bluuebunny/crossref_metadata_2025 huggingface dataset:
EDTA Titration of Calcium and Magnesium: Determination of Calcium in Canned Tomatoes
Authors: Steagall Edward F
Published: February 2020

This past year a food additives quality control program was established for Food and Drug Administration field laboratories; one phase involved the determination of calcium in canned whole tomatoes. One can of tomatoes containing declared added calcium and one can without added calcium were each analyzed by 18 participating laboratories. Results on the cans with added calcium showed a mean value of 0.031% with a standard deviation of ±0.0032%. Results on t he cans without added calcium showed a mean value of 0.005% with a standard deviation of ±0.0039%.
Rapid Instrumental Fat Determination
Authors: Malanoski A J , Greenfield E L
Published: February 2020

The Digital Fat Controller was evaluated for use in plant control and as a screening tool. The determination of fat by the Digital Fat Controller utilizes specific gravity with automatic computation and a “nixie” tube readout. No sample preparation is required and an analysis can be completed in 30–60 sec. Fiftysix samples were analyzed by both the automated method and the official AOAC method.
Gas Chromatographic Determination of Total Active Ingredient Content of Karathane Technical and Karathane WD. I. Development of the Method
Authors: Kurtz C P , Baum H , Swithenbank C
Published: February 2020

A new GLC method for the direct determination of the active ingredient in Karathane Technical and Karathane WD is presented. The internal standard (4,6-dinitro-o-cresol) in nitrobenzene solution is added to the sample, or the extract residue in the case of Karathane WD, and the solution is chromatographed on a flame ionization instrument, using an 8’ glass column packed with 3% QF-1 silicone oil on 60–80 mesh Gas Chrom Q. Column temperature is programmed from 100 to 230°C. A working standard of known composition is run in the same manner in series with the sample. The precision of a single determination of the total 2,4- and 2,6-dinitrooctylphenyl crotonate isomers (about 74%) in Karathane Technical and the total dinitrooctylphenols and mononitrooctylphenols (about 6%) is s = 0.5% absolute. Data on the analysis of a limited number of Karathane WD samples show good agreement for the total active ingredient.
Comparison of Several Methods for Extracting Chlordane Residues from Soil
Authors: Saha J G
Published: February 2020

Residues of chlordane were extracted from a field-contaminated clay loam soil with various solvents under a variety of conditions. Mixtures of hexane-acetone and hexane-2-propanol recovered only 1.93–2.64 ppm total chlordane residues from the air-dried soil as compared to 3.88–4.10 ppm (highest recovery) when 20% water was added to the soil prior to extraction by these solvents. Effects of the amount of water in the soil at the time of extraction, contact time with solvent or water, and extraction methods were also studied.
Detection of Minute Thiamine Concentrations via Thiochrome Assay
Authors: Dougherty R H , Cobb W Y
Published: February 2020

Different enzyme preparations have been investigated fqr use in the official method for thiamine (sec. 39.021). Purification of the phosphorolytic enzyme solutions used in this assay eliminates materials that fluoresce at the same wavelength as thiamine and thereby extends the limit of detection of the method to less than 0.004 μg thiamine/ml.
Improved Separation of Aflatoxins by Vapor-Programmed Thin Layer Chromatography and Controlled Relative Humidity
Authors: de Zeeuw Rokus A , Lillard H S
Published: February 2020

Vapor-programmed thin layer chromatography (VP-TLC) was found to give distinctly improved separations of the 4 common aflatoxins, B1, B2, G1, and G2. Fluorodensitometric evaluation of the chromatograms showed completely separated peaks with the recorded curve always coming back to the baseline. Both classical TLC separations and VP-TLC separations were highly dependent on the relative humidity under which the analysis was performed. Optimum resolutions thus require the availability of a room with controlled and variable relative humidity. However, when the VP-technique is used, changes in the humidity can be compensated for by suitably altering the vapor program.
Assay of Ipecac and Its Preparations. I. Development of the Method
Authors: Smith Edward , Sharkey Margaret F , Levine Joseph
Published: February 2020

A partition chromatographic method was developed which quantitatively separates the 2 major ipecac alkaloids emetine and cephaeline. The isolated alkaloids are determined by their ultraviolet absorbance at 283 nm. The method was applied to powdered ipecac root, ipecac sirup, and ipecac fluidextract. The results obtained show good precision.
GLC Analysis of Dyrene Residues, Using Chromosorb W (HP) with OV-17/QF-1 Silicone Coating
Authors: Mendoza C E , Shields J B
Published: February 2020

Quantitative GLC analysis of Dyrene in tomato and strawberry extracts was accomplished by using a column of Chromosorb W (HP) coated with 1.5% OV-17/1.95% QF-1 silicones. This column adequately resolved Dyrene, methoxy-Dyrene, and dimethoxy-Dyrene. Statistical analysis showed that recoveries based on the ratios of Dyrene recovered and the Dyrene standard added to blank extracts were more consistent than those based on the standard alone.
Cleanup of Pesticide and Polychlorinated Biphenyl Residues in Fish Extracts by Gel Permeation Chromatography
Authors: Stalling David L , Tindle Roger C , Johnson James L
Published: February 2020

Gel permeation chromatography was found to be an efficient and reproducible technique for removing lipids from fish extracts. Recoveries of DDT, DDD, DDE, methoxychlor, lindane, dieldrin, endrin, malathion, and parathion were found to be greater than 95%. Pesticide concentrations were equivalent to 0.01-1.0 ppm, based on the original fish tissue. Pesticide analysis was by gas chromatography, using an electron capture detector, and by liquid scintillation. Less than 0.5% of the lipids originally present in the fish extract was recovered in the pesticide-containing eluate. Several solvent and lipophilic gel systems were evaluated. A chromatographic system using cyclohexane and Bio Beads S-X2 gave the most satisfactory separations. Polychlorinated biphenyls were also recovered in good yields. When this technique was used in conjunction with the polychlorinated biphenyl separation technique of Armour and Burke, excellent results were obtained. The system, as described, may be adapted for automatic sample cleanup and may be used as the sole cleanup technique with some samples.
Quantitative Determination of Ammonium Glycyrrhizinate by Gas-Liquid Chromatography: Collaborative Study
Authors: Larry Damon
Published: February 2020

Six samples of carbonated beverage were spiked at levels from 0 to 400 p pm with foodgrade ammonium glycyrrhizinate and sent to 7 participating laboratories for collaborative study. To facilitate the analysis of samples containing microquantities of ammonium glycyrrhizinate, slight modifications were made in the published GLC method. Recoveries of ammon ium glycyrrhizinate were 116.4, 102.0, 93.4, 102.3, and 105.8% for 35, 100, 200, 300, and 400 ppm levels, respectively. The method has been adopted as official first action.
Microbiological Assay of Streptomycin in Feeds: 1971 Collaborative Study
Authors: Mayernik John J , Fiori Gloria Y , Hughes Shirley
Published: February 2020

The AOAC official first action method for the determination of streptomycin in feed in which the regular streptomycin assay agar is used was modified for application to the assay of low levels of streptomycin. The modifications consist of (1) increasing the sample size, (2) reducing the amount of agar in the assay plates, (3) lowering the concentration of the reference point on the assay plates, and (4) incubating the plates at 22–25°C instead of 37°C. Fifteen collaborators used the modified method to assay 6 feeds containing 5–30 g streptomycin/ ton. Mean recoveries ranged from 91.7 to 111.0% and coefficients of variation ranged from 5.8 to 8.7%. The method modified as described has been adopted as official first action for the assay of feeds containing 5–30 g streptomycin/ton.
Extraction of Lipid-Protein Complexes from Egg Yolk
Authors: Navarro J G , Borie F , Saavedra J
Published: February 2020

A residual lipid which is not removed by solvent extraction was detected and determined after enzymatic hydrolysis of defatted egg yolk protein. Free fatty acids were found to be the type of lipid bonded to the egg yolk protein. The mode of attachment of these fatty acids to the egg yolk protein is suggested and the composition of the fatty acids is reported.
Gas Chromatography of Choline in High Potency Multiple Vitamin Tablets and Liver Concentrates
Authors: Garavelli Caesar B
Published: February 2020

A procedure is described for the quantitative determination of 5–7 mg choline i n high potency reference multiple vitamin and mineral tablets and standard liver concentrates. The trimethylamine quantitatively produced in a sealed tube by treatment with aqueous 15% NaOH is determined by GLC. An average recovery of 97–98% was obtained for t h e vitamin tablets , and an acceptable average choline content of 13.5–14 mg/g was obtained for the liver concentrate samples.
Sterigmatocystin in Coffee Beans
Authors: Purchase Iain F H , Pretorius M E
Published: February 2020

Sterigmatocystin, a toxic fungal metabolite, was found in one of 2 samples of green coffee beans which had been condemned as unfit for human consumption. The analysis, which was carried out according to a modification of the AOAC official first action method for aflatoxin in coffee beans, showed 1143 ppb sterigmatocystin to he present in the sample. In addition, 3 confirmatory tests showed the presence of the compound. Screening coffee beans for sterigmatocystin is suggested as a routine practice.
Corrected Fluorescence Spectra of Polynuclear Materials and Their Principal Applications
Authors: Porro Thomas J , Anacreon Robert E , Flandreau Paul S , Fagerson Irving S
Published: February 2020

Corrected fluorescence spectra are presented for 20 polynuclear aromatic compounds. The applications of corrected spectra, as well as instrumentation and techniques for providing these spectra, are described.
Gas Chromatographic Determination of Diethylstilbestrol and Its Glucuronide in Cattle Tissues
Authors: Donoho Alvin L , Johnson William S , Sieck Robert F , Sullivan William L
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for the determination of diethylstilbestrol (DES) and its glucuronide (DES-G) in cattle tissues. Muscle, liver, and kidney samples are extracted with methanol and centrifuged. An aliquot of extract equivalent to 50 g tissue is evaporated to remove methanol and hydrolyzed overnight, using β-glucuronidase. In the resulting sample, free DES is purified by alkaline liquid-liquid extraction and is reacted in base with dichloroacetyl chloride to form the DES diester. The diester is measured by GLC, using a 5% UC W-98 column and electron affinity detection. Fat samples are assayed for free DES by extracting with chloroform and processing as other tissues, beginning with the alkaline purification. Residues from tissues of steers fed DES, assayed by both GLC and bioassay procedures, showed excellent agreement. In these studies the GLC procedure had a sensitivity of about 0.001 ppm. Lean and fat contained no DES residue when animals were slaughtered at 0 time off medicated feed. Liver and kidney contained residues on the order of 0.02 ppm at 0 time. The DES declined to nondetectable levels in liver and kidney by 96 hr after withdrawal. The assay procedure has been used successfully on a routine basis for several months.
Drained Weight Determination of Frozen Glazed Snow Crabmeat
Authors: Miller George A
Published: February 2020

A collaborative study was conducted on the official final action drained weight methods, 18.006–18.007 and 18.008–18.009, utilizing snow crab (Chionoectes). Three collaborators analyzed a total of 6 separate frozen packs. Two packs were analyzed by 18.008–18.009, the Alaska King Crab Marketing and Control Board method, and yielded an average recovery of 83% of put-in tissue weight; the 4 packs analyzed by 18.006–18.007 yielded an average recovery of 76% of put-in tissue weight. Both methods have been amended to include snow crabmeat.
Collaborative Study of the Chicken Embryo Bioassay for Aflatoxin B1
Authors: Verrett M Jacqueline , Winbush James , Reynaldo Edilberto F , Scott William F
Published: February 2020

A collaborative study of the bioassay for the detection of aflatoxin B1, 26.057–26.061, was undertaken with 9 laboratories participating. The study was designed to evaluate the toxicity of an aflatoxin B1 standard, and an unknown quantity of aflatoxin B1 extracted from peanut butter. The baseline was provided by an assay of an extract of an aflatoxin-free peanut butter and by the appropriate solvent and untreated control eggs. The data were analyzed for linearity of response and agreement of the LD-50’s and slopes. In general, a linear dose-response relationship was exhibited, and there was good agreement of the slopes and LD-50’s and their associated standard errors. The method has been adopted as official first action.
Gas-Liquid Chromatographic Determination of β-Asarone, A Component of Oil of Calamus, in Flavors and Beverages
Authors: Larry Damon
Published: February 2020

A method has been developed for the detection and quantitation of β-asarone in vermouths. Volatiles are isolated by steam distillation, and β-asarone is separated from interfering substances by solvent extraction and subjected to gas chromatographic analysis. Quantitation of samples containing 5–100 ppm β-asarone was achieved by direct chromatographic peak comparisons with standards prepared in 20% ethanol-water, which are treated the same as samples. Average recovery from light and dark vermouths spiked at 5, 15, 25, and 100 ppm was 98.8%.
Acid Ammonium Acetate Extraction and Electron Capture Gas Chromatographic Determination of Carbofuran in Soils
Authors: Caro Joseph H , Glotfelty Dwight E , Freeman Horatio P , Taylor Alan W
Published: February 2020

A method is presented for determining carbofuran residues in soils that gives improved recovery, especially in weathered soils, and allows quantitation of as little as 0.1 ppm without cleanup. The soil is extracted with 0.5M acid ammonium acetate and the carbamate in the extract is determined by electron capture gas chromatography as the dinitrophenyl ether. A systematic study was conducted to optimize extraction conditions. In tests of soils fortified with 1 ppm carbofuran, using optimized extraction conditions, recoveries varied with soil type, ranging from 61% in a peat to 92% in a silt loam. Recoveries of the metabolites 3-hydroxy- and 3-ketocarbofuran from field soils were at least as efficient as by HCl extraction. In addition to carbofuran, other methylcarbamate insecticide residues that may be determined by this method include Landrin, propoxur, and Bux.
Novel Techniques for the Examination of Physical Evidence—Their Admissibility as Evidence
Authors: Brunelle Richard L
Published: February 2020

Courts of law are traditionally conservative in nature and are very reluctant to change except with extreme caution. This resistance to change is in sharp contrast to the open-minded attitude of the scientific community toward the reception of new ideas. Scientific advancement is so rapid in this age of vast technological developments that it would be an impossible task to discuss all of the various developments in the area of scientific proof. This paper discusses a few specific topics that are not necessarily recent in origin but are currently of great interest or have been the subject of criticism for several years. An attempt is made to illustrate the historical understanding of judicial attitude regarding scientific evidence and also to present the present trends of the courts in determining the admissibility of scientific proof based on novel laboratory techniques.
Gas-Liquid Chromatographic Determination of Monosaccharides and Glycerol in Aged Distilled Spirits
Authors: Black Robert A , Andreasen Arthur A
Published: February 2020

Gas-liquid chromatography was utilized for the analysis of monosaccharides and glycerol in distilled spirits aged in new, charred white oak cooperage. Arabinose, xylose, fructose, glucose, galactose, and rhamnose were identified. Traces of fucose and mannose were indicated. Total concentration of sugars increased from 16 to 37 g/100 L at 100° proof and glycerol from 0.83 to 2.42 g/100 L at 100° proof during aging from 1 through 12 years. Compounds were identified by a comparison of GLC chromatograms of trimethylsilyl (TMS) ether derivatives, alditol acetates and trifluoroacetates, and TMS-aldono-l,4-lactones. Sugars and glycerol were quantitated as TMS ether derivatives with 3 % JXR organic phase on Gas-Chrom Q with an accuracy assessed at ±2—3%.
Rapid Method for Estimation of Carbohydrate and Calorie Content of Foods Containing a High Proportion of Sugar
Authors: Lamb Frank C , Kemper Karen
Published: February 2020

Correlations of refractometer sugar scale readings with total solids, carbohydrate, and calories are presented for 5 canned fruit products and 3 tomato products. Regression equations, standard errors of estimate, and correlation coefficients are given for each combination of dependent and independent variables. Correlations were highly significant in all instances. Standard errors of estimate indicate that total solids and carbohydrate may be estimated from refractometer readings within ±0.5% and calories within ±2 calories/100 g with 95% assurance in practically all instances.
Gas-Liquid Chromatographic Determination of Chloroform in Toothpastes, Using the Headspace Analytical Technique
Authors: Stutsman Martin J
Published: February 2020

Chloroform in toothpastes is determined by gas-liquid chromatography of the vapors in the headspace over a diluted sample, using an electron capture detector. The method is sensitive to small amounts of chloroform and avoids the injection of materials deleterious to the column. The 12' × 1/8" od stainless steel column is packed with acid-washed Gas-Chrom R coated with 2 0% Carbowax 20M. Recoveries of chloroform added to toothpastes range from 95 to 104%.
Quantitative Determination of Poly chlorinated Biphenyls—A Computer Approach
Authors: Zobel Michael G R
Published: February 2020

A computer method is presented which enables polychlorinated biphenyl (PCB) residue chromatograms to be resolved and quantitatively measured in terms of a sum of different standard Aroclors. The Aroclors 1242, 1254, and 1262 were used in this work, but the method is capable of using any number or combination from 1 Aroclor upward. The program constructs test chromatograms from standard peak heights, and, by a minimizing procedure, selects the test chromatogram nearest to the unknown. Spuriously large or small peak heights, caused by interfering compounds or metabolism, are automatically sorted and rejected. The results are output as both total and compositional PCB content, and in the form of a constructed line chromatogram. The method was applied to cardboard and pulp samples of widely differing PCB content. A modified program has enabled analysis of a heavily metabolized pork fat sample by comparing only the later eluting peaks. The “pre-metabolism” PCB content was estimated.
Congener Development in Bourbon Whisky Matured at Various Proofs for Twelve Years
Authors: Baldwin Sidney , Andreasen Arthur A
Published: February 2020

The color intensity and congener concentration of bourbon whiskies matured for 12 years decreased as the entry proof increased from 109 to 155°, except for fusel oil content which remained approximately constant. The average annual cumulative evaporation loss rates, in per cent of original proof gallons/year, were approximately the same at all 6 proofs, i.e., 3.0%/year or 3 6% for the 12 year period. The relative rates of formation of total barrel-derived material, a newly proposed parameter defined as the sum of the increase in volatiles and nonvolatiles in an aged product, were quite similar for comparable time intervals regardless of entry proof. There was greater variation among the relative rates of formation of individual congeners at the different entry proofs. Although all congeners except esters attained at least 5 0% of their ultimate (twelfth year) value during the first 4 years, it appears that appreciable congener development continues at least through 12 years. Esters developed linearly over the 12 year period.
Determination of Trace Amounts of Thallium in Urine, Using the Mercury-Film Electrode and Differential Pulse Anodic Stripping Voltammetry
Authors: Curtis Arvine R
Published: February 2020

Thallium concentrations as low as 0.2 ppb may be easily and accurately measured with no sample preparation. The urine is pipetted directly into the electrolysis cell containing 0.1M HClO4 and deaerated; a 2 min electrolysis is performed, and the thallium is oxidized from the mercury-thallium amalgam, using differential pulse anodic stripping voltammetry. The standards are spiked thallium-free urine solutions; thus the samples and standards reflect each other closely, and as the standard curves are repeatable to within ± 5% (down to 2 ppb thallium), the recoveries range from 95 to 105%. Lead is not a serious interference; however, cadmium does interfere and a complexing agent must be used when determining traces of thallium in the presence of cadmium.
A Modification in the Official Methods for the Determination of Metals in Feeds and Fertilizers by Atomic Absorption Spectrophotometry
Authors: Everson Robert J
Published: February 2020

A modification in the official methods for the determination of metals in feeds and fertilizers by atomic absorption spectrophotometry is presented. In lieu of digesting the samples in beakers and then filtering them into a volumetric flask, the samples are digested in a 250 ml volumetric flask, and then diluted to volume. This procedure and subsequent handling eliminates losses from spattering, transferring the sample from the beaker to the volumetric flask, and failure to thoroughly rinse the filter paper. The results obtained by the modification appear comparable to those obtained by the official methods.
Polycyclic Aromatic Hydrocarbon Profile Analysis of High-Protein Foods, Oils, and Fats by Gas Chromatography
Authors: Grimmer Gernot , Böhnke Heinz
Published: February 2020

A method is described for the determination of polycyclic aromatic hydrocarbons (PAHs) with 3–7 rings in (I) meat, poultry, fish, and yeast; and (II) oils and fats. The extraction of PAHs from group I is incomplete, and, therefore, group I samples must be dissolved homogeneously by saponification in 2N methanolic potassium hydroxide. The PAHs are concentrated by liquid-liquid extraction (methanolwater - cyclohexane, N,N - dimethylformamide - water-cyclohexane) and by column chromatography on Sephadex LH 20. The PAHs are separated by high-performance gas-liquid chromatography (GLC) with columns containing 5% OV-101 on Gas-Chrom Q and estimated by integration of the flame ionization detector signals in relation to an internal standard (3,6-dimethylphenanthrene and/or benzo(b)chrysene). The sensitivity is significantly higher than that obtained with ultraviolet spectroscopic methods. The reproducibility and margin of error were tested with meat samples fortified with 11 PAHs and with samples of sunflower oil. The method was further applied to meat, smoked fish, yeast, and unrefined sunflower oil. All samples investigated contained more than 100 PAHs (characterized by mass spectrometry) of which only the main components were determined: phenanthrene, anthracene, fluorene, fluoranthene, pyrene, benzo (a) anthracene, chrysene, benzo (b) fluoranthene + benzo (j) fluoranthene + benzo(k)fluoranthene, benzo(e)pyrene, benzo (a) pyrene, perylene, dibenz(a,j)anthracene, dibenz(a,h)anthracene + indeno (1,2,3-cd)pyrene, benzo(ghi)perylene, anthanthrene, and coronene. In contrast to other methods, the GLC profile analysis allows the recording of known and unknown PAH peaks simultaneously and also allows a compilation of all PAHs.
Semiautomated Analysis of Ergonovine Maleate or Methylergonovine Maleate Tablets and Injections by Colorimetric or Fluorometric Systems
Authors: Kirchhoefer Ross D , Wells Clyde E
Published: February 2020

Two semiautomated analytical systems have been developed to determine ergonovine and methylergonovine maleate in single tablets and injections. The active ingredient is dissolved in a tartrate buffer. In the fluorometric method the stream is automatically diluted with tartrate buffer and excited with ultraviolet light; the resulting fluorescence is measured and recorded. In the colorimetric method, the stream is automatically made basic with sodium hydroxide and extracted with n-butanol. The extract is mixed with p-dimethylaminobenzaldehyde reagent. After reaction, the solution is mixed with sodium nitrite solution, and the developed color is measured at 550 nm. Recoveries of 100% were obtained from spiked placebos. Standard deviations for powdered tablet and injection samples ranged from 0.63 to 1.24%. Comparisons with the USP XVIII methods are presented.
Simultaneous Assay for Six Alkaloids in Opium, Using High-Performance Liquid Chromatography
Authors: Ziegler Howard W , Beasley Thomas H , Smith David W
Published: February 2020

A method is described for the quantitative determination of morphine, codeine, cryptopine, thebaine, papaverine, and narcotine in opium by high-performance liquid chromatography. The alkaloids are isolated from a dilute acid extract by adsorption on an Amberlite XAD-2 resin column and eluted first with methanol and then with chloroform-methanol ( 3+1 ) . After solvent removal by reduced pressure evaporation, the alkaloids are redissolved in chloroformmethanol ( 3+1 ) . The sample solution, plus brucine as an internal standard, is injected onto a Corasil II column and eluted with hexane that is gradient programmed with a solution of chloroform-methanol-diethylamine ( 100+300+1). The absorbances of the separated alkaloids are continuously monitored at 254 nm, using a flow-through ultraviolet double-beam photometer.
Collaborative Study of a Semiautomated Method for the Determination of Crude Protein in Animal Feeds
Authors: Noel Rodney J , Hambleton Larry G
Published: February 2020

A semiautomated method consisting of digestion of animal feeds in a block digestor and determination of ammonia by ammonia-salicylate reaction has been studied collaboratively, along with the official final action Kjeldahl method, sec. 7.016. Each collaborator analyzed 16 feed samples, tryptophan, ammonium dihydrogen phosphate NBS standard, and ammonium sulfate primary standard. Statistical analysis showed that the 2 methods agreed. The semiautomated method has been adopted as official first action.
Separation of Pesticide Residues from Lipids Prior to Gas-Liquid Chromatographic Analysis
Authors: Lea Robert
Published: February 2020

Lipids are separated from dieldrin, endrin, and p,p′-DDE residues by saponification in ethanolic sodium hydroxide, acidification with dilute sulfuric acid, and adsorption chromatography on deactivated alumina, using petroleum ether as the eluant. Dieldrin, endrin, and p,p′-DDE are efficiently recovered (95–102%), and p,p′-DDT is converted to p,p′-DDE, which is then recovered with high yield (90–96%). Extremely low lipid carryover (<0.3–0.5%) is observed for 0.5–1.0 g samples of chicken fat.
High-Pressure Liquid Chromatographic Determination of Vitamin D3 in Resins, Oils, Dry Concentrates, and Dry Concentrates Containing Vitamin A
Authors: Hofsass Henry , Grant Anne , Alicino Nicholas J , Greenbaum Sheldon B
Published: February 2020

A high-pressure liquid chromatographic (HPLC) procedure has been developed for the determination of vitamin D3 in resins, oils, dry concentrates, and dry concentrates containing vitamin A. Specificity of the method for vitamin D3 in the presence of isomers and other related constituents was shown by ultimate recovery of the vitamin D3 and the individual constituents and their characterization by other methods such as ultraviolet spectrophotometry. Precision and accuracy are within 2%, and as many as 20 determinations may be completed in a working day. Excellent agreement with the official AOAC biological assay was found. A comparison of the response of isomers of vitamin D3 by the HPLC method vs. other instrumental and chemical procedures shows HPLC to be the most specific method for determining the bioactive isomers.
High-Performance Liquid Chromatographic Determination of Warfarin
Authors: Billings Toby J , Hanks Alan R , Colvin Billy M
Published: February 2020

A high-performance liquid chromatographic (HPLC) method for determining warfarin, 3-(α-acctonylbenzyl)-4-hydroxycoumarin, in rodenticide formulations is described. Samples containing warfarin are ground, extracted 1 hr on a rotary shaker with dioxane-1% sodium pyrophosphate (85+15), centrifuged, and filtered. The filtrate is injected onto an HPLC column containing C18-μBondapak with a precolumn of C18-Corasil. The eluting solvent is 0.0025N H3PO4-methanol (1+2) at a flow rate of 1.5 ml/min. Chromatography is complete within 10 min and warfarin is detected by ultraviolet absorption at 283 nm. Results indicate good reproducibility with a 2.4% average coefficient of variation for a variety of commercial samples containing 0.025–0.5% warfarin. This method is also applicable to samples containing sodium warfarin. The HPLC method is rapid and specific. Results obtained agree with those from more commonly employed ultraviolet spectrophotometric methods.
Detection of Sprouted Wheat by a Rapid Colorimetric Determination of α-Amylase
Authors: Mathewson Paul R , Pomeranz Yeshajahu
Published: February 2020

A method is described for the rapid, convenient detection or estimation of sprout-damaged wheat by determining its α-amylase content colorimctrically. A commercially available substrate in the form of dyed amylose tablets is used. The extent of sprout damage can be determined qualitatively, or quantitatively when actual α-amylase concentration is required. Amylase content is determined by visual comparison with prepared colored standards or by spectrophotometric analysis. The method requires only 5 min incubation time and no elaborate equipment, and is sufficiently simple for use at locations having minimal laboratory facilities.
Modified AOAC Method for Determination of Moisture in Corn Sirups
Authors: Engel C Earl
Published: February 2020

Investigation of the current AOAC vacuum oven filter aid method for determining moisture in corn sirups revealed that minor modifications are needed to make the method applicable to the com sirups now produced by the wet milling industry. The proposed method incorporates AOAC methodology which requires a drying temperature of 70°C for fructose-containing materials and continues the drying temperature of 70°C for high dextrose products. Other corn sirups will continue to be dried at 100°C. In addition, the proposed method incorporates some of the improvements which were evident in the original publication but were not included in the current AOAC method. The modified method has been adopted as official first action.
Identification of Polychlorinated Styrene Compounds in Heron Tissues by Gas-Liquid Chromatography-Mass Spectrometry
Authors: Reichel William L , Prouty Richard M , Gay Martha L
Published: February 2020

Unknown compounds detected in Ardea herodias tissues are identified by gas-liquid chromatography-mass spectrometry as residues of octachlorostyrene. Heptachlorostyrene and hexachlorostyrene were tentatively identified.
Determination of Protein Nitrogen in Plants
Authors: Gaines T Powell
Published: February 2020

A method is described for determining protein nitrogen (PN) in plants. Plant tissue extracted with 0.5% acetic acid to remove nonprotein nitrogen (NPN) prior to Kjeldahl analysis gave results very close to true PN, whereas AOAC crude PN method 2.049 gave results much too high. True PN was determined as the mean of 3 independently derived values and was used as the basis for comparing the proposed PN method with AOAC method 2.049. Failure of the AOAC method to differentiate between NPN and/or inorganic ammoniacal N and actual PN causes values derived from this method to be too high when it was used to determine PN in plants.
Identification of Post-Explosion Residues
Authors: Kaplan Meyer A , Zitrin Shmuel
Published: February 2020

A scheme for the identification of explosive residues from post-explosion scenes is described. The first step consists of organic and inorganic extractions rather than microscopic examination. The methods of identification which follow include thin layer and gas-liquid chromatography, infrared and ultraviolet spectroscopy, and chemical tests. The system, which has been used routinely by the Israel Police for 5 years, deals efficiently with standard military explosives as well as with home-made, improvised mixtures.
Confirming Heptachlor and Heptachlor Epoxide in Food Samples by Gas-Liquid Chromatography of Their Photo derivatives
Authors: Ward Paul M
Published: February 2020

The food sample extract is cleaned up on a Florisil column and the 6% ethyl ether in petroleum ether eluate is subjected to repeated concentrations, using a micro-Snyder column, to expel volatile materials that absorb ultraviolet (UV) light. The sample and standard solutions of heptachlor and heptachlor epoxide are placed in quartz cells and exposed to UV radiation in the dark. Characteristic photoderivatives of the respective pesticides which form in the sample extract are identified and measured by comparison with those formed in the irradiated standard solutions, using electron capture gas-liquid chromatography. Recoveries of the 2 pesticides from 13 products, fortified at levels from 0.01 to 0.3 ppm and determined after derivatization, ranged from 67 to 110%.
Rapid Digestion and Flameless Atomic Absorption Spectroscopy of Mercury in Fish: Collaborative Study
Authors: Munns Robert K , Holland David C
Published: February 2020

A collaborative study of the determination of mercury in fish has been completed in which wet oxidation of fish tissue in nitric acid, using vanadium as a catalyst, is compared with the AOAC official final action digestion technique, 25.103–25.105, involving a nitric-perchloric acid mixture. The study used tuna fish samples of known mercury content and included spike recovery studies in which methyl mercury solutions of known composition were provided to each laboratory. The study was designed to provide recovery information that bracketed the regulatory level of mercury in fish. The results indicate that the proposed digestion method is at least as precise and accurate as the AOAC method. The proposed method is also more rapid and less hazardous. It has been adopted as official first action.
Glucosinolates and Derived Products in Cruciferous Vegetables: Gas-Liquid Chromatographic Determination of the Aglucon Derivatives from Cabbage
Authors: Daxenbichler Melvin E , VanEtten Cecil H
Published: February 2020

A procedure is described for identifying and quantitatively determining the gīucosinolates found in edible cabbage. The intact glucosinolates are extracted and their aglucons are released into solvent after a special enzymatic hydrolysis step. The resulting isothiocyanates and oxazolidinethiones are separated by a gas-liquid chromatographic procedure that allows the individual aglucons to be identified and their amounts to be estimated by comparison with an internal reference.
Application of Reverse Phase Ion-Pair Partition Chromatography to Drugs of Forensic Interest
Authors: Lurie Ira
Published: February 2020

A method is described for determining a wide range of abused drugs by using 1 column, a single isocratic system, and a fixed wavelength (254 nm) ultraviolet detector. Paired-ion chromatography is performed on a reverse phase μBondapak C18 column. Acidic, basic, and neutral drugs, including their corresponding salts, can be determined without prior cleanup. A counter ion, 1-heptane sulfonate, is dissolved in the aqueous organic mobile phase to give a final pH of approximately 3.5. This technique is applicable to ergot alkaloids, phenylethylamines, opium alkaloids, local anesthetics, barbiturates, and other drugs of forensic interest. Five major opium alkaloids in gum opium, namely, morphine, codeine, thebaine, narcotine, and papaverine, can be separated in approximately 20 min.
Microdetermination of Tryptophan in Compounded Poultry Rations
Authors: Datta Salil C
Published: February 2020

A reliable method for the microdetermination of tryptophan in compounded poultry rations has been developed. Samples are hydrolyzed with Ba(OH)2, and the hydrolysate is passed through a Dowex-50 column to remove the salts and soluble carbohydrates. N-l-Naphthylethylenediamine is added to the purified feed hydrolysate, and color is read at 530 nm.
Balancing Patient Care and Force Protection at Military Medical Treatment Facilities
Authors: Nardi Sean , Ferguson Brian , Peck Sean , Ross Elliot , Walrath Benjamin
Published: February 2020

Objectives

This study aimed to identify delays of care due to base access security protocols at a stateside military medical treatment facility (MTF) for patients with a time-sensitive medical condition who are seeking emergency medical care at the MTF.

Methods

We retrospectively analyzed emergency medical services (EMS) run reports from January 1, 2017 to November 12, 2017 to hospital access points to assess patients who were initially denied access to the MTF. Time from EMS activation until patient delivery at the emergency department, number of time-sensitive complaints, number of time-sensitive conditions, and number of unauthorized access attempts are reported.

Results

During the 11-month period of review, 42 delays of care related to EMS activation by the sentry at hospital access points were identified. Of the 42, 14 were associated with a time-sensitive complaint, 2 with time-sensitive conditions, and none were unauthorized access attempts.

Conclusion

We identify the potential for patient harm due to delays in care resulting from the security protocols at our MTF. A review of force protection requirements with consideration for their impact on patient safety, especially in cases of time-sensitive conditions, has been conducted.
It Totally Possibly Could Be: How a Group of Military Physicians Reflect on Their Clinical Reasoning in the Presence of Contextual Factors
Authors: Konopasky Abigail , Ramani Divya , Ohmer Megan , Battista Alexis , Artino Anthony R , McBee Elexis , Ratcliffe Temple , Durning Steven J
Published: February 2020

Introduction

Contextual factors (eg, diagnostic suggestion and burnout) can affect physician clinical reasoning performance, leading to diagnostic error. Yet, contextual factors have only recently been studied and none of that work focused on how physicians appraise (ie, evaluate) the clinical situation as they reason. The purpose of this qualitative study was to use appraisal to describe the effect of contextual factors on clinical reasoning.

Materials and Methods

Physicians (n = 25) either viewed two video cases or participated in two live scenarios, one with contextual factors and one without. Afterwards, they completed a “think-aloud” reflection while reviewing the cases. Transcribed think-alouds were coded for appraisal markers, comparing cases with and without contextual factors.

Results

When contextual factors were present, participants expressed more emotional evaluation and uncertainty about those emotions. Across all types of cases, participants expressed uncertainty about the case and assessed what “could” or “would” have gone differently.

Conclusions

This study suggests that one major effect of contextual factors may be that they induce emotions, which may affect the process of clinical reasoning and diagnostic error. It also suggests that uncertainty may be common in clinical practice, and we should thus further explore its impact.
Towards a Treatment for Gulf War Illness: A Consensus Docking Approach
Authors: Jaundoo Rajeev , Bohmann Jonathan , Gutierrez Gloria E , Klimas Nancy , Broderick Gordon , Craddock Travis J A
Published: February 2020

Introduction

Gulf War Illness (GWI) currently has no known cure and affects soldiers deployed during the Persian Gulf War. It is thought to originate from exposure to neurotoxicants combined with battlefield stress, and previous research indicates that treatment first involves inhibition of interleukin-2 and tumor necrosis factor alpha, followed by the glucocorticoid receptor. However, the off-target effects of pharmaceuticals hinder development of a drug treatment therapy.

Materials and Methods

AutoDock 4.2, AutoDock Vina, and Schrodinger’s Glide were used to perform consensus docking, a computational technique where pharmaceuticals are screened against targets using multiple scoring algorithms to obtain consistent binding affinities. FDA approved pharmaceuticals were docked against the above-mentioned immune and stress targets to determine a drug therapy for GWI. Additionally, the androgen and estrogen targets were screened to avoid pharmaceuticals with off-target interactions.

Results

While suramin bound to both immune targets with high affinity, top binders of the hormonal and glucocorticoid targets were non-specific towards their respective proteins, possibly due to high structure similarity between these proteins.

Conclusions

Development of a drug treatment therapy for GWI is threatened by the tight interplay between the immune and hormonal systems, often leading to drug interactions. Increasing knowledge of these interactions can lead to break-through therapies.
Army Antimalarial Drug Development: An Advanced Development Case Study for Tafenoquine
Authors: Zottig Victor E , Carr Katherine A , Clarke John G , Shmuklarsky Moshe J , Kreishman-Deitrick Mara
Published: February 2020

Malaria is classified as a top-tier infectious disease threat associated with a high risk for mortality among U.S. service members deployed overseas. As malarial drug resistance degrades the efficacy of current gold standard drugs for malarial prophylaxis and treatment, it is vitally important to maintain a robust drug pipeline to discover and develop improved, next-generation antimalarial prevention and treatment tools. The U.S. Army Medical Materiel Development Activity (USAMMDA) manages the medical product development of the malarial drug tafenoquine for malarial prophylaxis to address the threat to U.S. service members. Tafenoquine is an effective prophylactic drug against all parasite life cycle stages and all malaria species that infect humans. Thus, it provides broad capabilities in a single drug for malarial prophylaxis and treatment. Partnerships with industry are a crucial part of USAMMDA’s medical product development strategy, by leveraging their drug development experience and manufacturing capabilities to achieve licensure and commercial availability. Additionally, these partnerships capitalize on expertise in the commercial market and help ensure that USAMMDA successfully translates a Department of Defense capability gap into a commercially available product. This article will highlight the strategies used to move this critical antimalarial drug through the development pipeline.
The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: evidence for a diverse, evolving population
Authors: Calhau João , Sobral David , Santos Sérgio , Matthee Jorryt , Paulino-Afonso Ana , Stroe Andra , Simmons Brooke , Barlow-Hall Cassandra , Adams Benjamin
Published: February 2020

Despite recent progress in understanding Ly α emitters (LAEs), relatively little is known regarding their typical black hole activity across cosmic time. Here, we study the X-ray and radio properties of ∼4000 LAEs at 2.2 < $z$ < 6 from the SC4K survey in the COSMOS field. We detect 254 ($6.8{\rm{ per\ cent}} \pm 0.4{\rm{ per\ cent}}$) LAEs individually in the X-rays (S/N > 3) with an average luminosity of $\rm 10^{44.31\pm 0.01}\, erg\, s^{-1}$ and average black hole accretion rate (BHAR) of $\rm 0.72 \pm 0.01$ M⊙ yr−1, consistent with moderate to high accreting active galactic neuclei (AGNs). We detect 120 sources in deep radio data (radio AGN fraction of $3.2{\rm{ per\ cent}} \pm 0.3{\rm{ per\ cent}}$). The global AGN fraction ($\rm 8.6{\rm{ per\ cent}} \pm 0.4{\rm{ per\ cent}}$) rises with Ly α luminosity and declines with increasing redshift. For X-ray-detected LAEs, Ly α luminosities correlate with the BHARs, suggesting that Ly α luminosity becomes a BHAR indicator. Most LAEs ($93.1{\rm{ per\ cent}} \pm 0.6{\rm{ per\ cent}}$) at 2 < $z$ < 6 have no detectable X-ray emission (BHARs < 0.017 M⊙ yr−1). The median star formation rate (SFR) of star-forming LAEs from Ly α and radio luminosities is $7.6^{+6.6}_{-2.8}$ M⊙ yr−1. The black hole to galaxy growth ratio (BHAR/SFR) for LAEs is <0.0022, consistent with typical star-forming galaxies and the local BHAR/SFR relation. We conclude that LAEs at 2 < $z$ < 6 include two different populations: an AGN population, where Ly α luminosity traces BHAR, and another with low SFRs which remain undetected in even the deepest X-ray stacks but is detected in the radio stacks.
The chemical compositions of accreted and in situ galactic globular clusters according to SDSS/APOGEE
Authors: Horta Danny , Schiavon Ricardo P , Mackereth J Ted , Beers Timothy C , Fernández-Trincado José G , Frinchaboy Peter M , García-Hernández D A , Geisler Doug , Hasselquist Sten , Jönsson Henrik , Lane Richard R , Majewski Steven R , Mészáros Szabolcs , Bidin Christian Moni , Nataf David M , Roman-Lopes Alexandre , Nitschelm Christian , Vargas-González J , Zasowski Gail
Published: February 2020

Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic association, we break the sample down into eight separate groups and examine how the kinematics-based classification maps into chemical composition space, considering only α (mostly Si and Mg) elements and Fe. Our results show that (i) the loci of both in situ and accreted subgroups in chemical space match those of their field counterparts; (ii) GCs from different individual accreted subgroups occupy the same locus in chemical space. This could either mean that they share a similar origin or that they are associated with distinct satellites which underwent similar chemical enrichment histories; (iii) the chemical compositions of the GCs associated with the low orbital energy subgroup defined by Massari and collaborators is broadly consistent with an in situ origin. However, at the low-metallicity end, the distinction between accreted and in situ populations is blurred; (iv) regarding the status of GCs whose origin is ambiguous, we conclude the following: the position in Si–Fe plane suggests an in situ origin for Liller 1 and a likely accreted origin for NGC 5904 and NGC 6388. The case of NGC 288 is unclear, as its orbital properties suggest an accretion origin, its chemical composition suggests it may have formed in situ.