bluuebunny/crossref_metadata_2025_split huggingface dataset:
Review of the Metabolism and Mode of Action of Cyclophosphamide
Authors: Fenselau Catherine 
Published: February 2020

Abstract
A review of recent studies of the pharmacology of cyclophosphamide is presented. Particular attention is paid to the use of mass spectrometry in the identification of the active compound phosphoramide mustard as a circulating human metabolite of cyclophosphamide, the development of an assay method for cyclophosphamide, phosphoramide mustard, and nornitrogen mustard, and a demonstration that alkylation by phosphoramide mustard proceeds through a symmetrical aziridinium ion.
Gas-Liquid Chromatography and Mass Spectrometric Ion Selective Detection of Sterigmatocystin in Grains
Authors: Salhab Abdulazim S , Russell Gerald F , Coughlin James R , Hsieh Dennis P H 
Published: February 2020

Abstract
A method was developed for direct gas-liquid chromatographic-mass spectrometric (GLC-MS) analysis of nonderivatized sterigmatocystin in wheat, rice, barley, and corn. Sterigmatocystin was extracted from spiked grain samples by 2 methods, both of which yielded high recoveries of 14C-labeled sterigmatocystin (&gt;90%). Extracts were cleaned up by gel permeation chromatography on polystyrene with tetrahydrofuran as the eluant. Chromatography of relabeled compound indicated good recoveries (&gt;90%). The GLC-MS system was modified to give an all-glass chromatographic pathway to the ion source. Short glass or quartz columns packed with silicone liquid phase on inert supports gave the best results. Trace levels of sterigmatocystin were very labile in all gas chromatographic systems and levels below 5 ppb in grains were detected only with great difficulty. The GLC-MS system was utilized in the mass fragmentography mode, with selective ion monitoring of the m/e 295, 306, and 324 peaks. These ions were present in only trace levels in all control grain samples, indicating minimal interference from other compounds. The limit of accurate detectability (20 ng) on spiked grain samples was lower than previously reported. Lower levels of sterigmatocystin (1 ppb or 4 ng on column) could be detected in grains by using the mass fragmentography mode, but these levels could not be measured accurately.
High-Performance Liquid Chromatographic Determination of L-Aspartyl-L-Phenylalanine Methyl Ester in Various Food Products and Formulations
Authors: Fox Lew , Anthony Gaylord D , Lau Edward P K 
Published: February 2020

Abstract
A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures &lt;1000 psig, an analysis can be performed in &lt;15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are ≤2.5%.
Monomolecular Film Method for Determining Microquantities of Fat in Egg Albumen
Authors: Taber Lawrence E 
Published: February 2020

Abstract
A very small amount of egg yolk (0.04–0.05%) in egg albumen interferes with the performance of the latter in the baking of angel food cakes. For many years no practical chemical test was available that would adequately determine these small amounts. In the proposed method, lipids are extracted from a sample of albumen, using a form of alkaline hydrolysis, and extracted again with petroleum ether. A known aliquot is expelled on a film of oxidized oil which has been suspended on the surface of distilled water. The resulting spot is measured by tracing its outline and measuring the area with a compensating planimeter.
Ion Selective Electrode for 2,4-Dichlorophenoxyacetic Acid
Authors: Hazemoto Norio , Kamo Naoki , Kobatake Yonosuke 
Published: February 2020

Abstract
An electrode responsive to 2,4-D (2,4-dichlorophenoxy acetic acid) was constructed by dissolving tetrazolium derivatives as an ion exchanger in a liquid membrane. The electrode exhibited rapid and Nernstian response to solutions of 2,4-D over the concentration range 10−1 to 10−4M. The presence of diverse substances such as acetate, benzoate, and 3-indoleacetate showed no appreciable effect on the electromotive force of the electrode.
High-Pressure Liquid Chromatographie Determination of Resmethrin and Ratios of the cis-trans Isomers
Authors: Zehner James M , Simonaitis Richard A 
Published: February 2020

Abstract
Total resmethrin ((5-benzyl-3-furyl)methyl cis, trans-(±)-2,2-dimethyl-3-(2-methylpropenyl)cyclopropanecarboxylate) in formulations and cis-trans ratios were determined by high-pressure liquid chromatography on a column of octadecylsilane on Zipax with methanol-water liquid phase. Pentachlorobenzene was the internal standard. The cis-trans ratio can be determined directly without hydrolysis to chrysanthemumic acid as in some other methods.
Improved Microbiological Procedure for Determining Bacitracin in Premixes and Mixed Feeds
Authors: Fassbender Carol A , Katz Stanley E 
Published: February 2020

Abstract
An improved microbiological procedure is presented for determining bacitracin in premixes and mixed feeds. Premixes are extracted with acidic 50% aqueous methanol, and mixed feeds are extracted with 50% dimethylformamide after washing with acetone to remove fats and pigments. Extracts are diluted with pH 6.0 phosphate buffer and assayed by using a 2-point assay system with Micrococcus flavus as the test organism. The simpler extraction coupled with the 2-point assay system measured bacitracin levels as low as 10 g/ton. Accuracy and repeatability of the 2-point system were at least equivalent to those for official AOAC methods.
Collaborative Study of the Determination of Sodium in Dietetic Foods by the Sodium Ion Electrode Method
Authors: McNerney Francis G 
Published: February 2020

Abstract
The dietetic food sample is diluted with total ionic strength adjusted buffer. The electrode potential of the sample is measured, known increments of sodium are added, and the electrode potential is measured after each addition. The mv readings obtained are plotted on Gran’s paper and the concentration of sodium in the sample is found from the intercept of the extrapolated straight line. Seven processed dietetic vegetables and 2 spiked samples were sent to 7 collaborators. There was a 95.8% agreement between the results from the 7 collaborators and the Associate Referee for the unfortified samples. Recoveries of 98.5 and 95.1% were obtained on fortified samples, based on results from 5 collaborators. The statistical analysis indicates minimal bias and adequate precision for determination of sodium in dietetic food at the current regulatory requirements. The method has been adopted as official first action.
Electron Capture Gas-Liquid Chromatographic Determination of Acetone in Butter
Authors: Love John L , Donnelly R Grant C 
Published: February 2020

Abstract
A method has been developed for the rapid, routine determination of acetone (2-propanone) at the mg/kg level in butter by electron capture gas-liquid chromatography of the 2,4-dinitrophenylhydrazone derivative. The method has potential for wider application to other carbonyls in food oils and fats.
Collaborative Study of Methods for the Determination of Chloride, Citrate, and Phosphate in Processed Cheese
Authors: Brzenk Henry R , Krett O Joseph 
Published: February 2020

Abstract
A collaborative study was conducted to compare the International Dairy Federation (IDF)/International Organization for Standardization (ISO)/Association of Official Analytical Chemists (AOAC) proposed methods for the determination of chloride and citrate in processed cheese with the corresponding current AOAC methods. Since there is no current AOAC method for phosphate, only the IDF/ISO/AOAC method was used. Five samples of processed cheese were prepared with varying added amounts of the anions of interest. The samples were analyzed in duplicate by 7 collaborating laboratories. For chloride, both methods are comparable, but since the IDF/ISO/AOAC method is simpler and faster it has been adopted as official first action to replace the current AOAC method, 16.224. For citrate, the colorimetric IDF/ISO/AOAC method is more rapid and simpler than the current AOAC gravimetric method. However, the AOAC method is more precise. Therefore, the proposed method has been adopted as official first action as an alternative to 16.237. For phosphate, 2 of the 7 laboratories were outliers by the Youden ranking test but the results by the remaining laboratories appear satisfactory. The phosphate method should receive further study to reduce the between-laboratory error component.
Sensitive Colorimetric Determination of Cholesterol in Dairy Products
Authors: Bachman Kermit C , Lin Jan-Hai , Wilcox Charles J 
Published: February 2020

Abstract
Cholesterol can be determined colorimetrically in dairy products at levels of ≥10 μg (coefficient of variation = 5.3%) with an o-phthalaldehyde reagent when non-cholesterol lipids arc eliminated prior to color development. Absorbance for 2 mg tripalmitin was found to be equivalent to about 20 μg cholesterol. Saponification followed by hexane extraction removed interfering lipids. Using the described procedure, 238 individual raw milk samples were found to contain 144.4±37.9 μg cholesterol/ml, while their skim milk portions had 26.5±6.4 μg cholesterol/ml (mean ± standard deviation). The o-phthalaldehyde cholesterol estimates agreed with those obtained by a gas-liquid chromatographic procedure when cheese and ice cream were analyzed by the colorimetric procedure with and without prior fat extraction.
Spectrophotometric Determination of Ferric, Ferrous, and Total Iron in Drugs by Reaction with α,α′-Dipyridyl
Authors: Sullivan Daniel J 
Published: February 2020

Abstract
The drug sample is dissolved in 0.2N HCl to yield a final concentration of 30 μg Fe/ml, an aliquot is reacted with α,α′-dipyridyl, and the pH is adjusted with an acetate buffer. For Fe(II), the color intensity is measured at 523 nm. For total iron, ascorbic acid is added to a separate aliquot of the sample solution, reducing all the iron present to Fe(II), which is then reacted with α,α′-dipyridyl, diluted to volume, and read at 523 nm. The Fe(III) content is determined by subtracting Fe(II) from total iron. This method is applicable to iron-containing drugs and drug dosage forms.
Extraction and Partition Chromatography of Tolbutamide as Ion-Pairs with Quaternary Ammonium Cations
Authors: Doyle Thomas D , Barkan Susan 
Published: February 2020

Abstract
The partition of tolbutamide (1-butyl-3-(p-tolylsulfonyl) urea) as ion-pairs with homologous tetraalkyl ammonium cations was studied. The determination of experimental extraction constants permitted quantitative calculation of distribution ratios, in agreement with theoretical relationships, over a continuous range of about one billion. The nature and the concentration of the counter-ion and solvent composition were the variables studied. Based on the theoretical results, a rapid partition chromatographic procedure was devised. A solution of tolbutamide sample in 10% aqueous tetraethyl ammonium hydroxide is incorporated in the system as the immobile phase in the partition column. A 1 + 1 mixture of chloroform and isooctane removes extraneous materials; then chloroform elutes the tolbutamide-tetraethyl ammonium ion-pair, which is converted to the free acid by passing the eluate through a phosphoric acid segment, and tolbutamide is determined spectrophotometrically without further treatment. Standard recoveries averaged 100.5 ± 0.70%; commercial tablets assayed 100.5 ± 0.85%.
Solvent Effects in the Partition of Phenols as Ion-Pairs with Tetrabutyl Ammonium Cations
Authors: Doyle Thomas D , Proctor Joseph B 
Published: February 2020

Abstract
The extraction of phenols as ion-pairs with tetrabutyl ammonium cations was studied with respect to variation of distribution as a function of solvent composition. The large solvent effect observed for 12 phenols gave quantitative agreement with an exponential relationship previously developed for other classes of ion-pairs and had approximately the same magnitude. An exception was noted for phenols substituted at the ortho position by nonpolar groups; decrease of the exponential value in these cases provided support for the controversial concept of specific solvation. Ortho substitution by polar groups led to a pronounced increase of extraction constants; this was explained in terms of delocalization of the anionic charge. Formylation via the Reimer-Tiemann reaction was observed as a complication in the extraction of some of the phenols.
Rapid Gas-Liquid Chromatographic Method for Determining Residues of Ethephon (2-Chloroethyl Phosphonic Acid) in Tomatoes
Authors: Ernst George F , Anderegg Marcia J P T 
Published: February 2020

Abstract
A rapid method is described for the determination of the growth regulator ethephon (2-chloroethyl phosphonic acid) in tomatoes. Samples are extracted with ethyl acetate. The extract is methylated, decolorized with carbon, and analyzed by gas-liquid chromatography on a column packed with 15% QF-1/10% DC-200 on Chromosorb W (HP). A flame photometric detector is used. Recoveries from tomatoes fortified with 0.1–11.0 ppm ethephon were 78—98%. The sensitivity of this method is about 0.1 ppm.
Thin Layer Chromatographic Determination of Sterigmatocystin in Cereal Grains and Soybeans
Authors: Shannon Gail M , Shotwell Odette L 
Published: February 2020

Abstract
A method has been developed for determining sterigmatocystin in yellow and white com, barley, oats, rye, sorghum, brown and wild rice, and soybeans. A partition column packed with activated magnesium silicate was used for cleanup. Averaged recoveries are 104% in white corn, 114% in rye, 100% in oats, 134% in brown rice, 96% in barley, 105% in sorghum and wild rice, and 92% in soybeans. The limit of sensitivity is 50 μg/kg for any of these commodities.
Microbiological Assay with Lactobacillus plantarum for Detection of Adulteration in Orange Juice
Authors: Vandercook Carl E , Smolensky Dora C 
Published: February 2020

Abstract
A microbiological assay has been developed io help detect adulteration in orange juice. Under standard assay conditions with diluted orange juice, the growth of Lactobacillus plantarum is proportional to the concentration of juice in the assay mixture. Imitation orange beverages did not support growth. Growth was also independent of the normal levels of common beverage ingredients such as sugar, acids, butylated hydroxyanisole, and orange oil. Commercial orange juices reconstituted from concentrates from various sources were assayed by the microbiological procedure, and the variability of results (coefficient of variation 24%) was about the same as or slightly lower than that for many of the other constituents used to estimate adulteration.
Gas-Liquid Chromatographic Determination of Methyl Anthranilate in Wine
Authors: Nelson Richard R , Acree Terry E , Lee Chang Y , Butts Robert M 
Published: February 2020

Abstract
A method is described for the gas-liquid chromatographic determination of methyl anthranilate in wine. Methyl anthranilate is extracted with Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane), concentrated, and quantitated by comparing the peak area with that of an internal standard (p-di-n-butoxybenzene). A synthetic wine solution (12% ethanol in water) as well as White Riesling and Concord wines containing various concentrations of added methyl anthranilate were analyzed. Recovery of methyl anthranilate in the range of 0.1–10 mg/L averaged 100.26% with an average relative error of 3.94%. The method is both rapid and reliable.
Infrared Spectrophotometric Analysis of Medicinal Gases for Trace Impurities
Authors: Brannon Wilson L , Benson Walter R , Schwartzman George 
Published: February 2020

Abstract
The feasibility of examining medicinal gases for trace impurities, using an infrared spectrophotometer in conjunction with a 10 m gas cell, was investigated. Many of the impurities for which the USP includes limits were detected and measured at concentrations at or below those permitted by the USP; these include sulfur dioxide, carbon dioxide, carbon monoxide, and water. However, others (hydrogen sulfide, nitric oxide, and nitrogen dioxide) were not detected at these levels by this technique. Methane was found at low levels in some samples.
Pilocarpine Hydrochloride in Ophthalmic Solutions: Modification of a High-Pressure Liquid Chromatographic Determination and Survey
Authors: Weber John D 
Published: February 2020

Abstract
Pilocarpine undergoes 2 important reactions in solutions, epimerization to isopilocarpine and hydrolysis to pilocarpic acid. There is no official USP limit for isopilocarpine or pilocarpic acid in pilocarpine hydrochloride ophthalmic solutions. An existing high-pressure liquid chromatographic (HPLC) method was modified by changing the buffer system to permit its use with constant-pressure as well as constant-volume instruments. The procedure separates all 3 components on a cation exchange resin ; pilocarpine and isopilocarpine are determined directly and pilocarpic acid indirectly. Ophthalmic solutions and drug substances were obtained from substantially all the United States marketers of pilocarpine opthalmic solutions and were analyzed by the modified HPLC method. Results of the survey show that isopilocarpine is present to the extent of 0.4–3% and pilocarpic acid at levels of 0.6–7% of total alkaloid.
Extractable Color of Capsicums and Oleoresin Paprika
Authors: Woodbury James E 
Published: February 2020

Abstract
A collaborative study of the method for extractable color in capsicums and oleoresin paprika was conducted to determine if the NBS neutral glass filter standard is superior to the chemical standard now used as a spectrophotometer check. For a 1000 ASTA (American Spice Trade Association) color value sample, the reproducibility standard deviation was 49 with the chemical standard compared with 14 with the NBS filter. The repeatability standard deviations were 9.0 and 8.9, respectively. For a 2000 ASTA color value sample, the reproducibility standard deviation was 162 with the chemical standard compared with 44 with the NBS filter. The repeatability standard deviations were 12.9 and 10.1, respectively. The study also indicated that 16 hr in acetone extracted 8.0% more of a capsicum than the 4 hr in the present AOAC method. The repeatability standard deviations for 4 hr vs. 16 hr were 2.1 and 1.6. The method has been adopted as official first action.
Collaborative Study of a Modified Method for the Extraction of Light Filth from Ground White Pepper, Cardamom, Celery Seed, Coriander, and Ginger
Authors: Dent Russell G 
Published: February 2020

Abstract
An improved method has been developed for the extraction of light filth from 5 ground spices, ginger, white pepper, coriander, celery seed, and cardamom. The method, a modification of 44.120, utilizes a cold isopropanol defatting, followed by wet sieving and flotation of light filth from 40% isopropanol with HCl and mineral oil-heptane (85+15). Collaborative results show that the proposed method is more rapid to perform than the present official first action methods, 44.116 and 44.120, and yields better recoveries. The method has been adopted as official first action.
Semiautomated Method for the Fluorometric Determination of Total Vitamin C in Food Products
Authors: Egberg David C , Potter Richard H , Heroff John C 
Published: February 2020

Abstract
A simple method employing simultaneous extraction and oxidation has been developed for the semiautomated determination of ascorbic and dehydroascorbic acids in food products. Recovery studies were conducted on ready-to-eat breakfast cereals and both fresh and canned fruits and vegetables, with average recoveries of 101, 100, and 102%, respectively. Reproducibility data were generated showing a relative standard deviation of 3.5%. The automated method was compared with the manual AOAC fluorometric method and with indophenol titration ; correlation coefficients were 0.9960 and 0.9926, respectively. The hydrolysis product of dehydroascorbic acid, 2,3-diketoguIonic acid, a reported interference in this method, was prepared and shown not to form an interfering fluorescent derivative.
Hydroxylamine Hydrochloride in Automated and Manual Methods for Riboflavin Determination
Authors: Jacobson Barabara S 
Published: February 2020

Abstract
The AOAC method for riboflavin determination has been modified to improve the precision of the manual method and greatly simplify its automation. In the AOAC method, permanganate oxidation is used for sample cleanup, and hydrogen peroxide is used to reduce excess permanganate. By substituting hydroxylamine. HCl for the hydrogen peroxide, the generation of oxygen gas, which can be troublesome, is eliminated without otherwise changing the assay. The resulting manual assay has a relative standard deviation of 1% as opposed to 2.5% for the same assay with hydrogen peroxide. This method is simple to automate, using a continuous flow system. The automated system performs 40 determinations per hour with a 1% relative standard deviation and results agree with those from the AOAC method at the 98% confidence level.
Gas-Liquid Chromatographic-Mass Spectrometric Detection and Identification of Ambergris
Authors: Governo Thomas F , Alessandro Rocco T , Prager Manfred J 
Published: February 2020

Abstract
A gas-liquid chromatographic-mass spectrometric method for the detection and identification of ambergris in its natural state or in perfume preparations is described. Solid samples are extracted; liquid samples are concentrated. Ambrein, a major component of ambergris, is separated by gas-liquid chromatography on an OV-17 capillary column, detected by flame ionization, and identified by mass spectrometry. Sample retention times and mass spectra were compared with those of purified material isolated from reference ambergris samples. Several types of perfume-related samples were tested. This method was satisfactory for samples of high concentration such as ambergris extracts and also for samples of low ambrein concentration typical of perfume formulations.
High Pressure Liquid Chromatographic Determination of 4,4′-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 6
Authors: Marmion Daniel M 
Published: February 2020

Abstract
Fourteen analysts from 9 laboratories evaluated a high pressure liquid chromatographic procedure for the determination of 4,4′-(diazoamino)-dibenzenesulfonic acid (DAADBSA) in FD&C Yellow No. 6. Each collaborator analyzed 5 samples nominally containing 0—0.050% DAADBSA. The repeatability and reproducibility of the method are estimated to be 0.003% and 0.020%, respectively. The method has been adopted as official first action.
Collaborative Study of Turbidimetric Microbiological Assay of Monensin in Chicken Rations
Authors: Breunig H Latham , Scroggs Robert E , Tonkinson Lealon V , Bikin Henry 
Published: February 2020

Abstract
A turbidimetric microbiological assay method for monensin in chicken rations was submitted in a modified form to 8 collaborating laboratories along with randomized and coded samples. Three laboratories used the manual method and 5 used the automated method. Other factors in the experimental design were ration types (broiler starter, broiler finisher, and pullet grower), feed form (meal vs. pellets), and potency level (90 and 110 g/ton) for one ration. Average recoveries for the ration types over all laboratories and feed forms were 87.7—93.13% of label, while mean recoveries in 2 feed forms were 91.7% for meal and 87.6% for pellets. Average recoveries in the 8 laboratories ranged from 84.6 to 106.64% of label for 90 g/ton rations and 87.1 to 106.6% for 110 g/ton rations. There was no significant difference between the manual and the automated methods. The collaborators’ assays were uniform with respect to within-laboratory variation. Relative standard deviations ranged from 4.51 to 10.76% with a median of 6.04%. Agreement with the plate assay is quite good. The turbidimetric method for monensin has been adopted as official first action.