bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ceramic Fiber as Filter Aid in Determination of Acid-Insoluble Lignin in Forages
Authors: McQueen Ralph E 
Published: February 2020

Abstract
Ceramic fiber was found to be a suitable alternative to asbestos in determining the acid-insoluble lignin content of 59 forages by AOAC official final action method 7.074-7.077. Replacement of asbestos is necessary because it is a recognized carcinogen. Blank values for ceramic fiber were less than those for asbestos, and repeatability of duplicate lignin determinations was similar for both filter aids. Lignin content (%) by the ceramic fiber method (X), over the range 0.74-12.63%, was highly correlated (0.997) with that using the asbestos method (Y) by the relationship: Y = 1.008X - 0.093. Correction of forage lignin estimates using ceramic fiber is necessary if they are compared with those obtained using asbestos because of the negative Mas of 0.093%.
Improved Method for Determination of Volatile Nitrosamines in Baby Bottle Rubber Nipples and Pacifiers
Authors: Sen Nrisinha P , Seaman Stephen W , Kushwaha Santosh C 
Published: February 2020

Abstract
A method is described for determining volatile nitrosamines in baby bottle rubber nipples and pacifiers. The method consists of (a) overnight soaking of the sample with dichloromethane in the presence of propyl gallate, an inhibitor for artifactual formation of nitrosamines; (b) extraction with dichloromethane using an ambient temperature column procedure; (c) distillation from aqueous alkali; (d) extraction of the aqueous distillate with dichloromethane and concentration of the extract using a Kuderna-Danish concentrator; and (e) final analysis by gas chromatography with detection by thermal energy analyzer. Major improvements over other published methods include a simpler extraction, a more efficient distillation and concentration to minimize losses, and incorporation of propyl gallate inhibitor as well as of a test to detect unsuitable dichloromethane solvent that otherwise might lead to artifactual formation. The method is highly accurate (~90% recovery) and precise (av. CV = 4.7% at &gt;9 ppb levels) and is applicable to determination of nitrosamines in both rubber- and plastic-based products.
Liquid Chromatographic Determination of Melamine in Beverages
Authors: Ishiwata Hajimu , Inoue Takiko , Yamazaki Takeshi , Yoshihira Kunitoshi 
Published: February 2020

Abstract
A liquid chromatographic method is described for the determination of melamine in beverages. Melamine is separated by column chromatography using cation and anion exchange resin and determined by ion-pair liquid chromatography using an ODS column and a mixture of acetonitrile and 0.05M phosphate buffer (pH 3.0) containing 0.005M sodium 1-laurylsulfate (1 + 4, v/v) as mobile phase. Recoveries of melamine ranged between 90.3 ± 7.8 and 102.1 ± 5.6% at levels of 0.6 to 2.4 ppm in 4 kinds of beverages. The quantitation limit was 2.5 μg melamine in 50 mL beverage. The method was applied to the migration test of melamine from melamine-formaldehyde resin products to the beverages.
Determination of Sorbic, Dehydroacetic, and Propionic Acids in Cheese by Liquid Chromatography and Gas Chromatography
Authors: Saito Isao , Oshima Harumi , Kawamura Norihisa , Uno Keiichi , Yama Masuo 
Published: February 2020

Abstract
A convenient and accurate method is presented for the determination of sorbic, dehydroacetic, and propionic acids in cheese by liquid chromatography and gas chromatography. The volatile acids are separated from cheese by steam distillation. Sorbic and dehydroacetic acids are determined by liquid chromatography using a reverse phase column and a mobile phase mixture (30 + 70) of methanol and 0.02M phosphate buffer, pH 7.2, containing 0.005M tetrabutyl ammonium. The effluent is monitored at 235 nm. After the distillate is acidified with formic acid, propionic acid is determined by gas chromatography with a flame ionization detector using a Porapak QS column. Average recoveries of sorbic, dehydroacetic, and propionic acids ranged from 92.3 to 99.5%. By this method, the acids could be determined without using organic solvent during extraction and cleanup.
Reverse Phase Liquid Chromatographic Assay for Calcium Pantothenate in Multivitamin Preparations and Raw Materials
Authors: Timmons Jo Anne , Meyer John C , Steible Daniel J , Assenza Sebastian P 
Published: February 2020

Abstract
A reverse phase liquid chromatographic (LC) method has been developed for the assay of calcium pantothenate in commercial multivitamin tablet formulations and raw materials. The assay was validated according to the Pharmaceutical Manufacturers Association Quality Control HPLC Committee guidelines. The chromatographic system includes a C-18 column and a mobile phase consisting of 0.25M sodium phosphate buffer, pH 2.5, and acetonitrile (97 + 3 v/v). The column effluent is monitored by UV detection at 205 nm. The sample preparation involves only extraction in water followed by filtration. The method is stability-indicating with a detection limit of approximately 50 ng/mL of the calcium pantothenate in the samples. The system is linear from at least 0.02 to 0.10 mg/mL. The mean recovery of spiked placebos ranged from 98.7 to 99.8%. The within-day precision of the assay on finished products (N = 6) ranged from 0.3 to 2.0% CV. A system suitability criterion for resolution is based on the separation between calcium pantothenate and 2 closely eluting compounds, saccharin and a saccharin degradation product, 2-sulfamoylbenzoic acid.
Evaluation of Selected Enzymes for Thiamine Determination
Authors: Defibaugh Phillip W 
Published: February 2020

Abstract
Seven commercially available enzymes were studied for suitability as substitutes in the AOAC thiamine determination, because the enzyme Takadiastase used in the method has not been available since 1976, and alternative enzymes were likewise unavailable or unsuitable for releasing thiamine from its phosphate esters. Four factors (substrate ester, enzyme level, time/temperature, and pH) at 2 levels were studied in a 24 factorial arrangement of treatments. Data were expressed in terms of mean percentage conversion (MPC) and were statistically evaluated by analysis of variance. Significant main effects and any interactions among treatments were calculated. Takadiastase and a-amylase (Miles) with MPCs of 101 and 102, respectively, appeared effective in dephosphorylation within method parameters. Potato phosphatase appeared marginally suitable. Wheat germ phosphatase, α-amylase (Sigma), Mylase 100, and Clarase 40,000 were judged unacceptable as enzyme substitutes.
Spectrophotometric Determination of Ascorbic Acid in Canned Fruit Juices, Cordials, and Soft Drinks with Iron(III) and 1,10-Phenanthroline as Reagents
Authors: Lau Oi-Wah , Luk Shiu-Fai 
Published: February 2020

Abstract
A simple and accurate spectrophotometric method has been developed for the determination of ascorbic acid in canned fruit juices, cordials, and soft drinks, based on the reduction of iron(III) by ascorbic acid to iron(II), which is then complexed with 1,10-phenanthroline. Background correction is necessary for most samples and can be achieved by copper(II)-catalyzed oxidation of the acid. The calibration graph was linear from 0 to 8 μg/mL of ascorbic acid with a slope of 0.12/ppm. The precision for the determination of ascorbic acid in a lemon drink containing 210 μg/mL of the acid was 0.9%. Many ingredients commonly found in fruit juices, cordials, and soft drinks do not interfere; however, tannic acid, pyrogallol, and sulfite interfere with the method. A wide range of samples was analyzed for ascorbic acid content by the proposed method. The samples included mango and lemon tea drinks and also grapefruit juices, for which no background correction is needed.
Limitations of the A-IM Method for Fecal Coliform Enumeration in the Pacific Oyster (Crassostrea gigas)
Authors: Kaysner Charles A , Weagant Stephen D 
Published: February 2020

Abstract
Use of the A-IM method, which was originally devised for testing water samples, has recently been extended for enumeration of fecal coliforms and Escherichia coli in shellfish and other food products. Results of our study indicate that while this method is reliable for analysis of growing waters, the use of the A-IM method for testing Pacific oysters may be less reliable because bacteria not belonging to the coliform group but which are sometimes present in these animals also give a positive reaction.
Square-Wave Voltammetric Determination of Acetaldehyde in Povidone
Authors: Lanniello Robert M , Colonnese Regina , Machnicki Nancy 
Published: February 2020

Abstract
A rapid, precise, and accurate method is described for the determination of acetaldehyde in povidone (polyvinyl pyrrolidone). The sample is dissolved in a basic aqueous electrolyte and analyzed using square-wave voltammetry. The proposed method allows for direct measurement of acetaldehyde under gentle conditions, thus avoiding loss of analyte due to volatility of acetaldehyde. The method is specific for acetaldehyde in the presence of other aldehydes and povidone process impurities.
Colorimetric Determination of Terbutaline Sulfate and Orciprenaline Sulfate via Nitrosation and Difference Spectrophotometry
Authors: El-Sadek Mohamed E , Abdel Latef Hisham E , Aboul Khier Afaf A 
Published: February 2020

Abstract
A colorimetric method is proposed for determination of terbutaline sulfate, orciprenaline sulfate, and their dosage forms. The suggested method depends on nitrosation of the 2 drugs by using sodium nitrite and hydrochloric acid. Addition of sodium hydroxide increases the intensity of the color developed. The difference between absorption values measured in acid and alkaline media is taken as a measure of concentration. Variables were carefully studied and optimized. Results for both compounds adhered to Beer's law over the range 2- 28 μg/mL. The method has proved to be accurate and precise for analysis of pharmaceutical dosage forms.
Rapid Liquid Chromatographic Determination of Dimetridazole and Ipronidazole in Swine Feed
Authors: Roybal Jose E , Munns Robert K , Hurlbut Jeffrey A , Shimoda Wilbert , Morrison Thomas R , Vieira Cassandra L 
Published: February 2020

Abstract
A simple and rapid method is described for the determination of dimetridazole (DMZ) and ipronidazole (IPR) in swine feeds at various levels (0.11-110 ppm). The drugs are released from feed by prewetting with a buffer, followed by extraction with either methanol or methylene chloride, depending on the drug level; if necessary, an acid-base cleanup is used before the liquid chromatographic analysis. The analytes are separated on a C18 column and monitored at 320 nm for detection and quantitation. Recoveries of DMZ from several feed formulations averaged 108% at the 92.8 ppm level with a standard deviation (SD) of 4.00% and a coefficient of variation (CV) of 3.70%, 101% at the 11.2 ppm level with an SD of 11.9% and a CV of 11.8%, and 100% at the 0.112 ppm level with an SD of 9.27% and a CV of 9.25%. Recoveries of IPR averaged 77.1% at the 12.9 ppm level with an SD of 1.75% and a CV of 2.27%; IPR recoveries averaged 35.2% at the 0.129 ppm level with an SD of 3.39% and a CV of 9.63%.
Standardization of Bacterial Numbers on Penicylinders Used in Disinfectant Testing: Interlaboratory Study
Authors: Cole Eugene C , Rutala William A , Samsa Gregory P 
Published: February 2020

Abstract
An interlaboratory study was conducted to evaluate a method of standardizing bacterial numbers on penicylinders used in the AOAC use-dilution method (4.007-4.015) of disinfectant testing. Eight participating laboratories followed a broth adjustment method using their media and stock cultures of Staphylococcus aureus ATCC 6538, Salmonella choleraesuis ATCC 10708, and Pseudomonas aeruginosa ATCC 15442. The culture broths that were used to inoculate the penicylinders were incubated for 48 h at 37°C after several (4-6) 24 h passages. McFarland turbidity standards of 1.0 and 0.5 were used to adjust visually the cultures of S. aureus and P. aeruginosa, respectively. S. choleraesuis was used undiluted. The results showed significant variability in numbers of test bacteria which adhered to die penicylinders, with mean values of 1.6 x 106 for S. choleraesuis, 3.5 x 106 for S. aureus, and 8.2 x 106 for P. aeruginosa. The results from collaborating laboratories attempting standardization of bacterial numbers on penicylinders demonstrated significant interlaboratory and cylinder variation for all 3 test organisms.
Development of Mass Spectral Library of Trichothecenes Based on Positive Chemical Ionization Mass Spectra
Authors: Hewetson David W , Mirocha Chester J 
Published: February 2020

Abstract
The positive chemical ionization (PCI) mass spectra of the trichothecenes were acquired on a quadrupole mass spectrometer and assembled into a computer-searchable library. These were compared with spectra generated by electron impact ionization (EI) for ease and efficiency in identification. The trichothecenes were derivatized as trifluoroacetic acid esters, trimethylsilyl ethers, and heptafluorobutyric acid esters. The PCI spectra were found to be more useful than those generated by EI, although both types need careful evaluation in making an identification. Software programs called PBMULT and PEAKS were created. The former searches each scan generated, whereas the latter was designed to search only those scans found within selected peaks of the total ion current. The results of both search routines are spooled and stored in a retrievable file. The search can be conducted without attendance of the operator.
Spectrophotometric Estimation of Rifampin-Isoniazid Mixture in Dosage Form
Authors: Sharma Suresh C , Das Sukomal , Talwar Santosh K 
Published: February 2020

Abstract
A spectrophotometric method for the simultaneous determination of rifampin and isoniazid in dosage form is described. By using a mixtore of methanol and water (2 + 3) as solvent, the absorbance of the mixtures of rifampin and isoniazid is measured at 264 nm and 335 am. The concentration of each can then be calculated by solving 2 simultaneous equations. The procedure was successfully applied to a number of commercial samples; the results agreed well with those for compendial method.
Determination of Olaquindox Residues in Swine Tissues by Liquid Chromatography
Authors: Nagata Tomoko , Saeki Masanobu 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for determination of olaquindox residues in swine tissues. The drug is extracted from tissues with acetonitrile, and the extract is evaporated to dryness. This residue is cleaned up by alumina column chromatography. LC analysis is carried out on a Nucleosil C18 column, and olaquindox is quantitated by ultraviolet detection at 350 nm. The average recoveries of olaquindox added to tissues at levels of 0.2, 0.1, and 0.05 ppm were 74.0, 68.6, and 66.3%, respectively. The detection limit was 2 ng for olaquindox standard and 0.02 ppm in tissues.
Determination of Nitrogen, Phosphorus, and Potassium in Water-Soluble Fertilizers by Inductively Coupled Plasma Emission Spectrometry
Authors: Nygaard Danton D , Sotera John J 
Published: February 2020

Abstract
A modification of an inductively coupled plasma (ICP) emission spectrometer is described that enables the simultaneous determination of nitrogen, phosphorus, and potassium in water-soluble fertilizers. A quartz extension tube is added to the ICP torch to exclude air from the plasma, thus allowing accurate nitrogen determination without adversely affecting sensitivity for other analytes. The modification also requires an 18 mg/L argon coolant flow to protect the tube from the heat of the plasma. Detection limits are 20 mg/L for nitrogen and 50 μg/L for phosphorus and potassium. Three NBS reference salts and 2 commercially available fertilizers were analyzed by the method, and results are in excellent agreement with known values.
Sample Preparation and Liquid Chromatographic Determination of Vitamin D
in Food Products
Authors: Bui Mai H 
Published: February 2020

Abstract
Vitamin D in different fortified foods is determined by using liquid chromatography (LC). Sample preparation is described for fortified skim milk, infant formulas, chocolate drink powder, and diet food. The procedure involves 2 main steps: saponification of the sample followed by extraction, and quantitation by LC analysis. Depending on the sample matrix, additional steps are necessary, i.e., enzymatic digestion for hydrolyzing the starch in the sample and cartridge purification before LC injection. An isocratic system consisting of 0.5% water in methanol (v/v) on two 5 /im ODS Hypersil, 12 x 0.4 cm id columns is used. Recovery of vitamin D added to unfortified skim milk is 98%. The results of vitamin D determination in homogenized skim milk, fortified milk powder, fortified milk powder with soybean, chocolate drink powder, and sports diet food are given
Spectrofluorometric Determination of BAY Vp 2674 Residues in Poultry Tissues
Authors: Waggoner T Bill , Bowman Malcolm C 
Published: February 2020

Abstract
A spectrofluorometric (SPF) method is described for determination of residues of BAY Vp 2674 in chicken and turkey tissues. The drug is extracted from tissues with dichloromethane-methanol. The organic extract is concentrated to near dryness and cleaned up by a series of partitionings with n-hexane, then dichloromethane against pH 2 buffer and dichloromethane against pH 12 buffer. The drug is partitioned into dichloromethane from pH 7 buffer and concentrated to dryness. The residue is dissolved in pH 3.5 buffer for SPF analysis at 282 nm (excitation) and 445 nm (emission). Recoveries of BAY Vp 2674 added to chicken and turkey tissues at levels of 0.05, 0.1, and 0.2 ppm range from 86 to 92% with a coefficient of variation of 3.4-10.1%. Detection limit is 0.02 ppm. A liquid chromatographic confirmatory procedure is also described, with ultraviolet and fluorescence detection
Determination of Cytotoxic Trichothecenes in Corn by Cell Culture Toxicity Assay
Authors: Porcher Jean-Marc , Lafarge-Frayssinet Christiane , Frayssinet Charles , Nurie Ahmed , Melcion Dominique , Richard-Molard Daniel 
Published: February 2020

Abstract
The great sensitivity of some cell species to toxins has been adapted to a direct biological determination of trichothecene contamination of food and feeds. The murine spleen lymphocyte stimulated by PHA (Phaseolus vulgaris phytohaemagglutinin) appeared to be the most convenient cells because of their particular sensitivity to cytotoxic trichothecenes and the opportunity to translate this cytotoxicity to immunosuppressive hazard, one of the most important concerns for trichothecenes. In this paper, the use of cell cultures was adapted for a survey of corn. The toxins were extracted by aqueous methanol, and the extract was defatted with hexane and purified on a silica gel/ Florisil column. This extract was then used for a gas chromatographic (GC) determination and the biological test. The growth of cells was measured by the incorporation of tritiated thymidine (3H Tdr), and the inhibition was expressed by the IC^: concentration of corn extract inhibiting by half the 3H Tdr incorporation. We have tested pure toxins, control corn, corn spiked with T-2 toxin, corn experimentally inoculated with toxigenic Fusarium strains, and naturally contaminated corn. A good correlation exists between IC50 and the T-2 toxin concentration as determined by GC analysis. The response is not affected by the presence of zearalenone or by small amounts of deoxynivalenol. A quantitative evaluation of cytotoxic trichothecenes in corn is valuable in the range of 100 ppb to 10 ppm, expressed as T-2 toxin equivalents. The result is obtained in 48 h
Liquid Chromatographic Determination of Amprolium in Poultry Feed and Premixes Using
Postcolumn Chemistry with Fluorometric Detection
Authors: Vanderslice Joseph T , Huang Mei-Hsia A 
Published: February 2020

Abstract
Two extraction and liquid chromatographic procedures are presented which separate amprolium from compounds in poultry feed or premixes that could interfere with its fluorometric determination. The procedures are based on earlier work on the determination of thiamine in food samples. Amprolium is extracted from feed with a hexane- aqueous sulfosalicylic acid mix, separated on a C18 column, and detected fluorometrically after postcolumn derivatization. For premixes, water extraction is used. Values for the amprolium content of poultry feed obtained with these procedures are in good agreement with those obtained with AOAC official methods. It is suggested that these methods with suitable modifications may be of use for routine analysis of amprolium in feeds. The overall methods are rapid and appear to give reasonable results
Simple Method for Distinguishing Maneb, Zineb, Mancozeb, and Selected Mixtures
Authors: Afsar HüYSEYIN , Demirata Birsen 
Published: February 2020

Abstract
Maneb, zineb, mancozeb, and arbitrarily selected mixtures of those can be differentiated by a simple method. Compounds are differentiated on the basis of colors produced after treatment of saturated solutions ofthe fungicides in n-propanol-acetone mixture (1 + 1 v/v), first with dithizone and then with monosodium dihydrogen phosphate solution in the same solvent. The color depends on the type and concentration of metal present in the sample
Chloride Determination in Foods with Ion-Selective Electrode After Isolation as Hydrogen
Chloride
Authors: Cerklewski Florian L , Ridlington James W 
Published: February 2020

Abstract
This report describes a sample preparation method in which chloride is isolated as hydrogen chloride from food samples prior to analysis with the chloride ion-selective electrode. Chloride analyses of selected foods with this method agreed with chloride values reported in food composition tables. Chloride analysis with the present procedure also agreed with the certified value for the chloride content of the National Bureau of Standards (NBS) Standard Reference Material, Nonfat Milk Powder. Reliability of the chloride isolation procedure was evident by the complete recovery of chloride added to food samples and a narrow range of 95% confidence limits calculated for each set of analyses. The usefulness of the chloride ion-selective electrode to determine chloride in foods is greatly enhanced by this procedure because matrix interference by other sample components is removed prior to analysis
Gas Chromatographic Determination of Alachlor in Microencapsulated Formulations: Mini-Collaborative Study
Authors: Tomkins David F 
Published: February 2020

Abstract
An isothermal gas chromatographic method for measuring alachlor in Micro-Tech® (microencapsulated) formulations was tested by 5 collaborators. The samples were prepared in acetone, and alachlor was determined using a gas chromatographic column of 10% SP- 2250 on 100-120 mesh Supelcoport. Di-n-pentylphthalate was used as the internal standard. Collaborators made single determinations on 5 samples distributed as blind duplicates. The mini-collaborative study generated 47 data points. The coefficient of variation (CV„- pooled) was 1.35%, and CVx-pooled was 0.73%. The method was simple to use and did not reveal any interferences in samples tested. The method has been adopted official first action as an AOACCIPAC method.