bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectrophotometric Determination of Aminacrine Hydrochloride in Creams, Jellies, and Suppositories
Authors: Bunch Elaine A 
Published: February 2020

Abstract
A visible spectrophotometric method has been developed for the quantitation of aminacrine hydrochloride in creams, jellies, and suppositories. Aminacrine hydrochloride was extracted into acidic ethanol and its visible spectrum was recorded. The amount present was calculated by determining the net absorbance between the absorbance maximum at about 402 nm and one-half the sum of the absorbances of the minima at about 389 and 412 nm. Aminacrine and a trace contaminant, 9(10H)-acridone, were independently identified by different thin layer chromatographic systems.
Simple Colorimetric Method for Determination of Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceuticals
Authors: Sane Ramesh T , Doshi Vipul J , Joshi Sanjay K 
Published: February 2020

Abstract
A simple colorimetric method is described for the determination of pyridoxine hydrochloride (vitamin B6). The method is based on the measurement of an orange species formed when pyridoxine hydrochloride is treated with diazotized dapsone and sulfanilamide in a mixture of trichloroacetic acid and sulfuric acid at room temperature, followed by treatment with an aqueous solution of sodium carbonate. Compounds such as thiamine hydrochloride, cyanocobalamin, and common excipients such as starch and talc which are present in various formulations with pyridoxine hydrochloride do not interfere in the reaction. Statistical validation showed that the method was highly precise and accurate. Results agree well with those obtained by other methods reported in the literature.
Improved Lipoxygenase Method for Measuring cis,cis-Methylene Interrupted Polyunsaturated Fatty Acids in Fats and Oils
Authors: Madison Bryan L , Hughes William J 
Published: February 2020

Abstract
An improved lipoxygenase method is described for the determination of cis,cis-methylene interrupted polyunsaturated fatty acids in fats and oils. The methodology is designed to overcome mechanical problems which in the past may have contributed to poor precision. This method provides improved repeatability which is imperative for assay methods used for quality control and other purposes
Applicability of a Carbamate Insecticide Multiresidue Method for Determining Additional Types of Pesticides in Fruits and Vegetables
Authors: Krause Richard T , August E Michael 
Published: February 2020

Abstract
Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbof uran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered.
High Resolution Gas Chromatographic Analysis of Nonpolar Chlorinated Hydrocarbons in Human Milk
Authors: Bush Brian , Snow John T , Connor Steven 
Published: February 2020

Abstract
A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than ±10% for all compounds at 20-50 ng/mL whole milk.
Simple Colorimetric Method for Determination of Episulfides, Using, 4-(p-Nitrobenzyl)-Pyridine
Authors: Petroski Richard J 
Published: February 2020

Abstract
Episulfides were determined by a simple colorimetric assay using 4-(p-nitrobenzyl)-pyridine, which has been used previously for the detection and analysis of epoxides, organophosphates, and other alkylating agents. With episulfides, absorbance was directly proportional to concentration up to an absorbance of at least 1.0. No interference was observed with a variety of non-episulfide sulfur-containing substances. The colorimetric method is useful in monitoring 1-cyanoepithioalkane formation from the degradation of glucosinolates containing terminal double bonds.
Modification of Klein’s Wet Ashing Procedure for Determination of Mercury
Authors: Vibhakar S , Nagaraja Krishnarajpet V , Kapur Omprakash 
Published: February 2020

Abstract
An investigation of the use of HC1 in Klein’s method (25.108-25.115) to prevent loss of mercury during wet digestion resulted in consistently good recoveries from jowar and fish samples. Recoveries for the modified method ranged from 90.9 to 97.0% compared with 14.4 to 35.5% for the original method.
High Pressure Liquid Chromatographic Determination of an O-Methyl, Methyl Ester Derivative of Ochratoxin A
Authors: Phillips Timothy D , Stein Aron F , Ivie G Wayne , Kubena Leon F , Hayes A Wallace , Heidelbaugh Norman D 
Published: February 2020

Abstract
The mycotoxin ochratoxin A (OA) was derivatized to an O-methyl,methyl ester (Me2) with diazomethane and then determined by high pressure liquid chromatography (HPLC). Both OA and OA-Me2 were chromatography by reverse phase HPLC with a mobile phase of acetonitrile-water (60 + 40). An increase in retention time of 309 s was observed with OA-Me2 which was detectable at 254 nm at levels as low as 3 ng. Recovery of OA as OA-Me2 from chicken kidney homogenates and human plasma was quantitative following simple extraction and cleanup procedures, reaction with diazomethane, and HPLC analysis. The novel method described should prove useful for measuring and confirming OA in tissues and in further studies on the biological fate of this mycotoxin.
Microbiological Determination of Lincomycin in Feeds and Supplements Containing High Concentrations of Bentonite
Authors: Stahl Gerald L , Kratzer D Dal 
Published: February 2020

Abstract
A microbiological method is described for determining lincomycin in complete feeds, supplements, andpre-mixes greater than 100 g/ton and containing high levels of bentonite. The AOAC method currently used is unsatisfactory for analyzing feeds with concentrations of bentonite greater than 5.5%. Study indicates that low lincomycin recoveries from high level bentonite feeds are a function of aqueous contact and subsequent binding. The present method involves an alternative extraction technique using formamide as the primary extractant. A binary solvent system of ethanol and phosphate buffer aids in the extraction, miscibility, and conversion to water solubility for subsequent testing. Forty-one feeds containing as high as 60% bentonite were assayed by the reported method and gave a mean recovery of 106% and a range of 94-114%. An inter-laboratory confirmation study produced a mean recovery of 103%, with a range of 93-114%. A factorial analysis of variance of the interactive effects between lincomycin level and bentonite level within the AOAC method and within the bentonite method showed no interactions which would influence percent recovery in either assay method.
Extraction and Cleanup Procedures for Determination of Diarylphosphates in Fish, Sediment, and Water Samples
Authors: Muir Derek C G , Grift Norbert P 
Published: February 2020

Abstract
Methods for determination of triaryl/alkylphosphates (TAPs) in water, fish, and sediment have been extended to determination of the diarylphosphate (DAP) degradation products. DAPs were extracted from water (adjusted to pH 0.5) by use of XAD-2 resin and determined by gas-liquid chromatography as butyl esters. Recovery of diphenylphosphate (DPP) and o-, m-, p-dicresylphosphates (DoCP, DmCP, DpCP) were &gt;95% in water samples fortified at 1,10, and 50 μg/L. DAPs were extracted from fish with methanol and the extracts were cleaned up on reverse phase (C18) silica cartridges. Recoveries were μ87% for DPP, DoCP, DmCP, and DpCP in fish muscle fortified at 50, 100, and 500 ng/g. Sediments were refluxed with aqueous methanol and DAPs were recovered by use of XAD-2 resin. Recoveries of DAPs from sediments fortified at 50 and 100 ng/g were μ76%. Interferences (1-10 ng/g) from phosphorus or nitrogen-containing GLC peaks prevented subng/g level analysis for DAPs in sediment and fish extracts.
Isomerization of Retinyl Palmitate Using Conventional Lipid Extraction Solvents
Authors: Mulry Mary C , Schmidt Ronald H , Kirk James R 
Published: February 2020

Abstract
The use or a chlorotorm-ethanol-water solvent system for the direct extraction of retinyl palmitate isomers from fortified food products was previously shown to be unsuitable because significant isomerization of all-trans-retinyl palmitate occurred during the extraction. This study investigated the extent of isomerization of retinyl palmitate in various extraction solvents when subjected to gold fluorescent laboratory light. Purified solutions of all-trans-retinyl palmitate in hexane were diluted with methyl t-butyl ether, hexane, methylene chloride, and stabilized chloroform and subjected to gold fluorescent laboratory light for 2, 4, and 6.5 h. Similar solutions were subjected to light or kept in the dark for 3.5 h. All-trans-, 9-cis-, and 13-cis-retinyl palmitate esters in the solutions were determined by using normal phase high performance liquid chromatography with fluorometric detection. Results demonstrated a noticeable increase in the 9-cis-retinyl palmitate concentration and a corresponding decrease in all-trans-retinyl palmitate concentration with time, in chloroform and methylene chloride compared with hexane. Chlorinated solvents in the absence of light did not promote isomerization of retinyl palmitate. Use of chlorinated solvents for the extraction of vitamin A esters should be avoided because they promote isomerization of retinyl palmitate when subjected to light, including gold fluorescent laboratory light.
Determination of Magnesium, Iron, and Zinc in Fertilizers by Flame Atomic Absorption and by Inductively Coupled Plasma Emission Spectroscopy: Comparison of Methods
Authors: Aten Carl F , Bourke John B , Walton John C 
Published: February 2020

Abstract
Determination of Mg, re, and Zn by inductively coupled plasma emission spectroscopy (ICP) and by the official flame atomic absorption spectrophotometric (FAA) method were compared. Samples were acid digests of commercial fertilizers. Neither matrix effects nor spectral interferences were encountered in the ICP analyses. Linear regression shows that the slopes obtained by plotting ICP results vs FAA results for each element differ from unity by less than 5%.
Discussion of Statistical Methods for Determining Purity of Citrus Juice
Authors: Brown Morton B , Cohen Eli 
Published: February 2020

Abstract
It is difficult to develop statistical methods to determine the purity of fruit juice because of country-to-country and environmental differences among fruit. A test of an unknown sample of citrus juice can err in 2 ways: Pure juice can mistakenly be rejected as adulterated, or adulterated juice can be accepted as pure. Many of the statistical procedures proposed maymisclassify a high proportion of samples of pure juice as adulterated. It is necessary to develop a statistical test that will only rarely reject samples of pure juice, and will have a good chance of rejecting adulterated juice.
Gas-Liquid Chromatographic Screening Method for Six Synthetic Pyrethroid Insecticides
Authors: Bolygó Glek , Zakar Ferenc 
Published: February 2020

Abstract
A method was developed for simultaneously determining 6 synthetic pyrethroid insecticides (fenpropanate, tetramethrin, permethrin, cypermethrin, fenvalerate, and deltamethrin) in apple, orange, grape, lemon, tomato, green pepper, and paprika, and sugar beet root and leaves. The pesticides were extracted with acetone and partitioned into methylene chloride. The extract was purified by column chromatography on active carbon-magnesia-diatomaceous earth and then on alumina. Analysis by gasliquid chromatography with 63Ni electron capture detection was completed in 6 min on a 3% SE-30 liquid phase, using a short column. Recoveries from fortified samples ranged from 68 to 89% in the range of 0.3-1.O ppm and from 67 to 83% in the range of 0.02-O.2ppm.
Identification and Estimation of the Alkaloids of Rauwolfia serpentina by High Performance Liquid Chromatography and Thin Layer Chromatography
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A procedure is presented for the identification and estimation of some of the alkaloids of Rauwolfia serpentina by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). Two extraction procedures were studied, one essentially similar to the current AOAC method, and one using warm methanol. For HPLC, a μPorasil column, methanol as eluting solvent, and a fluorometric delector were used. Rescinnamine was detected at 330 nm, at which wavelength reserpine fluorescence is negligible. Reserpine was detected at 280 nm, where rescinnamine fluorescence is small. Other alkaloids detected were raubasinine, ajmalicine, yohimbine, ajmaiine, and serpentine. For TLC, CHCI3-CH3OH 197+ 3) and CHCI3-CH3OH (80 + 20) were used as developing solvents and spots were detected under long- and shortwave UV light. A semiquantitative IICprocedure was also developed for serpentine, the content of which was found to be in the 0.2-0.25% range.
Gas-Liquid Chromatographic Determination of Dehydroacetic Acid in Squash and Wine
Authors: Daniels Daniel H , Warner Charles R , Selim Sami , Joe Frank L 
Published: February 2020

Abstract
A gas-liquid chromatographic procedure has been developed for the determination of the preservative dehydroacetic acid (DHA) in frozen cut squash and white wine. The cleanup procedure uses the acidic character of DHA to enhance separation from interfering substances. Recoveries were 93-104% from squash fortified at 30, 65, and 130 ppm and 96-99% from wine fortified at 50, 100, and 200 ppm. The method can be used to establish that the amount of DHA used in squash does not exceed the permissible level of 65 ppm.
Argon Plasma Emission Spectrometry of Uranium in Phosphatic Materials
Authors: Norman J D , Stumpe Louis A , Trimm Joe R , Johnson Frank J 
Published: February 2020

Abstract
A method is described for the determination of uranium by using a dc argon plasma emission spectrometer. Problems and interferences found in the method previously reported are overcome by using an improved sample pretreatment. A new synergistic system, 2% oxalic acid adjusted to pH 4.5 with triethanolamine, is used to quantitatively back-extract uranium from trioctylphosphine oxide in cyclohexane. This improved method yields excellent results for &gt;1 ppm uranium in nitric and hydrochloric acid solutions of phosphate rocks, phosphoric acids, phosphate fertilizers, phosphogypsums, organic phosphates, and waste solutions. Recovery data are given for synthetic and certified standards.
Determination of Glucose, Sucrose, Lactose, and Ethanol in Foods and Beverages, Using Immobilized Enzyme Electrodes
Authors: Mason Marc 
Published: February 2020

Abstract
An enzyme electrode coupling immobilized oxidase enzymes with a hydrogen peroxide-sensitive electrode is described. An enzyme or enzymes are immobilized in a thin microporous membrane which titsdirectly over a platinum anode held at +0.700 V relative to a Ag/AgCl2 reference electrode. When an enzyme substrate diffuses into the membrane, hydrogen peroxide is produced. The hydrogen peroxide is then oxidized at the platinum anode, producing anelectrical current that is directly proportional to hydrogen peroxide concentration, and hence substrate concentration. Glucose and sucrose in cereal samples, lactose in cheese, and ethanol in beer and wine were determined using enzyme electrodes. Relative precision of replicate analyses was better than ±2% and agreement with AOAC methods was good.
Evaluation of a Testing Program for Aflatoxin in Corn
Authors: Whitaker Thomas B , Dickens James W 
Published: February 2020

Abstract
A computer model that accounts for sampling and analytical variability was developed to simulate the aflatoxin testing program administered by the North Carolina Department of Agriculture (NCDA) to regulate aflatoxin in corn meal. Monte Carlo solution techniques were employed to account for conditional probabilities that rise from multiple samples being used in the testing program. The NCDA testing program was then evaluated by applying the computer model to a hypothetical group of 1000 corn meal lots with the same distribution of aflatoxin concentrations as was observed among aflatoxin assays made by NCDA on commercial lots of corn meal from 1977 to 1980. The average of the 1000 lots assayed was 17.7 parts per billion (ppb). The model predicted that 79.5% of the lots would be accepted and 20.5% of the lots would be rejected by the NCDA testing program. The accepted and rejected lots contained an average of 5.7 and 64.2 ppb aflatoxin, respectively. The testing program accepted 7.3% of the lots with more than 20 ppb aflatoxin (consumers' risk) and rejected 1.0% of the lots with 20 ppb or less (processors' risk). A correct decision was made 94% of the time.
Ion-Pair Partition Chromatography of Mef enamic Acid with Tetraalkylammonium Cations: Development of Analytical Method from Extraction Data
Authors: Adams William M 
Published: February 2020

Abstract
The ion-pair partition properties of mef enamic acid with the methyl, ethyl, n-propyl, and n-butyl homologs of tetraalkylammonium cation were studied in relation to a model of an assay procedure for acidic drugs. Variables studied included identity and concentration of pairing ion and composition of extracting solvents. Resulting data were used to develop a partition chromatographic assay procedure. Standard recoveries averaged 99.01 ± 0.82%. Assays of commercial capsules were reproducible
Detection and Determination of Error in Analytical Methodology. Part II. Correction for Corrigible Systematic Error in the Course of Real Sample Analysis
Authors: Cardone Mario J 
Published: February 2020

Abstract
A new perspective in the functional operation of corrigible errors is presented. If the incorrigible errors, calibration, and direct interference are absent, the new proposed calculation procedure will provide a correct analytical result; results obtained by the method of standard additions will agree with results from the conventional standard curve technique on the same sample; and different methods will produce the same analytical result on the same sample within the variance of the random error of the method(s). The technique is also a diagnostic tool for the detection and determination of the corrigible constant and proportional errors.
Today’s Chemical Realities
Authors: Horwitz William 
Published: February 2020

Abstract
The difficulty with current food safety laws arises from the apparent inability of the toxicologist to determine the biological significance of the extremely low concentrations that the chemist can currently measure. In discussions of this technical ability, however, the practical limitations of chemical measurement science are rarely mentioned. Some of these limitations are: (1) The reliability of identification and quantitation decreases exponentially as concentration decreases; (2) at very low concentrations baseline effects become the limiting factor; and (3) the cost of the analysis becomes exorbitant. The practical reality of trace chemical analysis in the interlaboratory environment must answer the question: When does the cost of the analysis exceed the value of the information gained as to the identity and amount of the material present, considering also the uncertainties associated with the analysis itself and with the biological effect of that concentration? The current practical limit of measurement is in the low parts per billion, e.g., aflatoxin contamination. 2,3,7,8-Tetrachlorodibenzodioxin can be determined in fish at the moderate parts per trillion level, but at an estimated cost in salaries and expenses of roughly $1000 per individual value reported, without capitalizing our $2,000,000 mass spectrometry laboratory.
High Pressure Liquid Chromatographic Determination of Capsaicin in Oleoresin and Personal Protection Aerosols
Authors: Law Mark W 
Published: February 2020

Abstract
A simple and accurate high pressure liquid chromatographic method has been developed for determination of capsaicin in oleoresin capsicum and mineral oil-based aerosol formulations intended for personal protection. Capsaicin, the main ingredient responsible for the spicy pungency of various hot peppers and paprika, is extracted with acetonitrile and aliquots are analyzed on a 10 μm C18 column at 280 nm with acetonitrile-water (45 + 55) mobile phase. Dihydrocapsaicin is also extracted and is simultaneously quantitated with propiophenone as an internal standard.
Identification of Chlorinated Nitrobenzene Residues in Mississippi River Fish
Authors: Yurawecz Martin P , Puma Bart J 
Published: February 2020

Abstract
Residues of lower chlorinated nitrobenzenes have been found at levels up to about 1 ppm in 8 samples of Mississippi River fish. Electron capture gas chromatography (EC/GC) was used for determination after extraction and cleanup using a procedure based on the AOAC multiresidue method for organochlorine and organophosphorus pesticides in nonfatty foods. The residues found included 2-, 3-, and 4- chloronitrobenzene and 2,3- and 3,4-dichloronitrobenzene; identity was confirmed by GC/mass spectrometry. GC retention times for 15 monochloro-through pentachloro-substituted nitrobenzene congeners were determined with OV-101 and mixed OV-101 + OV-210 columns at 130 °C In studies of the nonfatty food extraction and cleanup procedures of the AOAC method, recoveries of 15 chlorinated nitrobenzenes from spiked fish samples ranged from 68 to 116%. GC of cleaned up fish extract aliquots equivalent to 20 mg sample allowed quantitation of individual congeners at levels of about 0.025 and 0.005 ppm with 3H and 63Ni EC detectors, respectively. The contamination of Mississippi River fish with chlorinated nitrobenzenes appears to be localized in a 150 mile section of the river extending from St. Louis, MO, to Cape Girardeau, MO; no chlorinated nitrobenzenes (&lt;0.005 ppm) were detected in Mississippi River fish caught above or below this region of the river or in fish from the lower Missouri River, which joins the Mississippi River near St. Louis.