bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiresidue Method for Quantitative Gas Chromatographic Determination of Pesticide Residues in Sweet Cherries
Authors: Bicchi Carlo , D’Amato Angela , Balbo Cristina 
Published: February 2020

Abstract
A multiresidue method is described for determination of acephate, diazinon, dimethoate, fenitrothion, malathion, pirimicarb, trichlorfon, bromopropylate, dicofol, and tetradifon in sweet cherries for baby food at a limit of 0.01 ppm. Sweet cherry samples were extracted through a selective Extrelut column with methylene chloride and cleaned up with quaternary aminesilane-silica-dichloromethane. Extracts were then analyzed by gas chromatography (GC)/electron capture detection/flame photometric detection (FPD) and GC/nitrogen-phosphorous detection/FPD. Recoveries were determined by spiking sweet cherry homogenates with 10 pesticides at 0.1, 0.05, 0.02, and 0.01 ppm. Six determinations were performed at each level for each pesticide. Recoveries were 70% or better at the 0.01 ppm level.
Procedure for Detecting and Confirming Pentobarbital Residues in Dog Food by Gas Chromatography/Mass Spectrometry
Authors: Adam Laura A , Reeves Valerie B 
Published: February 2020

abstract
The method described detects and confirms presence of pentobarbital residues in dry, extruded feeds at concentrations of 5-20 ppb. Dried feed is ground to a uniform powder and shaken overnight in methanol. A portion of the methanolic extract is evaporated, and the residue is reconstituted in phosphate-buffered saline. The aqueous extract is cleaned with a solid-phase extraction cartridge designed to extract barbiturate residues from biological matrixes. Dimethyl sulfoxide, tetramethylammonium hydroxide, and iodomethane are added to derivatize pentobarbital. 1,3-Dimethylpentobarbital is then acidified with dilute hydrochloric acid and extracted with isooctane. The organic layer is transferred and evaporated under a stream of nitrogen. The residue is reconstituted in a small volume of ethyl acetate for analysis by gas chromatography/mass spectrometry. The limit of detection is approximately 0.7 ppb. The method was validated with pentobarbital-fortified feed samples containing high concentrations of meat and bone meal.
Comparison of SimPlate TotalTM Plate Count Test with Plate Count Agar Method for Detection and Quantitation of Bacteria in Food
Authors: Townsend David E , Naqui Ali 
Published: February 2020

abstract
The SimPlateTM Total Plate Count (TPC) test, developed by IDEXX Laboratories, Inc., detects and quantitates total bacterial concentration in food after 24 h of incubation. The performance of SimPlate TPC was compared with that of the plate count agar (PCA) method for enumerating total bacterial concentration of 255 food samples representing 15 different food matrixes. Total bacterial counts on SimPlate TPC were measured after 24 h of incubation and plotted against values obtained from PCA after 48 h. Simple regression analysis of the data showed strong correlation between the methods (r = 0.95); the sensitivity of SimPlate TPC for foodborne bacteria was 96% relative to PCA (slope = 0.96). It was concluded that SimPlate TPC is a suitable alternative for the detection and quantitation of foodborne bacteria. The method has been granted Performance Tested Certification by the AOAC Research Institute.
Liquid Chromatographic Method for Analysis of All-rac-α-Tocopheryl Acetate and Retinyl Palmitate in Milk-Based Infant Formula Using Matrix Solid-Phase Dispersion
Authors: William Chase G , Long Austin R 
Published: February 2020

abstract
A liquid chromatographic method is described for analysis of all-rac-α-tocopheryl acetate, tocopherols, and retinyl palmitate in milk-based infant formula. The vitamins are extracted from infant formula without saponification by matrix solid-phase dispersion and quantitated by normal-phase chromatography with fluorescence detection. Retinyl palmitate and vitamin E are quantitated isocratically with mobile phases of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results were similar to the certified and non-certified ranges for all-rac-α-tocopheryl acetate, retinyl palmitate, and tocopherols in the infant formula standard reference material (SRM) 1846. Results also compared favorably with the label declaration on a retail infant formula. Recoveries were determined on an analyte-fortified zero control reference material for milk-based infant formula and averaged 96.8% (n = 30) for retinyl palmitate and 91.5% (n = 25) for all-rac-α-tocopheryl acetate. Examination of 5 concentrations for each analyte gave results that were linear (r = 0.999) over the concentration examined, with coefficients of variation ranging from 1.02 to 5.86%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and vitamin E in fortified infant formula. Additionally, the method minimizes solvent use by using only 14 ml_ solvent per extraction.
Gas Chromatographic Determination Of Diphenylamine In Apples And Pears: Method Validation And Results Of Spanish Official Residue Monitoring Program 1995
Authors: Garrido Juan , Alba Mercedes De , Jimenez Irene , Cadado Elisa , Folgeiras Maria Luz 
Published: February 2020

abstract
A simple, fast, and inexpensive method is described for the determination of diphenylamine residues in apples and pears. The diphenylamine is extracted with acetone, and the extraction is followed by liquid-liquid partitioning and further analysis by gas chromatography with nitrogen-phosphorous detection. The method was validated with fortified samples at 4 concentration levels. A gas chromatographic/ mass spectrometric confirmatory procedure was developed and applied in routine analysis. The detection level of the proposed method is 0.005 mg/kg, and recoveries ranged from 80 to 100℅. The method was used to analyze 100 apple and pear samples from the Residue Monitoring of Hygiene Food Program 1995 of the Spanish Ministry of Health, which is conducted by our laboratory. The results obtained confirmed the viability of the method for routine analysis for this compound. A first evaluation was completed for the presence of diphenylamine residues in apples and pears produced in Spain.
Release of Fumigant Residues from Grain by Microwave Irradiation
Authors: Ren Yong-Lin , Desmarchelier James M 
Published: February 2020

abstract
Multiresidue analysis of fumigants is important because of their widespread use on staple foodstuffs, such as grain. Fumigants are usually extracted from grain either by solvent extraction or by purgeand- trap techniques. In this paper, fumigant residues in wheat were "extracted" by a microwave procedure. Wheat, in gas-tight Erlenmeyer flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for CH3Br PH3, CS2, and COS. Recoveries of fortified samples were &gt;90%. Completeness of extraction was assessed from the amount of fumigant retained by the microwave-irradiated wheat. This amount, determined from both solvent extraction and from further microwave irradiation, was always small(&lt;5℅ of the amount obtained from the initial procedure). Limits of quantitation were &lt;1 ng/g for ChhBr, PH3, and CS2. These low limits were essentially due to the absence of interference from solvents. The microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted.
pH-Metric Determination of the Acid Value of Vegetable Oils without Titration
Authors: Kuselman Ilya , Tur’yan Yakov I , Berezin Oleg Y , Kogan Lina , Shenhar Avinoam 
Published: February 2020

Abstract
The acid value (AV) of vegetable oils is determined without titration by using a new reagent consisting of triethanolamine in a solution of water and isopropyl alcohol. When the oil sample is mixed with the reagent in the pH-metric cell, free fatty acids from the sample are extracted into the reagent ( 3 - 4 min). The initial pH, called conditional pH´, is measured, a standard acid (HC1) is added, and the final pH, pH´2, is measured. AV is calculated from the difference between pH´! and pH´2. The method is applicable for quality control of vegetable oils during their production, trade, and use
Identification of the Source of Reagent Variability in the Xanthydrol/Urea Method
Authors: Biles Patricia Valdes , Ziobro George C 
Published: February 2020

Abstract
Contamination of food and food packaging material by rodent urine is evidence of insanitary conditions. Urea from rodent urine is used as a chemical indicator of contamination. The limit of detection of the xanthydrol/urea AOAC Method 959.14 by formation of dixanthylurea crystals is 4 μg urea isolated from urine on packaging material. Six different lots of xanthydrol from 5 different manufacturers were compared. Differences in urea detection sensitivity of the xanthydrol of up to 1000-fold were observed. Melting points showed further evidence of variability and impurities in xanthydrol lots. A liquid chromatographic method was developed to separate and identify the impurities. Confirmation of analytes was performed by gas chromatography/mass spectrometry.
Determination of (+/−) Elution Orders of Chiral Organochlorines by Liquid Chromatography with a Chiral Detector and by Enantioselective Gas Chromatography
Authors: Wetter Walter , Klobes Ulrike , Luckas Bernd , Hottinger Georg , Schmidt Gabi 
Published: February 2020

Abstract
Enantioselective gas chromatography (GC) with 5 modified cyclodextrins was applied to chiral organochlorines. A prerequisite for determining GC elution orders of enantiomers is the availability of enantioenriched standard solutions. In addition to compounds reported before (e.g., α-HCH, PCB 174, oxychlordane), we determined the sign of optical rotation of enantioenriched solutions of e-aeee-pentachlorocyclohexene-1 (β-PCCH), perdeuterated α-HCH (α-PDHCH), perdeuterated β-PCCH, and the persistent compound of technical toxaphene—2-exo,3-endo,5-exo,9,9,10,10-heptachlorobornane (B7-1453)—by liquid chromatography (LC) with a chiral detector. An enantioenriched solution of (β-PCCH was obtained by enantioselective degradation of α-HCH with (-)-brucine. In addition to forming an enantiomeric excess of (-)-α- HCH, we formed enantioenriched (+)-(α-PCCH. In a similar study, α-PDHCH showed the same behavior with respect to enantioselectivity. Dextrorotation of an enantioenriched solution of B7-1453 was also confirmed by LC with a chiral detector. Enantioseparation of chiral organochlorines on 5 chiral stationary phases resulted in several reversed elution orders. These results indicate that a careful check of elution orders of organochlorine enantiomers is necessary prior to comparison of literature data for the study of enantioselective processes in the environment.
Liquid Chromatographic Determination of Carotenoids and Vitamins A and E in Multivitamin Tablets
Authors: Sun Jidong 
Published: February 2020

Abstract
Carotenoids and vitamins A and E in multivitamin tablets can be determined simultaneously by reversed-phased liquid chromatography (LC) with a programmable UV detector. Samples were dissolved in dimethyl sulfoxide and thenextracted with hexane. A portion was injected onto a SymmetryC18,150 × 4.6 mm id, 5 μm column and chroma tographed with a mobile phaseof acetonitrile–0.25% ammonium acetate in methanol and 0.05% triethylamine in dichloromethane. A step gradient was used. The system was operated at 25°C with a flow rate of 1.5 mL/min. UV detection was at 325 nm for retinols, 285 nm for tocopherols, and 450 nm for carotenoids. Detection limits were less than 0.3 ng for retinol and retinyl acetate; 2 ng for α-tocopherol acid succinate; 10 ng for α-tocopherol, γ-tocopherol, and α-tocopherol acetate; and 0.4 ng for α-carotene and β-carotene. Intraday and interday coefficients of variation ranged from 1.40 to 5.20%. The sample preparation method and LC assay are practical for quality control and routine analysis of multivitamin tablets.
Fast Determination of Lead and Copper in Dairy Products by Graphite Furnace Atomic Absorption Spectrometry
Authors: Viñas Pilar , Pardo-Martí Mercedes , Campillo Natalia , Hernández-Córdoba Manuel 
Published: February 2020

Abstract
A rapid and direct procedure for determining lead and copper in dairy products by electrothermal atomic absorption spectrometry (ETAAS) is described. Samples are slurried in a medium containing 50% v/v hydrogen peroxide, 1 % v/v nitric acid, 0.5% w/v dihydrogen phosphate, and 20% v/v ethanol and directly injected into the furnace with no previous mineralization. Calibration is performed with aqueous standards. Limits of determination were 0.4 and 2.4 ng/mL for copper and lead, respectively. The reliability of the procedure was checked by comparison with the acid mineralization procedure and by analyzing 3 certified reference milk samples.
Principles To Guide International Standard Tests for Liquid Chemical Germicides: A Proposal
Authors: Miner Norman 
Published: February 2020

Abstract
This review discusses issues involved in developing standard tests for liquid chemical germicides and suggests some guiding principles to be considered for future development of harmonized international standard methods for testing disinfectants and sterilants. A published test method to measure sporicidal activity is used as an example of the implementation of these principles.
Multiresidue Determination of Pesticides in High-Organic-Content Soils by Solid-Phase Extraction and Gas Chromatography/Mass Spectrometry
Authors: Mogadati Paul , Louis Judith B , Rosen Joseph D 
Published: February 2020

Abstract
A multiresidue method based on solid-phase extraction cleanup and gas chromatography/ion trap mass spectrometry was developed to analyze 120 pesticides and pesticide metabolites in 2 soils with organic matter contents of 4.0 and 5.2%. Among the pesticides and the pesticide metabolites studied (almost all of which were spiked into soils at 0.075 ppm in triplicate), 107 (89%) of those spiked in soil containing 4.0% organic matter showed recoveries of 70–130%, as did 98 (82%) of those spiked in soil containing 5.2% organic matter. At a signal-to-noise ratio of 5 for all pesticides except chlorothalonil in soil containing 5.2% organic matter, limits of detection ranged from &lt;1 to 15 ng/g.
Quantitative Analysis of Sulpiride and Impurities of 2-Aminomethyl-1-Ethylpyrrolidine and Methyl-5-Sulphamoyl-2-Methoxybenzoate in Pharmaceuticals by High-Performance Thin-Layer Chromatography and Scanning Densitometry
Authors: Agbaba Danica , Miljkovic Tatjana , Marinkovic Valentina , Zivanov-Stakic Dobrila , Vladimirov Sote 
Published: February 2020

Abstract
A simple and reliable thin-layer chromatographic method for determining sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate was developed and validated. A methylene chloride–methanol–ammonia solution (25%; 18 + 2.8 + 0.4, v/v) solvent system is used for separation and quantitative evaluation of chromatograms. The chromatographic plate is first scanned at 240 nm to locate chromatographic zones corresponding to sulpiride and methyl-5-sulphamoyl-2-methoxybenzoate. Then 2-aminomethyl-1-ethylpyrrolidine is derivatized in situ with ninhydrin, and resulting colored spots are measured at 500 nm. The method is reproducible and convenient for quantitative analysis and purity control of sulpiride in its raw material and in its dosage forms.
Simultaneous Determination of Water and Enediols or Thiols in Chemical Products and Drugs Not Amenable to Direct Karl Fischer Titration
Authors: Kuselman Ilya , Sherman Felix , Bourenko Tat’Yana , Shenhar Avinoam 
Published: February 2020

Abstract
A method proposed for determining water and enediols or thiols is based on consecutive titration of the enediols or thiols by a novel reagent and of water by the conventional Karl Fischer reagent in the same cell. The time for both titrations is 8–20 min. The novel reagent consists of iodine, sodium acetate as a base, and potassium iodide in a nonaqeous solvent system. The method is applicable for quality control of chemical products and drugs during their production and trade.
Analysis of Pesticide Residues in Fruits, Vegetables, and Milk by Gas Chromatography/Tandem Mass Spectrometry
Authors: Sheridan Robert S , Meola John R 
Published: February 2020

Abstract
A method for detection, quantitation, and confirmation of more than 100 pesticides by gas chromatography (GC) with ion trap mass spectrometry (MS/MS) has been developed. The sensitivity of this method for many analytes is equal to or lower than those of selective GC detectors such as flame photometric detectors and electrolytic conductivity detectors. Using MS/MS, very low detection limits and good confirmation (1 precursor ion and 2 or more product ions) are achieved simultaneously. The entire list of pesticides is screened with 2 injections per sample. Samples are introduced onto the column by a temperature-programmed cold injection to maximize response. Each pesticide is run with its own unique set of parameters, which fragment the compound, retaining only the precursor ion. This ion is then refragmented to create a product spectrum. The selectivity of MS/MS gives a very clean spectrum, making compound identification and confirmation clear, even with a relatively dirty food matrix. If care is taken to maintain the injection port and guard column, this method can reliably identify and confirm more than 100 pesticides at the low parts-per-billion range.
Multiresidue Analytical Method for the Determination of Eight Penicillin Antibiotics in Muscle Tissue by Ion-Pair Reversed-Phase HPLC after Precolumn Derivatization
Authors: Verdon Eric , Couëdor Pierrick 
Published: February 2020

Abstract
A high-performance liquid chromatographic multiresidue method was developed for the determination of 8 penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, amoxicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in muscle tissue. This method involves extraction of the penicillins with phosphate buffer pH 9 followed by cleanup and concentration on a C18 solid¯phase extraction column and reaction with benzoic anhydride at 50°C for 5 min and with 1,2,4-triazole and mercury(II) chloride solution pH 9 at 65°C for 10 min. The derivatized compounds are eluted on a C18 column with a mobile phase containing acetonitrile and phosphate buffer (pH 6; 0.1 mol/L) loaded with sodium thiosulfate and ion-pairing tetrabutylammonium hydrogenosulphate. The method detection limit is approximately 3-11 μg/kg and the limit of determination was evaluated down to 25 μg/kg in line with the criteria of the EU decision No. 93/256/EEC.
A Test Strip for Diamines in Tuna
Authors: Hall Margot , Sykes Paul A , Fairclough Diane L , Lucchese Leonard J , Rogers Patricia , Staruszkiewicz Walter , Bateman Robert C 
Published: February 2020

Abstract
This study describes the production of a solid-phase assay (test strip/dipstick test) for putrescine and cadaverine in tuna based on the coupling of an amine oxidase to a peroxidase/dye system. The assay was linear to 75 μM in phosphate buffer, and the minimum detectable concentration was 0.5 μM (&lt;0.1 ppm), corresponding to 0.01 mg% in spiked extracts. Intra- and interassay precisions were &lt;20%. Test strips were stable at 4°C for at least 12 months. Lysine, ornithine, and histidine did not react with the assay, and histamine reacted only minimally. Sixteen fish samples were tested by test strip and the standard AOAC protocol, and results were in good agreement.
Liquid Chromatographic Analysis of Vitamin K1 in Milk-Based Infant Formula with Matrix Solid-Phase Dispersion
Authors: Chase G William , Eitenmiller Ronald R , Long Austin R 
Published: February 2020

Abstract
A liquid chromatographic method for vitamin K1 in milk-based infant formula is described. The vitamins are extracted from infant formula by matrix solid-phase dispersion and quantitated by reversed-phase chromatography with fluorescence detection. Vitamin K1 is converted to the fluorescent hydroquinone with a postcolumn zinc reductive reactor. The limit of detection is 12 pg, and the limit of quantitation is 38 pg on-column. Linear responses were obtained in the range 0.55-22.1 ng/mL (r2 = 0.9998). Recoveries of vitamin K1 from an analyte-fortified blank material for milk-based infant formula averaged 91.7% (n = 25). The method provides a rapid, specific, and easily controlled assay for vitamin K1 in fortified infant formula.
Isolation of Chloramphenicol from Whole Eggs by Supercritical Fluid Extraction with In-Line Collection
Authors: Pensabene John W , Fiddler Walter , Donoghue Dan J 
Published: February 2020

Abstract
Egg consumption, at more than 65 billion per year in the United States, represents a potentially significant source of exposure to drug residues, particularly if the laying hens are treated with antimicrobial compounds or fed a diet containing medicated feed. Residues resulting from the use of chloramphenicol (CAP) is especially problematic if this compound is not used in accordance with national registration, e.g., for the control of Salmonella microorganisms in poultry. The most commonly used methods for the determination of CAP in biological samples require the use of large amounts of organic solvent. As a result, a less solvent intensive supercritical fluid extraction (SFE) method was developed for CAP in whole chicken eggs, and the results were compared with those for a solvent extraction procedure. In the SFE method, the egg sample is extracted with supercritical CO2 (without a modifier) at 10 000 psi (680 bar), 80°C, and an expanded gas flow rate of 3.0 L/min to a total volume of 150 L. The CAP is trapped in-line on a Florisil sorbent bed. The CAP is eluted post-SFE by using the liquid chromatographic mobile phase solvent (water-methanol), and determined on a C8 column with ultraviolet detection at 280 nm. Recovery from eggs fortified at the 10 ppb level (n = 6) was 81.2 ± 4.3%. To obtain eggs containing incurred CAP, hens were given a single daily dose of 75 mg CAP (orally by gelatin capsule) for 2 consecutive days, and the eggs were collected over a 12-day period. The mean value for “normally incurred” CAP in the eggs (n = 17) analyzed by SFE ranged from none detected to 174.5 ppb, with an overall mean of 60.5 ppb, compared with a mean of 60.4 ppb for the solvent extraction method. No significant difference in results was found between methods. However, the SFE method is more rapid, uses less solvent, and gives recoveries similar to those for the solvent extraction method, making it ideal for regulatory monitoring.