bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Chromatographic/Mass Spectrometric Determination of Benzene in Nonstick Cookware and Microwave Susceptors and Its Migration into Foods on Cooking
Authors: Jickells Sue M , Philo Mark R , Gilbert John , Castle Laurence 
Published: February 2020

Abstract
Benzene in poly(tetrafluoroethylene) (PTFE) coatings of nonstick cookware was determined by heating a small amount of coating in a sealed vial. Gas chromatography/mass spectrometry (GC/MS) was used to analyze the vial headspace for benzene. A small survey (26 samples) of retail nonstick cookware detected benzene ranging from 2 to 50 μg/dm2 in 7 samples. Nonstick frying pans with various polymer coatings were obtained directly from 1 manufacturer. Benzene (6–30 μg/dm2) was detected in a number of these samples and was attributed to the use of a phenylmethyl silicone ingredient that contained benzene at 360 mg/kg. To determine the possible transfer of benzene from these coatings during normal use, several foods (puddings, cakes, and roast potatoes) were prepared in previously unused cookware. The foods were analyzed by using static headspace GC/MS. Benzene was not detected in any of these foods at a limit of detection of 2 μg/kg. In related studies, the determination of benzene release from microwave susceptors was performed by heating the materials in a sealed system at 190PC for 4 min. Benzene release above 1 μg/dm2 was not detected in 24 samples of susceptors. However, 1 specially supplied sample of nonmetallized susceptor released 10 μg/dm2 benzene when heated above normal anticipated temperatures of usage (to 220°C). Foods such as french fries and pizza when cooked according to the manufacturer’s instructions in susceptors contained no benzene with a limit of detection of 2 μg/kg. Even under abuse conditions of susceptors, the transfer of benzene to foods remained below this limit.
Optimization of Experimental Conditions for the Supercritical Carbon Dioxide Extraction of Pesticide Residues from Grains
Authors: King Jerry W , Hopper Marvin L , Luchtefeld Ronald G , Taylor Scott L , Orton William L 
Published: February 2020

Abstract
The efficiency of a supercritical carbon dioxide extraction system was investigated for the extraction at different pressures and temperatures of fortified grain samples containing organochlorine, organophosphorus, and organonitrogen pesticides from grain matrixes. The extractor unit was constructed using a gas booster pump and a Florisil sorbent trap for extracting and isolating the residues of interest. Using 20 g samples, extractions were performed between 40° and 80° C with pressures from 2000 to 10 000 psig. In most cases, pesticide recoveries exceeding 80% were recorded over the above range of temperature and pressure. Excellent recoveries and precision were recorded for an incurred methyl chlorpyrifos residue at the 0.043 ppm level. An improved liquid chromatographic assay was also developed for the analysis of carbofuran in grain samples.
Automated Beer Analyzer Method for Determination of Alcohol Content and Original Gravity of Beer: Summary of Collaborative Study
Authors: Gales Peter W , Schwiesow Mark 
Published: February 2020

Abstract
Two collaborative studies were conducted by the American Society of Brewing Chemists (ASBC) to evaluate use of an automatic beer analyzer for determination of alcohol content and original gravity of beer. Repeatability and reproducibility values obtained in the first study were satisfactory. The second study compared the automated method with the ASBC distillation method. Results by the 2 methods were similar; however, repeatability and reproducibility were better for the automated method. The automated method was adopted first action by AOAC International as an ASBC–AOAC method.
Sensitive Determination of Zearalenone and α-Zearalenol in Barley and Job's-Tears by Liquid Chromatography with Fluorescence Detection
Authors: Tanaka Touicm , Teshima Reiko , Ikebuchi Hideharu , Sawada Jun-Ichi , Terao Tadao , Icmnoe Masakatsu 
Published: February 2020

Abstract
A sensitive and reliable method for liquid chromatographic (LC) determination of zearalenone and α-azearalenol in barley and Job's-tears was investigated. The method by which these toxins were determined involves addition of an internal standard (zearalenone 6'-oxime) to barley and Job's-tears samples. Extracts from grain samples were cleaned up by passage through chromatography on piperidinohydroxypropyl Sephadex LH-20 as a lipophilic gel. Individual toxins were resolved by LC on a reversed-phase (ODS) column with fluorescence detection. The detection limit is estimated to be 0.2 ng for zearalenone and α-zearalenol standards. Known amounts of zearalenone and α-azearalenol (25-1250 ng) were added to a barley sample (5 g). Average recoveries for α-zearalenol and zearalenone, respectively, ranged from 96 to 102% (mean CV, 3.6%) and from 96 to 103% (mean CV, 3.3%). This method is applicable to determination of α-zearalenol and zearalenone in barley and Job's-tears with satisfactory sensitivity and accuracy.
The Chinese Total Diet Study in 1990. Part I. Chemical Contaminants
Authors: Chen Junshi , Gao Junquan 
Published: February 2020

Abstract
The Chinese total diet study in 1990 estimated the dietary intake of 24 chemical contaminants and 72 nutrients from 4 market baskets collected and prepared in 12 provinces. Twelve food group composites were made for each regional market basket. The overall dietary Pb, Cd, Hg, hexachlorocyclohexane HCH, and DDT intakes were well below their corresponding acceptable daily intakes. However, the Pb content of eggs from the 2 southern regions exceeded the tolerance limit. The Hg content of legumes just reached the tolerance limit, and Hg in eggs from the North 1 region exceeded the tolerance limit. The dietary HCH intake has decreased significantly since the 1980s, but dietary DDT intake has decreased rather slowly. Five organophosphorus pesticides were detected out of a total of 12 organophosphorus pesticides analyzed. Among them, methamidophos was the most outstanding. The intake of total committed dose equivalents (CDEs) of the 6 radionuclides was 0.24 mSv/a; only 1.5% was accounted for by 90Sr and 137Cs. 210Pb, 210Po 226Rg 228Ra accounted for 98.5% of the total CDEs. The main food sources of those radionuclides were cereals, vegetables, and aquatic foods. Aflatoxin B1 was detected at very low levels only in the cereal composite of the North 1 region. Aflatoxin M1 was not detected in any of the milk and milk products. The overall results show that there is no significant environmental contamination of the average Chinese diet.
Survey of Benzene in Foods by Using Headspace Concentration Techniques and Capillary Gas Chromatography
Authors: Mcneal Timothy P , Nyman Patricia J , Diachenko Gregory W , Hollifield Henry C 
Published: February 2020

Abstract
Recently, the combination of sodium or potassium benzoate with ascorbic acid was shown to produce low levels (ng/g) of benzene in fruit-flavored soft drinks. The presence of benzene also was reported in butter, eggs, meat, and certain fruits; levels of these findings ranged from 0.5 ng/g in butter to 500-1900 ng/g in eggs. Because benzoates are widely used as food preservatives, a limited survey of other foods containing added benzoate salts was conducted to investigate the potential for benzene formation. Selected foods that did not contain added benzoates but were previously reported to contain benzene were analyzed for comparison. More than 50 foods were analyzed by purge-andtrap or static headspace concentration and capillary gas chromatography. Benzene was quantitated by using the method of standard additions, and its identity was confirmed by mass selective detection. Results of this limited survey show that foods without added benzoates (including eggs) contained benzene at levels equal to or less than 2 ng/g. Slightly higher levels were present in some foods and beverages containing both ascorbic acid and sodium benzoate.
Liquid Chromatographic Determination of Moxidectin Residues in Cattle Tissues and Confirmation in Cattle Fat by Liquid Chromatography/Mass Spectrometry
Authors: Khunachak Alisa , Dacunha Adrian R , Stout Steven J 
Published: February 2020

Abstract
Moxidectin, a potent new endo- and ectoparasitic agent, is determined in cattle tissues by liquid chromatography (LC) with fluorescence detection. Moxidectin residues in cattle fat are confirmed with thermospray LC/mass spectrometry (MS). Moxidectin is extracted from the tissue with acetonitrile; the extract is partitioned with hexane, concentrated, and reacted with acetic anhydride, 1-methylimidazole, and dimethylformamide to produce a fluorescent product. The validated sensitivity of the LC/fluorescence method was 10 ppb, with a limit of detection typically between 1 and 2 ppb. Average recoveries from cattle fat, muscle, liver, and kidney were 99,95,89, and 92%, respectively. LC/MS confirmatory method determined the underivatized parent compound following the acetonitrilehexane partitioning step, with an average recovery of 108% at the 250 ppb level in cattle fat.
Comparison of Gel Permeation Chromatography, Sweep Codistillation, and Florisil Column Adsorption Chromatography as Sample Cleanup Techniques for the Determination of Organochlorine Pesticide Residues in Animal Fats
Authors: Armishaw Paul , Millar Roderick G 
Published: February 2020

Abstract
Methods using a commercial sweep codistillation apparatus, gel permeation chromatography (GPC), and Florisil column adsorption chromatography were compared as cleanup techniques for the determination of organochlorine pesticide residues in animal fats by Megabore capillary gas chromatography with electron capture detection. Animal fat that had been previously found to contain no detectable organochlorine residues was spiked with 17 organochlorine pesticides at levels ranging from 0.1 to 0.4 mg/kg and cleaned up by each of the 3 techniques. Recoveries obtained for all 3 methods were in the range 73-113%, with coefficients of variation between 1.1 and 11.2%. Equivalence of method performance was further demonstrated by performing replicate analyses of beef and sheep fat containing naturally incurred residues of heptachlor epoxide, dieldrin, p,p′-DDE, p,p′-DDD and p,p′-DDT. All 3 methods offer effective cleanup and acceptable recovery of organochlorine pesticides in animal fat. The sweep codistillation method has the advantages of low solvent and reagent use, simultaneous cleanup of 10 samples, and rapid turnaround, although thermal degradation of p,p′-DDT requires monitoring and control. GPC offers a high degree of automation but is a relatively slow sequential sample cleanup with high solvent use. Florisil column adsorption chromatography is a simple, proven technique but requires considerable solvent and reagent and has a low potential for automation.
Determination of Pyrethroid Residues in Vegetables, Fruits, Grains, Beans, and Green Tea Leaves: Applications to Pyrethroid Residue Monitoring Studies
Authors: Nakamura Yumiko , Tonogai Yasuhide , Tsumura Yukari , Ito Yoshio 
Published: February 2020

Abstract
Determination of natural pyrethrins and 12 synthetic pyrethroids in agricultural products was investigated. Vegetables and fruits were extracted with acetone, filtered after addition of coagulating solution, partitioned into n-hexane, and cleaned up on a Florisil column (as necessary). Pyrethroids were determined by gas chromatography/electron capture detection (GC/ECD) by using a methyl silicone-coated fused-silica capillary column, and recoveries were calculated by summing peak areas of the components. GC/mass spectrometry was used to identify the pyrethroids detected by GC/ECD monitoring. Grains and beans containing lipids were analyzed by extraction with acetonitrile, partition into n-hexane, Florisil column cleanup, and capillary GC/ECD. The coagulation method was suitable for nonfatty crops such as vegetables, fruits, and green tea leaves, because recoveries were good and Florisil column cleanup was not needed in most cases. The coagulation method was not applicable to lipid-containing crops such as grains and beans because of low recoveries. Recoveries for 18 crops at fortification levels of 0.25–1.0 ppm were 60.0–103.5%. No pyrethroids were detected from the nonfortified crops tested except green tea leaves, in which fluvalinate was detected at 0.89 ppm.
Determination of Ultratrace Levels of Lead in Infant Formula by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry
Authors: Thompson Joseph J 
Published: February 2020

Abstract
A simple method was developed for the accurate and precise determination of low- and sub-ppb (ng/g) concentrations of lead in infant formula by isotope dilution inductively coupled plasma mass spectrometry using ultrasonic nebulization. After addition of a known amount of 207Pb, samples were microwave digested and the ratio 207Pb/208Pb was measured in the digests. Agreement with certified values for lead in milk powder standard reference materials was good, and isotope dilution analysis using 206Pb yielded identical results for the standard reference materials. Lead concentrations determined for several infant nutritional products were verified by an independent method. Typically, relative standard deviations of &lt;4% were obtained with this method for lead concentrations above 2 ppb. The recovery of 2 ng of lead from an aqueous standard carried through the microwave digestion was 104 ± 4%. Infant formula (containing 0.6 ppb lead) to which 0.4 ng of natural-abundance lead had been added, to simulate a formula containing 0.9 ppb lead, was analyzed by isotope dilution, and the result was 96 ± 18% of the theoretical value. Thus, differences of 0.3 ppb lead could be clearly distinguished, and the detection limit was estimated to be 0.1 ng lead per gram of infant formula. The keys to accuracy for this method are minimizing contamination and accurately determining the concentration of lead in the isotopically enriched standard.
Thin-Layer Chromatographic Detection of Organophosphorus Insecticides Containing a Nitrophenyl Group
Authors: Patil Vitthal B , Shingare Murlidhar S 
Published: February 2020

Abstract
A Griess reaction that has been used to detect organic compounds containing an aromatic amino group was used to detect organophosphorus compounds containing a nitrophenyl group, such as ethyl parathion, methyl parathion, and fenitrothion. On reduction with stannous chloride in HCI–water (1 + 1), these compounds give respective amino derivatives, which are further diazotized and coupled with 1-naphthylamine to give intense pink–orange spots. This reagent also gives a bluish to violet spot with p-nitrophenol, a metabolite of fenitrothion. The procedure can be used to detect these insecticides in biological materials in forensic toxicology.
Liquid Chromatographic Method for Determining the Percent of Olestra in Lipid Samples
Authors: Tallmadge Daniel H , Peter Y T Lin 
Published: February 2020

Abstract
A liquid chromatographic (LC) method has been developed to determine the percent of olestra in lipid samples. To achieve the highest degree of accuracy, this method requires the use of an olestra standard with the same molecular composition as the olestra in the lipid sample to be analyzed. Samples were analyzed by reversed-phase LC using an evaporative light-scattering detector. Chromatography was performed with a 5 μm octadecylsilane- Zorbax column that separates olestra from other lipophilic components. Three types of olestra standards (soybean-oil olestra, unheated cottonseed- oil olestra, and heated cottonseed-oil olestra), each analyzed in soybean oil, showed linearity when the amount of olestra injected ranged from 20 to 160 fig (r= 0.9996). The area under the olestra peak (retention time 3.5 to 4.9 min) was used to quantify the amount of olestra in olestra-lipid samples, by comparing the olestra area for the sample with that of the standard using a curve derived by linear regression. The method was evaluated using 3 types of olestra blended with soybean oil and varying the percent of olestra in the olestra-lipid blend from 5 to 90%. Recovery of olestra from these olestra-lipid blends varied from 99.2 to 106.0%, demonstrating excellent accuracy, with method precision expressed as the coefficient of variation, 0.9%. Each error estimate was derived from 5 parallel determinations. With proper validation (e.g., running an olestra-free blank for each lipid matrix), this method provides a rapid, accurate, and precise technique for measuring the percent of olestra in lipids extracted from olestra-formulated foods and in olestra-lipid blends.
Screening of Organochlorine Pesticide and Polychlorinated Biphenyl Residues in Nonfatty Seafood Products by Tandem Solid-Phase Extraction Cleanup
Authors: Schenck Frank J , Wagner Roberta , Hennessy Michael K , Okrasinski Joseph L 
Published: February 2020

Abstract
A rapid multiresidue solid-phase extraction (SPE) technique for the isolation and subsequent gas chromatographic (GC) determination of organo-chlorine pesticide and polychlorinated biphenyl (PCB) residues in nonfatty fish, crabmeat, shrimp, and scallops is described. Samples are extracted with acetonitrile, and the extract is subjected to a cleanup using both C18 and Florisil SPE columns. The residues are determined by GC with electron capture detection. Because the injected extracts are free from matrix interferences, the amount of residue present is easily calculated. The average recoveries of 9 spiked (0.01–0.40 ppm) organo-chlorine pesticide residues from 6 different seafood products ranged from 93.8 to 98.4%. The average recoveries of spiked (0.50 ppm) PCB mixtures from 4 different seafood products ranged from 88.5 to 107.2%. This SPE method and the AOAC multiresidue method for organochlorine residues in fish produced comparable results for nonfatty seafood samples containing incurred organochlorine pesticide and PCB residues. The SPE method reduces organic solvent consumption by 95% and hazardous waste by 85% compared with the AOAC method. We were able to carry 10 seafood samples through the extraction and cleanup in less than 2 h by using the SPE method.
Immunoaffinity Column Cleanup/Liquid Chromatographic Determination of Aflatoxins: An Interlaboratory Study
Authors: Barmark Anna-Lena , Larsson Kjell 
Published: February 2020

Abstract
Nine laboratories from Denmark, Finland, Norway, and Sweden participated in a collaborative study to evaluate an immunoaffinity column cleanup/liquid chromatographic determination of aflatoxins B and G. Samples of peanut, fig, maize gluten, soya expel-ler, and copra spiked with total aflatoxin concentrations ranging from 1.37 to 28.60 ng/g were distributed. Altogether, 13 samples were analyzed. Of these, 6 were pairs of blind duplicates, 1 was an unknown negative sample containing ¼0.1 ng/g, and 2 were practice samples. A statistical presentation of the results is given. Although the results obtained were individually corrected for recovery, they were lower than expected in most cases. In some cases, the recoveries were unacceptably low, particularly for aflatoxin G2. Relative standard deviations for method repeatability (RSDr) and reproducibility (RSDR) were good but generally better for the peanut and fig samples than for the others. Results were better for aflatoxins B1 and G1 than for aflatoxins B2 and G2. RSDR values varied from 9 to 35%, and RSDR values varied from 17 to 81%. Horwitz ratio values were &gt;2.00 for 1 RSDR value and &lt;1.00 for 23 of the 35 calculated RSDR values.
Determination of Ethyl Carbamate (Urethane) in Alcoholic Beverages Using Capillary Gas Chromatography with Thermal Energy Analyzer Detection: Collaborative Study
Authors: Dyer Randolph H 
Published: February 2020

Abstract
A gas chromatographic (GC) procedure for the determination of ethyl carbamate (urethane) in distilled spirits and wines using a thermal energy analyzer (TEA) system was collaboratively studied by 5 laboratories. Distilled spirits such as whiskey, brandy, gin, rum, and vodka containing low solids can be injected directly into the GC system without extraction. Liqueurs require extraction. Wine, beer, sake, and similar samples containing significant solids or other interferences are extracted prior to injection. The sample is analyzed by GC/TEA operating in the nitrogen mode with capillary column capability (30 m × 0.53 mm) and automatic injection. Helium is the carrier gas. The GC system is calibrated with a 100 ppb standard, followed by the samples. The concentration of ethyl carbamate is determined by multiplying peak area ratios by the concentration of the standard. For the distilled spirits, the recovery averaged 92%. The within-labora-tory repeatability (RSDr) ranged from 4.3 to 12.5%, with overall average of 8.0%, and reproducibility (RSDR) varied from 4.8 to 22.0%, with an overall average of 17.4%. For the wines, the recovery averaged 85%, and the RSDr ranged from 8.9 to 42.8%, with an overall average of 34.4%. The method has been adopted first action by AOAC INTERNATIONAL.
Salmonella Detection in Cocoa and Chocolate by Motility Enrichment on Modified Semi-Solid Rappaport-Vassiliadis Medium: Collaborative Study
Authors: de Smedt J , Bolderdijk R , Milas J 
Published: February 2020

Abstract
A collaborative study was performed in 13 laboratories (including the authors’ laboratories) to validate motility enrichment on modified semi-solid Rap-paport-Vassiliadis (MSRV) medium for rapid detection of motile Salmonella in cocoa powder and chocolate. The MSRV method was compared with the AOAC standard culture method for detection of Salmonella in cocoa powder, milk chocolate, sweet chocolate, and dark chocolate. Chocolate samples were artificially inoculated with Salmonella at 2 levels of contamination. Cocoa powder was inoculated at 2 levels with naturally contaminated dust from cocoa beans. Uninoculated control samples were also included for each type of product. The sensitivity rate was 98.1 % for the MSRV method and 94.9% for the AOAC culture method. The specificity rate was 100.0% for both methods. There was no significant difference in the proportion of samples positive by MSRV and the AOAC culture methods for any of the food types. The MSRV method has been adopted first action by AOAC INTERNATIONAL.
Detection of Adulteration in Apple Juice by L-Malic/Total Malic Acid Ratio: Collaborative Study
Authors: Elkins Edgar R , Heuser John R 
Published: February 2020

Abstract
L-Malic acid is the predominate acid in pure apple juice and no D-malic acid should be present. Synthetic malic acid contains 50% D-malic acid, is inexpensive, and can be used to create nonauthentic apple juice. L-Malic/total malic ratios of 0.9 or less are indicative of a nonauthentic sample. Fourteen laboratories participated in a collaborative study to determine the L-malic/total malic acid ratio in apple juice. Ten samples of apple juice were sent to each laboratory. Authenticity of the samples varied from 0 to 100%. The coefficients of variation in all cases were acceptable, i.e., ca 5%. The method was adopted first action by AOAC INTERNATIONAL.
Sensitivity of the Quick Color Test for Indicating Lead Release from Ceramicware
Authors: Dolan Scott P , Capar Stephen G , Jacobs Richard M , Plunkett Randall J , Hawkins George S 
Published: February 2020

Abstract
A quick color test (QCT) for indicating the presence of leachable Pb on ceramicware was evaluated as a screening tool. Fourteen sets of cups and mugs (197 pieces) of undecorated glazed ceramicware were tested. The QCT indicated the presence of leachable Pb on 95% of the cups and mugs at or above approximately 2 μg/mL. The QCT is an inexpensive and rapid qualitative test for Pb that can be conducted with a portable kit.