Absorption Spectrometry Methods
Authors: Chow Helen , Gump Barry H
Published: February 2020

Phosphorus in wine may be determined directly or indirectly by atomic absorption spectrometry. The direct method uses the carbon rod atomizer as the excitation source and a phosphorus hollow cathode lamp. In the indirect determination, one measures the amount of molybdenum that will complex with phosphorus in the wine. Both nitrous oxide-acetylene and air-acetylene flames are suitable as atomization sources in this indirect method. The resultant data have been compared with those from the AOAC colorimetric method (11.032-11.034). A 2-sample comparison test showed the results to be insignificantly different at the 95% confidence limits.
Determination of Soy in Meat
Authors: Berkowitz David B , Webert Donald W
Published: February 2020

A number of methods may be used for determining soy flour in meat products. Highly purified soy products are more difficult to determine because the nonprotein components used to quantify the flour are reduced. Immunoassays have been used to directly measure protein content of soy products. Immunological methods for determination of soy proteins in meat are complicated by changes in the structure of the soy proteins during processing. These changes alter the available epitopes, changing the immunoreactivity of soy proteins. The epitopes available are dictated by the details of the processing. Other workers circumvented this problem by denaturing the soy protein with urea and mercaptoethanol, and then removing these agents by dialysis; whatever the initial protein conformation, all soy samples came to the same final conformation after the denaturing agents were removed. The assay used antibody made against the "renatured protein." These steps made the assay long and laborious. Attempts to develop a rapid assay were complicated by the same protein denaturation problems. Sodium dodecylsulfate gel electrophoresis coupled with immunoblotting may be the best quantitative approach.
Marine Fish as Source of Protein Supplement in Meat
Authors: Rasekh Jamshyd G
Published: February 2020

For the past 2 decades, a great deal of research has been done in fish technology, particularly in the area of mechanically deboned minced fish. Minced fish is the edible muscle flesh of fish that has been mechanically separated from the bones and skin. Ideally, the product is prepared from a high quality fish and resembles hamburger meat. In its final form, minced fish is used either as an ingredient or as an extender in seafood or in food products that require further processing. On the basis of technological advancements, the National Marine Fisheries Service of the U.S. Department of Commerce and the National Fisheries Institute jointly petitioned the U.S. Department of Agriculture in 1980 to add minced fish at a level of 15% in the meat formulation of frankfurters. This paper explores certain aspects of processing, production, acceptance, and hazard assessment of minced fish ingredients as possible protein supplements in meat and poultry food products relative to this request
Production of Antibodies and Development of Enzyme Immunoassay for Determination of Monensin in Biological Samples
Authors: Mount Michael E , Failla Douglas L
Published: February 2020

Monensin is converted to monensin bromoacetate, which provides successful coupling to protein and allows production of monensinspeciflc rabbit antisera. A modified indirect enzyme-linked immunosorbent assay (ELISA) was developed, which is highly sensitive (2 ng/mL) to monensin determination. Monensin recovery was 53- 81% at 10 ppb in sera or urine, and 81-130% at 100 ppb in dichloromethane- extracted feces or water. Overall recovery was 98.8% with coefficients of variation from 6 to 52% over the range of monensin concentrations studied. This is the first immunoassay reported for the carboxylic ionophore antibiotics.
Quantitative Liquid Chromatography of Ampicillin: Collaborative Study
Authors: Margosis Michel
Published: February 2020

A previously published liquid chromatographic method proposed for official use for the analysis of ampicillin in the market place was subjected to an international collaborative study. The method is rigorously defined in terms of performance requirements, yet allows a degree of flexibility to the individual analyst. Twenty-four participating laboratories from 9 countries submitted results of analysis of 3 samples. The data from one laboratory were rejected because they failed to meet the prescribed performance criteria. Evaluation of the data shows a coefficient of variation less than 1.8% between laboratories for each sample.
Purge and Trap Method for Determination of Volatile Halocarbons and Carbon Disulfide in
Table-Ready Foods
Authors: Heikes David L
Published: February 2020

A method developed for the determination of ethylene dibromide in table-ready foods has been modified and expanded to include 7 other volatile halocarbons and carbon disulfide. Samples are stirred with water and purged with nitrogen for 0.5 h in a water bath at 100°C. The analytes collected on a duplex trap composed of Tenax TA and XAD-4 resin are eluted with hexane and determined by gas chromatography with electron capture detection or Hall electrolytic conductivity detection. Flame photometric detection in the sulfur mode is used to determine carbon disulfide. Thick-film, wide-bore capillary columns are used exclusively in both the determination and confirmation of the halogenated analytes. The higher levels of analytes are also confirmed by full scan gas chromatography mass spectrometry (GC/MS). Samples are analyzed for carbon disulfide, methylene chloride, chloroform, 1,2-dichloroethane, methyl chloroform, carbon tetrachloride, trichloroethylene, 1,2-dibromoethane, and tetrachloroethylene. Initially, 19 table-ready foods from the Food and Drug Administration's Total Diet Study were analyzed by this method. A limited survey of those food items exhibiting high levels of analytes was conducted. Samples exhibited levels up to 3300 ppb (methyl chloroform in Parmesan cheese). Recoveries of all 9 analytes from fortified samples ranged from 83 to 104%. Chromatograms from this purge and trap method are clean, enabling quantitation levels of low parts per billion and sub-parts per billion to be achieved for the halogenated analytes. The quantitation limit for carbon disulfide is 12 ppb. Two compounds found in drinking water were identified by GC/MS as bromodichloromethane and chlorodibromomethane. Drinking water from several cities was analyzed for these trihalomethanes as well as for bromoform. Levels of up to 17 ppb bromodichloromethane were found. Recoveries ranged from 96 to 103%.
Capillary Gas Chromatographic Analysis of Amino Acids by Enantiomer Labeling
Authors: Bayer Ernst , Frank Hartmut , Gerhardt Jürgen , Nicholson Graeme
Published: February 2020

The optical isomers of amino acids can be easily separated by gas chromatography using capillary columns coated with the chiral polysiloxane peptide, Chirasil-Val. Quantitative trace amino acid analysis in complex mixtures such as biological fluids, sea water, or protein hydrolysates can be achieved by enantiomer labeling: The D-amino acid enantiomers, which do not occur naturally, are added to the sample prior to analysis as internal standards. Because the D-enantiomers show the same physical and chemical properties as the natural L-enantiomers, they are ideal standard references. In routine analysis, the derivatization is achieved with a new automated derivatization robot. The D-standard serves as overall internal standard for the whole analytical procedure from sample enrichment to derivatization, chromatography, and response of the detector.
Ion-Exchange Separation of Amino Acids with Postcolumn Orthophthalaldehyde Detection
Authors: Ashworth Raymond B
Published: February 2020

Moore's and Stein's classical ion-exchange separation of amino acids remains the standard by which all methods are judged. The adaptation of liquid chromatography (LC) equipment to amino acid analysis was inevitable because microprocessor control of gradients allowed almost infinite variation in gradient shape, producing superior resolution with only 2 buffers. The versatility of LC equipment allowed the instruments to be used for other assays. Adaptation of orthophthalaldehyde (OPA) to amino acid analysis increased detection sensitivity to the picomole range. A method for essential amino acids analysis in mechanically separated red meat and poultry products has been adapted to liquid chromatography using postcolumn hypochlorite oxidation, OPA derivatization, and fluorescence detection. Separation is achieved with 2 sequential concave exponential gradients combining ionic strength and pH increases with halidecontaining buffers. Hydroxyproline and proline are detected with increasing sensitivity through the use of 3-mercaptopropionic acid in a stabilized OPA reagent. Sample preparation is a critical part of the method. A defatting procedure removes fat and other nonprotein nitrogenous substances. The hydrolysis procedure is designed to protect tryptophan which can be routinely assayed in hydrolysates with a modified flow program. Corrosion damage to the equipment by halide buffers has brought about a search for alternative methodology.
Liquid Chromatographic Determination of Salinomycin Sodium in Feed Premix and Biomass Samples
Authors: Dimenna Gary P , Creegan James A , Turnbull Lennox B , Wright George J
Published: February 2020

A liquid chromatographic (LC) method has been developed for determination of sodium salinomycin (SS) in feed premix and biomass samples. SS is extracted from samples with acetonitrile, and the extract is diluted to volume. An aliquot is then injected directly into the chromatographic column, and refractive index detection is used to determine the presence of SS. The LC method proved to be both fast and specific; SS was quickly separated from lasalocid, monensin, and narasin. To test the efficiency of this extraction method, premix and biomass samples were spiked with SS. The mean recovery of SS from the spiked premix samples was 101.6%, and from the spiked biomass samples, 99.4%. Six premix samples were then assayed for SS in triplicate on 5 successive days, and 10 biomass samples were assayed for SS in triplicate on 3 different days. The coefficients of variation for the premix assay values ranged from 2.50 to 7.87%. For the biomass assay, CVs ranged from 0.9 to 3.5%. Premix and biomass samples were assayed for SS by this LC method in 2 laboratories and by a turbidimetric method using Bacillus subtilis in a third laboratory. The assay values obtained for SS were equivalent.
DNA Hybridization Assay for Detection of Salmonella in Foods: Collaborative Study
Authors: Flowers Russell S , Joan Klatt Mary , Mozola Mark A , Curiale Michael S , Gabis Damien A , Silliker John H
Published: February 2020

A collaborative study was performed in 11 laboratories to validate a DNA hybridization (DNAH) procedure for detection of Salmonella in foods. The DNAH procedure was compared to the standard culture method for detection of Salmonella in 6 foods: ground pepper, soy flour, dry whole egg, milk chocolate, nonfat dry milk, and raw deboned turkey. With the exception of turkey which was naturally contaminated, uninoculated and inoculated samples of each food group were analyzed. Results for the DNAH method were significantly better than for the standard culture method at the 5% probability level for the detection of Salmonella in turkey. There was no significant difference between the methods for the other 5 foods. The method has been adopted official first action.
Enzyme Immunoassay for Detection of Salmonella in Low-Moisture Foods: Collaborative Study
Authors: Flowers Russell S , Joan Klatt Mary , Robison Barbara J , Mattingly Jerome A , Gabis Damien A , Silliker John H
Published: February 2020

A collaborative study was performed in 15 laboratories to evaluate a modification of the enzyme immunoassay (EIA) method for detection of Salmonella in foods (46.B21-46.B29). The modified EIA requires 18-24 h pre-enrichment, 6-8 h selective enrichment, and 14-18 h M-broth post-enrichment prior to performing the assay, which requires 1-2 h. Total assay time is 40-52 h. The modified method was compared with the standard culture method for detection of Salmonella in 5 low-moisture foods: nonfat dry milk, milk chocolate, meat and bone meal, dry whole egg, and ground pepper. The modified method has been adopted official first action for use with low-moisture foods.
Determination of Ergotamine Tartrate in Tablets by Liquid Chromatography with Fluorescence Detection
Authors: Cieri Ugo R
Published: February 2020

A method is presented for the liquid chromatographic (LC) determination of ergotamine tartrate in tablets that is applicable even in the presence of other ingredients such as phenobarbital, belladonna alkaloids, and caffeine. The sample is transferred to a volumetric flask, a small volume of formic acid is added to dissolve and stabilize the ergotamine, and the solution is diluted to volume with methanol. The solution is mixed and filtered through paper. The LC system consists of a Rheodyne injector fitted with a 20 μL loop and a C,18 reverse phase column; the mobile phase is acetonitrile-water-triethylamine (700 + 300 + 0.5). Ergotamine tartrate is determined fluorometrically at an excitation wavelength of 250 nm and an emission wavelength of 430 nm. Recovery studies were conducted at the 0.3 and 1.0 mg levels. Average recoveries were 99.6 and 100.8%, respectively; relative standard deviations (RSDs) were 1.08 and 2.21%, respectively. Some commercial preparations containing ergotamine tartrate in combination with other ingredients were also analyzed. The RSDs for 5 determinations of each of 2 ground composites were 0.09 and 0.34%.
Spectrophotometric Determination of Aminacrine Hydrochloride in Creams, Jellies, and Suppositories: Interlaboratory Study
Authors: Bunch Elaine A
Published: February 2020

A previously reported visible spectrophotometric method for the analysis of aminacrine hydrochloride in creams, jellies, and suppositories was studied collaboratively by 8 laboratories. Aminacrine hydrochloride was extracted into acidic ethanol and its visible spectrum recorded. The amount present was calculated by determining the net absorbance between the absorbance maximum at about 402 nm and one-half the sum of the absorbance of the minima at about 389 and 412 nm. Each collaborator received 4 creams (0.2%), 1 jel (0.2%), 1 molded suppository (6 mg/3.198 g), and 2 gelatin-encapsulated suppository samples (12 mg/6.661 g and 14 mg/6.863 g). The cream samples included blind duplicates prepared to contain 0.212% aminacrine hydrochloride, 15% sulfanilamide, and 2% allantoin. Mean recovery for the authentic cream was 104.7% with a coefficient of variation (CV) of 9.22%. The commercial products contained these respective amounts (CVs): creams, 100.0% (2.48%) and 101.5% (2.16%); jel, 118.0% (9.58%); molded suppository, 102.7% (1.88%); and gelatin encapsulated suppositories, 93.1% (1.0%) and 94.3% (1.60%). Standard aminacrine hydrochloride provided for the study was 99.6% pure by nonaqueous titration. Thin layer chromatographic identification of aminacrine hydrochloride was also tested collaboratively. The method was not adopted by AOAC.
Reverse Phase Liquid Chromatographic Determination of Some Food Additives
Authors: Veerabhadrarao Madduri , Narayan Mandayam S , Kapur Omprakash , Sastry Chilukuri Suryaprakasa
Published: February 2020

Liquid chromatographic methods are described for the separation and determination of non-nutritive sweeteners, namely, acesulfame, aspartame, saccharin, and dulcin; preservatives such as benzoic acid and p-hydroxybenzoic acid; and caffeine and vanillin in ready-toserve beverages, ice candy, ice cream, squash beverage, tomato sauce, and dry beverage mix samples. These additives are separated on a ^Bondapak C18 column using methanol-acetic acid-water (20 + 5 + 75) as mobile phase and detected by UV absorption at 254 nm. Caffeine, vanillin, dulcin, and benzoic acid can be analyzed quickly by using a mobile phase of methanol-acetic acid-water (35 + 5 + 60). Aspartame can be separated in the presence of caffeine and vanillin by using the mobile phase pH 3 acetate buffer-methanol (95 + 5). Retention factors and minimum detectable limits are described. The percentage error and the percent relative standard deviation for 6 replicate samples ranged from 0.3 to 2.8 and from 1.64 to 3.60, respectively. Recovery of additives added to the foods named and analyzed by the direct method and by extraction ranged from 98.0 to 100.6% and from 91.6 to 101.8%, respectively. The proposed LC techniques are simple, rapid, and advantageous because all the additives can be detected in a single step, which makes it useful for the routine analysis of various food products.
Improved Efficiency for Colorimetric Determination of Furfural in Citrus Juices
Authors: Beeman Curt P
Published: February 2020

The operational efficiency of a method for colorimetric determination of furfural in citrus juices is improved by inclusion of a concentrationscreening step prior to the color reaction. The absorbance at 277 nm may be used to determine the appropriate dilution for samples exceeding the recommended maximum furfural concentration in the reaction mixture. As much as 1 h per sample may be saved in the time required for analysis.
Liquid Chromatographic Identification of Common Fish Species
Authors: Osman Magdi A , Ashoor Samy H , Marsh Paul C
Published: February 2020

Water-soluble sarcoplasmic proteins in aqueous blends of each of 31 fresh fish species were separated and quantitated by a simple liquid chromatographic (LC) method. The method revealed major qualitative and quantitative differences which were used for reliable identification of all species. Freezing for 6 months had no apparent effect on water-soluble fish proteins and did not change species-specific chromatograms. Cooking, however, caused significant changes which resulted in chromatograms different from those of fresh or frozen samples. Fish species identification by the LC method is rapid (total analysis time is about 1 h) and reliable and does not require special skills. It is applicable to fresh and frozen whole, sliced, filleted, and minced fish.
Detection and Quantitation of T-2 Mycotoxin in Rat Organs by Radioimmunoassay
Authors: Hewetson John F , Pace Judith G , Beheler Joanne E
Published: February 2020

A standard radioimmunoassay was compared with radiochromatography for the ability to detect unlabeled T-2 mycotoxin in organs from exposed animals. When 10% of HT-2, the only known metabolite that cross-reacts with T-2, was included and expressed as T-2 equivalents in the radiochromatographic detection, correlation between toxin detection in liver, spleen, and kidney by the 2 techniques was r = 0.98. An unknown metabolite was detected in heart extract by radiochromatography. Inclusion of this material in the T-2 equivalents detected by radiochromatography indicated a near-perfect correlation (r = 0.95; p > 0.05; slope = 0.82; y = intercept = 72) among all 4 tissues.
Use of Solid-Phase Extraction Systems to Improve the Sensitivity of Artemia Bioassays for Trichothecene Mycotoxins
Authors: Hoke Steven H , Carley C Michael , Johnson Eugene T , Broski Florence H
Published: February 2020

Solid-phase extraction was used to preconcentrate trichothecene mycotoxins from rivers and streams in order to develop and improve a rapid and sensitive bioassay using the brine shrimp Artemia salina. For T-2 toxin, HT-2 toxin, and 4,15-diacetoxyscirpenol, LCM values obtained were 172, 600, and 700 μg/L, respectively. The LC50 for 4-deoxynivalenol was 21 mg/L. A more than 5-fold increase in sensitivity was observed when solid-phase extraction (SPE) was used in conjunction with the Artemia bioassay. For T-2 toxin, HT-2 toxin, and 4,15-diacetoxyscirpenol, LC50/SPE values after solid-phase extraction were 21, 83, and 130 μg/L. The use of river and stream waters and chlorinated water did not seem to interfere with the bioassay.
Total Organic Carbon as an Index for Specification of Water for Injection
Authors: Matsuda Rieko , Ishibashi Mumio , Uchiyama Mitsuru , Hiraoka Tamio , Hoshida Haruhiko , Kunihiro Yasuyuki , Miki Hiromichi , Nishimoto Yukio , Inazu Kunihei , Mizuno Takanori , Watanabe Ryozo , Yano Kokuji
Published: February 2020

Determination of organic compounds present as contaminants in purified water is of great importance. Total organic carbon (TOC) may be a useful parameter for evaluating the purity of water. This paper describes and compares the analytical results for solutions of 12 model compounds obtained by 3 methods: total organic carbon (TOC) analysis, determination of potassium permanganate consumption, and UV spectroscopy. TOC analysis gave values corresponding to the expected amounts of organic carbon for all the model compounds, whereas the other 2 methods gave highly variable results.
Quantitative Determination of Linoleic Acid in Infant Formulas by Gas Chromatography
Authors: Lee Theresa W
Published: February 2020

A method has been developed for the quantitative determination of linoleic acid in infant formulas by gas chromatography (GC). A known amount of triheptadecanoin was spiked into the sample. Total lipid was extracted from the product by an ethyl ether-petroleum etherethanol system in a Mojonnier flask. The sample was saponified by methanolic KOH after the solvents were evaporated. Methyl esters of the fatty acids were prepared by boron trifluoride (BF3) in methanol and analyzed by gas chromatography. A glass column packed with 10% SP-2340 (75% cyanopropyl silicone) was used to separate and identify the methyl linoleate and the methyl heptadecanoate. The quantity of methyl linoleate was calculated by comparing the integrated peak areas of these 2 fatty acid methyl esters. This method was satisfactory for both milk protein-based and soy protein-based matrixes. The results obtained by this method are comparable to those obtained by the AOAC spectrophotometric method 28.082- 28.085.
Gas Chromatographic/Mass Spectrometric Determination of Erythromycin in Beef and Pork
Authors: Takatsuki Keigo , Suzuki Shigeru , Sato Nobutoshi , Ushizawa Isamu , Shoji Takuro
Published: February 2020

A gas chromatographic/mass spectrometric (GC/MS) method is described for the determination of residual erythromycin in beef and pork. This method allows detection and quantitation of residual erythromycin in beef and pork by using single-ion monitoring; confirmation by a full scan electron impact mass spectrum is possible if residual level in a sample is ≥ 1 ppm. Erythromycin is extracted with methanol from a sample and cleaned up by n-hexane washing followed by partition between chloroform and phosphate buffer solution. The cleaned up extract is chromatographed on a silica gel column, acid hydrolyzed, and acetylated in acetic anhydride-pyridine mixture (1 + 2) at room temperature. The reaction mixture is injected into the GC/MS apparatus, and detection and quantitation are conducted using single-ion monitoring at m/z 200. The recoveries (CV, %) at 1 and 0.1 ppm fortification levels are 86% (2.7%) and 72% (7.7%), and the detection limit is 0.01 ppm.
Gas Chromatographic, Liquid Chromatographic, and Titrimetric Procedures for
Determination of Glycerin in Allergenic Extracts and Diagnostic Antigens: Comparative Study
Authors: Del Grosso Alfred V , May Joan C
Published: February 2020

Three methods for the determination of glycerin are examined as applied to several allergenic extracts and diagnostic antigens. The liquid chromatographic procedure uses a sulfonic acid functional PSDVB resin (Aminex HPX-87H), a mobile phase of 0.013N H2S04; and refractive index detection. The titrimetric procedure involves oxidation of glycerin with sodium metaperiodate followed by potentiometric titration of the resulting formic acid with sodium hydroxide. Samples are quantitated by comparing the equivalence point obtained from the sample to those obtained from a series of standards. The gas chromatographic procedure includes a column of 5% Carbowax 20 M on 80-100 mesh Chromosorb WHP; p-cresol was used as an internal standard. The 3 procedures are shown to be valid for the majority of product types examined. A positive interference was encountered in the titrimetric analysis of a tuberculin purified protein derivative that contained simple sugars. Recoveries of added glycerin ranged from 95.0 to 100.2% by the liquid chromatographic method, from 98.7 to 101.4% by the gas chromatographic method, and from 99.8 to 101.6% by the metaperiodate oxidation method when interference from simple sugars was not present. Coefficients of variation determined from 8 replicates of samples that contained glycerin were 2.2% or less for the liquid chromatographic method, 2.3% or less for the GC method, and 3.6% or less for the metaperiodate oxidation method.