bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forms of Iron in Beer
Authors: Gorinstein Shela 
Published: February 2020

Abstract
Different forms of iron (total, ionic, and complexed) were investigated by colorimetry, emission spectroscopy, spectrophotometry, and electrophoresis on agar gel with the following results: The lowest concentration of complexed iron occurs in the sample of highest colloid-protein stability (limit of precipitation) ; the colloid protein stability is directly dependent on the content of complexed iron in hordein-globulin fractions ; a decrease in hydrogen ion concentration leads to an increase in the content of complexed iron; a low redox potential corresponds to high protein stability ; the change in fractional protein composition depends on the amount of complexed iron; the content of proteins in salt and in alcoholic fractions increases with added ferric ions, resulting in decreased colloid protein stability.
Loss of Chloride in the Official Method for the Determination of Sodium Chloride in Cereal Foods
Authors: Brammell Wallace S 
Published: February 2020

Abstract
The official final action method for sodium chloride in cereal foods, 14.129, was found to give erroneously low results because of loss of chloride during ashing. Comparison of the data with values obtained by the official first action potentiometric method, 32.A01–32.A06, which does not require ashing, showed that large and variable losses of chloride occurred. Official ashing methods for other foods specify addition of sodium carbonate to prevent conversion of chloride to volatile forms, but this was not specified in 14.129. In the present study it was found that sodium carbonate did not completely prevent loss of chloride. The official first action potentiometric method, 32.A01–32.A06, has been adopted as official first action for the determination of chloride in cereal foods to replace 14.129, which was repealed, official first action. A cross-reference to 32.A01–32.A06 has been added to 14.096.
Improved Thin Layer Chromatographic Method for the Isolation and Estimation of Sterigmatocystin in Grains
Authors: Athnasios Albert K , Kuhn Gustav O 
Published: February 2020

Abstract
A modified thin layer chromatographic (TLC) method has been developed in conjunction with the method of Stack and Rodricks which effectively separates sterigmatocystin from interfering materials and eliminates the time-consuming column chromatographic cleanup step. Initial extraction with acetonitrile-water (9+1) containing KCl is followed by partition of the extract first against hexane and then against CHCl3. The CHCl3 extract is evaporated and the residue is dissolved in benzene and applied directly to pre-coated high resolution TLC plates, which are developed in benzene-acetic acid (90+10). Visualization of the sterigmatocystin on TLC plates is enhanced by an AlCl3 spray reagent, and concentrations of sterigmatocystin as low as 50 μg/kg can be estimated by comparing fluorescence intensity against a pure sterigmatocystin standard. The method has been applied to barley, white and yellow corn, oats, and wheat. Recoveries of added toxin in the range of 50—400 μg/kg ranged from 86.3% for yellow corn and oats to &gt;96% for barley, wheat, and white corn.
Semiautomated Fluorometric Analysis of Riboflavin in Nutrient Premixes Containing Reduced Iron
Authors: Roy Ram B , Buccafuri Anthony , Salpeter Jerry 
Published: February 2020

Abstract
A simple, rapid, and reproducible semiautomated method is described for routine analysis of riboflavin in premixes containing high levels of reduced iron. Reduced iron is separated from premixes by a magnet before digestion with sulfuric acid solution. The presence of ferrous sulfate, ferric pyrophosphate, and sodium ferric pyrophosphate in premixes did not affect the analytical results for riboflavin. Pretreating sample extracts with potassium permanganate and hydrogen peroxide gave variable results for riboflavin. Possible causes and mechanisms of iron interferences in fluorometric riboflavin analysis are briefly discussed. The procedure developed is capable of analyzing 40 samples/hr.
Collaborative Study of Assay Method for Erythromycin in Pelleted Feeds Containing Binding Agents
Authors: Winkler Victor W , Nyman Melvin A 
Published: February 2020

Abstract
A modified method for analysis of erythromycin in feeds containing the pelleting adjuvants bentonite and Masonex has been evaluated by collaborative study. Erythromycin is freed from the binding action of these adjuvants by an aqueous methanolic pH 8 buffer presoak before extraction with methylal. The recovery values for mash and pellets of 6 different sample types range from 86.6 to 103.0% of theory with a grand mean of 96.8%. This modification has been adopted as official first action.
Simple and Rapid Paper Chromatographic Method for the Simultaneous Determination of Histidine and Histamine in Fish Samples
Authors: Foo Lai Yeap 
Published: February 2020

Abstract
A simple and rapid method for the simultaneous determination of histamine and histidine in fish samples is described. The method entails paper chromatography and is sensitive from 0.5 μg to at least 30 μg. The method is reproducible to within ±5% and compares favorably with a biological method for histamine determination.
Determination of Dexamethasone in Milk by High Pressure Liquid Chromatography
Authors: DePaolis Anneli M , Schnabel Gabrielle , Katz S E , Rosen Joseph D 
Published: February 2020

Abstract
A rapid and sensitive high pressure liquid chromatographic method for the analysis of dexamethasone (9α-fluoro-11β,17α,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione) in milk has been developed. The corticosteroid can be quantitated at 20 ppb, with the limit of detectability estimated at 5 ppb. Recoveries ranged from 72 to 94%. After dexamethasone was injected into 5 Holstein-Friesian cows, no residues were found in milk, even after the first milking.
Collaborative Study of a Semiautomated Method for the Analysis of Prednisolone and Prednisone Tablets
Authors: Brower James F 
Published: February 2020

Abstract
A semiautomated colorimetric method for the determination of prednisolone and prednisone was collaboratively studied by 6 collaborators. In the method, an alcoholic solution of the drug is extracted with chloroform and the extract is reacted with tetramethylammonium hydroxide and blue tetrazolium; the absorbance of the resulting color is read at 525 nm. Collaborators were supplied with 4 composites of tablets of different dosage levels, 2 containing prednisolone and 2 containing prednisone. Results agreed with those obtained by the author using the CSP total steroid assay method. The coefficients of variation of the individual collaborator’s results for prednisolone and prednisone ranged from 0.54 to 2.38 and from 0.34 to 2.19%, respectively. This method has been adopted as official first action.
Identification of 1-(1-Cyanocycloalkyl)amines, Intermediates in the Synthesis of Phencyclidine and Its Analogs
Authors: Gagné Denise R , Pike Richard K 
Published: February 2020

Abstract
Eight 1-(1-cyanocycloalkyl)amines are identified by spectroscopic techniques. Their ultraviolet and mass spectra are similar, but proton magnetic resonance and infrared spectra are distinctly different; reference spectra and data are provided. Gas-liquid and thin layer chromatographic systems for their qualitative analysis are discussed.
Simple and Rapid Gas-Liquid Chromatographic Determination of Diethylstilbestrol in Biological Specimens
Authors: Kohrman Karen A , MacGee Joseph 
Published: February 2020

Abstract
Diethylstilbestrol (DES) is readily extracted into toluene from biological fluids or tissue homogenates. Sodium carbonate is added to the initial mixture to eliminate potentially interfering substances. The toluene is extracted with a very small volume of aqueous trimethylphenylammonium hydroxide. This solution generates dimethyl DES in the vaporizer of a gas-liquid chromatograph. An internal standard, dienestrol (DI), is added at the beginning of the procedure and is partitioned and methylated in the same manner as DES. The DES and DI derivatives are well separated in less than 6 min on an OV-17 column. The entire analysis requires less than 15 min for a fluid specimen and less than 25 min for a solid tissue specimen. Seven samples can be analyzed each hour on a single column with a flame ionization detector. The relative standard deviations at levels from 2.5 to 100 ppm in bile are &lt;5%. The lower limit of sensitivity is 8 ppb in a 1 ml bile sample.
Evaluation of Rapid Partitioning Cleanup Method for Pesticides
Authors: Friestad Håkon O 
Published: February 2020

Abstract
A partitioning cleanup method performed in test tubes with small solvent volumes, and using syringes instead of separatory funnels for phase separations, has been tested for potential as a general cleanup method for a variety of pesticidal compounds. More than 50% recoveries were obtained for most of the 60 compounds tested, even though minimal manipulation rather than maximum recovery was the aim. Since the recoveries usually are constant, procedural losses can be compensated for by correction factors.
Collaborative Study of a Method for the Detection of Clostridium botulinum and Its Toxins in Foods
Authors: Kautter Donald A , Solomon Haim M 
Published: February 2020

Abstract
The mouse toxicity and protection technique for the detection and identification of Clostridium botulinum and its toxins in foods was collaboratively studied by 11 laboratories. Each laboratory received 4 samples of cream of mushroom soup; 2 contained spores and toxin of C. botulinum type A, 1 contained spores and toxin of C. botulinum type E, and 1 contained spores of C. sporogenes. The media used were cooked meat medium (beef heart or chopped liver broth) and trypticase peptone glucose yeast extract broth with trypsin. The results indicate that this method has a high degree of repeatability and reproducibility. All 11 laboratories correctly identified the toxins and the nontoxic sample in the food and detected and identified the viable spores in the samples by means of the subsequent cultures. This method has been adopted as official first action.
Ball-Point Pen Ink Examination by High Pressure Liquid Chromatography
Authors: Colwell Lawrence F , Karger Barry L 
Published: February 2020

Abstract
High pressure liquid chromatography was applied to the analysis of ball-point pen inks. A written line was sampled by extracting 10 plugs punched with a syringe needle. All separations were performed on a 25 cm silica gel (10 μm) column with a mobile phase of 2% formamide in methanol. Differences in ball-point pen inks based on different dyes or relative dye amounts were easily established. Of special note was the ability to distinguish inks based on the ratio of vehicle (resins, viscosity adjusters, etc.) to dye or on the types of vehicles employed.
Analysis for Chloride Ion in High Purity Water and Heavy Water of Pressurized Reactors and Cooling Systems by Ion Selective Electrode
Authors: Sekerka Ivan , Lechner Josef F , Harrison Les 
Published: February 2020

Abstract
A rapid, simple, sensitive, and reliable determination of parts per billion (ppb) levels of chloride ion is described for high purity water or heavy water of pressurized and high temperature reactors, steam generators, and cooling systems by mercurous chloride-mercuric sulfide ion selective electrode. The method has been applied to heavy water samples of CANDU-type nuclear reactors as well as to the water of conventional steam generators. The manual method consists of treating 100 ml aliquots of standard solutions and water samples with 1 ml 2M HNO3. A calibration curve is constructed from the millivolt readings obtained in the standard solutions, and chloride ion concentration of the samples is determined by comparing the mv reading of the sample with the calibration graph. The automated and computerized version provides all operations automatically, together with a direct printout of the concentration and indexing. The electrode displays near-Nernstian response for the range 0.05–3.500 ppm chloride and can be used for concentrations as low as 0.02 ppm. Comparative tests and coefficients of variation are highly satisfactory.
Mass Spectral Coding Technique for Identification of Drugs and Related Compounds in Reference Compendia
Authors: Barron Robert P , Benson Walter R , Roach John A G 
Published: February 2020

Abstract
A modification of the spectral abbreviation technique originally described by Hites and Biemann is proposed for identifying compounds through a coding of mass spectral data. Data from 2 closely related compounds (trimethadione and paramethadione), acquired by using 3 instruments, are presented. The technique appears to overcome observed differences in low resolution spectra when the same compound is analyzed by electron impact on mass spectrometers differing in design, manufacturer, principle of ion separation, and operator. A list of spectra coded by this technique could constitute a rapid manual system of reproducing mass spectral data, using the significant high mass ions of low abundance as well as the frequently more abundant lower mass ions. This system is compared with existing systems.
Rapid Preparation of Micro Sample and Gas-Liquid Chromatographic Determination of Methoxychlor Residues in Animal Tissues and Water
Authors: Solomon John , Lockhart W Lyle 
Published: February 2020

Abstract
Methods are described for analyses of methoxychlor (2,2-bis(p-methoxyphenyl)-l,l,l-trichloroethane) in tissues of fish and invertebrate animals and in water samples. These micro methods offer economy in solvents and materials, and reduce health and fire hazards. Furthermore, the methods sufficiently reduce sample weights to allow analyses of small animals (mayflies) or animal organs. Samples are extracted in a ball-mill with n-hexane, and lipids are removed from fatty samples by freezeout. Small Florisil columns give final lipid cleanup and partial separation of methoxychlor from interfering materials. Methoxychlor is determined on a short gas-liquid chromatographic column (retention time 2.2 min). Animal tissue samples as small as 0.1 g and water samples of 5 ml can be analyzed at sensitivities of 10 and 1 ppb, respectively. Methoxychlor recoveries were 84–101% (fish and crab tissue), 92-100% (cod liver oil), and 98-107% (water) over a concentration range of 0–10 ppm. Results obtained for fish tissue by using micro procedures agreed to within 20% of results reported by an independent laboratory using an established method.
Quantitative Determination of Thiourea in Citrus Fruits
Authors: Mandrou Bernadette , Brun Suzanne , Kingkate Amara 
Published: February 2020

Abstract
A quantitative method for thiourea determination in orange peels is proposed, with direct reflectance spectrometric measurements on chromatoplates. Thiourea is separated on a silica gel plate with methanol-chloroform (10+90), and the spots are characterized with 2,6-dichloroquinone chloroimide; this colorimetric reaction is unstable, so thiourea is quantitated on the chromatogram by direct ultraviolet reflectance spectrometric measurements at 240 nm. Comparison between this method and the AOAC colorimetric method shows interferences and higher results in the colorimetric assay. By slightly modifying the extraction technique, such as purifying the extract on an alumina column, it is possible to decrease these interferences and to avoid erroneous results with the AOAC colorimetric method. For both methods, colorimetry in solution and reflectometry on chromatoplates, applied after the proposed extraction technique, the sensitivity is about 1 ppm and the reliabilities are similar.
Comparison of Igepal and Sodium Lauryl Sulfate as Defatting Agents in Extraneous Materials Analysis of Chocolate Liquor
Authors: Mastrorocco Donald A , Wagner Geraldine H 
Published: February 2020

Abstract
A detergent solution, 2% igepal CO 630, was compared with the AOAC-approved 2% sodium lauryl sulfate in the extraneous materials analysis of chocolate liquor. Thirty-two liquor samples were analyzed by one technician using both detergent solutions. No appreciable difference was noted between insect fragment and rodent hair counts obtained with the 2 detergent solutions. Igepal costs less and its use results in fewer filter papers to read. A wide range of insect fragment and rodent hair contamination should be studied with this reagent.
Thin Layer Chromatographic Determination of Aflatoxin B1 in Eggs
Authors: Trucksess Mary W , Stoloff Leonard , Pons Walter A , Cucullu Alva F , Lee Louise S , Franz Anthony O 
Published: February 2020

Abstract
A method for determining aflatoxin in dairy products was modified for eggs, initially by additional cleanup steps. The modified method proved practical for use in survey analyses and was sufficiently sensitive to detect aflatoxin B1 at levels less than 1 ng/g in eggs from hens on experimentally contaminated feed and in spiked eggs; interfering compounds in eggs received from many different producing areas were eliminated. Although recovery was greater than 75% when the aflatoxin was extracted immediately after spiking, recovery was usually less than 30% when the aflatoxin was extracted after more than 24 hr. Adding sodium chloride, sodium sulfate, or urea to the extracting solvent remedied this defect, which is thought to be related to the binding of aflatoxin to egg protein.
Analysis of Foods for Arsenic and Selenium by Acid Digestion, Hydride Evolution Atomic Absorption Spectrophotometry
Authors: Ihnat Milan , Miller Hanford J 
Published: February 2020

Abstract
A method based on acid digestion, hydride evolution atomic absorption spectrophotometry for estimating microgram and submicrogram quantities of As and Se in foods was developed and evaluated. Samples up to 3 g dry weight were digested with HNO3-HClO4-H2SO4. As and Se in aliquots of the digests were reduced with NaBH4 to volatile hydrides, using laboratory-constructed and commercially available generators. As and Se were estimated by transient signal atomic absorbance measurements as the hydrides were decomposed in an Ar-H2-entrained air flame. Recoveries of inorganic As and Se added at levels of 0.1—1.0 μg/g to a variety of foods ranged from 70 to 125%. Analyses of several standard reference samples indicated the method is capable of recovering native analytes. Detection limits for the determinative step and the method as a whole were as low as 5 and 25 ng, respectively, for both elements.
Gas-Liquid Chromatographic Determination of α-Cyano-3-phenoxybenzyl α-Isopropyl-4-chlorophenylacetate Residues in Cabbage
Authors: Talekar Narayan S 
Published: February 2020

Abstract
A gas-liquid chromatographic method is described for residues of a synthetic pyrethroid, Sumicidin (α-cyano-3-phenoxybenzyl α-isopropyl-4-chlorophenylacetate), on cabbage. The plant material is Soxhlet-extracted with hexaneacetone (1+l) and subsequently cleaned up on Florisil with benzene-ethyl acetate (9+1) eluting solvent. Gas-liquid chromatographic analysis was performed on a 0.5 m × 2 mm stainless steel column containing 3% OV-101 + 3% Apiezon L on 80–100 mesh Gas-Chrom Q, with tritium electron capture detection. Sumicidin recovery was 97% when added at the 0.5 ppm level. Routine Sumicidin residue monitoring data presented.
Liquid Chromatographic Determination of Azinphos Methyl Oxon in Foliar Dislodgeable Residues and in Soil Surface Dusts from an Azinphos Methyl-Treated Orange Grove
Authors: Kvalvåg John , Ott Daniel E , Gunther Francis A 
Published: February 2020

Abstract
Specific parts of the worker environment in an orange grove that had been sprayed with azinphos methyl formulation were tested for azinphos methyl oxon. Extracts of soil surface dusts and dislodgeable residues from orange leaf surfaces were prepared and analyzed by liquid chromatographic procedures incorporating an ultraviolet absorption detector primarily for quantitation and an on-stream chemical reaction detector primarily for confirmation. Azinphos methyl oxon residues were found in both types of samples collected 3–59 days after spraying. Foliar dislodgeable residues of the oxon ranged from a high of 0.057 μg/sq cm of leaf surface on the 17th day to a low of 0.014 μg/sq cm on the 59th day for trees treated with a low-volume spray. The corresponding range in soil dust samples was 5.2 μg/g (ppm) of dust on the 10th day to 1.4 μg/g on the 59th day. Values were 9.7 and 2.7 μg/g, respectively, for samples from under trees similarly treated with a high-volume spray.
Microbiological Assay for Saponin in Alfalfa Products
Authors: Livingston A Lyle , Whitehand Linda C , Kohler George O 
Published: February 2020

Abstract
A bioassay is described for determining medicagenin-type saponin in dried alfalfa, leaf protein concentrates, and alfalfa sprouts. Samples are extracted by refluxing 2½ hr with 50% ethanol, ethanol is evaporated, and aliquots of an aqueous solution are added to potato dextrose agar (PDA) and assayed for saponin by using the fungus Trichoderma viride. The growth of the fungus on PDA is compared with a standard saponin, and saponin levels are calculated by means of a slope ratio analysis.
Collaborative Study of Determination of Amount of Seafood in Seafood Cocktails
Authors: King Frederick J , Regan Paul J 
Published: February 2020

Abstract
Method 18.B02–18.B03 for shrimp in shrimp cocktail was used to determine the amount of seafood ingredient in 6 seafood cocktails: clam, crab body meat, crab leg meat, fish, oyster, and shrimp. Duplicate samples of each kind of seafood cocktail were studied by 10 collaborators. Their results indicate that the method is suitable for a variety of seafood cocktails if 2 revisions are made. A revised version of 18.B02— 18.B03 was adopted as a procedure for seafood in seafood cocktails other than shrimp.
Collaborative Study of the Differential Pulse Polarographic Analysis of Cacodylate Injections
Authors: Holak Walter 
Published: February 2020

Abstract
Samples containing cacodylate are heated with magnesium nitrate to decompose the cacodylate moiety, releasing pentavalent arsenic. The arsenic is reduced to the polarographically active trivalent state by heating with hydrobromic acid and hydrazine sulfate. Differential pulse polarography is performed in a 1M HQ supporting electrolyte, using a standard addition method for quantitation. The results from 6 collaborators showed an average of 97.00% of declared potency for commercial ampoules, with a relative standard deviation of 2.99%. Two synthetic cacodylic acid solutions prepared to contain 9.01 and 30.02 mg/ml gave averages of 100.03 and 99.38% of amount added, with relative standard deviations of 1.56 and 1.42%, respectively. The method has been adopted as official first action.
Interference by Acetylated Aminoacetic Acid in Nonaqueous Titration of Nicotinic Acid
Authors: Soliman Sobhi A , Abdine Hassan , Morcos Magdi G 
Published: February 2020

Abstract
A nonaqueous titration procedure is described for determining aminoacetic acid and nicotinic acid in mixtures and elixirs. The effect of acetylated aminoacetic acid on the potentiometric titration of nicotinic acid is discussed. Above a 2:1 ratio of aminoacetic acid to nicotinic acid, the former interferes with titration. The titration curve of nicotinic acid becomes progressively flatter with increasing amounts of the acetylated compound. Above this ratio, nicotinic acid had to be separated from the mixture by dissolving in ethanol for a successful titration.
Gas-Liquid Chromatographic Determination of β-Asarone in Wine: Collaborative Study
Authors: Dyer Randolph H 
Published: February 2020

Abstract
The gas-liquid chromatographic determination of β-asarone (cis-2,4,5-trimethoxy-l-propenylbenzene) in wine was collaboratively studied by 9 analysts. The samples were first distilled and then extracted into hexane prior to chromatography. The mean recovery for 8 spiked samples, analyzed as blind duplicates, was 89.27%. The reproducibility coefficient of variation was 17.9%, and the repeatability coefficient of variation was 8.3%. No unfavorable remarks were noted. The method has been adopted as official first action.