bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Diastereomeric Purity of Tranylcypromine Sulfate by Proton Magnetic Resonance Spectroscopy with Lanthanide Shift Reagent
Authors: Hanna George M , Lau-Cam Cesar A 
Published: February 2020

Abstract
Use of proton nuclear magnetic resonance spectroscopy and the lanthanide shift reagent, Eu(hfc)3, resulted in a simple and reliable method for determination of the diastereomeric purity of rrans-2- phenylcyclopropylamine sulfate (tranylcypromine sulfate). Eu(hfc)3 effectively simplified the complex overlapping pattern of the 5 nonequivalent phenyl protons to a virtually first order pattern. At a shift reagent to substrate molar ratio of 0.75, and a substrate concentration of 0.25M (as the free base) in CDC13, the resonances for the cisand frans-orf/io-phenyl protons at 11.39 and 9.99 ppm, respectively, were sufficiently resolved to be of use in quantitative work. Analysis of synthetic diastereomeric mixtures of 2-phenylcyclopropylamine sulfate by the proposed method yielded results that were in close agreement with the expected values. The mean recovery (SD) of rrans-diastereomer was 100.51% (0.40) (n = 6). Levels of &lt;2% of c/s-diastereomer were measurable in cis-trans mixtures
Liquid Chromatographic Determination of Chloramphenicol Residues in Meat:
Interlaboratory Study
Authors: Aerts Rene M L , Keukens Henk J , Werdmuller Geziena A 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for the determination of chloramphenicol (CAP) residues in meat at the 10 Mg/kg level was tested in an interlaboratory study. The method used, based on aqueous extraction and sample cleanup with a cartridge containing Extrelut, was published earlier. A prestudy to familiarize collaborators with the method was performed before the actual interlaboratory precision study. The meat samples used in the precision study were prepared by diluting dosed chicken and pig muscle tissues with blank tissues from other species. Fourteen laboratories received 20 meat samples; 13 laboratories actually participated in the study. Two blank samples and 2 positive samples each of pig, calf, chicken, lamb, and cow meat were tested. The chloramphenicol concentrations in the positive samples ranged from 6.5 to 21 Mg/kg. The overall mean reproducibility coefficient of variation was 17.9% after the results per laboratory were corrected for the mean recovery obtained within each sample series. The overall mean recovery was 55.1% with a coefficient of variation of 18.0% at the 10 Mg/kg level. The limit of detection, based on chromatograms of blank samples, was estimated to be 1.5 Mg/kg of chloramphenicol. No false positives or false negatives were observed in the concentration range tested; only 2 false positive results above the detection limit (1.7 and 6 Mg/kg) on a total number of 60 blank analyses (3.3%) were observed.
Rapid and Simple Method for Isolation and Gas Chromatographic Determination of N-Nitrosodimethylamine in Dimethyldithiocarbamate Formulations
Authors: Wigfield Yuk Y , Mclenaghan Charles C 
Published: February 2020

Abstract
A rapid and simple method to isolate and determine JV-nitrosodimethylamine (NDMA) in formulations of ferbam or dibam has been developed. Depending on the type of formulation, the sample is extracted or diluted with water which is subsequently extracted with dichloromethane. NDMA is isolated by passing the organic fraction through a silica gel column and eluting the column with acetone. The acetone eluate is analyzed directly for NDMA by using a gas chromatograph connected to a thermal energy analyzer detector (GC/ TEA). The limit of detection (LOD) is 40 pg (0.04 ppm) and the limit of quantitation (LOQ) is 100 pg (0.1 ppm). The recovery range for this method is 85-112% for ferbam spiked at 0.33-0.75 ppm, and 91- 113% for dibam spiked at 0.32-1.09 ppm. Sixteen commercial samples of ferbam and 4 of dibam were analyzed; one ferbam sample contained 19.8 ppm NDMA while all others contained less than 1 ppm. Chem-Elut extraction tubes were found to generate trace quantities of nitrosamine from samples containing amine. If amine is absent, an extraction tube could be used in place of dichloromethane extraction to give similar values in recovery range, LOD, and LOQ.
Determination of Total Vitamin C by Ion Exclusion Chromatography with Electrochemical Detection
Authors: Kim Hie-Joon 
Published: February 2020

Abstract
A rapid and sensitive liquid chromatographic method for determination of total vitamin C in foods and beverages is described. Ascorbic acid and dehydroascorbic acid are extracted with sulfuric acid solution, and the dehydroascorbic acid in the extract is reduced to ascorbic acid by dithiothreitol at pH 7. The reduction is complete in 2 min at room temperature. The resulting total ascorbic acid is separated on an anion exclusion/high speed column with 20mM sulfuric acid as eluant and detected amperometrically with a platinum electrode operating at +0.6-0.8 V vs Ag/AgCl reference electrode. Dithiothreitol (retention time, 3.2 min) does not interfere with the separation and detection of ascorbic acid (retention time, 1.3 min). The dehydroascorbic acid content can be estimated as the difference in ascorbic acid content measured with and without reduction by dithiothreitol. The completeness of the reduction was demonstrated by purposely allowing the oxidation of ascorbic acid in the food extract and determining the total vitamin C after reduction. The determinations of vitamin C content in selected foods and beverages were in good agreement with the expected values. Total analysis time for vitamin C is 10 min and the detection limit is 0.1 ng. The method is specific for vitamin C, and interference by other food constituents is minimal.
Gas Chromatographic Determination of Cholesterol in Egg Products
Authors: Beyer J D , Milani F X , Dutelle M J , Bradley R L 
Published: February 2020

Abstract
A method has been developed for quantification of cholesterol in fresh egg yolks, spray-dried egg yolks, fresh whole eggs, and spray-dried whole eggs. The method uses saponification followed by petroleum ether extraction of cholesterol. Separation of organic and aqueous layers is enhanced by sodium chloride. Petroleum ether extracts are dried under nitrogen and redissolved in chloroform-methanol (2 + 1) for injection into a gas chromatography Cholesterol is separated and quantitated on a high temperature capillary column coated with 5% diphenyl and 95% dimethyl polysilicone crosslinked gum. The method was compared with the current AOAC method 17.017-17.022, and results indicated no significant difference (α = 0.05). However, the proposed method allowed separation and analysis of 16 samples in 7 h while the current AOAC method allowed separation and analysis of only 4 samples in 9 h.
One-Step Sample Preparation Technique for Broad Spectrum Gas Chromatographic/Mass Spectrometric Determination of Organic Priority Pollutants in Water
Authors: Alfieri Angelo , Crawford George , Ahmad Ijaz 
Published: February 2020

Abstract
A rapid and cost-effective sample preparation technique is described for the qualitative and quantitative determination of a broad spectrum of organic contaminants in water. The technique involves simultaneous in-situ acetylation of phenols with acetic anhydride and onestep extraction of phenol acetates and basic and neutral organic compounds from water. The extract is concentrated and analyzed by gas chromatography/mass spectrometry. The recovery and precision data of selected base, neutral, and phenolic compounds are given. The advantages and disadvantages of the in-situ acetylation/extraction technique are discussed
Liquid Chromatographic Determination of Total Formaldehyde in Drinking Water
Authors: Tomkins Bruce A , Mcmahon John M , Caldwell William M , Wilson David L 
Published: February 2020

Abstract
Formaldehyde is readily quantitated at fig/L levels in drinking water. The analyte present in 1 L water samples is derivatized with 2,4- dinitrophenylhydrazine in a 2M acid medium and then extracted with chloroform. After the solvent is exchanged for methanol, the product is separated and quantitated using reverse-phase liquid chromatography with UV detection (365 nm). Reporting limits as low as 20μg/L (corrected for laboratory blank) are routinely achieved. Formaldehyde recovery typically exceeds 90% at 20-200 μg/L. The method was applied to hot and cold water samples from thirty-four 1- and 2- story houses equipped with poly(acetal) plumbing elbows and tees. The drinking water samples were accompanied by sets of blanks and spikes specified by a quality assurance/quality control plan. Formaldehyde was observed above the reporting limit in 80% of hot and cold water samples from the 1-story dwellings, but in less than 50% of those from the 2-story dwellings. The results may depend on both the construction of the houses (1- vs 2-story) and the time of year the water is sampled (mid-summer).
Determination of Carbofuran and Its Metabolites in Rice Paddy Water by Using Solid Phase Extraction and Liquid Chromatography
Authors: Beauchamp Keith W , Liu Dave D W , Kikta Edward J 
Published: February 2020

Abstract
A procedure for the determination of carbofuran and its metabolites (carbamate and phenolic) in rice paddy water is described. Water samples are concentrated on a C-18 solid phase extraction (SPE) column and eluted with methanol-water. The eluate is analyzed by reverse-phase liquid chromatography (LC) and measured by a wavelength programmable ultraviolet (UV) detector. The limit of detection for the method is 0.4 μg/L. Recovery studies were carried out at levels ranging from 1 to 15 μg/L in both rice paddy water and distilled water; recoveries ranged from 85.9 to 112.9%.
Availability of Phosphorus in Bone Meal
Authors: Baker Alice M , Trimm Joe R , Sikora Frank J 
Published: February 2020

Abstract
Two commercially available bone meal products (grades 0-12-0 and 6-12-0) were examined. Samples were prepared according to AOAC method 2.007, and total and available phosphorus contents were determined. Portions of these preparations were reground to pass through successively smaller sieves, and subsequent analyses indicated the availability of phosphorus to be directly proportional to fineness of grind. A quantity of the citrate-insoluble fraction of the bone meal was obtained by following AOAC extraction procedures. Agronomic studies were conducted that compared this insoluble fraction with the original bone meal material and with reagent grade Ca(H2P04)2,H20. The data indicated poor correlation between the analytically defined and agronomically determined availability of phosphorus.
Liquid Chromatographic Determination of Vitamin D in Infant Formula
Authors: AGARWAL Vipin K 
Published: February 2020

Abstract
A method is described for the determination of vitamins D2 + D3 in milk- and soy-based infant formula. Vitamins D2 and D3 are extracted from the saponified sample and converted to isotachysterols with acidified butanol. Reverse-phase liquid chromatography (LC) is used to remove interferences, and total vitamin D is quantitated using normal-phase LC. Recoveries of spiked samples averaged 97.6% for milk-based infant formula, and 98.8% for soy-based infant formula. This method quantitates vitamin D2 + D3 in infant formulas containing as low as 40 IU/qt when prepared according to label direction
Liquid Desorption of Organic Solvents from Industrial Sludges
Authors: Ceccon Luciano , Turello Alessandro , Mocellin Graziella , Colugnati Luigi 
Published: February 2020

Abstract
Analysis of organic solvent residues in industrial sludges is usually based on preliminary extraction of solvents from the matrix, followed by gas chromatographic determination. Liquid desorption with carbon disulfide is one of the most frequently used methods of recovery. Because of the number of parameters that can affect desorption efficiencies, we evaluated recoveries from 2 wastes with different physicochemical characteristics. Results were similar for both matrixes. The study of the kinetics of recovery showed that equilibrium was reached within about 5 min. On the other hand, specific adsorption phenomena were observed not only for strongly polar solvents even at the highest concentrations, but also for weakly polar compounds at the lowest concentrations. Water content of the matrix had little effect on recovery of the solvents examined, except for 2- ethoxyethanol, which yielded notably lower extractions when the moisture content of the matrix increased.
Liquid Chromatographic-Atomic Absorption Spectrophotometric Method for Determination of Methyl Mercury in Seafood: Collaborative Study
Authors: Holak Walter 
Published: February 2020

Abstract
A previously developed method that uses a simplified sample preparation procedure and atomic absorption detection of liquid chromatographic eluates for the determination of methyl mercury in seafood has been collaboratively studied. The unique feature of the method involves the use of a specially designed interface for the generation of mercury vapor. Methyl mercury is isolated from the blended sample by chloroform elution from a diatomaceous earth-hydrochloric acid column. The organomercury compound is then extracted into a small volume of 0.01M sodium thiosulfate solution. An aliquot of this solution is injected onto a Zorbax ODS column and eluted with methanol-ammonium acetate solution (3 + 2), pH 5.7, containing 0.01% mercaptoethanol. Mercury is detected by flameless atomic absorption spectrophotometry using the interface. The samples analyzed in the study were unspiked swordfish, unspiked and spiked lobster, and unspiked and spiked tuna. The spiked samples contained methyl mercury both above and below the U.S. Food and Drug Administration guideline level of 1 fig Hg/g. Reproducibility relative standard deviations ranged from 10.5% at 1 fig Hg/g to 18.2% at about 0.1 fig Hg/g. Accuracy, measured by comparison to reference values obtained by the Associate Referee, ranged from 94.4 to 99.6%. The method has been adopted official first action.
Reliability of Repeatability and Reproducibility Measures in Collaborative Trials
Authors: Karpinsk K F 
Published: February 2020

Abstract
The acceptability of a new analytical method is generally assessed in terms of repeatability and reproducibility estimates derived from a collaborative study. Procedures are presented for calculating confidence intervals and operating characteristic curves for acceptance criteria based on the repeatability and reproducibility estimates. Comparisons of the reliability of estimates are provided for various numbers of collaborators. With a small number of collaborators, the estimates of reproducibility are not reliable and decisions regarding acceptability of a method will be heavily based on the method’s repeatability rather than the property of most interest, namely, the reproducibility of the method.
Confirmation of Phorate, Terbufos, and Their Sulfoxides and Sulfones in Water by Capillary Gas Chromatography /Chemical Ionization Mass Spectrometry
Authors: Stout Steven J , Dacunha Adrian R , Boyd John E , Devine James M 
Published: February 2020

Abstract
A gas chromatographic/mass spectrometric method capable of confirming phorate, terbufos, their sulfoxides, and sulfones in water is reported. Parents and their metabolites are separated in less than 5 min using a short capillary GC column and high carrier gas linear velocities. Positive ion chemical ionization mass spectrometry generates (M + H) ions indicative of the different molecular weights of the analytes and at least one confirmatory fragment ion for each analyte. Residues have been qualitatively confirmed at the 1 ppb level in fortified water samples from a variety of sources. Apparent residues in control water were less than 0.1 ppb.
Pesticide Residues in Milk and Fish Samples Collected from Two Egyptian Governorates
Authors: Dogheim Salwa M , Nasr Eslam N , Almaz Monir M , EL-Tohamy Mahmoud M 
Published: February 2020

Abstract
Because of the intensive use of pesticides for the control of certain pests In Egypt, country-wide residue monitoring programs must be established that can cover all the Egyptian Governorates exposed to pesticide treatments. To do so, limited programs must be adopted first, so that current situations and future needs for improved programs are identified. The present paper reports results from a limited monitoring program, which started in 1985 in one governorate and then expanded to include another in 1986. Fish and milk samples were the commodities selected for residue analysis. The results showed that milk samples collected from Beni-Suef Governorate in 1986 had lower levels of organochlorine residues compared to those collected in 1985. Residues in boltifish and catfish samples in 1986 were much higher than those detected in 1985. In comparison with Beni-Suef Governorate, and contrary to expectations, milk derived from Fayoum Governorate in 1986 was more contaminated with pesticides. While the amount of residues in boltifish was comparatively higher, catfish samples were less contaminated.
Methodology for Evaluation of Compatibilities of Cosmetic Perfumes and Plastic Containers
Authors: Taverna Myriam , Baillet Arlette E , Baylocq Danielle 
Published: February 2020

Abstract
The study was designed to investigate compatibility of plastic containers and perfumes. First, a gas chromatographic/ mass spectrometric (GC/MS) system was developed for identification of fragrance components. Then a quantitative extraction and GC analysis was developed. Honeysuckle fragrance was added to a cosmetic emulsion at 0.5 mg/100 mg level. The cosmetic was stored for 2 months at 37° C in 6 different plastic containers and in a glass bottle as a test control. The cosmetic was extracted with dichloromethane and analyzed by GC. The results obtained after storage were compared with the original analysis and showed an important loss of some perfume components stored in different plastic containers. Sorption of these components was then studied by extracting components fixed by the plastic; some of the physicochemical factors involved in such interactions are identified.
Criteria for Determining Purity of Fusarium Mycotoxins
Authors: Bennett Glenn A , Shotwell Odette L 
Published: February 2020

Abstract
Physical and chemical properties that may be used to determine the purity of several Fusarlum mycotoxins have been investigated. A combination of analytical procedures, which include high performance thin-layer chromatography (HPTLC), liquid chromatography (LC), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), ultraviolet spectrometry (UV), and nuclear magnetic resonance (NMR) spectrometry have been used to examine mycotoxin standards obtained from commercial sources and from laboratory fermentations. Results of this investigation indicate that commercially available standards are greater than 90 % pure, but the label weight of purchased reference standards in individual containers should be verified. Mycotoxin standards, determined to be greater than 98 % pure by HPTLC, LC, and GC/MS, were examined by UV spectrometry and the coefficients of extinction were determined. An interlaboratory study, involving 5 collaborators who determined coefficients of extinction (in methanol) for identical samples, gave the following results: α-zearalenol (λ236 = 28 538 ± 558); β- zearalenol (λ238 = 24 963 ± 747); deoxynivalenol (λ219 = 6395 ± 349, lot 1), (6020 ± 228, lot 2); and T-2 toxin (λ202 = 3681 ± 255). UV maxima and coefficients of extinction are also reported for HT-2 toxin (λ202 = 1959), diacetoxyscirpenol (λ203 = 2487), neosolaniol (λ203 = 2644), nivalenol (λ220 = 5142), and fusarenon-X (λ217 = 5997).
Liquid Chromatographic Determination of the Herbicide Isoxaben and Its Soil Metabolite in Soil and Soil-Turf Samples
Authors: Rutherford Bonnie S 
Published: February 2020

Abstract
A method Is described for the determination of residues of isoxaben and its principal soil metabolite In soil and soil-turf samples. Both compounds are extracted from samples by refluxing with methanol-water. An aliquot of the extract Is partitioned Into dichloromethane and purified by alumina column chromatography. Separate fractions containing isoxaben and metabolite are collected and subjected to liquid chromatography at conditions that are optimized for each compound. The detection limit for both compounds is 0.005 ppm. Residue identities are confirmed by chromatography on a different LC system.
Quantitative Multiresidue Analyses for Volatile Organics in Water and Milk, Using a Fused Silica Open-Tubular Wide-Bore Capillary Column and Automated Headspace Gas Chromatography
Authors: Mcneal Timothy P , Hollifield Henry C 
Published: February 2020

Abstract
A modified multiresidue capillary gas chromatographic (GC) procedure has been developed using automated headspace sampling and a wide-bore fused silica open-tubular (FSOT) capillary column for the determination of volatiles in water and milk. Compounds are quantltated by the method of standard additions. An IBM System 9000 computer with the CAPMC3 chromatographic applications package and a BASIC linear regression program are used for data reduction. Data are presented for solutions prepared by fortifying water and milk with volatile solvents such as acetone, methyl ethyl ketone, benzene, methylene chloride, and chloroform, which are commonly used in the manufacture of packaging materials and adheslves. The wide-bore FSOT capillary columns showed dramatically improved detection for certain compounds, compared with normal-bore capillary GC columns. Data presented for various chemicals demonstrate the improved limits of detection from the use of automated headspace gas chromatography with wide-bore capillary columns and flame ionization detection.
Sulfamethazine (Sulfadimidine) Residues In Canadian Consumer Milk
Authors: Larocque Lyse , Carignan Germain , Sved Stephen 
Published: February 2020

Abstract
A survey on the presence of sulfamethazine (sulfadimidine) residues In consumer milk has been conducted In 10 cities across Canada. In each city, homogenized milk was purchased at 3 different retail outlets, each supplied by different processing plants. A total of 30 samples was analyzed by a liquid chromatographic method. The limit of quantitation was 5 ppb. In addition to automatic integration, visual inspection of the chromatograms was required to distinguish between low concentrations of sulfamethazine and 2 unknown interfering peaks. Two samples, from different cities, contained 11.4 and 5.24 ppb of the drug. Drug Identity was confirmed by mass spectrometry. All other samples appeared to be free of the drug.
Diagnostic Data Evaluation. Part IV. Evaluation of A Check Sample Series To Determine Analyst Performance
Authors: Malanoski Anthony J 
Published: February 2020

Abstract
Data from a check sample series were subjected to diagnostic data evaluation. The chemical analyses that were performed were moisture, protein, and fat In meat products. Four performance outliers were Identified (1 protein, 1 moisture, and 2 fat values). With the performance outliers excluded from the statistical evaluation, the analyst standard deviation ranged from 0.088 to 0.218 for protein, 0.145 to 0.393 for moisture, and 0.271 to 0.378 for fat. No bias was present. All laboratories were able to meet the established standards. With the limited number of samples it was not possible to attribute any reasons for the outliers.