bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Pressure Liquid Chromatographic Determination of Theobromine and Caffeine in Cocoa and Chocolate Products
Authors: Kreiser Wesley R , Martin Robert A 
Published: February 2020

Abstract
A method was developed for determining theobromine and caffeine in cocoa and chocolate products by high pressure liquid chromatography. After a simple hot water extraction, both theobromine and caffeine were separated by using a reverse phase Cl s column and a mobile phase of methanol-water-acetic acid (20+ 79+1). Theobromine and caffeine were quantitated at 280 nm; average recoveries were 98.7 and 95.0%; and coefficients of variation were 2.31 and 3.91%, respectively.
Fluorometric Determination of Methylergonovine Maleate and Ergonovine Maleate in Tablets and Injections
Authors: Kirchhoefer Ross D 
Published: February 2020

Abstract
A column cleanup, followed by a shakeout and fluorometric determination, has been developed to determine methylergonovine maleate and ergonovine maleate in tablets and injections. The ether eluate is extracted with tartaric acid solution. An aliquot is diluted with sodium tartrate solution, and this solution is excited at 325 nm. The resulting fluorescence is measured at 432 nm. Results obtained using this method compare favorably with those from the official NF XIV procedure and a semiautomated procedure. Recoveries of 100 and 99% were obtained from one sample each of spiked excipient tablets of methylergonovine maleate and ergonovine maleate, respectively.
Ion Selective Electrode for Determination of Chloride Ion in Biological Materials, Food Products, Soils, and Waste Water
Authors: Sekerka Ivan , Lechner Josef F 
Published: February 2020

Abstract
The chloride ion selective electrode is used for a rapid, simple, and reliable determination of chloride ion in biological materials (blood serum, urine, fish, and plant tissues), food products (milk, beef extract, nutrient broth and orange, tomato, and grapefruit juices), soils, and waste water (industrial and municipal). The method consists of treating the samples with perchloric acid (pH 1) and potassium peroxydisulfate and determining the chloride content either by a calibration curve or by known addition or analyte addition, using the chloride ion selective electrode. Such sample treatment eliminates most of the interferences occurring in the samples, including iodide, complexing and reducing compounds, and macromolecular and surface-active species. The method is suitable for a wide range of chloride concentration, e.g., 5010 ppm CI in nutrient broth and 4890 ppm in beef extract and as low as 12 and 80 ppm in soil extracts.
Electrolytic Determination of Surface Lead in Empty Metal Containers
Authors: Estiandan Fe S , Schafer Glen H , Gedang Delia B 
Published: February 2020

Abstract
The lead content of an empty metal container (tin can) can be determined by an electrolytic process using a constant voltage power supply and dilute acid electrolyte. The ionic lead in the solution after electrolysis is determined by anodic stripping voltammetry.
Semiautomated Analyses of Some Ergot Alkaloid Formulations
Authors: Kirchhoefer Ross D 
Published: February 2020

Abstract
The following pharmaceutical preparations were assayed using a modification of a semiautomated procedure for methylergonovine and ergonovine maleate: ergotamine tartrate tablets and injections, ergotamine tartrate tablets and suppositories with caffeine, methysergide maleate tablets, and dihydroergocornine-dihydroergocristine - dihydroergokryptine mesylate sublingual tablets. These formulations could be assayed by either the fluorometric or by the colorimetric procedure. Good results were obtained using the fluorometric and colorimetric methods for these compounds. The standard deviation for an ergotamine tartrate injection solution was 1.76, using the colorimetric system, with a mean of 98.7% of declared potency. The method compares favorably with the NF XIV procedure for ergotamine tartrate and caffeine tablets. In addition, low level dissolution rates can easily be determined on ergotamine tartrate and caffeine tablets using the fluorometric system.
High Pressure Liquid Chromatographic Determination of Polynuclear Aromatic Hydrocarbons in Oysters
Authors: Hanus James P , Guerrero Humberto , Biehl Edward R , Kenner Charles T 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) procedure is described for determining 13 polynuclear aromatic hydrocarbon (PNA) compounds in oysters at the 2 ppb level. These compounds are extracted from shellfish with acetonitrile and partitioned into petroleum ether; the petroleum ether is removed and the residue is saponified. The aromatic compounds are isolated by passing the saponified residue through silica gel and further purified and fractionated by μStyragel gel permeation chromatography. The individual PNAs are then quantitatively determined by using a reverse phase HPLC column coupled to fluorescence, spectrophotometric, and 254 nm absorbance detectors in series. Recoveries from spiked samples generally were &gt;80%.
Application of Vertical Plate Gel Electrophoresis to the Separation of Pigmented and Non-Pigmented Trout and Salmon Species
Authors: Coduri Richard J , Bonatti Karen , Simpson Kenneth L 
Published: February 2020

Abstract
Pigmented and non-pigmented trout and salmon species were obtained from the ocean and from aquaculture facilities. Sarcoplasmic extracts of each sample were made and protein separations were obtained using vertical plate gel electrophoresis (VPE); rainbow, brook, and brown trout were easily distinguished from coho, chinook, and sockeye salmon. No correlation or relationship appears to exist between pigment concentration and VPE protein pattern. These fish can thus be distinguished regardless of the level of pigmentation.
Spectrofluorometric Determination and Thin Layer Chromatographic Identification of Tyramine in Wine
Authors: Gonzalo Julian C Rivas , Moreno Concepcion Garcia , Cerro Auxiliadora Gomez , Font Abel Mariné 
Published: February 2020

Abstract
A method is described for determining tyramine in wine by sand column extraction in an alkaline medium with anhydrous sodium sulfate. Tyramine is identified and quantitated by spectrofluorometry after the final extract is reacted with α-nitroso-β-naphthol; identity is confirmed by thin layer chromatography. The average recovery was 98.93%. The method is applied to samples of 3 different wines obtained throughout the vinification process. Tyramine, which was not present in the must, appears in considerable quantities 15 days after the vinification process has begun.
Relative Productivity of Five Selective Plating Agars for the Recovery of Salmonella from Selected Food Types
Authors: Andrews Wallace H , Wilson Clyde R , Poelma Paul L , Romero Aida 
Published: February 2020

Abstract
During a 3-year period, the relative productivity of brilliant green (BG), bismuth sulfite (BS), Salmonella-Shigella (SS), Hektoen enteric (HE), and xylose lysine desoxycholate (XLD) agars for recovering Salmonella from 9 food types was determined. Following preenrichment, selective enrichment of food samples in tetrathionate broth followed by streaking to BS agar was the single most productive selective enrichment broth-agar combination for recovery of Salmonella in 5 of these food types. A study of the performance of these 5 agars used individually and in various combinations, showed that none of the 5 agars used individually nor any of the possible paired combinations of these agars could be used to satisfactorily detect Salmonella in the 9 food types. The use of all 5 agars was not necessary because one combination of 4 agars (BG, BS, HE, and XLD) recovered 100% of the Salmonella isolates, as compared with the number of Salmonella isolates recovered by the 5-agar combination, in each food category. This particular 4-agar combination, along with two 3-agar combinations (BG, BS, and XLD agars, and BS, HE, and XLD agars), were each able to recover more Salmonella isolates than the combination of BG, BS, and SS agars, the combination currently recommended by the AOAC. Finally, the relative costs of using these agars, singly and in various combinations, were determined.
Volumetric Method for Determining Traces of Organic Chlorine in Lipids
Authors: Cunningham Hugh M , Lawrence Guillaume L 
Published: February 2020

Abstract
The official AOAC method for determining chlorine in cake flour lipids has been modified to determine chlorine in lipids of animal carcasses cooled with chlorinated water. The sensitivity of the method has been improved 1000- fold to attain a detection limit of 2 ppm CI in lipids. Recovery of the fine silver chloride precipitate was improved through centrifugation rather than filtration. The official method also did not take into consideration that when the silver chloride precipitate is exposed to light, it is converted to free chlorine and silver. Recovery of organic chlorine ranged from 84.6% at 4.1 ppm to 100.1% at 100 ppm. A number of samples of commercially chlorinated beef, pork, and chicken and laboratory-chlorinated chicken were analyzed by this method. In all cases where the level of chlorination was sufficient to result in a chlorine level in lipids in excess of 2 ppm, the chlorine content of the carcass lipids was measurable.
Automated Urease-Chromous Method for Determining Nitrogen in Fertilizers
Authors: Wall Larry L , Gehrke Charles W 
Published: February 2020

Abstract
An automated urease-chromous colorimetric method (AUCM) has been developed for determining nitrogen in fertilizers. The method is applicable to fertilizer samples that contain only ammoniacal, nitrate, and urea nitrogen. The concept of this method, combining nitrate reduction and enzymatic urea hydrolysis to produce a single method for total nitrogen, is new. The AUCM is an almost totally automated method with only an acidic dissolution step as the manual sample preparation. The urea is hydrolyzed to ammonia and carbon dioxide with urease, and the nitrate is reduced to ammonia with chromous ion within the continuous flow analytical system. The final step, also within the analytical system, is the spectrophotometric measurement of the ammonia, employing the ammonia-salicylate-hypochlorite chemistry. The sampling rate is 30 samples/hr. The method is not applicable to fertilizer samples containing refractory organic nitrogen forms, water-insoluble nitrogen, or significant levels of biuret. The average per cent nitrogen recovery by the AUCM for ammonium nitrate-diammonium phosphate bulk-blended fertilizer samples was 99.7, suspensions and liquids 99.7, urea fertilizers 97.8, and urea-diammonium phosphate bulk blends 98. The relative standard deviation for the analytical system was 0.40%, and for the method, 0.70%. The sample preparation is short and simple. This method offers many advantages as a screening method for fertilizer industry and control laboratories.
Spectrophotometric Method for Hydroxymethylfurfural in Honey
Authors: White Jonathan W 
Published: February 2020

Abstract
A new method is described for hydroxymethylfurfural (HMF) in honey; accuracy and precision are improved over the most used optical and chemical methods. With a clarified honey solution containing 0.1% sodium bisulfite as reference and a similar solution without bisulfite as sample, a difference spectrum is obtained which represents only the HMF in the sample, without the interfering absorption of the honey. The average recovery was 97.5% for 24 additions to honey of 0.8-40 mg HMF/100 g. Forty honey samples ranging from 0 to 40 mg/100 g were analyzed by 3 methods with the following average results: Winkler optical method, 7.25; Winkler chemical method, 4.83; and new bisulfite method, 5.05 mg HMF/100 g honey. Values by the latter 2 methods did not differ at the P = 0.05 significance level.
Application of Orthogonal Functions to the Spectrophotometric Determination of Calciferol in Oily Injections
Authors: Hassan Sayed M 
Published: February 2020

Abstract
The method of orthogonal functions has been applied to the rapid spectrophotometric determination of vitamin D in oily injections. The method involves saponification of the sample and extraction of the unsaponifiable matter with ether. After cautious evaporation of ether, the residue is dissolved in isopropanol and the absorbance of the solution is measured in the range 246–296 nm at 10 nm intervals. For BPC injections, the saponification step may be omitted. A suitable dilution of the sample in isopropanol is measured in the range 250.5– 300.5 nm at 10 nm intervals. Accurate and precise results are obtained in both cases.
DC Polarography of Cephradine and Its Application to Capsules
Authors: Nuñez-Vergara Luis J , Squella Juan A , Gonzalez Ernesto M 
Published: February 2020

Abstract
A polarographic method has been developed for the quantitative analysis of cephradine and its dosage forms. Direct determinations on capsules are carried out; excipients and coloring matter do not interfere in the determination. The electroactive product is formed by acidic hydrolysis with 5.0N HCl and heating at 80°C for 60 min. Two polarographic waves are obtained: I = - 0.46 v and II = - 0.78 v vs. SCE. Both reduction waves are diffusion controlled. Wave I is preferred for analytical purposes. The precise chemical identity of the electroactive product has not been determined, but UV spectral data and the TLC Rf value are reported. A linear relation is established for levels of cephradine between 10-2 and 10-5M in 5.0N HCl.
Simultaneous Extraction and Fractionation and Thin Layer Chromatographic Determination of 14 Mycotoxins in Grains
Authors: Takeda Yuiko , Isohata Etsuko , Amano Ryuji , Uchiyama Mitsuru 
Published: February 2020

Abstract
A simple, systematic analytical method for multiple mycotoxins was developed for detecting 14 mycotoxins: aflatoxins Bl, B2, G1, and G2, sterigmatocystin, T-2 toxin, diacetoxyscirpenol, neosolaniol, fusarenon X, zearalenone, ochratoxin A, citrinin, luteoskyrin, and rugulosin. These mycotoxins were extracted with 20% H2SO4-4% KCl-acetonitrile (2+20+178), defatted with isooctane, and transferred to chloroform. The chloroform extract was cleaned up by silica gel column chromatography; the first 10 toxins were eluted with chloroform-methanol (97+3) and the remaining 4 toxins with benzene-acetone-acetic acid (75+20+5). Each fraction was analyzed by thin layer chromatography for the final determination. The method has been applied to polished rice, rough rice, corn, wheat, and peanuts as an analytical screening procedure. The detection limits in these commodities ranged from 10.0 to 800.0 μg/kg, depending on the mycotoxin, but all limits were superior to those obtained for the individual mycotoxins by using other methods.
High Pressure Liquid Chromatographic Determination of Aflatoxins in Corn
Authors: Pons Walter A 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method is proposed for determining aflatoxins in corn. The sample is extracted with methanol-10% NaCl (4+1) , pigments are precipitated with zinc acetate, and the extract is cleaned up on a small (2 g) silica gel column. Aflatoxins in the purified extract are resolved by normal phase HPLC on a microparticulate (10 μm) silica gel column with water-saturated chloroform-cyclohexane-acetonitrile solvent, and detected by fluorescence on a silica gel-packed flowcell. The method was compared with chloroform-water extraction of the official CB method on 15 samples of contaminated corn. In 5 of the 6 samples containing aflatoxins B1, B2, G1, and G2, methanol-10% NaCl extracted more aflatoxin than did cloroform-water, as measured both by HPLC and by thin layer chromatography. In samples containing only B1 and B2, the 2 extraction solvents were virtually equivalent. Agreement was good between HPLC and TLC for each extraction solvent. Average recovery of aflatoxins Bl, B2, Gl, and G2 added to yellow cornmeal at 3 levels was &gt;90%.
Comparison of Mineral Wool Insulations in the Forensic Laboratory: Second Collaborative Study
Authors: Miller Elmer T 
Published: February 2020

Abstract
A method for comparing mineral wool insulationswas collaboratively studied a second time.Specimens are examined microscopically forcolor, disposition of resin, fiber diameters,quantity of slugs, and other gross microscopiccharacteristics. The resin is burned off and thefibers are annealed at 500°C. The heat-cleanedfibers are examined for shortwave ultravioletfluorescence, microscopic appearance, solubilityin HCI, and indices of refraction according to45.002-45.007. Ten collaborators examined 9specimens of mineral wool, 4 of which werefrom one large lot of Owens-Corning Fiberglasand 2 of which were from a single Johns-Manville ceiling tile. The other 3 were fromdifferent sources. Eight collaborators correctlyconcluded that the Owens-Corning samplescould have had a common origin, that theJohns-Manville samples could have had a commonorigin, and that the others were of independentlydifferent origins. Two collaboratorsin the same laboratory, using other than therecommended equipment, concluded that theOwens-Corning samples were one class, that theJohns-Manville samples were one class, andthat the others were of different origin, but theyfound slight differences in the refractive indicesof the Johns-Manville samples and did not concludecommon origin for them. The method hasbeen adopted as interim official first action.
Teratology
Authors: Staples Robert E 
Published: February 2020

Abstract
Two categories of collaborative studies are defined. Examples of each type are presented through teratologic studies conducted at the National Institute for Environmental Health Sciences (NIEHS) in collaboration with an Environmental Protection Agency laboratory and a laboratory in the USSR. These studies and the few pertinent studies found in the literature point out the problem of obtaining repeatability and uniformity of results among tests conducted to determine teratogenic potential. Collaborating laboratories should take more time to select the procedures to be used, to standardize the intended protocol in greater detail, to train participating personnel uniformly, and to test for repeatability by use of a known teratogen, before tackling major interests. Establishment of an archives would improve duplication of published results by making available additional pertinent unpublished information. Finally, possible advantages of collaborative studies for the testing of teratogenic potential are offered.
Comparison of Carcinogenicity Studies with Aldrin and Dieldrin
Authors: Ritper David L 
Published: February 2020

Abstract
Laboratory testing of animals is the principal method used to identify chemical carcinogens. However conflicting results are often obtained. This is emphasized in a cross-comparison of 6 aldrin-dieldrin studies; 3 were positive for tumor induction and 3 were negative. Four components of the assays are examined: husbandry, compound administration, observation, and interpretation of results.
Induction of Enzyme Activity in Cell Culture: A Rapid Screen for Detection of Planar Poly chlorinated Organic Compounds
Authors: Bradlaw June A , Casterline James L 
Published: February 2020

Abstract
Induction of aryl hydrocarbon hydroxylase (AHH) activity in rat hepatoma cell line serves as a simple and rapid method to detect minute (pg) amounts of certain classes of compounds, e.g., dibenzo-p-dioxins, dibenzofurans, and biphenyls. This method may provide a quick screen for such substances in extracts from foods prior to chemical identification. AHH activity is measured by conversion of benzo[a]pyrene (BP) to 3-hydroxy BP in homogenized cell extracts from control and treated cultures and is reported as pmol product formed/mg protein/min. Substances screened by this method include polyhalogenated analogs of dibenzo-p-dioxin (24 compounds), dibenzofuran (11 compounds), biphenyl (7 compounds), and extracts from several food sources. Response of the most reactive compound, 2,3,7,8-tetrachlorodibenzop- dioxin (TCDD) was used to prepare a standard curve, and the AHH activity induced by mole doses of test substance is reported as an ED50 response (the estimated dose needed to produce 50% maximum enzyme induction). The AHH activity induced by food extracts is equated to the standard curve and reported as TCDD equivalents. A potent ED50 response in cell culture appears to correlate well with known toxic responses in other mammalian and avian systems for certain test substances. This correlalation suggests that the cell culture enzyme induction method is a useful model for screening food extracts that are suspected to be contaminated with polychlorinated planar substances. A collaborative study would demonstrate the reproducibility of the method.
Gas Chromatographic Determination of 1,4-Dioxane in Polysorbate 60 and Polysorbate 80
Authors: Birkel Thomas J , Warner Charles R , Fazio Thomas 
Published: February 2020

Abstract
A gas chromatographic method is presented for the quantitative determination of 1,4- dioxane in polysorbate 60 and polysorbate 80. Dioxane is isolated from the matrix by closedsystem vacuum distillation with water as the carrier solvent. The distillate is chromatographed on Chromosorb 104 and detected by flame ionization. Recoveries of dioxane from polysorbate 60 samples fortified at 0.5, 1, 2, and 20 ppm averaged 90, 91, 85, and 75%, respectively. Recoveries from polysorbate 80 fortified at the same levels averaged 100, 88, 95, and 95%, respectively. Samples of polysorbate 60 and polysorbate 80 were found to contain from 5.5 to 378 ppm dioxane.
Gas-Liquid Chromatographic Determination of Sorbic Acid and Sodium Benzoate in Table Sirup
Authors: Zygmunt Lucian C 
Published: February 2020

Abstract
A gas-liquid chromatographic method is described for the simultaneous determination of sorbic acid and sodium benzoate in table sirup. The preservatives are extracted from acidified sirup with ethyl acetate and are analyzed on a gas chromatograph equipped with a flame ionization detector and a glass column (4 ft × 4 mm id) containing 9% SP-1200 and 2% H3PO4 on Chromosorb W (AW). Coefficients of variation for sorbic acid and sodium benzoate are 0.62 and 0.41%, respectively. Analysis time is less than 20 min, with recoveries exceeding 90%.
Effects of pH and Sodium Chloride Concentration on the Reaction Between Nitrite and Sulfanilic Acid/N-(Naphthyl)ethylenediamine
Authors: Hildrum Kjell Ivar 
Published: February 2020

Abstract
The reaction between nitrite and sulfanilic acid/N-(naphthyl) ethylenediamine has been investigated. In buffer systems, the rate of the reaction was pH-dependent with an optimum at pH 3.0 (±0.2). Adding sodium chloride to the system significantly increased the rate of the reaction.
High Pressure Liquid Chromatographic Determination of Pentachlorophenol by Using Paired Ion Chromatography Reagents
Authors: Hayes Elmer H 
Published: February 2020

Abstract
A high pressure liquid chromatographic (HPLC) method for determining pentachlorophenol in formulations is described. Samples containing pentachlorophenol are accurately weighed in suitable volumetric flasks and diluted with dioxane. The sample is then injected onto a stainless steel column containing μBondapak C18. The mobile phase is 60% methanol/PIC A and 40% water/PIC A. This method is simple and eliminates many of the extractions required in other methods of analysis.
Atomic Absorption Spectroscopic Determination of Molybdenum in Plant Tissue and Blood Plasma
Authors: Khan Shahamat U , Cloutier Richard O , Hidiroglou Michel 
Published: February 2020

Abstract
A method is presented for determining molybdenum in plant tissue and blood plasma by flame and flameless atomic absorption spectroscopy (AAS). The samples are digested with HNO3- HClO4, and the metal is separated by chelation, extracted into methyl isobutyl ketone, and analyzed by AAS. Recoveries of molybdenum from fortified samples ranged from 92.0 to 98.9%. The limits of detection on the flame and graphite furnace were 10 and 2 ng/mL, respectively.