bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of the Carbon Disulfide Evolution Method for Dithiocarbamate Residues
Authors: Keppel George E 
Published: February 2020

Abstract
A study was made of the analytical method for dithiocarbamate fungicide residues based on decomposition by hot mineral acids to the amine and carbon disulfide and colorimetric measurement of the carbon disulfide. Increased recoveries are obtained by the following modifications: adding a reducing agent (stannous chloride) to the sample before treatment with hot acid; svibstituting diluted sodium hydroxide for lead acetate solution to remove hydrogen sulfide and other interferences; and using boiling diluted hydrochloric acid. With these modifications, recoveries of N,N-dimethyldithiocarbamates from crops ranged from 85.3 to 103.8% (average 94.7%). Ethylenebisdithiocarbamates, with the exception of zineb (range 89.1–96.8%, average 92.0%), gave appreciably lower recoveries, indicating further study is necessary.
Studies on the Effect of Sulfuric-Fuming Nitric Acid Treatment on the Analytical Characteristics of Toxaphene
Authors: Kawano Y , Bevenue A , Beckman H , Erro F 
Published: February 2020

Abstract
Toxaphene and a similar compound prepared from purified camphene were used in comparative studies for the analysis of residues of this pesticide before and after treatment of the compounds with a mixture of sulfuric-fuming nitric acid. The analytical characteristics of toxaphene were not affected by the acid treatment, as shown by GLC, TLC, and IR. The technique is useful for the GLC analysis of toxaphene residues in the presence of DDT and certain other insecticide residues.
Method for the Extraction of Light Filth from Plant Gums
Authors: Roaf Andree L , Brickey Paris M 
Published: February 2020

Abstract
A new method has been developed for the extraction of extraneous materials from plant gums. Hydrochloric acid and autoclaving are used to break down and disperse partially insoluble gums, followed by sieving and extracting using a trap flask. Collaborative studies gave reproducible recoveries of rodent hairs and insect fragments, and the method is recommended for adoption as official first action.
Automated Quantitative Determination of Selected Nitrogen-Containing Drugs
Authors: Leaton J R 
Published: February 2020

Abstract
Pharmaceutical preparations and selected raw materials ar e analyzed by anautomated nitrogen analyzer for the quantitative estimation of the organo-nitrogen compound. The assay method is based on a catalytic combustion process in which the drug is decomposed to elemental nitrogen, which is measured volumetrically. Tablets, powders, liquids, and suspensions are analyzed with little or no sample preparation. Recoveries from commercial preparations ranged from 98 to 102% of theory or declared amount. Degree of selectivity and specificity is limited; the chemical composition of the drug analyzed must he known. Guidelines for operating conditions are given.
Cholinesterase Inhibition Autoanalysis of Insecticidal Organophosphates and Carbamates
Authors: Voss Günther 
Published: February 2020

Abstract
An automated cholinesterase inhibition method gave satisfactory results during the development of insecticidal organophosphates and carbamates. Up to 40 samples/hr were analyzed with a precision equal to that of purely chemical methods performed manually. The lower limit of detectability of the method depends primarily on the inhibition potency of the particular compound under investigation and upon whether the system is operated in a pre-inhibition (most sensitive) or simultaneous inhibition (least sensitive) mode. Monocrotophos, for example, was analyzed in the concentration ranges of 0.1–2.0, 1–20, 10–200, and 100–2000 ppm; the last two concentration ranges were analyzed in the simultaneous inhibition mode. Sensitivities better than those achieved with human plasma :holinesterase, i.e., 0.1 ppm for monocroophos, were obtained by using a more sensiive type of cholinesterase, such as peacock ilasma cholinesterase. Examples of experinents, such as determinations of the stability if formulations, rates of hydrolysis, parti timing behavior of insecticides, solubilities in vatcr, and the determination of a cholineserase-inhibiting impurity in a technical samde of phosphamidon, are also described and locumented by original AutoAnalyzer reordings.
Statistical Examination of a Rapid Method for the Determination of Chlorinated Hydrocarbon Residues in Human Blood
Authors: Bonderman D P , Choi U Y , Hetzler H L , Long K R 
Published: February 2020

Abstract
An orderly examination of the laboratory parameters involved in the recovery of the chlorinated hydrocarbon residue, p,p′-DDE, from human blood serum by the method of Dale, Curley, and Cueto is reported. The age of the serum, amount of hexane used for extraction, duration of mixing time, and temperature were varied; the results were examined statistically to discern the possible effects. All these factors had a statistically significant effect upon the results of the analytical quantitation performed by GLC. The aging time of these rum and the amount of hexane used for the extraction as well as the aging time and duration of mixing time were intercorrelated. Modification for use of the published procedures based upon these findings is suggested.
Collaborative Study of a Chemical Method for Calcium Pantothenate
Authors: Hubbard W D , Sheppard A J 
Published: February 2020

Abstract
A chemical method for determining calcium pantothenate in pharmaceutical preparations has been studied collaboratively. The pantothenate molecule is cleaved with acid, and the resulting β-alanine is treated with a chlorinating solution and then with potassium iodide. The free iodine is measured spectrophotometrically at 358 mμ. The average coefficient of variation for all samples studied collaboratively is 8.9%. The method is recommended for adoption as official first action.
Vitamin A in Liquid Feed Supplements
Authors: Parrish D B , Aguilar Dalia 
Published: February 2020

Abstract
Maleic values were determined on vitamin A extracts from liquid feeds so that estimates could be made of biopotency of the vitamin A; the AOAC method is not suitable for this assay. Biopotencies were 57–81% of total vitamin A found. For comparison, maleic values were determined on Vitamin A Reference Solution and on chicken, quail, and rat livers. Most vitamin A in those sources appeared to be the all-trans form. Results of bioassays of vitamin A in liquid feeds indicate that further work is required before the assays are suitable for comparative purposes with results of biopotency estimates using maleic values.
Recommended Changes in the Sugar Chapter of the Official Methods of Analysis of the Association of Official Analytical Chemists
Authors: Kviesitis Boris 
Published: February 2020

Abstract
Changes are recommended in the arrangement of Chapter 29, “Sugars and Sugar Products”, since the present arrangement makes it difficult to determine which of the methods are acceptable for molasses analysis. It is recommended that a new section, “Molasses and Molasses Products”, be established as part of Chapter 29.
Collaborative Study on a Potentiometric Titration of Soluble Chlorides in Feeds
Authors: Sharpe D L 
Published: February 2020

Abstract
In the method described, a weighed feed sample is placed in 200 ml water, 1 ml nitric acid is added, and the chlorides present are titrated with silver nitrate. The titration is performed with a potentiometer equipped with a silver-silver chloride reference electrode a nd a silver indicating electrode. Collaborative s tudy showed that the method is more precise than the official method. An arithmetic mean for the coefficients of variations was 8.0 and 4.1, respectively, for the official and the potentiometric method.
Effect of Soluble Components on Crude Fat Determination in Grains and Stock Feeds
Authors: Debecze George I 
Published: February 2020

Abstract
Individual and collaborative tests were made to demonstrate the differences between fat values obtained by the “washed” and “unwashed” methods and to define the crude fat method that yields the true fat values. In an individual study on 18 samples and in a collaborative test by 7 participants on 20 commercial feed samples, the fat values by the two methods were identical on many samples; the washed method yielded lower fat values on certain samples and higher values on other samples. The differences were as much as –49% or +64%. The results were statistically evaluated. Based on these results, it is recommended that a statement be included in method 22.033 for aqueous extraction of samples containing large quantities of water-soluble substances prior to the fat determination.
Infrared Determination of Dithianon
Authors: Double R C 
Published: February 2020

Abstract
An infrared spectrophotometric method of analysis of dithianon in concentrates and formulated powders containing zineb and sulfur has been developed. Dithianon is extracted with chloroform from the concentrate or formulation; the extract is evaporated and diluted to a specific volume with chloroform; and the dithianon present is determined from the infrared absorption at 1275 cm-1. From 20 to 80 mg dithianon in 10 ml chloroform are readily determined.
Determination of Zinc Phosphide and Its Stability in Rodent Baits
Authors: Guerrant G O , Miles J W 
Published: February 2020

Abstract
An improved method for determining zinc phosphide has been developed that employs liberation of phosphine by refluxing with hydrochloric acid with subsequent determination by the alkalimetric quimociac phosphorus method. Zinc phosphide was found to he relatively stable when used on apple and potato baits for rodent control, with over 70% of the activity remaining after 99-day exposure under simulated baiting conditions. Decomposition occurs more rapidly in the juices of the moist surface of freshly prepared bait than on the dried baits. Decomposition is slow in a carbon dioxide atmosphere and is accelerated by moisture.
Modifications of the Assay of Bacitracin in Feeds
Authors: Craig G H 
Published: February 2020

Abstract
Modifications of the official first action method for bacitracin in final feeds have been investigated. An improved petroleum ether cleanup of the feed in a Goldfisch apparatus replaces the present acetone wash in a centrifuge tube. A more sensitive assay makes it possible to assay at a final concentration of 0.04 unit/ml instead of 0.10 unit/ml. Standard curves prepared in blank extracts of several types of feed at dilutions used in assaying bacitracin in the 4–10 g/ton range were similar to simultaneously prepared curves in buffer.
Fatty Acid Composition of Cocoa Butter Oil by Urea Fractionation and Programmed Temperature Gas Chromatography
Authors: Iverson John L , Harrill P G , Weik Robert W 
Published: February 2020

Abstract
This proposed urea fractionation procedure concentrates esters with similar GLC retention times in separate fractions. GLC peaks of esters present in cocoa butter oil in trace amounts (0.001–0.1%), which are normally hidden under major peaks, can then be detected. By modified programmed temperature GLC techniques, it is possible to detect the short and long chain length fatty acids present in cocoa butter oil. The odd and even chain length saturated acids from C10 to C28, mono-unsaturates C16 to C24, branched acids C16 to C24, and linoleic and linolenic acids were detected.
Thin Layer and Gas-Liquid Chromatography of Cholesterol in Fats and Oils. II. Collaborative Study
Authors: Thorpe C W 
Published: February 2020

Abstract
A method employing TLC-GLC for detecting animal fats in vegetable fats was subjected to collaborative study. The method involves preparative TLC of unsaponifiable matter followed by GLC of the isolated sterols. The results of this study, based on GLC determination of cholesterol in the isolated sterols, indicate that low levels (2.5%) of animal fat can be detected. The possibility of obtaining false positive results is greatly reduced compared with direct GLC of unsaponifiable matter or column chromatographic fractionation of unsaponifiable matter followed by GLC analysis.
Collaborative Study of Confirmative Procedures by Single Sweep Oscillographic Polarography for the Determination of Organophosphorus Pesticide Residues in Nonfatty Foods
Authors: Gajan Raymond J 
Published: February 2020

Abstract
Ten laboratories collaboratively studied several single sweep oscillopolarographic methods designed to be used as confirmative procedures for several organophosphorus pesticide residues determined by GLC. Polarographic methods for the detection and determination of parathion, methyl parathion, diazinon, and/or malathion at 0.5 and 2.0 ppm in extracts of apples and lettuce were included in this study. All 10 laboratories successfully detected the organophosphorus pesticide residues and quantitative results were reported by seven laboratories. These results show that the polarographic methods can be used for rapidly confirming results obtained by the multiple detection procedures now in use.
Comparison of Ten Methods for the Analysis of Milk for Residues of Chlorinated Pesticides
Authors: Lawrence James H , Burke Jerry A 
Published: February 2020

Abstract
Ten methods for the analysis of milk for residues of chlorinated pesticides were used to analyze a sample of milk containing a residue of heptachlor epoxide and fortified with p,p’-TDE, 1.00 p pm fat basis. Based on the p,p’-TDE determined, average recoveries above 90% were obtained with six methods, and 89, 85, 79, and 56% recoveries, respectively, with four methods. Cleanup efficiency for determination by electron capture GLC and thin layer chromatography varied from good to poor.
A Validation Study for the Automated Analysis of Corticosteroids in Drugs
Authors: Brower James F 
Published: February 2020

Abstract
A validation study for the analysis of seven corticosteroids in tablets, using an automated blue tetrazolium reaction, has been completed. The method is sensitive and applicable to concentrations normally found in dosage forms and does not require extensive sample preparation. Standard deviations for betamethasone, cortisone acetate, dexamethasone, hydrocortisone, methyl prednisolone, prednisolone, and prednisone by the automated procedure are reported, and the assay results were compared to those by the USP or NF method. The interference of common tablet excipients on the automated method was also determined.
Collaborative Study of an Ion Exchange Method for Ephedrine in Ephedrine Sulfate Sirup NF
Authors: Smith Donald J 
Published: February 2020

Abstract
An ion exchange procedure for Ephedrine Sulfate Sirup NF, based on the ability of ephedrine to be retained on a polystyrene sulfonate cation exchange resin column, was studied collaboratively by eight laboratories. The compound is held on the column by a positive charge located in the cationic center of the molecule, it is then eluted with hydrochloric acid, and its ultraviolet absorption is measured. The addition of 57.88 mg ephedrine sulfate to Ephedrine Sulfate Sirup NF resulted in recoveries of 58.39 and 57.72 mg, or 101 and 100%, respectively. Recoveries for collaborative samples, each containing 19.22 and 19.33 mg/5 ml, were 99.8 ± 1.83 and 101 ± 4.09%, respectively.
GLC Determination of DDVP Extracted or Vacuum-Trapped from PVC Resin Formulations
Authors: St Clair Akos D , Lamberton J G , Claeys R R , Goulding R L 
Published: February 2020

Abstract
A vacuum trapping apparatus was developed for the collection of volatiles and for the determination of rates of volatilization of DDVP from Vapona-PVC resin formulations. More than 99% of the total volatiles was collected by this apparatus. To determine the total content of DDVP in the resin four extracting solvents were tested. Acetone was the most effective solvent. An improved GLC procedure was developed for the quantitation of DDVP. Several liquid phases were compared and optimum chromatographic parameters were examined. Tailing peaks were obtained with DC-11 and DC-11 + Epon 1001. Carbowax 20M gave symmetrical peaks, but optimum column efficiency was obtained on a 7% neopentyl glycol adipate column. The relative standard deviation for the analysis of DDVP by GLC was ±1.8%.
Ultraviolet Determination of Strychnine in Commercial Bait Formulations
Authors: Wapensky Lawrence A 
Published: February 2020

Abstract
A UV method of analysis of strychnine suitable for a commercial bait formulation has been devised. The strychnine is extracted in 0.5% (v/v) H2SO4 and the resulting extract is cleaned up. Strychnine is determined by the difference in absorbance at 254 and 287 mµ. The results reported by this approach correlate well with those obtained by a gravimetric determination of strychnine as the strychnine picrate.
Interferences in the Polyvinyl Alcohol-Borate-Iodine Complex
Authors: Monte-Bovi Anthony J 
Published: February 2020

Abstract
The blue complex formed when solutions of iodine and certain grades of polyvinyl alcohol react with borates under specified conditions has been suggested as a qualitative test for ionic boron. This study attempted to determine the effect of other substances on the formation of the blue complex. Many interferences were found. Procedures are modified to circumvent the presence of such interfering substances.
Neutron Activation Analysis of Nitrogen in Feedstuffs
Authors: Doty W H , Wood D E , Schneider E L 
Published: February 2020

Abstract
The application of neutron activation analysis to the determination of nitrogen in various feeds and feedstuffs has been investigated. Samples were bombarded with fast neutrons to induce the 14N(n, 2n)13N reaction. 13N is a positron emitter with a 10 min half-life. The positrons annihilate in or near the sample to produce 0.51 MeV gamma rays, which are then counted in a detector system. Phosphorus and silicon interfere and are compensated for in the technique. A total of 419 individual runs were made on 53 samples covering 16 different types of materials. Total analysis time was 15 min per sample with a production rate of 12 samples per hr. The coefficient of variation of runs by the automated method typically ranged from 0.90 to 1.73 on the different sample groups. A good correlation between protein determined by the Kjeldahl technique and that determined by the automated method was demonstrated.
Determination of Dimers and Polymers in Heated Fats and Oils by Sublimation
Authors: Huang Anita , Firestone David 
Published: February 2020

Abstract
A sublimation procedure is described for separating dimers and polymers from oxidized or polymerized fats and oils. Under the described conditions, involving sublimation at 90°C and 0.02–0.05 mm Hg pressure, common fatty acid methyl esters standards yielded 99–2100% sublimate, methyl esters of commercial vegetable oils yielded 97.4-99.2% sublimate, heated cottonseed oils yielded 64–83% sublimate, a thermal dimer acid yielded 1.0% sublimate, and laboratory-prepared oxidative dimers and polymers yielded 7.5% sublimate. A comparison of the sublimation procedure with urea adduction gave good correlations with thermally oxidized oil samples; however, with fresh vegetable oil or with samples consisting of predominantly thermal or oxidative dimers, sublimation gave more accurate results than urea adduction.
Detection of Toxicity of Aflatoxins, Sterigmatocystin, and Other Fungal Toxins by Lethal Action on Zebra Fish Larvae
Authors: Abedi Z H , Scott P M 
Published: February 2020

Abstract
The effects of 13 fungal toxins (and one derivative) on the larvae of zebra fish, Brachydanio rerio (Hamilton-Buchanan), were investigated. The most toxic were sterigmatocystin, gliotoxin, and aflatoxin B1, which were lethal at concentrations of less than 1 µg/ml. Aflatoxins B2, G1, and G2, stemphone, diacetoxyscirpenol, ochratoxin A, aspertoxin, and patulin also showed toxicity to the larvae, while aflatoxin B1 hemiacetal, penicillic acid, and griseofulvin were non-toxic at the levels tested. Specific morphological effects were noted with sterigmatocystin, aflatoxins, and stemphone. The usefulness of zebra fish larvae as bioassay test organisms for fungal toxins is discussed.
Determination of Alcohol-Insoluble Solids in Frozen Peas
Authors: Winter F H 
Published: February 2020

Abstract
The frozen contents of the package are thawed in a plastic bag and then transferred to a mechanical blender. A portion of the blended sample is refluxed with 95% denatured alcohol, weighed on a filter in a Büchner funnel, and washed with 80% denatured alcohol. The filter is then dried 2 hr and weighed. The method was applied to 18 samples of frozen peas with over 100 replications. The mean standard deviation for six collaborators who replicated two samples five times each was ±0.30.
Differentiation of Geographic Origin of Spices. II. Oregano by Gas Chromatography and Thin Layer Chromatography
Authors: Stahl William H Stahl , Skarzynski Jean N , Voelker William A 
Published: February 2020

Abstract
Both a gas chromatographic and a thin layer chromatographic procedure have been devised to differentiate the origin of oreganos. The gas chromatographic procedure utilizes the observation that the ratio of the concentration of carvacrol to thymol in Greek oregano is approximately 7:1, whereas in Mexican oregano it is 1:1. The decision can be reinforced by a fluorescence thin layer chromatographic technique, using a hexane-ethyl acetate-tetrahydrofuran mixture as the developing solvent. A two-dimensional TLC, using acetone-ethermethylene chloride for the second development, affords a clean-cut separation of all spots and is particularly useful in the diagnosis of mixtures.
Cyclodiene Chemistry. III. Derivative Formation for the Identification of Heptachlor, Heptachlor Epoxide, cis-Chlordane, irans-Chlordane, Dieldrin, and Chromatography
Authors: Chau Alfred S Y , Cochrane W P 
Published: February 2020

Abstract
An improved method, involving potassium tert.-butoxide and tert.-butanol treatment followed by acetylation, is described for the similtaneous confirmation of heptachlor, heptachlor epoxide, and cis- and trans-chlordanes in cleaned-up feed samples. Parent pesticide residues can be identified at levels of 0.01 ppm and above. As a confirmative test for dieldrin, the formation of an acetate and subsequent conversion to a “ketone” by acetic anhydride/ sulfuric acid treatment is used. The concentrated sulfuric acid-catalyzed isomerization of endrin is also reported.
Derivative Formation for the Confirmation of Endosulfan by Gas Chromatography
Authors: Chal A S Y 
Published: February 2020

Abstract
Chemical conversions followed by GLC analysis are described for the confirmation of residues of α- and β-endosulfan in agricultural crops. Both isomers were reduced to the same diol by lithium aluminum hydride in tetrahydrofuran. Subsequent silylation to the disilyl ether can be used for the routine confirmation of both isomers down to a level of 0.02 p pm in a 10 g sample extract. Alternatively, the insecticide or its reduction product can be acetylated. By this procedure, 0.03 ppm or more of the parent insecticide can be identified in a 10 g sample extract.