bluuebunny/crossref_metadata_2025_split huggingface dataset:
Voice Identification with the Aid of Spectrographic Analysis
Authors: Nash Ernest W 
Published: February 2020

Abstract
The human voice, as an instrument of crime, is used more often than a weapon and automobile combined. Some crimes are committed by the voice alone; therefore, to be able to identify a speaker by his voice is a very desirable goal in the fight against crime. However, desire has been somewhat hindered by the lack of technology and instrumentation. The use of spectrograms (voiceprints) to assist the expert in making an objective evaluation of the voices in question is discussed. The scientific reason for accepting the identification of a speaker’s voice is the uniqueness of man. Therefore, if a unique person uses unique physiological body parts to produce the sounds of speech, it logically follows that sound will also be unique. By the visual examination of the spectrographic analysis, a trained expert is able to compare the uniqueness.
Method for Differentiating Optical Isomers of Amphetamine by the Simple and Direct Examination of Microcrystals in Gold Chloride Solution
Authors: Clark Jack Hylton 
Published: February 2020

Abstract
Although it has been asserted and generally accepted that d- and l-amphetamine cannot be distinguished by the simple, direct examination of their microcrystal forms, using ordinary light microscopy, a method of observation is described that will easily result in just such a determination. The d- and l-isomers may be distinguished because of their right- or left-oriented, overlapped crystal formations, in a drop-side-up position of the slide.
Infrared Spectrophotometric Analysis of Aldicarb Formulations
Authors: McDermott William H 
Published: February 2020

Abstract
The infrared method described for the assay of aldicarb formulations measures the carbamate carbonyl absorption band at 5.75 μm after extraction with methylene chloride in a Soxhlet extractor. An average recovery of 100.2% was obtained on laboratory-prepared simulated formulations. The standard deviation on repeatability studies on 2 formulations was ±0.2% at the 10% level. The coefficient of variation was ±2%.
Automated Nitrogen Method for Feeds
Authors: Gehrke Charles W , Wall Larry L , Absheer Joseph S 
Published: February 2020

Abstract
A totally automated method for the determination of nitrogen in feeds has been developed. The apparatus consists of Technicon Auto-Analyzer modules. The SOLIDprep Sampler II has been interfaced with the continuous digestor to provide complete solubilization and digestion of dry samples of feed, grain, and forage materials. Hydrogen peroxide is used as an aid for the wet digestion in the continuous digestor. Mercury, selenium, or copper metal catalysts were not effective for increasing the recovery of nitrogen during the continuous digestion. Nitrogen recoveries of 88–90%, relative to ammonium sulfate, have been obtained on several materials, i.e., corn grain, wheat, barley, rice, alfalfa, fescue, mixed feeds, and feed concentrates. The recoveries from these materials average about 100±2% when an empirical standard, soy hydrolysate, is used. The system operates at 20 samples/hr and has provided precise and accurate nitrogen analyses on collaborative samples. Other laboratories cooperated with us in evaluating the method by providing representative samples and their Kjeldahl analyses. This method provides a significant reduction in the labor required for large numbers of nitrogen analyses in feeds.
Aflatoxin M1 in Milk: Evaluation of Methods
Authors: Stubblefield Robert D , Shannon Gail M , Shotwell Odette L 
Published: February 2020

Abstract
Six published methods for the determination of aflatoxin M1 in liquid and powdered milk were compared because a quantitative assay sensitive to 0.1 μg/L was needed for routine analysis. Each method was tested with both spiked and naturally contaminated samples at levels of 0.1, 0.5, and 1 μg/L or 1, 5, and 10 μg/kg; recoveries of M1 were determined. Data revealed that 2 methods, one for liquid milk and one for powdered milk, had the desired sensitivity and recoveries. In the liquid milk method, M1 is extracted and milk protein is precipitated simultaneously with methanol-water (4+1); in the powdered milk method, M1 is extracted with acetone-water (70+30) and milk protein is then precipitated with a lead acetate solution. Both methods remove fats from the aqueous acetone or methanol solutions with hexane before partition of M1 into chloroform. Aflatoxin M1 is determined by thin layer chromatography of the chloroform extracts and either visual or densitometric measurement of mycotoxin on thin layer plates. Modifications were made to simplify the methods and to reduce the time required to complete the assays.
Evaluation of the Response of Dugesia tigrina to Aflatoxin B1
Authors: Llewellyn Gerald C 
Published: February 2020

Abstract
Groups of brown planaria, Dugesia tigrina, were exposed to varying concentrations of aflatoxin B1. Whole animals maintained in 3.125 μg/ml of toxic solution show ed 50% lethality in 2 days; 1.562 μg/ml required 4 days; 0.781 μg/ml required 7 days; and 0.312 μg/ml required 15 days. Even greater lethal responses occurred when cut portions of planaria were exposed to the toxin, with the head sections in all concentrations showing higher levels of lethality than the tail sections. Regeneration of excised heads and tails was inhibited in 3.125 μg/ml medium; minimal regeneration occurred in 1.562 and 0.781 μg/ml environments. D. tigrina, exposed to concentration levels of 0.312 and 0.156 μg/ml of aflatoxin B1 in spring water, regenerated head and tail portions in a normal manner. No gross pathological abnormalities were observed in any regenerated tissue. The lethal response to low concentrations of the toxin suggests that the head portion of D. tigrina is one of the more sensitive organisms to aflatoxin B1.
Determination of Soluble Solids in Roasted Coffee
Authors: Vree Pieter H , Yeransian James A 
Published: February 2020

Abstract
Six laboratories participated in a study of the determination of soluble solids in 9 samples of roasted and ground coffee by 3 methods. In a previous report the reproducibility of the Navellier method and of the method used by the European Decaffeination Association (EDA) was found to be comparable to the current AOAC method. Interlaboratory comparisons show better agreement for the Navellier and EDA methods, with somewhat higher values than the AOAC method. The EDA method has been adopted as official first action to replace method 15.012, which was repealed, official first action.
Collaborative Study of Rapid Fat Determination in Meat and Meat Products by Modification of the AOAC Method
Authors: Pettinati Julio D , Swift Clifton E , Cohen Edward H 
Published: February 2020

Abstract
The rapid method for fat determination reported by this laboratory has been evaluated by 10 collaborating laboratories in a comparison with the AOAC method. The method is similar to the official method except that a 3–4 g sample of meat or meat product is dried in an open extraction thimble for 30 min at 125°C and extracted with ethyl ether for 45 min at maximum reflux, and fat content is determined gravimetrically after complete removal of solvent from the extract. Collaborators performed 6 replicate analyses on samples of ground beef, frankfurters, and fresh pork sausage by both methods. A statistical treatment of the results showed that fat contents determined by the modified method agreed with those obtained by the official method. The expected standard deviation, se, averaged for the 3 types of meat product, was ±0.83% fat which is 1.5 times the value obtained by the official method, ±0.56% fat.
Identification of Drugs by Chemical Ionization Mass Spectroscopy
Authors: Saferstein Richard , Chao Jew-Ming 
Published: February 2020

Abstract
Methods of identifying drugs by chemical ionization (Cl) mass spectroscopy have been investigated. This type of ionization is accomplished by the reaction of the drug with either ionized gaseous methane or isobutane. The resulting spectrum is less complex than that produced by conventional mass spectroscopy and usually results in the formation of a molecular ion plus one (M + 1). The isobutane CI spectra of 62 commonly abused drugs were determined. The mechanism for the formation of fragmentation ions is discussed.
Recovery of Arsenic by Dry Ashing from Animal Tissue Fortified With Organoarsenicals or Arsenic Trioxide
Authors: George Glenn M , Frahm Larry J , Patrick McDonnell J 
Published: February 2020

Abstract
A study was conducted to establish whether or not arsenic recovery from animal tissue is independent of arsenic source. Control chicken liver and kidney tissues were fortified with 1.0 or 2.0 ppm arsenic from arsenic trioxide, roxarsone, arsanilic acid, nitarsone, or carbarsone. The tissue samples were dry ashed and total arsenic was determined colorimetrically. Arsenic recovery for the organoarsenical-fortified tissue samples is essentially complete for all drugs tested. Mean recoveries ranged from 98 to 109% of the theoretical amount expected.
Gas-Liquid Chromatographic Determination of Rotenone and Deguelin in Plant Extracts and Commercial Insecticides
Authors: Delfel Norman E 
Published: February 2020

Abstract
Retention times on 3% methyl silicone in glass columns at 160°C were 0.85 and 1.39, respectively, for deguelin and stigmasterol acetate, the internal standard; and flame ionization detector responses were 1.00 and 1.47, respectively, compared to rotenone as 1.00 in both cases. Rotenolone, when present, interfered with the determination of deguelin. Rotenoid extracts from Derris elliptica and Lonchocarpus nicou roots lacked other interfering materials. Tephrosia vogelii leaflets contained fat-soluble contaminants that were minimized by using acetonitrile for extraction and by subsequent partitioning with hexane. When the GLC assay was applied to commercial samples, rotenone results were comparable to label values in 2 samples and rotenoid oxidation products were detected in 2 others. The precision of GLC was ±4.1%, and the results agreed with those by thin layer densitometry (TLD) within 2.1% for rotenone and 2.9% for deguelin. A minor improvement of TLD for analysis of T. vogelii extracts is also described.
Holst Filtration Apparatus for Van Soest Detergent Fiber Analyses
Authors: Holst David O 
Published: February 2020

Abstract
New filtration equipment was developed to improve the acid-detergent method of fiber fractionation. This apparatus incorporates a vacuum manifold with an air metering device that provides the operator very precise control over the partial vacuum, permitting a very gradual change in vacuum level as needed for proper filtration. The partial pressure is provided by a water aspirator. A hot water jacket permits a continuous flow of hot water around the sample during the filtering process to keep the sample hot. This speeds filtering on practically all samples and is essential for reliable results on samples high in carbohydrates and salts. As a result of this new filtration equipment we do not need asbestos for a filter aid. This eliminates the need for duplicate acid-detergent fiber analyses when using 72% H2SO4 for the cellulose and lignin determinations. Six independent analyses were performed on each of 9 samples (3 feces, 3 orts, and 3 feeds) for the determination of acid-detergent fiber and its constituents. The average maximum differences for these analyses indicate that this filtration apparatus and the method are reproducible and have reduced the filtration time from several hours, on some samples, to 15 min.
Nitrate Determination by a Modified Conway Microdiffusion Method
Authors: Stanford George , Carter John N , Simpson Elmer C , Schwaninger Daniel E 
Published: February 2020

Abstract
The proposed modified Conway microdiffusion method provides for consecutive determinations of NH4- and NO3-N in a given aliquot of soil extract. Analyses of primary nitrate standards showed essentially complete recovery in the range of 1 to 20 ppm NO3-N (4 to 80 μg N/aliquot). Results for (NH4 + NO3)-Ν and NO3-N in soil extracts are comparable to those obtained, respectively, by macrodistillation with Devarda’s alloy and by the phenoldisulfonic acid colorimetric method. The method is rapid and suitable for routine analyses of soil extracts, the equipment is inexpensive, and no interferences are apparent.
Comparison of Two Methods for the Analysis of Pigmenting Xanthophylls in Dried Plant Materials
Authors: Livingston Arvin L , Knowles Richard E , Kohler George O 
Published: February 2020

Abstract
A previously reported procedure for carotene and non-epoxide xanthophyll (NEX) has been modified for the analyses of dried plant materials and mixed feeds, including those which contain xanthophyll esters. The method employs an ambient temperature extraction and saponification technique which permits rapid analyses of carotenoid pigment sources, including dehydrated alfalfa, grass, corn gluten meal, marigold petal meal, and mixed feeds containing these materials. The results were compared with those by the official first action modification of 39.018–39.023 for carotene and xanthophyll in these materials. The reported method gave the same or significantly higher analyses (p≤0.01 or 0.05) for corn, marigold, and one of the alfalfa meals but lower analyses for the grass meal tested. In only 2 of 10 cases were the variances between methods significantly different (p≤0.01 or 0.05), and in both cases the AOAC method gave the lower variance.
Analysis and Chemical Confirmation of Citrinin in Barley
Authors: Hald Benedicte , Krogh Palle 
Published: February 2020

Abstract
A method is described for the quantitative estimation of citrinin in barley by extraction of acidified grain with chloroform. After filtration, the citrinin concentration is estimated visually or densitometrically, using quantitative TLC, by comparison with a citrinin standard. The method will precisely determine concentrations of 0.5 ppm, with a lower limit of detection of about 0.2 ppm. A chemical confirmatory test involving formation of the acetate of citrinin is also described.
Atomic Absorption Spectrophotometric Determination of Dibutyltin Dilaurate in Finished Feeds
Authors: George Glenn M , Albrecht Marven A , Frahm Larry J , Patrick McDonnell J 
Published: February 2020

Abstract
Dibutyltin dilaurate is extracted from finished feed with warm chloroform. The chloroform extract is filtered and a 25 ml aliquot is concentrated in the presence of methanol until all traces of chloroform are removed. The methanol solution is diluted and feed interferences are removed by filtration. The filtered solution is aspirated into an atomic absorption spectrophotometer with a triple-slot burner head, using an air-acetylene flame. The instrument response to tin at 286.3 nm is recorded. Essentially theoretical recovery (100.5— 101.9%) has been obtained for tin in laboratory-mixed feeds.
Simplex Optimized J-Acid Method for the Determination of Formaldehyde
Authors: Czech Fred P 
Published: February 2020

Abstract
This paper is the first in a number of didactic reports on the application of simplex optimization to analytical methods and instruments. The use of simplex optimization allows rapid determination of the best conditions for analytical purposes. Some basic concepts used in simplex optimization operations are introduced, described, and exemplified. A rapid and highly sensitive method for the colorimetric analysis of formaldehyde via J-acid is derived by means of simplex optimization. The method is over 5 times as sensitive as the original J-acid procedure and almost 10% more sensitive than the simplex optimized chromotropic acid procedure. The average relative standard deviation is about ±1.6%. The limit of detectability is estimated to be 70 ppb.
Determination of Carbon Dioxide in Cucumber Brines
Authors: Fleming Henry P , Thompson Roger L , Etchells JOHN L 
Published: February 2020

Abstract
A simple, accurate method for determining carbon dioxide in fermenting cucumber brines is described. The method involves distillation of carbon dioxide from the acidified brine into standardized sodium hydroxide inside a closed jar. The sample is injected by a syringe and needle through a rubber serum stopper placed in the jar cap, into an acid solution. A small vial of sodium hydroxide placed inside the jar traps the carbon dioxide as it distills from the acidified solution. After being held in the jar 24 hr at 37°C, the vial is removed; the remaining base is titrated to the phenolphthalein end point with standardized hydrochloric acid. Advantages of the method include a limited working time, minimized loss of carbon dioxide during analysis, and a relatively small sample size.
Extraction of Polychlorinated Biphenyls: Evaluation of a Column Technique Applied to Polar Bear and Seal Tissue
Authors: Bowes Gerald W , Lewis Jennifer A 
Published: February 2020

Abstract
A column extraction procedure was evaluated for the extraction of polychlorinated biphenyls (PCB) from polar bear and seal liver and fat tissue. DDE (2,2-bis (p-chlorophenyl)-l,l-dichloroethylene) was also present in these tissues, and was quantitated for comparative purposes. Two solvent systems were compared: hexane and chloroform-methanol. The chlorinated hydrocarbons were also separated from the liver and fat by digestion of tissue in hot perchloric-glacial acetic acid, and treatment of tissue with acetone and hot isopropanol (considered to be an exhaustive extraction method for lipid). Six replicate extractions were performed for each of the 4 procedures applied to the 4 tissues. The results suggest that the column technique is excellent for extraction of these chlorinated hydrocarbons from animal tissue. Hexane eluted through a sodium sulfate- tissue mixture in a column was as effective in extracting PCB and DDE from polar bear and seal fat as the standard method of comparison (acetone-isopropanol), and slightly less effective (2—4%) in recovering them from liver. These results also indicate that PCB and DDT compounds are associated with the nonpolar lipid component in the cell. A fraction collection study with polar bear liver and fat shows that hexane removes the compounds rapidly from the 2 tissue types. Most of the PCB and DDE is eluted in the first 50 ml.
Determination of Low Levels of Cadmium in Foods Using a Chelating Ion Exchange Resin
Authors: Baetz Richard A , Kenner Charles T 
Published: February 2020

Abstract
A method is described for the determination of cadmium in foods which utilizes the AOAC HN03, H2S04, H202 digestion procedure catalyzed by V2O5. The cadmium is separated from the neutralized digest by a chelating ion exchange resin, eluted with H2S04, and determined by atomic absorption spectrophotometry. The average recovery of 0.30 ppm cadmium added to 7 commodities was 94% with a standard deviation of 2.8%, which compares favorably with the AOAC dithizone extraction method. The transfer, washing, and elution of 6 samples by the proposed method requires approximately 2 hr. The method allows the determination of as little as 10 ppb cadmium.
Chlorinated Hydrocarbon Pesticide Residues in Foodstuffs: Comparison of Methods
Authors: Smart Nigel A , Hill Alan R C , Roughan Patricia A 
Published: February 2020

Abstract
The AOAC, de Faubert Maunder et al., and Wood methods have been examined for determining BHC, aldrin, heptachlor, DDT, and their major metabolites in milk, butter, cheese, and eggs. Also, the AOAC and the Laboratory of the Government Chemist (UK) methods have been investigated for these pesticides in apples, and both of the latter methods, together with a current EEC method, have been evaluated for measuring the pesticides in potatoes, carrots, and cabbages. Recoveries for these methods were determined by using samples with both added and incurred pesticide residues. There were no gross discrepancies in the results obtained by the different methods, although for certain foodstuffs and in certain situations some methods appeared preferable to others.
Colorimetric Determination of Paraquat Residues in Soil and Water
Authors: Pope John D , Benner Jacquelyn E 
Published: February 2020

Abstract
A modified colorimetric method is presented for the determination of paraquat in agricultural arunoff samples. The soil extraction step of existing methods is shortened, making the method more suitable for routine analysis of large numbers of samples. Recoveries from spiked soil samples (0.5–5.0 ppm) and water samples (0.1–2.0 ppm) averaged 91-98 and 80-94%, respectively.
High-Pressure Liquid Chromatographic Determination of Uncombined Intermediates in FD&C Red No. 40
Authors: Singh Manjeet 
Published: February 2020

Abstract
A high-pressure liquid chromatographic method was developed for the isolation and determination of uncombined intermediates in FD&C Red No. 40 (Allura Red AC, food color). Samples of FD&C Red No. 40 containing 0.1–0.4% cresidine sulfonic acid, 0.1–0.4% Schaeffer's salt, and 0.3–1.0% 6,6'-oxybis(2-naphthalenesulfonic acid) were prepared and analyzed using this method. Recoveries ranged between 92 and 101%. When 32 samples of FD&C Red No. 40 were analyzed by the conventional column chromatographic method as well as by the high-pressure liquid chromatographic method, good agreement was obtained between the 2 methods.
Solubility of Sterigmatocystin
Authors: Steyn Martin 
Published: February 2020

Abstract
The solubility of sterigmatocystin, a carcinogenic and toxic mycotoxin, was determined in 48 solvents. The results indicated that with few exceptions, it is relatively insoluble in most solvents tested. There seemed to be no correlation between the solubility of sterigmatocystin and the dipole moments, dielectric constants, or solubility parameters of the solvents.
Assay of L( + )-Ascorbic Acid in Buttermilk by Densitometric Transmittance Measurement of the Dehydroascorbic Acid Osazone
Authors: Beljaars Paul R , Steenbergen Horrocks Wouter Van , Rondags Theo M M 
Published: February 2020

Abstract
A study is presented for the quantitative analysis of ascorbic acid in buttermilk samples, using densitometric transmittance measurements. The procedure is based on oxidation of ascorbic acid to dehydroascorbic acid, followed by reaction with 2,4-dinitrophenylhydrazine to form the dinitrosazone. The osazone is separated from interfering substances in the sample by thin layer chromatography (TLC) on silica gel G plates developed with chloroform-ethyl acetate-acetic acid (60+35+5) . The TLC plates are scanned with a flying-spot densitometer. The relationship between integrated signal and concentration is linear for 0.08—1.00 fig ascorbic acid (coefficient of variation 3—4%). Deviations from Beer's law start to appear at levels higher than 1.00 fig ascorbic acid. A mean coefficient of variation of 3.5±1.1% (P = 95%) was established for standard spot measurements (3 spots averaged) on 15 chromatoplates. Recovery of ascorbic acid added to buttermik was 98% (coefficient of variation 7.2%). Results of this study are compared with those reported for spectrophotometric, titrimetric, and potentiometric procedures. The proposed method is less accurate because of interferences and the subsequent variables which arise as a result of taking transmittance measurements through an opaque medium.
Possible Interference in the Measurement of Lead and Cadmium from Elements Found in Fish Muscle
Authors: Childs Ernest A , Gaffke John N 
Published: February 2020

Abstract
The effects of various elements found in fish muscle on the measurement of lead and cadmium by atomic absorption spectrophotometry in either an aqueous or an organic solvent system were evaluated. Although a number of elements altered the measurement, the composite effect for both cadmium and lead in either solvent system was &lt;± 10%. The extent of interference of all added elements was found to be a function of the amount of lead or cadmium present.