bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative Confirmation of Dimethoate Residues in Wheat Plants by Single Ion Mass Spectrometry
Authors: Lee Young W , Westcott Neil D 
Published: February 2020

Abstract
A gas chromatographic-single ion mass spectrometric method was developed for determining dimethoate residues in wheat plants. The base peak (m/e 87) of dimethoate was chosen as the single ion peak, and methyl stearate was used as an internal standard for this analysis. The minimum detectable concentration of dimethoate by this method was about 0.1 ppm for a 20 g wheat plant sample. The recoveries of dimethoate were about 89% at 0.13 ppm and &gt;96% at 0.5-1 ppm.
Identification Tests for Propantheline Bromide
Authors: Brannon Wilson L , Benson Walter R , Smith Myron M 
Published: February 2020

Abstract
A method is described for the isolation and identification of propantheline bromide from bulk drug substances and dosage forms, both alone and in combination with other drug sub-stances. The method permits the specific identification of the intact drug substance, using both infrared spectroscopy and thin layer chromatography.
Reverse Phase High Pressure Liquid Chromatographic Determination of Some Iodoamino Acid Contaminants in Sodium Liothyronine or Sodium Levothyronine
Authors: Smith Donald J , Graham Joseph H 
Published: February 2020

Abstract
Some iodoamino acids have been separated and determined by high pressure liquid chromatography on octadecylsilane reverse phase packing with a mobile phase consisting of methanol, potassium phosphate monobasic, and orthophosphoric acid at 44°C. The method separates and quantitates mixtures of 3,5-diiodothyronine, liothyronine, isoliothyronine, and levothyroxine. The procedure provides an accurate, sensitive, and rapid estimation of decomposition and/or impurities in standards in approximately 30 min, at the &lt;75 pmole level, using an ultraviolet detector at 254 nm.
Microbiological Assays for Antibiotics and Vitamins: Considerations for Assuring Accuracy
Authors: Kavanagh Frederick , Ragheb Hussein S 
Published: February 2020

Abstract
Factors that may influence the accuracy and precision of microbiological manual and semiautomated turbidimetric methods as well as diffusion assays are discussed. Influence of kind of equipment, media, test bacteria, sample preparation, form of dose response lines, operations, and personnel on quality of assays is examined with the objective of reducing to insignificance those factors under control of the analyst that are responsible for low quality assays.
High Pressure Liquid Chromatographic Determination of Chlorophacinone in Formulations
Authors: Grant Ralph G , Pike Richard K 
Published: February 2020

Abstract
A simple and rapid method is described determining for 2- ((p-chlorophenyl) phenylacetyl-1,3- indandione (chlorophacinone) in rodenticides formulated as tracking powders and whole grain and crushed grain baits. The bait is extracted with methanol containing an internal standard, and the extract is injected into a high pressure liquid chromatograph. The sample is analyzed by reverse phase chromatography on octadecyl (C18) bonded to glass beads with a mobile phase of methanolwater (35+65) plus 0.75% NH4OH. A 5 μL injection containing 240 ng benzophenone internal standard and 77 ng chlorophacinone produces half scale peaks at 280 nm with a full scale absorbance of 0.01 absorbance unit. Two formulations and a spiked sample were analyzed by the method. Recovery as determined by peak area was &gt;97%.
Gas-Liquid Chromatographic-Mass Spectrometric Determination of α- and β-Naphthylamines in FD&C Red No. 2 (Amaranth)
Authors: Stavric Bozidar , Klassen Raymond , Miles Walter 
Published: February 2020

Abstract
A method is described for the simultaneous quantitation of trace amounts of α- (α-NA) and β-naphthylamines (β-NA) with detectability in the 0.1 ppb range and sensitivity of 50 picomoles in certified food grade amaranth (FD&C Red No. 2; C.I. Food Red 9; CI 16185). The amaranth sample is extracted with benzene, and the evaporated residue is derivatized with perfluorooctanoic anhydride. The resulting derivatives are separated by gas-liquid chromatography and identified and quantitated by mass spectrometric monitoring of the m/e at 539.04. The method was used for quantitation of α-NA and β-NA in randomly chosen samples of amaranth. Of 11 samples from different manufacturers, 5 were free of the β-isomer; the remaining samples contained up to 1.2 ppb β-NA. The concentration of α-NA ranged from no detectable amount to 970 ppb; the majority of the samples contained less than 7 ppb.
Microdetermination of Naphthionic Acid in Serum and Amniotic Fluid
Authors: Stavric Bozidar , Craig Jane , Klassen Raymond , Willes Robert 
Published: February 2020

Abstract
A simple, rapid, sensitive, and reproducible microdetermination of naphthionic acid (NA) in serum and amniotic fluid is described. The detection limit of the method is 1 ng NA in 20 μL serum, and 3 ng NA in 50 μL amniotic fluid. The concentration of nonderivatized NA was measured by fluorescence spectrophotometry (excitation 328 nm, emission 420 nm) of the supernate, after precipitation of proteins with absolute ethanol and heating for 30 min at 75°C. Standard deviations of determinations for 2, 10, and 50 ng NA in 20 μL serum were 10.1, 7.59, and 7.64%, respectively. An analyst can perform about 100 determinations daily; results are available within 2 hr of sampling. A modification of the procedure to permit quantitation of NA in urine is also described.
Deep Solvent Trough for Thin Layer Chromatography
Authors: Trucksess Mary W , Stoloff Leonard 
Published: February 2020

Abstract
A deep solvent trough for thin layer chromatography is described. By use of this device a second development of a thin layer plate containing slow moving background compounds can be made without interference from these compounds when the solvent polarity is increased. A score line across the plate, separating the compounds of interest from the background, in combination with a solvent depth that bridges the score line, results in interference-free secondary development and reduced development time.
High Performance Liquid Chromatographic Determination of Nine Phenolic Antioxidants in Oils, Lards, and Shortenings
Authors: Page B Denis 
Published: February 2020

Abstract
A simple, rapid technique is described for the determination of 2- and 3-tert-butyl-4-hydroxyanisole (BHA), tert-butylhydroquinone (TBHQ), 3,5-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-hydroxymethylphenol (Ionox-100), 2,4,5-trihydroxybutyrophenone (THBP), propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), and nordihydroguaiaretic acid (NDGA) in vegetable oils, lards, and shortenings. The antioxidants are partitioned from hexane-oil into acetonitrile, concentrated under vacuum, and determined by reverse phase, gradient elution, high performance liquid chromatography with detection at 280 nm. The mobile phase is wateracetonitrile with 5% acetic acid. With this system, only Ionox-100 and OG are not resolved. Recoveries from soya-sunflower seed oil spiked at 16 and 100 ppm and from lard at 32 ppm for 8 of the 9 antioxidants ranged from 96 to 103%, 100 to 102%, and 98 to 102%, respectively. The recoveries of BHT, due to incomplete extraction, were 84, 85, and 87%, respectively.
Analytical Reference Materials. II. Preparation and Sample Integrity of Homogeneous Fortified Wet Sediment for Polychlorinated Biphenyl Quality Control Studies
Authors: Chau Alfred S Y , Carron John , Lee Hing-Biu 
Published: February 2020

Abstract
A simple method fox the preparation of a large quantity of homogeneous wet sediment spiked with polychlorinated biphenyls (PCBs) is presented. By using a large blender and adding water to form a thick slurry, more than 2 kg spiked wet sediment was homogenized and 100-200 subsamples of 10-15 g, each suitable for checking precision and accuracy of a method or a laboratory, could be obtained. Eighteen Lake Ontario sediment subsamples were analyzed to check homogeneity. The mean recovery was 97.9% for a 1:1 mixture of Aroclors 1254 and 1260 fortified at 1 ppm; the coefficient of variation was 5.4%. For the Georgian Bay sediment, recovery for 5 replicates was 97.8% with a coefficient of variation of 3.2% for the same Aroclor mixture fortified at 0.629 ppm. Subsamples stored at — 20°C for up to 3 months showed no losses of PCBs for these 2 sediments. Stability data also provided additional support for the homogeneity of the subsamples for these 2 sediments.
Screening Method for Vitamins A and D in Fortified Skim Milk, Chocolate Milk, and Vitamin D Liquid Concentrates
Authors: Henderson Susan K , Mclean Lucia A 
Published: February 2020

Abstract
Vitamin A was determined in fortified chocolate milk and skim milk; vitamin D was determined in fortified chocolate milk, skim milk, and vitamin D concentrates, using reverse phase high pressure liquid chromatography (HPLC). The sample is saponified, extracted with hexane, and chromatographed in an HPLC system on a 10 μm Vydac TP reverse phase C18 column, using acetonitrile-methanol (9+1) as the mobile phase. For 6 replicates, the recoveries of vitamins A and D, using this procedure, were 99 and 98%, respectively.
Distribution of Aflatoxins B1 and M1 in Contaminated Calf and Pig Livers
Authors: Stoloff Leonard , Trucksess Mary W 
Published: February 2020

Abstract
The determination of aflatoxins B1 and M1 in multiple sections of livers from 4 calves and 1 pig exposed to high levels of aflatoxins showed a uniform distribution of the aflatoxins in each liver, within the precision of the analytical method used. The thin layer chromatographic method has an expected within-laboratory coefficient of variation of 15%.
Thin Layer Densitometric Determination of Gallic Acid and Gallotannins in Wine and Cider
Authors: Dadic Miroslav , Van Gheluwe Joris E A , Weaver Robert L 
Published: February 2020

Abstract
Free gallic acid and total gallotannins are determined in wine and cider by thin layer densitometry. The beverage is extracted with ethyl acetate and the extract is subjected to thin layer chromatography on silica gel. After elution with chloroform-ethyl formate-formic acid (50+40+ 10), the dry plate is sprayed uniformly with a freshly prepared solution of 0.3% aqueous FeCl3 and 0.3% aqueous K3FeCN6. If the gallic acid spot appears (Rf 0.28), densitometry readings are taken at 600 nm, and free gallic acid (GAF) is calculated from the formula GAF = GA (μg, from calibration curve) × 1.25. The calibration curve was obtained by plotting thin layer densitometric readings at 600 nm (prussian blue) vs. μg gallic acid. In a second method, the beverage is hydrolyzed, and extraction and densitometry are performed as before to give “total gallic acid after hydrolysis:” GAH (mg/L) = GA (μg, from calibration curve) × 25. Total gallotannins (GALLT) are calculated from the formula: GALLT (mg/L) = GAH – GAF. Results for 10 wines and 5 ciders are presented and briefly discussed.
Gas-Liquid Chromatographic Determination of Dioxathion and Quintiofos in Organophosphorus Dip Washes
Authors: Keating Molly I 
Published: February 2020

Abstract
A rapid method for the analysis of dip washes is described which eliminates the usual solvent extraction procedure. The dip wash is initially diluted with acetone and then with petroleum ether. The diluted dip wash is analyzed by gasliquid chromatography, using an alkali ionization detector sensitive to phosphorus compounds. The method was applied to the determination of dioxathion (2,3-ρ-dioxanedithiol S,S-bis(O,O-diethyl phosphorodithioate)), and quintiofos (O-ethyl O-8-quinolyl phenylphosphonothioate) dip washes. Average recoveries from fouled dip washes were 100 and 104%. GLC of these compounds with an internal standard is described, which improves the precision of the method to ±2%.
High Performance Liquid Chromatographic Determination of Bendiocarb on Wool
Authors: Zehner James M , Simonaitis Richard A , Bry Roy E 
Published: February 2020

Abstract
A high performance liquid chromotographic method is presented for determining bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate) on wool. Bendiocarb is extracted from wool with methanol containing methyl benzoate as internal standard, eluted through a Zorbax ODS column with methanol-water (55 + 45), and detected with a UV detector at 280 nm. The method can be used to determine bendiocarb at 0.001–0.02% by weight. The limit of detection is 0.0004%, or 4 ppm. At 4 analyses each, recovery at 0.013% was 101%, standard deviation 2.8%; at 0.003%, recovery was 96%, standard deviation 5.6%; at 0.001%, recovery was 103%, standard deviation 2.9%.
Extraction of Pentachlorophenol and Tetrachlorophenol Residues from Field-Contaminated Carrots and Potatoes: Comparison of Several Methods
Authors: Bruns Gary W , Currie Robert A 
Published: February 2020

Abstract
A number of solvent extraction systems were investigated for their efficiency in removing residues of pentachlorophenol (PCP) and tetrachlorophenol (TCP) from field-contaminated carrots and potatoes. Greatest numerical yields of PCP and TCP, for both carrots (9 and 5 ng/g, respectively) and potatoes (147 and 11 ng/g, respectively), were obtained by Soxhlet extraction with acidified acetone for 44 hr. Within the limits of experimental error, equivalent results could be obtained by using a 20 hr Soxhlet extraction with acidified acetone for carrots, and a 5 min blending with acidified acetone for potatoes. Extracts were reacted with diazoethane to form the ethyl ethers of PCP and TCP, followed by cleanup on a Florisil column. A gas-liquid chromatograph equipped with a 63Ni linearized electron capture detector was used for identification and quantitation.
Container-Derived Contamination of Maple Sirup with Methyl Methacrylate, Toluene, and Styrene as Determined by Headspace Gas-Liquid Chromatography
Authors: Hollifield Henry C , Breder Charles V , Dennison John L , Roach John A G , Adams William S 
Published: February 2020

Abstract
Samples of maple sirup and associated plastic packaging were examined for the presence of methyl methacrylate, toluene, and styrene by a head space gas chromatographic procedure. The volatile components common to the sirup and the plastic container were identified by gas chromatography-mass spectrometry. The quantities of these contaminants in the sirup were determined at ppb levels by the standard additions technique and repetitive headspace analysis.
Mass Loss on Drying for Instant Coffee: Collaborative Study
Authors: Clinton William P , Manni Paul H , Ferry John M 
Published: February 2020

Abstract
A collaborative study was undertaken to define an acceptable routine working method for determination of mass loss in instant coffee. Fourteen laboratories of 24 invited to participate submitted results. The repeatability standard deviation and coefficient of variation were 0.026 and 0.7%, respectively. The reproducibility standard deviation and coefficient of variation were 0.153 and 3.8%, respectively. The method has been adopted as official first action.
Survey for Aflatoxins and Zearalenone in Canned and Frozen Sweet Corn
Authors: Stoloff Leonard , Francis Octave J 
Published: February 2020

Abstract
Aflatoxins and zearalenone were determined in 263 samples of canned or frozen sweet corn, collected from packing plants during the 1976 and 1977 packing seasons. As anticipated from geographic, agronomic, and microbiological considerations, no aflatoxin or zearalenone was found. Based on this sampling, the highest incidence of detectable aflatoxin that could be statistically anticipated in the major packing areas is 1.5%.
Coprecipitation of Heavy Metals Directly in Graphite Crucibles for Furnace Atomic Absorption Spectrometry
Authors: Nichols John A , Woodriff Ray 
Published: February 2020

Abstract
A rapid, direct method is described for separating trace heavy metals from excessive quantities of matrix constituents for analysis of digested biological materials by furnace atomic absorption spectrometry. The analytes are coprecipitated with ammonium pyrrolidinecarbodithioate and collected on a porous graphite filter medium which is suitable, after a brief drying step, for direct insertion into an electrothermal atomizer. A constant-temperature furnace is used to verify collection efficiency of the micro-scale procedure for cadmium, copper, and zinc, and to examine the procedural criteria necessary for accurate results. The procedure is very rugged with respect to precipitation variables, and only slightly sensitive to possible gas-phase chemical interferences during atomization at sub-optimal temperatures. Thus, the procedure should eliminate matrix interferences during analysis of complex samples with a carbon rod atomizer. Direct insertion minimizes blanks, avoids resolubilization problems, and allows rapid handling of large numbers of samples.
Sensitive Gas-Liquid Chromatographic Method for Asulam Residues in Peaches
Authors: Bardalaye Promode C , Thompson Neal P , Carlson David A 
Published: February 2020

Abstract
The current analytical method for determining residues of the herbicide asulam (methyl (4-aminobenzenesulfonyl) carbamate) is the nonspecific colorimetric procedure based on the coupling reaction of N-1-naphthylethylenediamine with the diazotized amine. A new analytical method for determining the residues of this herbicide and its 2 known major metabolites, acetylasulam and sulfanilamide, in peaches has been developed and evaluated using gas chromatography with an N-P detector. The method is based on the hydrolytic conversion of the parent compound and the known metabolites to the common product sulfanilamide which is then analyzed by gas-liquid chromatography as its per N-methylated derivative. The identity of the derivative has been confirmed by chemical ionization mass spectrometry. The method was tested by using fortified crop extracts and also by analyzing crop treated by postemergent application of the herbicide for weed control. Sensitivity of the method is 5 ng and the detection limit in the crop is 0.1 ppm. Recoveries ranged from 70 to 80% from peaches at fortification levels of 1, 5, and 10 ppm. At a fortification level of 0.1 ppm the recovery is 50-60%.
Modification of the AOAC Method for Determination of Fumigants in Wheat
Authors: Jr Marion Clower 
Published: February 2020

Abstract
The official first action AOAC method for determination of residues of fumigants in grains has been modified for use by 6 laboratories in an FDA pesticide surveillance program. A 15% OV-I7 gas-liquid chromatographic column, installed in a chromatograph equipped with a constant current 63Ni electron capture detector, provides for improved resolution, multiresidue capability, and lower limits of detection. A study was made of the behavior of chloroform, carbon tetrachloride, ethylene dichloride, trichloroethylene, tetrachloroethylene, and ethylene dibromide through the method. Recoveries from fortified wheat samples averaged 105-115%. Experimental evidence is presented which suggests that part of the consistent trend toward high recovery can be attributed to selective sorption of acetone by the CaCI2 used in the final drying step.
Determination of Aflatoxins in Compound Feedstuffs Containing Citrus Pulp
Authors: Jain Anant V , Hatch Roger C 
Published: February 2020

Abstract
A method is described for determining aflatoxins B1, B2, C1, and G2 in compound feedstuffs containing citrus pulp. A finely ground sample is extracted with methylene chloride in a blender and cleaned with lead acetate. An aliquot of the cleaned extract is partitioned into methylene chloride and evaporated to dryness. The residue is dissolved in 0.5 mL chloroform. A 10 μL sample is applied to a thin layer chromatographic (TLC) plate and developed in 2 dimensions. Aflatoxins B1( B2, G1, and G2 are resolved and quantitated visually. The average recoveries were 96, 104, 98, and 102%, respectively. As little as 5 μg aflatoxin B1, or G1/kg, and 1.5 μg aflatoxin B2 or G2/kg can be determined by this procedure.
Modification of Official Method for Analysis of Carotenes and Xanthophylls in Dried Plant Materials and Mixed Feeds
Authors: Gimeno Alberto 
Published: February 2020

Abstract
The official method (43.018–43.023) for extraction and separation of carotenes and xanthophylls in dried plant materials and mixed feeds is modified. These pigments are extracted from samples lacking xanthophyll esters by stirring 2 hr, followed by 1-hr cold saponification. The official method recommends 16-hr static extraction preceding the cold saponification. For samples containing xanthophyll esters, we preceded the 20-min hot saponification step by 2 hr stirring. This extra step increased the yield of mono- and dihydroxy pigments, especially from marigold meal. For separation, Merck silica gel 60 plus Hyflo Supercel is substituted for silica gel G in adsorbent I, resulting in 30-min separation. Also, at least 4 separations can be performed using the same adsorbent, and the column is more easily cleaned between separations. Results of the modified method were comparable to those of the official method.
High Pressure Liquid Chromatographic Determination of Sorbitol in Bulk Sorbitol
Authors: DOkladalova J , Barton A Y , Mackenzie E A 
Published: February 2020

Abstract
An HPLC procedure for determining sorbitol in bulk sorbitol is described. An Aminex HPX-87 column (Bio-Rad) is used with water as a mobile phase and with a refractive index detector to monitor column eluate. Sorbitol is separated from pentaerythritol, erythritol, ribitol, ethylene glycol, propylene glycol, arabitol, galactitol, mannitol, iditol, and other carbohydrates. The precision of the sorbitol determination, characterized by a 95% confidence interval, corresponds to ±1.22%.
Rapid Method for Extraction and Colorimetric Estimation of Morphine in Indian Opium
Authors: Vaidya Prabhakar V , Pundlik Mukund D , Meghal Sharadchandra K 
Published: February 2020

Abstract
A rapid method for the extraction and estimation of morphine in Indian opium is described. Methanolic extract of opium is treated with activated charcoal and the colorless extract obtained contains all of the major opium alkaloids. Morphine content is estimated colorimetrically by using hydrogen peroxide–copper–ammonia. The reaction is specific for morphine, and no other major opium alkaloid responds. The results obtained by the proposed method are in general agreement with those obtained by the nitroso method.
Reverse Phase Thin Layer Chromatographic Procedure for Identification of Digoxin and Related Fluorescing Substances
Authors: Bloch Doris E 
Published: February 2020

Abstract
A one-step method was developed to replace the current USP monograph procedures for identification of digoxin and determination of related fluorescing substances. The new method is much quicker than the previous tests, which required paper chromatography and fluorometric measurements, respectively. Using reverse phase silica gel plates (C18 bonded to silica gel), digoxin was separated from digitoxin, gitoxin, and digoxigenin mono-digitoxoside, and partially resolved from digoxigenin bis-digitoxoside. A digoxin reference standard is used to correlate Rf values for identification, and a dilute solution of gitoxin is also co-spotted to give a maximum intensity limit for related fluorescing substances.