bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method for Testing the Purity of Israeli Citrus Juices
Authors: Lifshitz Abraham , Stepak Yedael , Brown Morton B 
Published: February 2020

Abstract
An extensive study of Israeli orange and grapefruit juices has been carried out in the last 7 years (1966-1973). About 1000 samples of natural citrus juices were examined for a large number of analytical parameters. On the basis of statistical evaluation of the data of the first year and consideration of their ease of performance, 5 analytical parameters were selected: Brix, formol number, chloramine T number, total sugars, and chlorides. A multivariate normal test was performed under which adulteration or dilution of 15% or more is very likely to be detected at a 1 % level of significance. Analytical results obtained each subsequent year were integrated into multiyear results. Pasteurization of the juice and storage for 6 months did not affect the power of the method.
Modification of the Gutzeit Arsine Generation Method for Improved Recoveries of Arsenic
Authors: Ishida Kohzoh , Braun Heinz E 
Published: February 2020

Abstract
A minor modification in the arsine generation method is described which permits improved recoveries (average of 9%) of arsenic in fortified and field-treated soil samples. The modification involves the controlled addition of hydrochloric acid to permit a less vigorous reaction with the zinc and the formation of arsine gas at a slower rate.
Rapid Method of Screening Forage Breeding Material, Using a Fibrometer
Authors: Arora Surendra K , Das Bhagwan 
Published: February 2020

Abstract
A simple device, a fibrometer, has been devised for measuring the bulk value of a forage sample. The bulk value obtained by using the fibrometer was significantly and negatively correlated with acid-detergent fiber and cellulose. It was also significantly and positively correlated with in vivo and in vitro dry matter digestibility. This method reduces the effort required to analyze a large number of breeding materials for nutritional value and is also economical.
Confirmation of Chlorinated Paraffins by Dechlorination
Authors: Zitko Vladimir 
Published: February 2020

Abstract
Confirmation of chlorinated paraffins (C20舓C28) by dechlorination with sodium bis(2-methoxyethoxy) aluminum hydride is described. The minimum amount of chlorinated paraffins required for the test is 10 μg. Chlorinated paraffins containing up to 50% chlorine yield paraffins, unsaturated hydrocarbons, and hydroxy compounds. Maximum yield of straight chain C20舓C28 paraffins is obtained after 2 hr at 150°C. Chlorinated paraffins containing 70% chlorine yield unsaturated hydroxy compounds with fluorescence excitation and emission maxima at 320舓340 and 420舓450 nm, respectively. The presence of chlorinated paraffins in an antifouling paint was confirmed by the described procedure. The technique can also be used to analyze lipid-containing extracts of biological samples.
Determination of Selenium in Animal Feed Premix by Atomic Absorption Spectroscopy
Authors: Ng Samuel , Munroe Maurice , McSharry William 
Published: February 2020

Abstract
An atomic absorption spectrophotometry method for the determination of selenium in animal feed premixes is described. The method involves digesting the samples by heating with perchloric acid and hydrogen peroxide. No pre-concentration or separation is required other than filtering the insoluble material remaining after digestion. Concentrations from 0.0057 to 0.42% selenium were measured. The relative standard deviation over this range averaged 4.6%. A matrix effect, which could be overcome by either preparing the standards with a matrix or using the standard addition technique, was noted at ≤0.02% selenium. The results obtained by each method and by x-ray fluorescence are shown and compared with the claimed selenium content. When the matrix effect is overcome, results by atomic absorption spectroscopy and x-ray fluorescence agree within 15% or better at all levels.
Simple and Fast Fluorometric Method for the Determination of Glycine (Or Any Primary Amine) in Dietetic Beverages
Authors: Coppola Elia D , Hanna J Gordon 
Published: February 2020

Abstract
The reagent fluorescamine (4-phenylspiro- (furan-2 (3H),l´-phthalan)-3,3´-dione), which reacts selectively with primary amines in alkaline solution, has been used to determine glycine in dietetic beverages in a simple and fast fluorometric procedure. As little as 0.02% glycine can be determined. An average recovery of 100.3±3.76% was obtained for added glycine in a series of 9 determinations. The method can be used as a screening procedure to confirm or exclude the presence of glycine in dietetic beverages.
Conductivity Detector for Nitrogen Compounds: Maintenance Program Enabling Gas-Liquid Chromatographic Analysis of Trace Residues in Crude Soil Extracts
Authors: Sarna Leonard P , Webster G R Barrie 
Published: February 2020

Abstract
A maintenance program for the Coulson conductivity detector is described which incorporates a new rapid method of decontaminating the stainless steel transfer lines and the vent valve of the detector system. Regular use of these maintenance procedures facilitites use of the Coulson conductivity detector for the analysis of trace residues of nitrogen-containing herbicides in crude soil extracts by maintaining detector sensitivity over an extended period of time and ensuring reliable performance from the instrument. Thus it is possible to avoid lengthy cleanup of analytical samples and the losses of material which might be involved, and to make maximum use of selective response of the Coulson conductivity detector. Approximately 2 days' down time is required every 3 months for this procedure.
Direct Determination of N'-Phenyl Urea Derivatives in Herbicide Technical Products and Formulations, Using Gas-Liquid Chromatography
Authors: Buser Hansueli , Grolimund Karl 
Published: February 2020

Abstract
The direct gas-liquid chromatography of a number of N'-phenyl-.N,N-dimethylureas and N'- phenyl-N-methoxy-N-methylureas has been investigated. Representatives of both groups have been studied in detail, calibration curves using an internal standard have been established, and herbicide technical products as well as formulations have been analyzed quantitatively. A 2 or 3% silicone SE-30 column was used in conjunction with a flame ionization detector. Operating temperatures were chosen on the basis of thermal stability data obtained by differential scanning calorimetry. Gas-liquid chromatography- mass spectroscopy coupling has confirmed that intact urea compounds elute from the chromatographic column.
Pro-Milk Method for the Determination of Protein in Milk by Dye Binding
Authors: Sherbon John W 
Published: February 2020

Abstract
The Pro-Milk method was compared to the official final action Udy method, 16.037-16.040, for 166 samples of raw milks from individual cows and to the official final action Kjeldahl method, 16.035, for 54 similar samples. Averages ± standard deviations of the differences were 0.019±0.017 and 0.027±0.109% protein for the 2 methods, respectively. Fat test or protein level of the samples did not affect the magnitude of the difference between the Pro-Milk and either of the other 2 methods. The Pro- Milk comparisons have also been made on samples of processed milks with similar results. A number of comparisons of the Pro-Milk method to other methods for protein in milk have been reported in the literature. The principles of the Pro-Milk method differ from the Udy method only in the type of dye used. Periodic calibration and routine control of the Pro-Milk method is required because of variability in assay of the Amido Black 10B dye.
Quantitative Determination of L-Ascorbic Acid by Gas-Liquid Chromatography
Authors: Schlack Janis E 
Published: February 2020

Abstract
A gas-liquid chromatographic method for L-ascorbic acid in foods and food products has been devised. Ascorbic acid is extracted into an ethanol solution, precipitated with lead acetate, regenerated from the lead salt as its trimethylsilyl derivative, and chromatographed on an SE- 30 column. Recoveries averaged 100.1%; the standard deviation was ±0.23%.
Isolation of Volatile N-Nitrosamines in Edible Vegetable Oils and Cooked Bacon Fat
Authors: White Richard H , Havery Donald C , Roseboro Emma L , Fazio Thomas 
Published: February 2020

Abstract
Volatile N-nitrosamines can be isolated from cooked bacon fat by the following procedures: The sample is distilled from alkaline solution and the nitrosamines are extracted with methylene chloride and cleaned up on a silica gel column (procedure A). The same procedures, preceded by an extraction with methylene chloride- sodium hydroxide, are used for isolation of N-nitrosamines from soybean oil samples (procedure B). Gas-liquid chromatography with the thermionic detector was used for the determinative step. Recoveries of 14 N-nitrosamines added to 25 g soybean oil samples at 10 and 20 ppb ranged from 67 to 100% for procedure B; these recoveries were 5舓10% higher than those from procedure A. No nitrosamines were detected in 4 commercial samples of soybean oil; however, they were found in cooked bacon fat at levels ranging from 45 to 207 ppb (μg/kg).
Preparative Method for Gas Chromatographic/Mass Spectral Analysis of Trace Quantities of Pesticides in Fish Tissue
Authors: Veith Gilman D , Kuehl Douglas W , Rosenthal Jeffry 
Published: February 2020

Abstract
A large capacity, low efficiency pesticide cleanup method is combined with a small capacity, high efficiency method for gas chroma tographic/mass spectral analysis of fish tissue. Trace chemicals are extracted from the tissue, removed from the bulk of the co-extracted lipids through selective desorption from Micro Cel-E, and isolated from the remaining lipids by gel permeation chromatography. The procedure is capable of cleaning up the extract from several hundred grams of fish, minimizes sample contamination, and permits identification of xenobiotic chemicals present at ng/g concentrations.
Rapid Screening Method for Aflatoxins and Zearalenone in Corn
Authors: Thomas Fred , Eppley Robert M , Trucksess Mary W 
Published: February 2020

Abstract
The methanol-water extraction system used in AOAC Method II for aflatoxins extracts both the aflatoxins and zearalenone from corn. Using this methanol-water extraction system as a base, a rapid screening procedure has been developed for these mycotoxins. The methanol-water extract is defatted with hexane and the pigments are precipitated with copper carbonate. The aflatoxins and zearalenone are subsequently extracted into chloroform and are then detected by half-plate TLC. An elapsed time of about 1 hr is required to analyze 1 sample. The sensitivity of the method is about 2 μg/kg for aflatoxin B1 and 100 μg/kg for zearalenone.
Gas-Liquid Chromatographic Determination of Coumarin (1,2-Benzopyrone) in May Wine
Authors: Dyer Randolph H , Martin Glenn E , Butts Boyd B 
Published: February 2020

Abstract
A method for the determination of coumarin (1,2-benzopyrone) in wine is described. The method calls for the gas chromatographic comparison of chloroform extracts of 2 aliquots of the sample, 1 aliquot having been spiked with a known amount of coumarin. The results of a series of prepared samples containing from 2.5 to 10.0 mg coumarin/L are given and these show an average of 3.7 relative per cent error. The results of the analysis of 10 May wines are also given. The method is fast, and accurate results are obtained. It is suggested that an Associate Referee be appointed and that the coumarin method be collaboratively studied.
Collaborative Study of a Joint AOAC-OICC (Office International du Cacao et du Chocolat) Method for the Determination of Alkalinity of Ash in Cacao Products
Authors: Rostagno Walter 
Published: February 2020

Abstract
In order to develop a uniform method for the determination of alkalinity of soluble and insoluble ash, AOAC methods 13.005 and 13.006 and OICC method 4b/1952 were compared. Five samples were sent to 10 collaborators: A, high ash cocoa; B, low ash cocoa; C, breakfast chocolate containing 30% A and 70% sugar; D, plain chocolate containing 25% B, 45% sugar, and 30% cocoa butter; and E, milk chocolate containing 10% B, 28% milk solids, 40% sugar, and 22% cocoa butter. The following within-laboratory and between-laboratory standard deviations were obtained from analysis of the collaborative data for alkalinity in soluble ash: OICC—Samples A and B, 1.5116 and 3.4337; Samples C–E, 0.7285 and 1.0394; AOAC—Samples A and B, 1.2800 and 3.6996; Samples C–E, 0.2956 and 0.8001. Corresponding values for alkalinity in insoluble ash were: OICC—2.1753 and 3.6856, 0.5100 and 1.0029; AOAC—1.5652 and 5.5006, 0.3129 and 1.6501. On the basis of these results, a joint AOACOICC method, based on the determination of alkalinity in soluble ash by the AOAC method and the determination of alkalinity in insoluble ash by the OICC method, has been adopted as official first action.
Detection of Ochratoxin A in Barley, Using Silica Gel Minicolumns
Authors: Hald Benedicte , Krogh Palle 
Published: February 2020

Abstract
A simplified procedure has been developed to detect ochratoxin A in cereals which can be used in the field where equipment for thin layer chromatography is not available. The procedure includes extraction of the acidified sample with chloroform, purification over sodium bicarbonate, and minicolumn chromatography. Under longwave ultraviolet light ochratoxin A appears as a blue-green fluorescent band at the lower end of the column. Contamination levels as low as 12 ppb can be detected by this method.
Automated Fluorometric Determination of Thiabendazole
Authors: Ott Daniel E 
Published: February 2020

Abstract
An automated fluorometric method is presented for the determination of thiabendazole (2-(4’-thiazolyl)benzimidazoIe) in 0.1/V HC1 solutions. Test solutions of at least 1.1 ml starting volume are sampled and pumped successively at the rate of 60/hr into a fluorometer equipped with a simple flowcell. The minimum level of detection of the fungicide is about 0.05 μg/ml.
Collaborative Study of a Method for the Analysis of Dry Methoxychlor Formulations
Authors: Pease Harlan L 
Published: February 2020

Abstract
A collaborative study has been completed on a method for determining methoxychlor content in dry formulations. The method is based on a total halogen determination plus a selective, qualitative thin layer chromatographic (TLC) measurement to establish that p,p’-methoxychlor is the primary halogen-containing organic species present in the formulation. After extraction of the sample with toluene, the toluene solution of methoxychlor is treated with sodium biphenyl to convert all halogen to the halide. The halide is then extracted with a solution of nitric acid and titrated with silver nitrate according to the Volhard procedure or potentiometrically, using a pH meter assembly. Based on the results obtained from 7 collaborators, the standard deviation of the method is about 0.48% at the 50% level. The qualitative TLC measurement is made on an aliquot of the initial toluene extract, using a selective halogen detection system. The method has been adopted as official first action.
High-Pressure Liquid Chromatographic Determination of Uncombined Intermediates and Subsidiary Colors in FD&C Blue No. 2
Authors: Singh Manjeet 
Published: February 2020

Abstract
A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates and subsidiary colors in FD&C Blue No. 2 (indigotine, C.I. No. 73015). Samples of FD&C Blue No. 2 containing 0.1–0.3% isatin, 0.1–0.3% isatin 5-sulfonic acid, 0.1–5.0% monosulfonated indigo, and 1.0–18.0% 5,7’-disulfonated indigo were prepared and analyzed by using this method. Recoveries ranged between 92 and 102%.
Fast, Short-Column Separation and Fluoromeitric Determination of Monosodium Glutamate in Foods
Authors: Coppola Elia D , Christie Spence N , Coppola J Gordon 
Published: February 2020

Abstract
In a simple and fast procedure, monosodium glutamate in food products is first separated by a short ion exchange column and subsequently determined fluorometrically with fluorescamine. An average recovery of 90.8% with a standard deviation of ±6.67% was obtained for added monosodium glutamate in a series of 8 products. As little as 0.05% monosodium glutamate can be determined. The method is faster than the official method and saves 5 hr/ determination.
Isolation and Characterization of the Photoalteration Products of cis- and trans-Chlordane
Authors: Onuska Francis I , Comba Michael E 
Published: February 2020

Abstract
Ultraviolet irradiation of cis- and trares-chlordane yielded 3 photolysis products. The expected half-caged analog of cis-chlordane was formed in high yield, and 2 minor photoproducts of trans-chlordane were observed. One of these products was a half-caged isomer. The individual photoproducts were isolated by thin layer chromatography and characterized by infrared, nuclear magnetic resonance, and mass spectrometry.
Collaborative Study of a Semiautomated Colorimetric Analysis of Digoxin Tablets
Authors: Juhl William E 
Published: February 2020

Abstract
A semiautomated thiobarbituric acid colorimetric analysis for digoxin was collaboratively studied by 6 laboratories. Collaborators were supplied with 3 composites of tablets of different dosage levels. Results agreed with the USP method. The coefficients of variation ranged from 0.46 to 2.73%. The method has been adopted as official first action.
Determination of Procaine and Related Local Anesthetics. I. Partition Chromatographic Separation and Assay of Mixtures of Procaine with Tetracaine and with Propoxycaine
Authors: Doyle Thomas D , Proctor Joseph B 
Published: February 2020

Abstract
Determination of ionization and extraction constants for procaine, tetracaine, and propoxycaine led to selection of a simple partition chromatographic system for separation and assay of mixtures of these anesthetics. A 65% solution of chloroform in isooctane elutes tetracaine or propoxycaine from a pH 4:sodium bromide column; procaine is retained and subsequently eluted by chloroform as the bromide ion-pair. The anesthetics are then determined spectrophotometrically. Results of assay of standard and commercial formulations are presented.
Agar Well Technique for Antibiotics in Animal Feeds
Authors: Thorpe Virginia A 
Published: February 2020

Abstract
The agar well technique compares favorably with the cylinder plate assay in accuracy, sensitivity, and precision. It is more flexible and more rugged, and growth of seed organism is not inhibited. The wells are precision cut with Grafar gel punch assembly with sets (6) of 10, 7, 5, 4, and 3 mm cutters. The wells are easily and rapidly filled with short, disposable Pasteur pipets fitted with rubber bulbs. The smaller wells are filled with capillary pipets. The diameter of the well (independent of volume) appears to be a function of concentration. For every decrease in the diameter size of the well, concentration can be increased, at least to the next higher level of the standard response line. Extracts of chlortetracycline containing as much as 3.2 μg/ml can be analyzed if the 3 mm wells are used and with no sacrifice in accuracy or precision. This works especially well for antibiotic premixes. The technique has been used successfully for penicillin, streptomycin, chlortetracycline, oxytetracycline, oleandomycin, and tylosin.
Collaborative Study of the Determination of Boric Acid in Caviar by Emission Spectroscopy
Authors: Franco Vincent , Holak Walter 
Published: February 2020

Abstract
Caviar samples were spiked at the 0.1 and 0.2% levels and digested with nitric acid in a closed Teflon-lined digestion vessel to prevent volatility losses. The boron was complexed with 2-ethyl-l,3-hexanediol and extracted into methyl isobutyl ketone. The emission of the boron oxide band was measured in a nitrous oxidehydrogen flame. The mean recoveries at the 0.1 and 0.2% levels for 6 collaborators were 95.7 and 97.1%, respectively. The method has been adopted as official first action.
o-Toluenesulfonamide in Saccharin Preparations
Authors: Stavric Bozidar , Klassen Ray 
Published: February 2020

Abstract
Twenty saccharin-containing table sweeteners, in the form of tablets, liquids, crystals, or blends, and manufactured or distributed by 15 different companies, were analyzed for their o-toluenesulfonamide (o-TS) content. A previously described procedure for the determination of o-TS in commercial saccharin was found to be applicable to the determination of o-TS in these preparations. o-TS was found in all analyzed samples, in amounts ranging from 57 to 3811 ppm. In some cases the concentration of o-TS varied even from lot to lot from the same manufacturer. One pair of lots contained 57 and 67 ppm o-TS, respectively, while in another 711 and 3003 ppm o-TS were found. Gas-liquid chromatographic patterns of samples from the same distributor (or manufacturer) were similar and characteristic of the brand. Recoveries of o-TS from liquid and tablet preparations were almost quantitative, while recoveries from saccharin blends were in the 95–103% range.
Atomic Absorption Spectrophotometry: Determination of Chromium in Plants
Authors: Cary Earle E , Olson Oscar E 
Published: February 2020

Abstract
A previously reported method for the determination of chromium in plants and biological materials has been simplified. The method, which involves wet digestion, isolation and concentration of chromium by liquid-liquid extraction, and final determination by atomic absorption spectrophotometry, is sensitive to about 20 ng chromium. Recovery studies and analysis of standard materials show that this method is reliable.
Collaborative Study of a Method for the Isolation of Light Filth from Breading of Frozen Food Products
Authors: Kvenberg John E 
Published: February 2020

Abstract
A method has been developed for the isolation of light filth from food breadings. The method involves a detergent boil, wet sieving, and flotation in an acid-alcohol, mineral oil flotation system in a Corning percolator. Collaborative studies resulted in clean filter papers and acceptable recoveries of added rodent hairs and insect fragments. The method has been adopted as official first action.
Sensitive Trapping and Gas Chromatographic Method for Vinyl Chloride in Air Samples
Authors: Ives N Fred 
Published: February 2020

Abstract
A simple and sensitive method is described for determining vinyl chloride monomer in air. Vinyl chloride monomer from a sample of air is trapped onto a Tenax GC trap cooled with Dry Ice. The trap is installed on a gas chromatograph by a simple valve arrangement. The trap is heated, and the entire sample is flushed onto the gas chromatographic column. Vinyl chloride is determined at 6 and 60 ppb (v/v) levels with recoveries ranging from 79 to 104%.
Reduction of Aflatoxins B1 and B2 with Sodium Borohydride
Authors: Asho Samy H , Chu Fun Sun 
Published: February 2020

Abstract
Reduction of aflatoxin B1 and a flat ox in B2 with sodium borohydride quantitatively yielded new fluorescent derivatives, designated as aflatoxin RB1 and aflatoxin RB2. Mass spectronietric data showed that RB1 and RB2 were trihydroxy derivatives of B1 and B2, respectively. Nuclear magnetic resonance analysis revealed that new chemical shifts were present in aflatoxins RB1 and RB2 in addition to those of the parent aflatoxins. The new compounds had lower melting points and different ultraviolet and infrared spectra compared to aflatoxins B1 and B2 and the monohydroxy derivative aflatoxicol. They were less toxic to chick embryos than the parent toxins. Since the reduction yields were quantitative and since the reduction products could be detected at low levels comparable to those for B1 and B2, the reduction reaction could be used as a confirmatory test for both aflatoxins B1 and B2. Preliminary results obtained from gas-liquid chromatography (GLC) analysis of the trimethylsilyl derivatives of aflatoxins RB1 and RB2 indicated that these compounds could furnish the basis for developing an analytical GLC method for aflatoxins B1 and B2.