bluuebunny/crossref_metadata_2025_split huggingface dataset:
Normal Phase Liquid Chromatographic Determination of Nanogram Quantities of Ivermectin in
Cattle Blood or Plasma
Authors: Schnitzerling Herbert J , Nolan James 
Published: February 2020

Abstract
A method has been developed for determining ivermectin in 5 mL samples of cattle blood by a 2-step process: cleanup solvent extraction followed by direct injection onto a normal phase liquid chromatography (LC) system with UV detection. Recovery was 77-80% ±5.5% standard deviation. Endogenous interference that may be present caused the lower limit of detection to be set at 4-5 ng/mL. The method was used to show that in blood the distribution of ivermectin favors plasma in a fixed proportion over cellular material, and further to provide a time-course profile of ivermectin in the whole blood of injected cattle. In whole blood, ivermectin concentration peaked between 3 and 5 days and dissipated slowly with a half-life of 3 days.
Atomic Absorption Spectrophotometric Determination of Liver Copper: Collaborative Study
Authors: Osheim David L , Ross Frank P 
Published: February 2020

Abstract
Eleven collaborating laboratories conducted replicate analyses on 4 blind duplicate pairs of bovine liver samples that either had naturally acquired copper levels or were spiked with one of 3 copper levels. A National Bureau of Standards Bovine Liver sample (SRM 1577, 193 ± 10 mg copper/kg) and a 1000 mg copper/L standard were also submitted to the collaborators. The method requires the tissue to be digested with concentrated HN03 at 60°C, diluted to volume with water, and analyzed by atomic absorption spectrophotometry. The intralaboratory coefficients of variation (CV„) ranged from 5.6 to 19%; the interlaboratory CVX values ranged from 7.1 to 21%. The lower limit of detection was estimated to be 1 mg copper/kg tissue. The method has been adopted official first action.
Improved Polarographic Method for Determination of Glyphosate Herbicide in Crops, Soil,
and Water
Authors: Friestad Hakon O , Bronstad Jan O 
Published: February 2020

Abstract
A prior method for determination of glyphosate in water samples has been modified to accommodate samples of crops and soils. Differential pulse polarography as the determinative step enables analysis in an aqueous medium, which is important during extraction of this compound. Residues are cleaned up and concentrated by ion exchange on a strong basic resin in OH- form. The method is rapid, is applicable to a relatively broad selection of sample types, and gives recoveries consistently better than 60% with good precision. The main shortcoming of the method is that the limit of detection of 0.5-1.0 ppm may sometimes be inadequate. The metabolite, aminomethyl phosphonic acid, is not detected.
Liquid Chromatographic Determination of Primidone in Tablets: Collaborative Study
Authors: Roberts Stanley E 
Published: February 2020

Abstract
Six laboratories collaboratively studied a liquid chromatographic (LC) method for the quantitative determination of primidone in tablets. Two lots each of commercially prepared 50 and 250 mg tablets and 2 authentic mixtures, at 50 and 250 mg levels, were sent to each collaborator. Samples were dissolved in the mobile phase, filtered, and injected into the chromatograph. Average recoveries for the 8 samples ranged from 97.5 to 101.2%, and coefficients of variation ranged from 0.53 to 3.01%. The LC method has been adopted interim official first action.
Analysis of USP Epinephrine Injections for Potency, Impurities, Degradation Products, and d-Enantiomer by Liquid Chromatography, Using Ultraviolet and Electrochemical Detectors
Authors: Kirchhoefer Ross D , Sullivan Gerard M , Allgire James F 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was adapted for the determination of epinephrine and related impurities in intravenous and cardiac injections; ultraviolet (UV) and electrochemical detectors (EC) were used in series. Epinephrine was determined and related impurities, i.e., adrenalone, epinephrine sulfonic acid, and norepinephrine, were detected directly in a small portion of the injection solution. Diastereoisomers of the epinephrine enantiomers were prepared by derivatization and determined by LC with a UV detector. The recovery of epinephrine added to epinephrine injection was 100%. The recovery of d-enantiomer from ad, I mixture was 100%. Impurities at levels &lt; 1% were easily detected. The LC method with UV detection is faster and more convenient than the USP XX method. In addition, impurities can be detected in the same portion of sample. The procedure is stability- indicating.
Simple Automated Wet Digestion of Animal Tissues for Determination of Seven Elements by Atomic Absorption Spectroscopy
Authors: Salisbury Craig D , Chan Wayne 
Published: February 2020

Abstract
A simple, automated wet digestion procedure was developed for the quantitative determination by atomic absorption spectroscopy (AAS) of arsenic, cadmium, copper, mercury, lead, selenium, and zinc in animal tissue. A commercial digestion block system with automated temperature programming was used. Recoveries of all elements from spiked bovine liver and kidney samples exceed 95%. The analytical results obtained for samples of NBS Bovine Liver (No. 1577a) agree well with certified values. The procedure is safe and requires minimum analyst time.
Analysis of Phenols by Chemical Derivatization. IV. Rapid and Sensitive Method for Analysis of 21 Chlorophenols by Improved Chloroacetylation Procedures
Authors: Lee Hing-Biu , Hong-You Robert L , Chau Alfred S Y 
Published: February 2020

Abstract
A quantitative, rapid, sensitive, and isomer-specific method for the analysis of chlorophenols in natural water by in situ chloroacetylation is presented. Without pre-extraction, phenols in water are chloroacetylated by chloroacetic anhydride in the presence of K2CO3. Because of differences in reaction kinetics and stability, various chloroacetates were removed from the reaction mixture at different intervals. If analysis of other classes of neutral organic compounds is also required, a more elaborate procedure involving solvent extraction of organic compounds and back-extraction of phenols into K2CO3 solution followed by chloroacetylation is proposed. When a 12 m OV-1 fused silica capillary column was used, 22 phenol chloroacetates were easily resolved in a single run. Using distilled and natural water samples, this method has been validated and shown to be applicable over a concentration range of 0.1 to 100 μg/L of the phenols studied.
Irace Level Detection of Chlorinated Paraffins in Biological and Environmental Samples, Using
Gas Chromatography/Mass Spectrometry with Negative-Ion Chemical Ionization
Authors: Schmid Peter P , Muller Markus D 
Published: February 2020

Abstract
A method is described for detection of chlorinated paraffins (CPs) in biological and environmental samples. Sample preparation includes sulfuric acid treatment followed by adsorption chromatography on ilumina, which yields the CPs in one fraction that is almost free of interfering material. Using gas chromatography/mass spectrometry j with negative-ion chemical ionization, the limit of detection is 5 ng (corresponding to the lower ppb range). CP levels of 30 ppm, 200 ppb, ' and 5 ppb were found in sewage sludge, human fat, and sediment, respectively.
Purge and TVap Method for Determination of Ethylene Dibromide in Table-Ready Foods
Authors: Heikes David L 
Published: February 2020

Abstract
An improved method has been developed for the determination of ethylene dibromide (EDB, 1,2-dibromoethane) in a variety of tableready foods. Samples are mixed with water and sparged with nitrogen for 1 h with stirring in a water bath at 100°C. The EDB collected on the adsorbent Tenax TA is eluted with hexane and determined by gas chromatography (GC) with electron capture (EC) and confirmed with Hall electrolytic conductivity (HECD) detection using a second GC column. The highest levels of EDB were also confirmed by full scan GC/mass spectrometry (GC/MS). Twenty-five table-ready foods from the Food and Drug Administration's Total Diet Study that were analyzed by this method exhibited levels up to 70 ppb (pecans). Recoveries from fortified samples ranged from 91 to 104%. Values from this procedure were compared to those obtained by a modified Rains and Holder codistillation method. In all 25 samples this purge and trap procedure showed equivalent or superior recoveries and detected levels of EDB.
Liquid Chromatographic Determination of Hypoxanthine Content in Fish Tissue
Authors: Burns Garth B , Ke Paul J 
Published: February 2020

Abstract
A liquid chromatography (LC) method for determining the hypoxanthine content in fish tissues has been developed. Hypoxanthine is extracted with 0.6M perchloric acid, and determined by LC on a reverse phase microparticulate column with UV absorbance detection. The mobile phase is 0.01M potassium phosphate buffer (pH 4.5). The percent relative standard deviation for measurements by the recommended method was less than 7% with a detection limit of 10 ng. Recoveries of hypoxanthine added to various fish tissues were better than 90%. The operational errors, interferences, and recoveries for spiked samples have been investigated and compare favorably with an established xanthine oxidase enzyme method. The described LC method is simple, rapid, and specific for measuring hypoxanthine content in various fish tissues. Some post-mortem studies have indicated the method may also be used for the determination of adenosine monophosphate, inosine monophosphate, and inosine.
Isotopic Composition of Carbon in Vinegars
Authors: Krueger Dana A , Krueger Harold W 
Published: February 2020

Abstract
Measurements of δ13C and 14C-activity were performed on vinegars from various known sources. Natural vinegar can be distinguished from petrochemical acetic acid by 14C-analysis: Natural vinegar currently gives values of &gt; 112% of modern activity; petrochemical acetic acid yields values of 0% of modern activity. Apple cider vinegar can be distinguished from corn-derived vinegar by δ13C-analysis: Cider vinegar gives δ13C-values near — 26%o; corn-derived vinegars yield δ13C-values near - 10% δ13C-Analysis also can be applied, with some restrictions, to wine vinegars. These techniques are applied to a series of retail vinegars.
Effect of pH on Absorbance of Azo Dye Formed by Reaction Between Nitrite and Sulfanilamide/
N-(l-Naphthyl)ethylenediamine in Residual Nitrite Methods for Foods
Authors: Davis Carl E , Leffler Richard , Anderson John B , Soderberg David L , Meredith Filmore I 
Published: February 2020

Abstract
Current methods used for determining residual nitrite concentration in foods involve forming an azo dye that is measured spectrophotometrically. Conventional procedures do not specify control of pH for the final colored solution. Because many indicator dyes are pH-dependent, absorbance of the azo dye may vary not only because of nitrite concentration differences, but also because of pH variation. Thus, erroneous results could arise from a standard curve developed at one pH and used for a test sample at a different pH. This would cause an inaccurate concentration conversion from the standard curve. In this study, absorbances at λmax wavelengths were recorded at 28 pH values (range 1.0-4.5) for each of 5 nitrite concentrations. A mathematical equation was fitted to these data and its plot gives a 3-dimensional response surface showing the relationships between pH, nitrite concentration, and absorbance. A modification for the spectrophotometric measurement of nitrite is proposed.
Vitamin A and Vitamin E Content of Infant Formulas Produced in the United States
Authors: Landen William O , Hines Don M , Hamill Thomas W , Martin James I , Young Ednar , Eitenmiller Ronald R , Soliman Abdel-Gawad M 
Published: February 2020

Abstract
Vitamin A (vitamin A palmitate) and vitamin E (a-tocopheryl acetate) levels were determined in 77 samples of fortified infant formulas manufactured by 4 firms in the United States from 1981 to 1983 and were compared by formulation base (soy, milk) and manufacturing firm. For vitamin A and vitamin E, the mean values (IU/100 kcal) were 454 ± 95 (range 248-614) and 2.0 ± 0.7 (range 1.1-5.0), respectively. No significant differences (a = 0.05) were found in levels (IU/100 kcal) of vitamin A and vitamin E between milk- and soy-based formulas. When the mean vitamin A and vitamin E levels of formulas produced by the various firms were compared on an IU/100 kcal or percent of label declaration basis, significant differences (a = 0.05) were found among firms. Mean vitamin A levels for the various products compared to label declarations ranged from 126% of declared for the ready-to-use formulas to 139% of declared for the powders. Mean vitamin E levels ranged from 97% of declared for ready-to-use formulas to 118% of declared for concentrates. Except for one sample that contained 248 IU vitamin A/100 kcal, the formulas met the requirements of the 1980 Infant Formula Act.
Atomic Absorption Spectrophotometric Determination of Cobalt in Foods
Authors: Barbera Reyes , Farre Rosaura , Montoro Rosa 
Published: February 2020

Abstract
A method is described for the determination of cobalt in foods. After wet digestion, iron in the sample is removed by liquid-liquid extraction, and cobalt is isolated and extracted. Final determination is done by flame atomic absorption spectrophotometry. Analysis of NBS reference materials by this procedure gives results in close agreement with certified values. The limit of quantitation is 4.3 ng/mL. Recovery studies and analysis of standard materials show that this method is reliable.
Determination of Reserpine in Commercial Tablets by Liquid Chromatography with Fluorescence Detection
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A procedure is presented for the determination of reserpine in commercial tablets by liquid chromatography (LC). The sample is extracted with methanol if only reserpine is present. If the sample contains other ingredients, CHCl3 is used for extraction from aqueous suspension; the CHCl3 is subsequently completely evaporated in the presence of methanol. For LC, a normal phase column, methanol as the eluting solvent, and a fluorometric detector are used. A recovery study indicated that no measurable degradation of reserpine occurs during evaporation of the CHCl3 extract. Several commercial tablets containing reserpine alone or in combination with other ingredients were analyzed by the proposed method, and the results were compared with those obtained by the current official USP methods for reserpine.
Detection of Parasites in Fish Muscle by Candling Technique
Authors: Valdimarsson Grimur , Einarsson Hjalti , King Frederick J 
Published: February 2020

Abstract
This study determined optimum conditions for detecting codworms in skinned cod fillets by using candling tables under commercial conditions. The best balance of factors was sought for obtaining maximum lighting conditions, reducing operator fatigue, retaining natural fillet color, and having a high contrast between parasites and fish flesh. Based on the results obtained, a recommended procedure has been adopted by AOAC.
Liquid Chromatographic Determination of Aminocarb in Technical and Formulated Products: Collaborative Study
Authors: Slahck Stephen C 
Published: February 2020

Abstract
An LC method for determination of aminocarb (Matacil™) in aminocarb technical and formulated products has been developed and subjected to a collaborative study with 10 participating collaborators. Formulations are extracted with tetrahydrofuran-buffer (60 + 40) and analyzed by reverse phase chromatography, with n-butyrophenone as internal standard. Collaborators were furnished with standards and samples of technical and 180 oil flowable products for analysis. Coefficients of variation obtained on these samples were 0.72 and 1.7%, respectively. The method has been adopted official first action.
Simultaneous Liquid Chromatographic Determination of Rotenone and Pyrethrins in Formulations
Authors: Bushway Rodney J , Johnson Harold , Scott Donald W 
Published: February 2020

Abstract
This paper describes a reverse phase liquid chromatographic (LC) method to simultaneously determine rotenone and pyrethrins in pesticide formulations. The mixed standards along with the formulations were accurately weighed to contain approximately 200 (μg rotenone and 150 (μg pyrethrins/mL. Stabilized tetrahydrofuran was used to dissolve all substances. An aliquot was injected into the LC system equipped with a Zorbax ODS column, and chromatographed with a mobile phase of acetonitrile-water (70 + 30). Rotenone and the pyrethrins were monitored at 240 nm and 0.4 AUFS. Retention times for rotenone, pyrethrin II, and pyrethrin I were approximately 7, 11.5, and 25.5 min, respectively. For 3 different formulations analyzed 6 times each, the percent coefficients of variation were all &lt; 3. This method is also applicable to products containing either rotenone or pyrethrins. No significant interferences were observed from the inactive ingredients of the formulations at the concentrations added.
Determination of Polychlorinated Dibenzo-p-Dioxins in Technical Pentachlorophenol
Authors: Singh Joginder , Miles Walter , Barrette Jean P 
Published: February 2020

Abstract
Thirty-four technical pentachlorophenol samples from 4 different manufacturers were analyzed for the presence of hexa-, hepta-, and octachlorodioxins. A double column procedure for extraction and cleanup was used for processing the samples, followed by gas chromatographymassspectrometry for qualitative and quantitative determinations. All runs were performed isothermally on a packed glass column of 3% Dexsil 400. Octachloronaphthalene was used as an internal standard for quantitative estimations. The amounts of chlorodioxins found ranged from 1 to 38.5 ppm hexachlorodioxin, 119 to 562 ppm heptachlorodioxin, and 361 to 1723 ppm octachlorodioxin. Interfering polychlorinated diphenyl ethers and polychlorinated dibenzofurans were also observed in these samples.
Improved Cleanup for Gas Chromatographic Determination of Propiconazole Residues in Soil, Wheat Grain, Straw, and Leaves
Authors: Bai Quing-Yun , Liu Chang Wu 
Published: February 2020

Abstract
A simple and sensitive method is described for determination of propiconazole, a new type of broad-spectrum systemic fungicide, in soil, wheat grain, straw, and leaves. Pesticide residues in or on grain and green plant materials are extracted with methanol (or a mixture of methanol and water (4 + 1), for soil), partitioned into methylene chloride, and cleaned up on an alumina column for grain and soil or an activated charcoal column for green plant materials. The amount of residue is quantitatively measured by gas chromatography using an alkali flame ionization detector in the nitrogen-sensitive mode. Recoveries from soil, grain, and green plant materials fortified at 0.1-5 mg/ kg are better than 80%. The practical detection limits of this method are 0.01 mg/kg in grain and soil and 0.02 mg/kg in green plant materials.
Liquid Chromatographic Analysis of Dehydroacetic Acid and Its Application to Wines
Authors: Welling Paul L M , Van Duyvenbode Marianne C , Kaandorp Ben H 
Published: February 2020

Abstract
A simple liquid chromatographic procedure is described for determination of the preservative dehydroacetic acid (DHA) in wine. No cleanup procedure is necessary; the sample is injected onto an NH2 column without further pretreatment. The mobile phase is a 9 + 1 mixture of acetonitrile-sodium acetate buffer adjusted to pH 4 with acetic acid. Total run time is less than 10 min. Dehydroacetic acid is determined by using the absorbance at 307 nm; the detection limit is estimated to be 0.2 ppm. The method may also be suitable for detecting DHA in a variety of foodstuffs in low concentrations
Liquid Chromatographic Determination of Carbadox Residues in Animal Feed
Authors: Roybal Jose E , Munns Robert K , Shimoda Wilbert 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for determining residues of carbadox in the 0.01-10 ppm range in swine feed is described. Carbadox is extracted from ground feed with 25% acidified methanol- CHCl3, removed from emulsion-forming coextractables via an alumina column, separated from highly colored pigments by acid-base liquid- , liquid partitioning, and finally isolated from interferences on a second | alumina column. Isocratic reverse phase LC at 305 nm is used for quantitation. The average overall recovery at the 0.1,0.5, and 1.0 ppm J spike levels was 83.0% with a standard deviation of 2.04% and a coefficient of variation of 2.46 %.
Assessment of Protein Quality Methodology for Infant Formulas
Authors: Mitchell Geraldine Vaughan , Jenkins Mamie Young 
Published: February 2020

Abstract
Rat bioassay was used to assess the protein quality of powdered infant formulas and to evaluate the feasibility of using modified casein diets (containing the same source and level of fat and carbohydrate contributed by the infant formulas) as reference standards. Modification of the casein diet to match the milk-based formulas caused a significant reduction in weekly protein efficiency ratios (PER) and net protein ratios (NPR) at the third and fourth weeks. Modification of the casein diet to simulate the soy-based formulas had no significant effect on NPR values; PER values were more varied. When PER and NPR values of the powdered milk-based formulas were expressed relative to the unmodified reference standard, the relative values were lower than when each matched reference was used. With few exceptions, the relative weekly PER values of the soy-based formulas were similar regardless of the standard used. The relative NPR values of the formulas had a pattern similar to the relative PER values. The data indicate that protein quality evaluation of infant formulas using rat bioassay warrants the use of matched casein reference diets for each type of formula.
Corrected Relative Net Protein Ratio (CRNPR) Method Based on Differences in Rat and Human Requirements for Sulfur Amino Acids
Authors: Sarwar Ghulam , Peace, Robert W , Botting Herbert G 
Published: February 2020

Abstract
The requirement for sulfur amino acids was calculated for growing rats fed 8% protein diets. The r a t and human requirements for sulfur amino acids were compared and a correction factor was developed to reflect the differences. This correction factor was used to determine corrected relative net protein ratio (CRNPR) values for a number of potential meat extenders and their mixtures with beef. The methionine + cystine requirement of growing rats was estimated to be 4% of protein for 8% protein diets. The methionine + cystine requirement of rats was about 50% higher than that of humans (2.65% of protein). Based on this comparison (rat/human), a correction factor of 1.5 was developed to correct RNPR values of those protein products that were deficient in sulfur amino acids for r a t growth. The CRNPR values of beef, casein, soybean protein products, pea concentrate, and peanut meal were 100,100, 91-97, 75, and 73, respectively. Mixtures (50:50 protein basis) of beef with casein, soybean concentrate, soybean isolate, pea concentrate, peanut meal, rapeseed concentrate, rapeseed isolate, sunflower isolate, or wheat gluten were equal to beef in CRNPR values. The CRNPR method is a good predictor of protein quality for humans of those protein products that are deficient in sulfur amino acids.