bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of trans Unsaturation by Infrared spectrophotometry and Determination of Fatty Acid Composition of Partially Hydrogenated Vegetable Oils and Animal Fats by Gas Chromatography/Infrared Spectrophotometry: Collaborative Study
Authors: Ratnayake Wakisundera M N 
Published: February 2020

Abstract
An infrared spectrophotometric (IR) method for the determination of total trans unsaturated fatty acid (trans) content and a combined gas–liquid chromatographic/infrared spectrophotometric (GC/IR) method for determination of fatty acid composition of partially hydrogenated vegetable oils (PHVO) were studied collaboratively in 12 laboratories using 7 PHVO samples, including 1 pair of blind duplicates. The test samples were methylated and analyzed for total trans content by IR and for fatty acid composition by GC/IR using a capillary column coated with SP-2560 or another suitable cyanoalkylsiloxane stationary phase. From the measured IR absorption, the isolated trans content was calculated using a calibration curve of absorption versus trans content developed with 2-component calibration standard mixtures of methyl elaidate and oleate. The GC provided the levels of mono-trans-octadecadienoates (18:2t), di-trans-octadecadienoates (18:2tt) and mono-trans-octadecatrienoates (18:3t). The trans-octadecenoate (18:1t) content was calculated with the formula: 18:1t = IR trans−0.84 × (18:2t + 18:3t − 1.74 × 18:2tt. The cisoctadecenoate (18:1c) content was obtained as the difference between total octadecenoates (18:1) and 18:1t. Reproducibility relative standard deviations (RSDR) for 15 to 35% trans content determined by IR were in the range of 8.8–11.7%, whereas RSDR for the test sample with 5% trans content was 34.6%. RSDR values for 18:1t by the GC/IR followed the same pattern as that of IR trans values: 36.4% for the test sample with 4.9% 18:1t versus 7.8–12.5% for test samples with 14.9 to 32.6% 18:1t. The content of 18:1 c in the test samples varied from 24.7 to 34.5% and their RSDR values ranged from 3.8 to 10.5%. The mean values for 18:1t and 18:1c compared favorably with the absolute levels determined by a silver nitrate-thin layer chromatography/GC procedure. The IR and GC/IR methods are recommended for determination of trans content and fatty acid composition, respectively, of partially hydrogenated fats derived from vegetable oils, terrestrial animal fats or such oils and fats isolated from food products containing &gt;5% trans fatty acids. For samples containing ≤5% trans fatty acids, a direct GC method (American Oil Chemists' Society Official Method Ce 1c-89) is available for determination of both trans content and fatty acid composition, because at lower trans levels, overlap of 18:1 cis and trans isomers on GC with very polar capillary columns is negligible. The IR method for determination of isolated trans unsaturated fatty acid content in partially hydrogenated fats and the capillary GC/IR method for determination of total cis- and trans-octadecenoic isomers and general fatty acid composition in hydrogenated vegetable oils and animal fats have been adopted first action by AOAC INTERNATIONAL.
Rapid Determination of Methyl Parathion and Methyl Paraoxon in Milk by Gas Chromatography with Solid-Phase Extraction and Flame Photometric Detection
Authors: Baynes Ronald E , Bowen John M 
Published: February 2020

Abstract
Methyl parathion (MPT; O,O-dimethyl-O-4-nitro-phenyl phosphorothioate) and its active metabolite, methyl paraoxon (MPO; O, O-dimethyl-O-4-nitro-phenyl phosphate), were isolated from raw milk by solid-phase extraction (SPE) and determined by gas chromatography with flame photometric detection. The SPE method was compared with a traditional liquid-liquid extraction (LLE) procedure to determine whether SPE had suitable sensitivity and better efficiency in extracting MPT and MPO from milk of cows and goats. Method detection limits were higher for SPE, but the differences were not significant (t-test). Recoveries of MPT and MPO from raw milk samples spiked at 0.05, 0.5, and 5.0 pg/mL ranged from 80.0 to 118%, and the coefficients of variation were usually less than 10% for both methods. LLE required more organic solvents and was more time consuming compared with SPE.
Development of a Method of Analysis for 46 Pesticides in Fruits and Vegetables by Supercritical Fluid Extraction and Gas Chromatography/Ion TVap Mass Spectrometry
Authors: Lehotay Steven J , Eller Konstantin I 
Published: February 2020

Abstract
A multiresidue method using supercritical fluid ex-traction (SFE) and gas chromatography/ion trap mass spectrometry (GC/1TMS) was developed for analysis of 46 pesticides in fruits and vegetables. The SFE procedure used 2 commercial instruments that trapped the extracts on solid-phase material. Silica gel chemically bound to octadecylsi-lane (ODS) collected the extracted pesticides efficiently, and elution of the trap with acetonitrile gave high recoveries. Extracts thus obtained were sufficiently clean for subsequent GC/ITMS analysis. The SFE conditions were 320 atm and 60°C (0.85 g/mL CO2 density) and 1.6 mL/min CO2 flow rate for 6 extraction vessel volumes. Trapping on 1 mL ODS occurred at 10°C, and a 0.4 mL/min flow rate of acetonitrile at 40°–50°C was used to elute the pesticides. Quantitative and qualitative analyses of the 46 pesticides were performed simultaneously by GC/ITMS. Studies of fortified samples gave &gt;80% recoveries for 39 pesticides, and recoveries of &gt;50% for the other pesticides, except methamidophos and omethoate. Grapes, carrots, potatoes, and broccoli were used as samples during method development, and a blind experiment involving incurred and fortified samples was used to test the approach. Results of the blind study compared satisfactorily with results from 7 laboratories using traditional GC detectors and solvent-based extractions.
Development of a Sample Preparation Technique for Supercritical Fluid Extraction for Multiresidue Analysis of Pesticides in Produce
Authors: Lehotay Steven J , Aharonson Nadav , Pfeil Emy , Ibrahim Medina A 
Published: February 2020

Abstract
Supercritical fluid extraction (SFE) of fruits and vegetables poses unique sample preparation considerations because the sample size is small (1–3 g) and the analyte is distributed in a moist solid matrix. The goal of this research was to develop practical sample preparation procedures for SFE of pesticide residues in produce so that acceptable accuracy and precision are maintained. In this study, 130 extractions of potato, fortified with up to 40 pesticides, were performed with 2 commercial SFE instruments. Extracts were analyzed by gas chromatography with ion trap mass spectrometry or electron capture detection. Four sample preparation procedures were tested and Hydromatrix was used to control the amount of water in the sample. The highest recoveries and lowest standard deviations were obtained when 20–50 g samples were blended with an equal amount of Hydromatrix and dry ice was added to keep the samples frozen. The dry ice helped produce a homogeneous flowable powder and greatly reduced the degradation or vaporization of several pesticides. Recoveries of most pesticides from subsamples of &lt;4 g with this procedure were 90–105%, with relative standard deviations of 1–6%. Only diphenylamine and disulfo-ton gave reduced recoveries with this procedure. When samples were extracted sequentially with an autosampler, certain pesticides were degraded in the extraction vessels over a period of several hours. To avoid losses of these pesticides, the sample in the extraction vessel was either purged with CO2 to remove oxygen or kept frozen until extracted. Peach and orange check samples were analyzed with the method, and results were comparable with those from traditional analyses.
Analysis of Total Free and Glucose-Conjugated Pyrethroid Acid Metabolites in Tea Infusions as Hexafluoroisopropyl Esters by Gas Chromatography with Electron Capture Detection
Authors: Mortimer Richard D , Weber Dorcas F , Sun Wing F 
Published: February 2020

Abstract
A gas chromatographic method with electron capture detection (GC–ECD) has been developed to quantitate the sum of free acids of pyrethroid metabolites, their glucosides, and their other base-cleav-able conjugates that are extracted from tea leaves when a tea infusion is prepared. Four representative glucoside conjugates were synthesized; hydrolytic conditions were established; and extraction, derivatization and GC conditions were developed for analysis of these pyrethroid acid metabolites at ≥0.01 ppm on dry tea. GC/mass spectrometry was used to confirm assignment of residues found in some tea samples.
Liquid Chromatographic Determination of trans-10-Hydroxy-2-Decenoic Acid Content of Commercial Products Containing Royal Jelly
Authors: Bloodworth Bosco C , Harn Chan Sheot , Hock Chua Teck , Boon Yio Oon 
Published: February 2020

Abstract
Thirty-nine samples of commercial products containing royal jelly were analyzed by liquid chromatography for their trans-10-hydroxy-2-decenoic acid (10-HDA) content. Most of the samples contained 10-HDA. Samples claimed to be pure royal jelly contained 1.98 to 6.37% 10-HDA (w/w). The 10-HDA content of samples claimed to contain royal jelly as an ingredient ranged from nondetectable to 1.28% (w/w).
Total Dietary Fiber Determined as Neutral Sugar Residues, Uronic Acid Residues, and Klason Lignin (The Uppsala Method): Collaborative Study
Authors: Theander Olof , Åman Per , Westerlund Eric , Andersson Roger , Pettersson Dan 
Published: February 2020

Abstract
A joint AOAC/American Association of Cereal Chemists (AACC) collaborative study was conducted to determine by the Uppsala method the dietary fiber content and its composition in various foods. The method includes preparation of a residue by treatment with thermostable α-amylase and amyloglucosidase and then ethanol precipitation of solubilized dietary fiber components while leaving low-molecular weight carbohydrates in solution. After acid hydrolysis of residue, neutral polysaccharide residues are determined as alditol acetates by gas-liquid chromatography, uronic acid residues are determined by colorimetry, and ash-free acid-insoluble residue (Klason lignin) is determined gravimetrically. Total dietary fiber, including enzyme-resistant starch, is calculated as the sum of nonstarch polysaccharide residues and Klason lignin. Nine laboratories completed the study, analyzing in duplicate 8 unknown dried products that included 4 cereal products, green peas, potato fiber, carrots, and apples. Total dietary fiber contents of products tested ranged from 4.6 to 84.3%, with an average RSDR value of 8.4% (range, 4.8–11.1%). Total neutral polysaccharide residues ranged from 3.8 to 64.1%, with an average RSDR value of 7.5% (range, 5.4–10.5%). Individual neutral sugars (rhamnose, arabinose, xylose, mannose, galactose, and glucose) and uronic acid residues present at more than 1% generally had good RSDR values (3.3– 22.8%), whereas, as expected for Klason lignin, only the wheat bran sample with a high content (16%) had an excellent RSDR value (5.0%). The gas chromatographic-colorimetric-gravimetric method (Uppsala method) for determination of total dietary fiber (as neutral sugar residues, uronic acid residues, and Klason lignin) has been adopted first action by AOAC INTERNATIONAL.
Simultaneous Determination of Arsenic, Selenium, and Antimony in Environmental Samples by Hydride Generation for Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Anderson Kim A , Isaacs Brandon 
Published: February 2020

Abstract
Total arsenic, selenium, and antimony are determined simultaneously by inductively coupled plasma atomic emission spectrometry (ICP AES) with hydride vapor generation. A1 g wet, 0.25 g dry, or 10 mL water sample is digested by 1 of 2 methods in a 10 mL volumetric culture tube on a programmed heating block by heating with nitric acid and then boiling in a mixture of sulfuric and perchloric acids. For soils, a 0.25 g sample is digested in a 10 mL volumetric culture tube with hydrochloric acid. After digestion, the sample is treated with additional hydrochloric acid. Arsenic, selenium, and antimony are reduced to their hydrides by sodium borohydride in a simplified continuous- flow manifold. A standard pneumatic nebulizer separates the gaseous hydrides (AsH3, SeH2, and SbH3), which are then quantitated by ICP AES at 193.696,196.026, and 231.147 nm, respectively. The detection limits for As, Se, and Sb are 0.55,1.0, and 0.41 μg/L, respectively. Recoveries from 10 matrixes are 65 to 109%; recovery ranges for As, Se, and Sb are 81–109,87–108, and 65–123%, respectively. The method demonstrates good accuracy and precision for environmental samples and is especially suited for analysis of small samples. It requires no additional apparatus for hydride generation or sample introduction.
Multivessel Supercritical Fluid Extraction of Food Items in Total Diet Study
Authors: Hopper Marvin L , King Jerry W , Johnson James H , Serino Alberta A , Butler Robert J 
Published: February 2020

Abstract
An off-line, large capacity, multivessel supercritical fluid extractor (SFE) was designed and constructed for extraction of large samples. The extractor can simultaneously process 1–6 samples (15–25 g) by using supercritical carbon dioxide (SC–CO2), which is relatively nontoxic and nonflammable, as the solvent extraction medium. Lipid recoveries for the SFE system were comparable to those obtained by blending or Soxhlet extraction procedures. Extractions at 10 000 psi, 80°C, expanded gaseous CO2 flow rates of 4–5 L/min (35°C), and 1–3 h extraction times gave reproducible lipid recoveries for pork sausage (relative standard deviation [RSD], 1.32%), corn chips (RSD, 0.46%), Cheddar cheese (RSD, 1.14%), and peanut butter (RSD, 0.44%). In addition, this SFE system gave reproducible recoveries (&gt;93%) for butter fortified with c/s-chlordane and malathion at the 100 ppm and 0.1 ppm levels. Six portions each of Cheddar cheese, saltine crackers, sandwich cookies, and ground hamburger also were simultaneously extracted with SC-CO2 and analyzed for incurred pesticide residues. Results obtained with this SFE system were reproducible and comparable with results from organic-solvent extraction procedures currently used in the Total Diet Study; therefore, use and disposal of large quantities of organic solvents can be eliminated.
Determination of Sulfonylurea Herbicides in Grains by Capillary Electrophoresis
Authors: Krynitsky Alexander J , Swtneford Douglas M 
Published: February 2020

Abstract
A capillary electrophoresis (CE) method was developed to separate and determine residues of 5 sulfonylurea herbicides in grains (wheat, barley, and corn). This work demonstrated the practicality of using CE for residue analysis of sulfonylureas. The method yielded good recoveries and adequate sensitivities at tolerance levels (0.05–0.1 ppm). The compounds investigated were metsulfuron methyl (Ally), thifensulfuron methyl (Harmony), chlorsulfuron (Glean), rimsulfuron (DPX-E9636), and tribenuron methyl (Express). Acetonitrile extracts of grain samples were partitioned with hexane and then cleaned up with cation exchange solid-phase extraction cartridges. Quantitation was performed by micellar electrokinetic capillary chromatography using a high-sensitivity optical cell. Average recoveries at the 0.05 ppm level ranged from 72.9 to 118.5%. The lower limit of detection was approximately 0.02 ppm, except for rimsulfuron and tribenuron methyl, for which the lower limit of detection was 0.035 ppm. The method was less complicated and showed better sensitivity than current single-analyte liquid chromatographic enforcement methods.
Estimation of 1992–1993 Dietary Intake of Organochlorine and Organophosphorus Pesticides in Fukuoka, Japan
Authors: Nakagawa Reiko , Herakawa Hironori , Hori Tsuguhide 
Published: February 2020

Abstract
To estimate Japanese daily intakes of organochlorine pesticides such as hexachlorocyclohexanes (HCHs), 1,1,1 -trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDTs), dieldrin (aldrin), heptachlor-epoxide (heptachlor), and hexachlorobenzenes (HCBs) from foods, fish, fish products, meat, eggs, milk, and milk products were analyzed as major sources of these pesticides in the diet. Estimated daily intakes (EDIs) per person were 0.56 μg for total HCH, 0.20 μg for γ-HCH, 0.09 μg for dieldrin, 1.42 μg for total DDT, and 0.15 μg for HCB. Similarly, daily intakes of organophosphorus pesticides such as malathion and chlorpyrifosmethyl were estimated by analyzing wheat and wheat products as major contributing foods. EDIs of malathion and chlorpyrifos-methyl were 0.22 and 0.24 μg, respectively. Daily intakes of total HCH, dieldrin, and total DDT in fiscal year 1992–1993 decreased 29,44, and 40%, respectively, but γ-HCH intake increased 167%, in comparison with results of total diet studies for fiscal years 1980–1984. It was also shown that increase in γ-HCH intake was due to recent increase in consumption of imported meat and meat products. Malathion intake did not change significantly. This method, which estimates EDIs based on concentrations of pollutants in main foods and statistical data of food consumption from the Japanese National Nutrition Survey, is considered to be sufficiently accurate for use as a simplified total diet study.
Determination of Ephedrine, Pseudoephedrine, and Norephedrine in Mixtures (Bulk and Dosage Forms) by Proton Nuclear Magnetic Resonance Spectroscopy
Authors: Hanna George M 
Published: February 2020

Abstract
A simple, specific, and accurate 1H nuclear magnetic resonance (NMR) spectroscopic method has been developed for quantitative determination of the Ephedra alkaloids (−)-ephedrine, (+)-pseudoephedrine, and (±)-norephedrine, either singly or in mixtures with each other. Determination of individual alkaloids was carried out in D2O solution, with acetamide as internal standard. Although calculations were based on integrals for the C–CH3 protons, those for the N–CH3 and –CH–O– protons may also be useful, depending on the compound. Determination of diastereomeric cross-contamination of ephedrine and pseudoephedrine—or of the concentrations of these alkaloids in the presence or absence of (±)-norephedrine—was feasible by using the integrals for the –CH–O– protons after addition of a trace of DCI. Mean recoveries for ephedrine and pseudoephedrine from their respective synthetic mixtures with the internal standard (acet- amide) were ≥99.9 ± 0.6% (n = 10) and 99.6 ± 0.8% (n = 10) of the amount added. Recovery for pseudoephedrine from diastereomeric mixtures with ephedrine was &gt;99.4 ± 0.7% (n = 10) of the amount added, with as little as 1.92% still being measurable. Mean recovery of (±)-norephedrine from mixtures with ephedrine and pseudoephedrine was &gt;99.7 ± 2.5% (n = 4) of the amount added, with about 1% still being measurable. Application of the proposed NMR spectroscopic method to commercial dosage forms, including ephedrine sulfate injections and pseudoephedrine hydrochloride tablets, yielded assay results ranging from 97.8 to 100.2% (mean, 99.2%) and from 98.7 to 100.5% (mean, 99.7%) of declared, respectively.
Proton Nuclear Magnetic Resonance Spectroscopic Detection and Determination of Ethylene Glycol Dimethacrylate as a Contaminant of Methyl Methacrylate Raw Material
Authors: Hanna George M , Lau-Cam Cesar A 
Published: February 2020

Abstract
A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1–11% of dimer yielded a dimer recovery of 100.5 ± 2.05% (mean ± standard deviation). Correspondence (correlation coefficient, r=0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.
Comparative and Multilaboratory Studies of Two Immunodiffusion Method Enrichment Protocols and the AOAC/Bacteriological Analytical Manual Culture Method for Detection of Salmonella in All Foods
Authors: Feldsine Philip T , Falbo-Nelson Maria T , Hustead David L , Flowers Russell S , Flowers Mary J 
Published: February 2020

Abstract
The single enrichment immunodiffusion (1-step), the preenrichment and selective enrichment immunodiffusion (2-step), and the AOAC/Bacteriological Analytical Manual culture methods for Salmonella were evaluated for equivalence in 2 separate studies, a comparative evaluation and a multilaboratory dilution study. In the comparative study, all 3 methods were performed on 10 food types. For 550 samples, analyses resulted in 99.3 and 99.6% agreement between the culture method and the 1-step and 2-step methods, respectively. False negative rates were 0.9 and 0.3% for 1-step and culture, and 0.0% and 0.6% for the 2-step and culture, respectively. Subsequently, 6 food types were included in a multilaboratory dilution-to-extinction study. A sequential dilution series of Salmonella in foods was analyzed by the 3 methods to determine their lower limits of detection for Salmonella. A total of 1185 samples analyzed resulted in 98.9% agreement between 1-step and culture, and 99.7% agreement between 2-step and culture. False negative rates were 1.8 and 0.1% for 1-step and culture, and 0.4 and 0.1% for 2-step and culture, respectively. During these evaluations, 1735 samples and controls representing 10 different naturally contaminated and inoculated foods were tested. The data indicate statistical equivalence of all 3 methods when analyzing all food types.
Determination of Magnesium in Fertilizers by Inductively Coupled Plasma Atomic Emission Spectrometry: Studies of Some Spectral and Interelement Effects at Different Wavelengths
Authors: Matilainen Rose , Tummavuori Jouni 
Published: February 2020

Abstract
Four analytical wavelengths of magnesium were tested for determination of Mg from fertilizers by inductively coupled plasma atomic emission spectroscopy (ICP-AES): 202.528, 285.213, and 383.826 nm (Mg I) and 279.553 (Mg II). The effects of fertilizer matrix elements on Mg determination were examined by adding matrix elements to fertilizer solutions. Multiple linear regression calculations proved a valuable technique for evaluating the effects of matrix elements on Mg determination. The observed interferences at Mg wavelengths may be both spectral and interelement. Interelement effects were typically caused by Na, K, and Ca, and spectral effects, by P, Fe, and S. The best wavelength for determination of Mg in fertilizers by ICP-AES was 383.826 (Mg I).