bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Testing of Gelatin Hydrolysis in Rapid Perfringens Medium
Authors: Smith Marilyn , Mood Thomas J 
Published: February 2020

Abstract
Rapid perfringens medium (RPM) was previously shown to be effective for detection of low numbers of Clostridium perfringens in foods. The detection system of RPM is based on a stormy fermentation of litmus milk. RPM also contains 6% gelatin, and the present work was performed to determine if gelatin hydrolysis can be tested directly in this medium. Twenty-three strains of C. perfringens and related species were inoculated into tubes of RPM and lactose gelatin. All strains were positive for stormy fermentation on RPM after 24 h incubation at 46°C. Seventeen exhibited gelatin hydrolysis on both RPM and lactose gelatin. Tubes of RPM inoculated with slurries of food samples spiked with each of 11 strains of C perfringens were positive for stormy fermentation and gelatin liquefaction. Most C. perfringens hydrolyze gelatin, so this test augments stormy fermentation in RPM as an additional indicator for the presence of this pathogen.
High Pressure Liquid Chromatographic Determination of Putrefactive Amines in Foods
Authors: Hui Julia Y , Taylor Steve L 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) procedure is described for determining the following putrefactive amines: histamine, tyramine, putrescine, cadaverine, tryptamine, and β-phenylethylamine. The amines were extracted from tuna or cheese with methanol. Futher cleanup was performed by sequential extractions with butanol and HC1. The acid extract was dried, and residues were derivatized with dansyl chloride. HPLC separations were performed on an Ultrasphere-ODS column at 33°C. A gradient elution program was used; the total elution time was less than 17 min. Linear standard curves with high correlation coefficients were obtained. The procedure allowed good recoveries of histamine, tyramine, putrescine, and cadaverine; recoveries of tryptamine and β-phenylethylamine were lower but constant. With this method, some swiss cheese samples were found to contain considerable amounts of histamine, tyramine, putrescine, cadaverine, and β-phenylethylamine. Canned tuna samples had very low levels of these amines. Since the presence of amines at high levels has been associated with tuna decomposition, this method may be useful in identifying decomposed fish.
Coupled-Column System for Quantitating Low Levels of Aflatoxins
Authors: Bicking Merlin K L , Kniseley Richard N , Svec Harry J 
Published: February 2020

Abstract
The combination of Styragel and Florisil columns allows recovery of aflatoxins at low levels. Two switching valves between the columns reduce the analysis time and exposure to solvents. Florisil is modified with oxalic acid, allowing recovery of aflatoxins at levels below 500 pg. The method is useful for contaminated corn and peanut meal samples.
Critical Re-appraisal of Fluorometric Method for Determination of Selenium in Biological Materials
Authors: Koh Tee-Siaw , Benson T H 
Published: February 2020

Abstract
The reaction of 2,3-diaminonaphthalene (DAN) with Se(IV) to form a fluorescent Se-DAN complex is the basis of a fluorometric method for determination of Se. With the aid of metabolically incorporated 75Se the method was critically re-examined. The study showed that loss of 75Se was negligible when liver or blood was microwave-dried or thermally dried at temperatures up to 120°C; during HC1 reduction of Se(VI) to Se(IV), a temperature up to 210°C could be used with no loss of 75Se; it was unnecessary to perform pH adjustment of solution for formation of Se-DAN complex before solvent extraction; it was unnecessary to carry out the chelation/extraction step in diffuse light; solvent phase containing Se-DAN complex could be left in contact with aqueous phase up to one week under fluorescent light with no effect on analytical results. From this study we were able to dispute or overcome a number of criticisms and myths which have been laid against the fluorometric method for many years. As a result, an improved single tube method was developed. The withinbatch variation of the improved method was about 2%, while the between-batch variation over a period of 2 years was less than 10%. The method can handle 200 samples per batch and is applicable to a wide range of biological samples including liver, orchard leaves, barley, wheat, lucerne (alfalfa), poultry feed, fish, hair, blood, urine, and milk.
Identification of Pacific Rockfish (Sebastes) Species by Isoelectric Focusing
Authors: Lundstrom Ronald C 
Published: February 2020

Abstract
Isoelectric focusing (IEF) is currently the most reliable method available for the identification of fish species. The high resolution of this method usually allows discrimination between even closely related species. One genus, the Sebastes, does present a problem however. Using both low and high resolution, IEF is unable to differentiate several species. Disc electrophoresis, used in an AOAC official final action method, does not differentiate the rockfish reliably. Using IEF, identical protein patterns were obtained for Pacific Ocean perch (Sebastes alutus), Bocaccio rockfish (S. paucispinis), and yelloweye rockfish (S. ruberrimus). A second group, comprised of silvergray rockfish (S. brevispinis), yellowtail rockfish (S. flavidus), black rockfish (S. melanops), and canary rockfish (S. pinniger), also has identical protein patterns. Widow rockfish (S. entomelas) and chilipepper rockfish (S. goodei) each had a unique pattern, different from the above 2 groups and from each other. The actual taxonomic relationships of these rockfish species are not clear and further work with IEF may help in this regard. Users of IEF and disc electrophoresis for identification purposes should be aware of this problem when working with the Sebastes.
Reverse Phase High Pressure Liquid Chromatographic Determination of Vitamin K1 in Infant Formulas
Authors: Bueno Martin P , Villalobos Melina C 
Published: February 2020

Abstract
A reverse phase high pressure liquid chromatographic (HPLC) method for quantitating vitamin K1 in enzymatic hydrolysates of infant formula is described. The vitamin is extracted with n-pentane before determination by isocratic and isothermal reverse phase HPLC. Recovery of vitamin Ki added io 5 infant formulas ranged from 84 to 103%
Improved Apparatus for Rapid Mercury Determination by Cold Vapor Atomic Absorption Spectrometry
Authors: Kupchella Lawrence , Syty Augusta , Mahfood John J 
Published: February 2020

Abstract
A glass reaction vessel is described and the convenience and simplicity of its use in cold vapor atomic absorption spectrometric determination of mercury are pointed out. The vessel is easy to construct and requires only 15 s for collection of the analytical signal. It provides for continuous flow of carrier gas, and contains a septum-covered sample injection port, a buret for rapid introduction of reagent, and a drain stopcock. Using this apparatus, the relative standard deviation is 2.9% at the 40 ng Hg/mL level. The detection limit is 1 ng/mL. Applicability of the apparatus is proved by analysis of 3 commercial waste water quality control samples.
Reverse Phase High Pressure Liquid Chromatography and Fluorescence Detection of Ethoxyquin in Milk
Authors: Perfetti Gragia A , Joe Frank L , Fazio Thomas 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method has been developed for the determination of ethoxyquin (l,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) in milk. Milk solids are precipitated by adding acetonitrile, and the water-acetonitrile supernate is washed with hexane to remove fat. Addition of sodium chloride causes the water-acetonitrile solution to separate into an aqueous phase and an acetonitrile phase, thus separating ethoxyquin from most water-soluble impurities. A large volume of water is then added to the acetonitrile layer and ethoxyquin is partitioned into hexane, which is removed at reduced pressure. The residue is dissolved in the mobile phase and analyzed on a 4.6 mm id × 250 mm Ultrasphere ODS column using fluorescence detection (excitation 230 nm; 418 nm cutoff filter). Water-acetonitrile with a diethylamine-acetic acid buffer is the mobile phase. Recoveries from samples fortified at 1, 5, and 10 ppb averaged 78% with a coefficient of variation of 5.0%. Low levels (&lt;1 ppb) of apparent ethoxyquin were found in commercial milk samples that were analyzed by using the method.
Detection and Determination of Error in Analytical Methodology. Part I. In the Method Verification Program
Authors: Cardone Mario J 
Published: February 2020

Abstract
A total method verification program is presented, composed of the initial developing laboratory’s method validation process and the end user’s method evaluation studies. Both processes escalate in a cyclic fashion and the communicative pathway is the method transfer process. The participating laboratories acquire data by the intralaboratory procedures described and the cross-over studies entail the interlaboratory (collaborative) procedures described. During the entire process, the diagnostic techniques described result in the detection and determination of error in the methodology.
Effects of Grinding and Storage for One Month on Retention of Vitamin A in Premixes and Mineral Supplements
Authors: Parrish Donald B , Patterson Karen 
Published: February 2020

Abstract
Tested standardized procedures for handling premixes and mineral supplements from time of sampling to time of analysis for vitamin A have not been developed, which could account for some unexplained inconsistent and low analytical results. Grinding premix samples and storing them in a freezer for one month had little effect on amount of vitamin A found, but there was a significant loss (about 10%) after storage for one month at room temperature. Results on replicated determinations of vitamin A in unground and ground mineral supplements and on effect of storage were somewhat more variable than for premixes, but only the loss (about 12%) during storage for one month at room temperature was significant.
Liquid Chromatographic Determination of 2,4-Dinitro-l-Naphthol and 1-Naphthol in External D&C Yellow No. 7
Authors: Goldberg Allen L , Calvey Robert J 
Published: February 2020

Abstract
A sensitive, reproducible method that uses liquid chromatography in the reverse phase mode with a C-18 column is described for determining 2,4-dinitro- 1-naphthol and 1-naphthol in Ext. D&C Yellow No. 7. With this method, these 2 compounds are eluted in a reproducible pattern by increasing the organic nature of a buffered mobile phase. Average recoveries of 2,4-dinitro-l-naphthol and 1-naphthol added to samples of Ext. D&C Yellow No. 7 at levels ranging from 0.003 to 0.20% were 103.9 and 94.7%, respectively.
Gas Chromatographic Determination of Glucono-δ-Lactone in Foods
Authors: Tsuda Taizo , Nakanishi Hiroshi 
Published: February 2020

Abstract
A method is described for the gas chromatographic (GC) determination of glucono-δ-lactone in foods. A sample was homogenized with 60-70°C water and filtered. The filtrate was buffered with NH4OHNH4CI pH 10 solution, and was passed through a QAE-Sephadex A25 column. The column was washed with water and glucono-δ-lactone was eluted with 0.1N HC1. An aliquot of the eluate was evaporated to dryness and derivatized with pyridine, N,O-bis(trimethylsilyl)trifluoroacetamide, and trimethylchlorosilane at room temperature. GC separation of glucono-δ-lactone as the TMS derivative was performed on a 2% OV-17 column at 180°C. Recoveries from bread, jelly, soybean curd, and other foods fortified with 0.1% glucono-δ-lactone ranged from 92 to 106%, with standard deviations from 2.2 to 9.8%. The detection limit was approximately 0.025%.
Retention Indexes for Electron Capture Gas Chromatography on Programmed Temperature High Resolution Capillary Column
Authors: Nakamura Akio , Tanaka Ryoichi , Takashi Kashimoto 
Published: February 2020

Abstract
A simple method and a series of compounds for a retention indexing study on a linear programmed capillary gas chromatograph are described. References are chlorobenzenes and decachlorobiphenyl, which show the same behavior in this system as Kovat's references (n-alkanes). This retention index system and gas chromatograph with cryogenic coolant apparatus and electron capture detection, is suitable for measuring the retention index of various compounds with characteristic detection ranging from low volatility to high molecular weight.
Simple Colorimetric Method for Determination of Metaproterenol Sulfate in Pharmaceuticals
Authors: Sane Ramesh T , Sawant Satish V , Doshi Vipul J , Mhalas Jagannath G , Paarikh Ajay K , Gijare Ashok S , Deshpande Deepak S 
Published: February 2020

Abstract
A simple coiorimetric method is described for the determination of metaproterenol sulfate (orciprenaline sulfate). The method is based on measurement of a colored species formed when metaproterenol sulfate is treated with diazotized dapsone, p-nitroaniline, or benzocaine at room temperature, followed by treatment with an aqueous solution of trimethylamine in the case of benzocaine. Compounds such as starch, talc, and common excipients do not interfere in the reaction. Statistical validation showed that the method was precise and accurate. The results agree well with those obtained by other methods reported in the literature.
First Derivative Spectrophotometric Determination of Strychnine and Brucine in Nux Vomica Liquid Extract
Authors: Korany Mohamed A , Seif El-Din Ahmed A 
Published: February 2020

Abstract
A simple, rapid, and accurate method is presented for determining strychnine and brucine in nux vomica liquid extract. The 2 alkaloids are directly extracted from the alkaline liquid extract with 0.1N H2S04, and the liberated alkaloids are determined separately using first derivative spectrophotometry. The minimum strychnine and brucine concentrations detectable by means of this method are 3.0 μg/mL. The method has been successfully applied to the analysis of 3 batches of nux vomica liquid extract.
Confirmatory Method for Sulfamethazine Residues in Cattle and Swine Tissues, Using Gas Chromatography-Chemical Ionization Mass Spectrometry
Authors: Stout Steven J , Steller William A , Manuel Arthur J , Poeppel Manfred O , Dacunha Andrian R 
Published: February 2020

Abstract
A gas chromatographic (GC) method has been reported for the determination of sulfamethazine residues in cattle and swine tissues. The extracts from this procedure were found to be directly amenable to examination by gas chromatography–mass spectrometry (GC-MS), allowing positive confirmation of an apparent residue of sulfamethazine. Chemical ionization mass spectrometry (CIMS) was chosen as the MS technique because it generated an ion indicative of intact sulfamethazine and fragment ions indicative of the amine functionality and sulfanil moiety. Positive ion (PI) chemical ionization mass spectrometry was adequate by itself for a confirmatory technique. Negative ion (NI) chemical ionization mass spectrometry alone could not be used for the confirmatory analysis of sulfamethazine, but it did offer a means to check the quantitative data from the positive ion analyses and provided complementary confirmatory data. Satisfactory recoveries were obtained for sulfamethazine in swine and cattle tissues at the tolerance level of 0.1 ppm. Apparent sulfamethazine residues in control tissues were less than 0.01 ppm.
Determination of Citrinin in Corn and Barley on Thin Layer Chromatographic Plates Impregnated with Glycolic Acid
Authors: Gimeno Alberto 
Published: February 2020

Abstract
A method is described for the determination of citrinin in corn and barley. The mycotoxin is extracted with a mixture of acetonitrile-10% glycolic acid in water, defatted with isooctane, and transferred to chloroform according to published methods. The mycotoxin is separated by thin layer chromatography (TLC) on plates previously impregnated with 10% glycolic acid solution in ethanol; identity is confirmed by chemical tests. Citrinin is then quantitated by the limit detection method. Recoveries of citrinin from corn and barley samples spiked at levels of 50, 80, 150, 300, 500, and 1000 μg/kg were in the range 91-98%. The minimum detectable concentration is 15-20 μg/ kg. Recoveries obtained with and without glycolic acid in the extraction solvent were compared. Sensitivities on TLC plates (limits of detection, μg/spot) impregnated with glycolic acid were compared with those on plates impregnated with oxalic acid.
Improved Reverse Phase Liquid Chromatographic Determination of Vitamins A and D in Fortified Milk
Authors: Wickroski Alphonse F , Mclean Lucia A 
Published: February 2020

Abstract
A method for determination of vitamins A, D2, and D3 on the same 6 mL sample of fortified milk is described. A special indicator permits selection from the cleanup column of a fraction that contains all vitamin D and is free of cholesterol interference for final measurement by reverse phase liquid chromatography. Conservation of analyst's time and expensive solvents results from the relatively small sample processed. The average recoveries and standard deviations were, respectively, 94.1% and 4.8 for vitamin D2, 91.1% and 5.2 for vitamin D3, and 92.2% and 2.6 for vitamin A in nonfat skim milk; 86.5% and 9.4 for vitamin D2, and 83.7% and 4.9 for vitamin D3 in homogenized whole milk. Detectable minima are about 100 IU vitamin A/qt and 50 IU vitamin D2 or D3/qt.
Protein Efficiency Ratio: AACC/ASTM Collaborative Study
Authors: Hackler L Ross , Bodwell Clarence E , Happich Muriel L , Phillips John G , Derse Phillip H , Elliott James G , Hartnagel Ralph E , Hopkins Daniel T , Kapiszka Eugene L , Mitchell Geraldine V , Parsons Grace F , Prescher Elmer E , Robaidek Eugene S , Womack Madelyn 
Published: February 2020

Abstract
Eight laboratories (7 of the laboratories conducted animal experiments) participated in a collaborative study to standardize some of the methodology associated with animal bioassays for determining protein efficiency ratios and to suggest improvements which would reduce the variation among laboratories. One-, 2-, 3-, and 4-week protein efficiency ratios (PER) with 0-, 2-, or 4-day adaptation periods were obtained from each laboratory, respectively, for 6 protein sources: casein, lean beef, lactalbumin, textured vegetable protein, peanut flour, and wheat flour. Analyses were computed for PER and adjusted PER (APER). From the analysis of variance for PER and APER, significant (P &lt; 0.05) effects were observed due to laboratories, adaptation length, protein sources, and/or interactions among these variables. In general, APER values show much less variation among laboratories than PER values. The reproducibility and repeatability variances were significantly (P &lt; 0.05) greater for an assay length of 2 weeks than they were for 3- or 4-week assays. Two protein sources, casein and textured vegetable protein, were fed at both high (10%) and low (6%) levels of protein. Analysis of variance of PER values shows a significant (P &lt; 0.05) laboratory by protein level by assay length interaction.
Method for Determination of Organohalogen Pesticide Residues in Vegetable Oil Refinery By-Products
Authors: Young Susan , Marion Clower , Roach John A G 
Published: February 2020

Abstract
A method using gel permeation and Florisil column chromatographic cleanup techniques is described for determination of residues of nonpolar organohalogen pesticides and pesticide alteration products in vegetable oils and their refinery by-products. Supplemental Florisil separation and alkali cleanup techniques are used to facilitate determinations. Residues are determined with a 63Ni electron capture gas chromatographic detection system used in conjunction with 3 different gas chromatographic columns. Residue identities are confirmed by gas chromatography-mass spectrometry. Recoveries of 7 organohalogen pesticides, ranging from 90 to 103%, were determined by the supplemental Florisil separation technique to augment previously reported recovery data determined for initial GPC and Florisil cleanup steps. Soybean, peanut, and cottonseed deodorizer distillates and crude and refined oil, as well as additional refinery by-products, were analyzed. Nine to 13 organohalogen residues ranging from 0.5 to 6.3 ppm were determined in the 2 soybean deodorizer distillate samples used to develop and test the method. Identities of residues present at ≥0.3 ppm were confirmed by gas chromatography-mass spectrometry. An intralaboratory trial of the method provided additional recovery and residue determination data as follows: Recoveries ranging from 102 to 116% were obtained for 4 pesticides added to peanut oil deodorizer distillate. Residues determined in 1 soybean deodorizer distillate sample supported previously obtained data for this sample.
Reverse Phase Liquid Chromatographic Screening Procedure for Parts-Per-Million Levels of/P-ToIuidine in D&C Red No. 6 and D&C Red No. 7
Authors: Bailey John E 
Published: February 2020

Abstract
A reverse phase liquid chromatographic method is described for the determination of p-toluidine in D&C Red No. 6 and D&C Red No. 7. The procedure employs octylsilanized silica gel as the stationary phase and gradient elution with a mobile phase of aqueous acetonitrile solutions containing ammonium sulfate-sulfuric acid electrolytes (pH 2). The dye is first mixed with an aqueous extraction solution containing tetrabutyl ammonium sulfate and sulfuric acid and is then extracted with chloroform. The dye migrates to the organic layer, leaving theptoluidine in the aqueous layer as the protonated amine. The limit of determination for the method is 1.9 ppm. Recoveries of p-toluidine averaged 91.8% from samples of D&C Red No. 6 and 94.6% from samples of D&C Red No. 7
Atomic Absorption Spectrometric Determination of Arsenite in Water Samples by Graphite Furnace After Extraction with Ammonium sec-Butyldithiophosphate
Authors: Chakraborti Dipankar , Irgolic Kurt J , Adams F 
Published: February 2020

Abstract
Arsenite—but not arsenate, methylarsonic acid, or dimethylarsinic acid—is extracted from water samples by 5 mL of a 0.01M hexane solution of rec-dibutylthiophosphate. A 10 μL aliquot of the extract is injected into an atomic absorption spectrometer with a graphic furnace for the determination of arsenic. The calibration curve is linear to 1500 Dg As. Quantities of arsenic as low as 100 ng As (0.2 ppb As when contained in 500 mL) can be confidently determined. The method was tested with natural river water and synthetic river water. The relative standard deviations associated with the recoveries of arsenite from natural water and synthetic river water spiked with arsenite range from 4.8 to 8.0%. Ten to 15 arsenite determinations can be completed in 1h.
Alumina Blending Technique for Separation of Pesticides from Lipids
Authors: Gillespie Allesia M , Walters Stephen M 
Published: February 2020

Abstract
An evaluation of an extraction technique for elimination of lipids during pesticide residue analysis was undertaken, which included a study of the parameters involved in an attempt to optimize the separation and recovery of selected pesticides from lipid samples. The choice of alumina, the degree of water deactivation of alumina, the amount of alumina relative to the weight of sample taken, the volume and composition of extraction solvent, the blending time, and the filtration procedure were all significant factors. Optimization of these factors resulted in &gt;90% recoveries of selected chlorinated pesticides from fortified fatty samples. In addition, the amount of co-extracted lipid material was about one-third of that obtained with the official method (AOAC 29.014), and less analytical time was required for the extraction by the proposed technique. The formation of troublesome emulsions sometimes encountered with the official method was also eliminated.