bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Identification of Maleic Acid in Pharmaceutical Maleate Salts
Authors: Brannon Wilson L , Schwartzman George , Levine Joseph 
Published: February 2020

Abstract
Difficulties are encountered in the USP melting point identification test for maleic acid extracted from chlorpheniramine maleate. A general procedure is described for the isolation and infrared identification of the maleic acid moiety of pharmaceutical salts from drug substances or dosage forms. This procedure permits the concurrent infrared identification of the amine moiety.
Collaborative Study of a Method for the Analysis of Metoxuron and Its Formulations
Authors: Sauer Horst H , Bosshardt Hans P 
Published: February 2020

Abstract
The method collaboratively studied is based on 3 steps: free interfering amines are removed by acid extraction; dimethylamine is liberated by alkaline hydrolysis; and the liberated amine is distilled into an absorbing solution and continuously titrated. Interfering byproducts are separately determined by a thin layer chromatographic method. Two samples of metoxuron, the technical active ingredient, and an 80% wettable powder, were analyzed by 18 collaborators from Europe, the United States, and South America; results were satisfactory with an overall coefficient of variation of about 0.8%. Only one outlier was noticed. The method was adopted in 1974 as a full CIPAC method. The method was adopted in 1975 as an official first action AOAC method.
Comparison of Antibiotic-Amended Potato Dextrose Agar and Acidified Potato Dextrose Agar as Growth Substrates for Fungi
Authors: Mislivec Philip B , Bruce Verneal R 
Published: February 2020

Abstract
Fifteen fungal species, all isolated from foods, were compared for their growth abilities on potato dextrose agar acidified to pH 3.5, and on nonacidified potato dextrose agar amended with 40 ppm Chlortetracycline hydrochloride. Comparisons were made at 16, 21, 26, 32, and 37°C. Of the 15 species, only Penicillium expansum exhibited better growth on the acidified medium than on the nonacidified antibiotic medium, while 9 species grew better on the nonacidified antibiotic medium. Five species grew equally well on either medium.
High-Performance and Gas-Liquid Chromatography of Methyl Parathion Formulations
Authors: Jackson Edwin R 
Published: February 2020

Abstract
Methyl parathion formulations (a synthetic sample, a technical material, and 6 emulsifiable concentrates) were analyzed by high-performance liquid chromatography (HPLC), gas-liquid chromatography (GLC), and infrared (IR) spectroscopy. The HPLC method used in ultraviolet detector and a Permaphase ODS column with a methanol-water mobile phase. The GLC method used an SE-30/OV-210 column and flame ionization detection. The IR spectrum was recorded at 8.16 μm. A synthetic sample formulated to contain 45.5% methyl parathion (analytical grade) was analyzed 8 times by each method. HPLC yielded an average value of 45.4%, GLC 45.9%, and IR 45.7%. Analyses of variance of this repeatability study showed that the differences between the GLC mean and both the theoretical value and the HPLC mean were small, but significant. Technical methyl parathion and 6 emulsifiable concentrates were analyzed in duplicate by each method. Variance calculations for each set of duplicates by each method indicate a high probability of difference in the methods. High results from the IR analysis are probably due to impurities in the technical material because analysis of the synthetic sample was satisfactory. The HPLC and GLC methods appear to be precise and will be studied collaboratively.
Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Simazine
Authors: Hofberg Arthur H , Heinrichs Lee C , Gentry Gene A 
Published: February 2020

Abstract
A gas-liquid chromatographic method for the determination of simazine in a wettable powder formulation containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The samples were dissolved in dimethylformamide containing dioctyl phthalate as an internal standard, chromatographed on Carbowax 20M, and detected by using a flame ionization detector. Analysis of the 2 samples, based on peak height measurements, showed the following results: 1.5% overall coefficient of variation, 1.03% coefficient of variation for random error, and 0.23% systematic error. Sample A was an 80% powder formulation; Sample B was a 5% dilution of Sample A by the addition of inert material. The coefficients of variation were 1.20% for Sample A and 1.54% for Sample B. The larger variation in Sample B most likely resulted from nonuniform mixing during the dilution of Sample A. Since all collaborators used the same reference standard, the variation found in Sample A is more indicative of the variability of the method. The method has been adopted as official first action.
Rapid Screening Procedure for the Determination of Preservatives in Ground Beef: Sulfites, Benzoates, Sorbates, and Ascorbates
Authors: Karasz Albert B , Maxstadt John J , Reher Juergen , Decocco Frank 
Published: February 2020

Abstract
A procedure is described for the examination of large numbers of ground beef samples for the 4 most commonly used preservatives. A single sample solution is prepared and aliquots are taken for the various tests. Sulfite is determined colorimetrically with acid-bleached p-rosaniline. Ascorbic acid is titrated with 2,6-dichloroindophenol. Benzoic and sorbic acids are measured by ultraviolet absorption. Negative samples are rapidly sorted out in this procedure and positive samples are completed for quantitative determination of the preservative. Recoveries are 95% for sodium sulfite, 103% for sodium benzoate, 90% for potassium sorbate, and 81 % expected recovery for sodium ascorbate. The limit of detection is 0.005% for potassium sorbate, and 0.01% for the 3 other preservatives.
Collaborative Study of the Determination of Color in White Wines
Authors: Wildenradt Herb L , Caputi Arthur 
Published: February 2020

Abstract
A collaborative study was conducted on the determination of color in white wines by transreflectometry. The instrument used is designed to give a photometric response approximating the International Commission on Illumination CIE-z tristimulus function and provides transmittance values obtained from a 2.5 cm sample pathlength. Seven collaborators analyzed 13 samples (10 wines and 3 potassium dichromate solutions). Average transmittance values of the samples ranged from 75.34 to 87.56%. The standard deviations obtained in the study varied from 0.20 to 0.67 % transmittance. In view of the simplicity and reproducibility of the method, it has been adopted as official first action.
Colorimetric Assay of Reserpine in Formulations and Biological Fluids
Authors: Karawya Mohamed S , Sharaf Abdel-Aziz A , Diab Aly M 
Published: February 2020

Abstract
Two colorimetric methods are presented for determining reserpine. In the first method, an iron hydroxamate complex is formed through the ester group in position 16 in the reserpine molecule. The color is measured at 535 nm (0.5–6 mg/25 ml). This method is useful for routine and control analyses of reserpine formulations. In the second method the tertiary amino group of reserpine reacts with 2% citric acid in acetic anhydride to form a red-violet complex which is measured at 505 nm (5–400 μg/10 ml). This method could be useful in measuring trace amounts of reserpine present in biological fluids.
Gas-Liquid Chromatographic Determination of Diethylstilbestrol at Low Levels in Mixed Feeds
Authors: Einig Richard G 
Published: February 2020

Abstract
A gag-liquid chromatographic method for the determination of diethylstilbestrol (DES) at 2 ppb in mixed feeds and ingredients is presented. The DES is extracted into ethanol, the solvent is evaporated, and the residue is redissolved in chloroform. The extract is purified by washing the chloroform solution with carbonate buffer and transferring the DES to sodium hydroxide. The sodium hydroxide is washed with chloroform, the pH is adjusted to 10.3, and the DES is transferred to chloroform. The extract is derivatized with heptafiuorobutyric anhydride, chromatographed on an SE-30 glass column, and measured with a 3H electron capture detector. The method has been used for routine testing of a wide variety of feeds and ingredients.
Gas-Liquid Chromatographic Determination of Alachlor (2-Chloro-2′,6′-diethyh-N-(methoxymethyl)-acetanilide) Herbicide Residues in Corn and Soybeans
Authors: Ammann Barbara Dohman , Call Daniel J , Draayer Hans A 
Published: February 2020

Abstract
A method has been developed for the extraction and determination of alachlor (2-chloro-2′,6′-diethyl-N-(methoxymethyl)-acetanilide) residues in green corn and soybeans. Residues are extracted with acetonitrile and cleaned up on a Fiorisil column. The methylene chloride extract is sufficiently clean for electron capture gas-liquid chromatographic analysis and for verification by thin layer chromatography. Average recoveries of spiked samples (0.2 ppm) were 69 and 82% for corn and soybeans, respectively. This procedure could be useful for the detection of the parent compound in these crops soon after field application, but it does not detect metabolites.
An Improved Protein Parameter for Analytical Control of Cured Pork Production
Authors: Perrin Carrol H , Kelly Patrick C 
Published: February 2020

Abstract
Protein content expressed on a fat-free basis, PRF, has been proposed as a control of weight gain or meat content of cured pork. However, PRf is complicated to use, since it is a direct measure of meat content of the fat-free part of the sample. It is doubtful that this was the intention of the control. We propose the use of protein, fat-corrected basis, PRC, which is directly related to meat content of the sample as well as to weight gain. This would mean that conclusions about product quality could be made with greater certainty. PRC = PR + kF, where PR = % meat protein, F = % fat, and k is a constant.
Uses of Field Desorption Mass Spectrometry in the Pharmaceutical Industry
Authors: Brent David A 
Published: February 2020

Abstract
Field desorption (FD) is a gentle method of ionizing molecules from the solid state. The method is still in its infancy and remains more of an art than a science. Purines, pyrimidines, pteridines, and nucleosides represent some of the compound classes which are studied repeatedly in our laboratory. Often the primary information sought is the molecular weight. Many of these compounds are thermally unstable or nonvolatile. In these instances, FD mass spectrometry has proven to be quite helpful. Molecular weights are obtained in a short time, eliminating the need for more time-consuming derivatization or chemical degradation methods. FD has been applied to the study of drug metabolism and has shown great promise in determining polar metabolites, including direct analysis of glucuronide, sulfate, and amino acid conjugates. Some problems have been encountered in handling samples of biological origins. Salt impurities introduced by the separation procedure may interfere with the desorption process. Cluster ions and background noise make it difficult to assign molecular ions, and some compounds do not yield molecular ions with FD.
High-Pressure Liquid Chromatographic Analysis of Urea Herbicides in Foods
Authors: Lawrence James F 
Published: February 2020

Abstract
A method is described for the direct analysis of the urea herbicides linuron, monuron, diuron, chlorbromuron, fluometuron, chloroxuron, and fenuron in cabbage, corn, potatoes, turnip, and wheat at 0.01–1.0 ppm. The samples are extracted with acetone; the filtrate is partitioned with hexane-methylene chloride (1+1) followed by 2 other extractions with methylene chloride. The organic phases are dried and concentrated for column chromatographic cleanup on 2 % deactivated Florisil. The column fractions are evaporated just to dryness and redissolved in 10 ml isooctane for high-pressure liquid chromatography on a 25 cm silica gel (5 μm) column. Isopropanol in isooctane is the mobile phase, and compounds are measured by ultraviolet absorption at 254 nm. Recoveries are &gt;80% in most cases. These results are confirmed by alkylation with sodium hydride-methyl iodide in dimethyl sulfoxide to form the methyl products which are analyzed by the same chromatographic system or by gas-liquid chromatography.
Reference Raman Spectra of Ten Phosphorus-Containing Pesticides
Authors: Nicholas Mark L , Powell David L , Williams Theodore R , Huff Sarah R 
Published: February 2020

Abstract
The Raman spectra of malathion, ethion, methyl parathion, parathion, EPN, O,O-diethyl-O-(2,4-dichlorophenyl) phosphorothioate, dichlorvos, mevinphos, tributyl phosphorotrithioite, and 2,4-dichlorobenzyltributylphosphonium chloride have been recorded. These spectra are presented, along with tables giving values for the frequencies.
Gas-Liquid Chromatographic Determination of Chlorphoxim Residues in Water and Fish by In-Block Methylation
Authors: Dale William E , Miles James W , Churchill Frederick C 
Published: February 2020

Abstract
A gas-liquid chromatographic method has been developed for the analysis of residues of chlorphoxim, 2-chloro-α-(((diethoxyphosphinothioyl)oxy)imino)-benzeneacetonitrile, in water and fish. The method is based on the in-block methylation of chlorphoxim with 0.01M trimethylanilinium hydroxide in methanol. The derivative, O,O-diethyl O-methyl phosphorothioate, was determined quantitatively by using a flame photometric detector specific for phosphorus. The in-block reaction is 70% efficient. Water samples were extracted with hexane; fish were extracted with methylene chloride and cleaned up on an acetonitrile-hexane partition column. Recoveries from water and fish samples spiked with chlorphoxim averaged 86.3 and 80.4%, respectively. Limits of detection were 10.0 ppb for 5 g samples of fish and 0.10 ppb for 300 ml water samples.
Gas-Liquid Chromatographic Determination of Azinphos Ethyl in Human Plasma and in Mouse Plasma, Tissue, and Fat
Authors: Stein Vincent B , Pittman Kenneth A 
Published: February 2020

Abstract
A new method for the determination of azinphos ethyl (O,O-diethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate) in human plasma and in mouse plasma, tissue, and fat has been developed. The method is based on extraction with benzene or hexane and cleanup of fat and tissue samples by a minicolumn containing Florisil and sodium sulfate. Azinphos ethyl is eluted from the column with 10% acetonitrile in benzene and is concentrated to an appropriate volume for gas-liquid chromatographic analysis, using a 63Ni electron capture detector and a glass column containing 3% OV-1 on Gas-Chrom Q. The method is sensitive to 0.005 ppm in human plasma, 0.01 ppm in mouse plasma, 0.08 ppm in mouse liver, 0.05 ppm in mouse brain, and 0.10 ppm in mouse fat. The limit of detection is 2 pg; mean recoveries ranged from 96 to 98%.
Gas-Liquid Chromatographic Determination of Chloramphenicol in Agricultural Crops
Authors: Sasaki Kumiko , Takeda Mitsuharu , Uchiyama Mitsuru 
Published: February 2020

Abstract
A method is presented for the gas-liquid chromatographic determination of chloramphenicol in agricultural crops. Chloramphenicol is extracted with ethyl acetate, cleaned up by silicic acid column chromatography, acetylated with acetic anhydride and pyridine, and then measured by gas-liquid chromatography with electron capture detection. Two stationary phases, DEGS + phosphoric acid and Reoplex 400, were used. The sensitivity was ca 8 ng (40% full scale deflection). The efficiency of the analytical method was evaluated by analyzing crops fortified with chloramphenicol. The average recovery ranged from 72% in unpolished rice to 86% in Chinese radishes.
Investigation and Identification of the Bromination Products of Dimethoxyamphetamines
Authors: Bailey Keith , Gagné Denise R , Pike Richard K 
Published: February 2020

Abstract
The qualitative analysis of the aromatic bromination products of the 6 isomeric dimethoxyamphetamines and their hydrochloride or hydrobromide salts is described. Their ultraviolet, mass, and proton magnetic resonance spectra are not sufficiently different for distinction but infrared spectra allow a positive identification to be made and reference spectra are provided for the bromination products of 2,4-, 2,5-, 2,6-, 4,5-, and 3,5-dimethoxyamphetamines. The application of gas-liquid and thin layer chromatography for the analysis of these products is discussed. The bromination of 2,3-dimethoxyamphetamine consistently gave mixtures which could not be separated satisfactorily; spectra are included for completeness of the comparison of products.
Gas Chromatographic Resolution of Organochlorine Insecticides on Mixed Phase Systems. II. OV-1/OV-25, OV-210/OV-25, and OV-225/OV-25 Systems
Authors: Yamato Yasuhiro , Suzuki Manabu , Watanabe Tadao 
Published: February 2020

Abstract
The resolution of organochlorine insecticides and related compounds on OV-1/OV-25, OV-210/OV-25, and OV-225/OV-25 mixed phase column systems was investigated. α-BHC, β-BHC, and γ-BHC (lindane) were resolved on the 0.5% OV-210/2% OV-25 system; α-BHC, β-BHC, and γ-BHC were separated on the 0.5% OV-225/2% OV-25 or 1% OV-1/2% OV-25 system. Heptachlor, heptachlor epoxide, aldrin, and endrin were resolved on the 0.5% OV-1/2% OV-25 system. Dieldrin was separated on the 5% OV-210/2% OV-25 or 5% OV-225/2% OV-25 system. DDT and its related compounds except p,p′-DDE and o,p′-DDE were resolved on the 5% OV-210/2% OV-25 or 0.5% OV-225/2% OV-25 system.
High-Pressure Liquid Chromatography of Benzo (a) pyrene and Benzo(ghi)perylene in Oil-Contaminated Shellfish
Authors: Guerrero Humberto , Biehl Edward R , Kenner Charles T 
Published: February 2020

Abstract
A high-pressure liquid chromatographic procedure is described for the determination of benzo (a) pyrene and benzo(ghi)perylene. These polynuclear aromatics are extracted with acetonitrile and partitioned into petroleum ether, the petroleum ether is removed, and the residue is saponified. The compounds are purified and isolated by passing the residue through a silica gel column and a high-pressure liquid chromatographic column, and detected by their ultraviolet absorption. Recoveries of standards through the procedure averaged 104%.
Simplex Optimization as a Step in Method Development
Authors: Dols Thomas J , Armbrecht Bernard H 
Published: February 2020

Abstract
In the course of method development, an optimization procedure should be performed before critical performance characteristics are measured. Interaction among the operational steps should be assumed to exist. The analysis of variance or the simplex procedures are designed to determine defined optimal responses. Other things being equal, the simplex method is more efficient in terms of the number of experiments required. This is due, in part, to the sequentially operated feedback strategy employed. Decisions are made according to 5 defined rules.
Rapid Determination of Butylated Hydroxyanisole, tert-Butylhydroquinone, and Propyl Gallate in Edible Oils by Electron Capture Gas-Liquid Chromatography
Authors: Page B Denis , Kennedy Barry P C 
Published: February 2020

Abstract
A rapid method is described for the determination of 2- and 3-tert-butyl-4-hydroxyanisole (2- and 3-BHA), tert-butylhydroquinone (TBHQ), and propyl gallate (PG) as their heptafluorobutyrates in edible oils. A solution of the oil in ether-benzene is treated with heptafluorobutyric anhydride (HFBA) in the presence of trimethylamine as catalyst. Excess HFBA is destroyed and a suitably diluted aliquot is analyzed by electron capture gas-liquid chromatography. An internal standard is added before derivatization to aid quantitation and identification of the antioxidants. Average recoveries from an oil spiked at 1, 5, 5, and 5 ppm TBHQ, 2-BHA, 3-BHA, and PG were 110, 105, 106, and 102%, respectively. At these low levels, however, some late-eluting peaks interfered. Butylated hydroxytoluene is not determined by this method.
Colorimetric Method for the Determination of Ethylene Dibromide Residues in Grains and Air
Authors: Rangaswamy Jois R , Vijayashankar Yadathora N , Muthu Mysore 
Published: February 2020

Abstract
A method based on the hydrolytic debromination of ethylene dibromide (EDB) in the presence of an oxidizing agent has been developed. Bromine liberated from inorganic bromide is used to brominate p-rosaniline. The intensity of the resulting violet-red bromo compound in chloroform is measured at 580 nm. The relationship between absorbance and concentration of EDB is linear in the range of 5–60 μg. The method is very sensitive and as little as 0.50 ppm unchanged EDB residue in a 20 g sample of fumigated grain and 1 ppm EDB in a 10 ml air sample can be detected.
Quantitative Determination of 4,4′-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 5 by Ion Exchange Chromatography
Authors: Fratz D Douglas 
Published: February 2020

Abstract
An ion exchange chromatographic procedure separates 4,4′-(diazoamino)-dibenzenesulfonic acid (DAADBSA) from FD&C Yellow No. 5 and DAADBSA is determined spectrophotometrically. Recoveries of DAADBSA added to FD&C Yellow No. 5 at levels of 0.01 to 0.4% ranged from 90 to 130%. DAADBSA was found in commercial samples of FD&C Yellow No. 5 in amounts ranging from 0.006 to 0.022%.
A Review of Sampling Plans and Collaboratively Studied Methods of Analysis for Aflatoxins
Authors: Schuller Pieter L , Horwitz William , Stoloff Leonard 
Published: February 2020

Abstract
Aflatoxins are the only food contaminants being monitored routinely on an international scale with methods operating at the order of magnitude of 10 μg/kg. At this concentration level, methods of analysis which can achieve coefficients of variation of 30–40% with recoveries of 70% or greater in interlaboratory collaborative studies can be considered eligible for referee status. In most cases, sample reproducibility is the variable limiting the reliability of methods of analysis. The inherent uncertainty of the identity of chromatographically separated entities requires the application of confirmatory tests to verify that the characteristic measured results from the presence of aflatoxin. The methods are also inoperable without a verification of the identity, purity, and concentration of the reference standards used. Screening methods which reliably eliminate negative samples from further consideration are indispensible for the practical operation of monitoring programs.
Analysis and Optimization of a Quantitative Organic Soil Neutralization Test for Disinfectants
Authors: Whitmore Elaine J , Miner Norman A 
Published: February 2020

Abstract
An analysis and optimization of a test to quantitatively assess the resistance of disinfectants to neutralization by organic soil is presented. The recommended method uses sterile, dry baker’s yeast as a standard organic soil, and 24-hr cultures of Staphylococcus aureus and Pseudomonas aeruginosa as test organisms. The test determines the maximum per cent (w/v) of organic soil which a disinfectant can tolerate and remain able to kill about 106 test organisms/ml in 10 min at 25°C. This per cent is defined as the organic soil neutralization number. The procedure offers several advantages over other organic soil capacity tests.
Differential Pulse Polarography of Cacodylate Injections
Authors: Holak Walter 
Published: February 2020

Abstract
A method was developed for the analysis of cacodylate injections, using differential pulse polarography for measuring As (III). The cacodylate molecule is decomposed to As(V) by heating with Mg(NO3)2 · 6H2O; As(V) is then chemically reduced to As (III) and polarographed in 1M HCl supporting electrolyte. The method of standard addition is used for quantitation. Recoveries based on the analysis of synthetic cacodylic acid solutions containing approximately 9 mg arsenic/ml ranged from 99.1 to 101.7%.