bluuebunny/crossref_metadata_2025_split huggingface dataset:
Injection–Extraction Procedure for Rapid Determination of Relative Pungency in Fresh Jalapeño Peppers
Authors: Rymal Kenneth S , Cosper Richard D , Smith Durward A 
Published: February 2020

Abstract
A unique injection-extraction procedure allowing the direct spectrophotometric determination of relative pungency of fresh Jalapeño pepper is described. Intact pepper pods were injected with absolute methanol, using a hypodermic syringe. After 30 min, pods were flushed with additional methanol, and capsaicinoids in the extract were determined by absorbance at 275 nm. Mean percent recovery was 66.5%, sx = 3.43. The method eliminates the time consuming chromatographic cleanup needed with other spectroscopic methods.
Polarographic and Colorimetric Methods for Determination of Cyclophosphamide
Authors: Ellaithy Moustafa M , El-Tarras M Fayez , Tadros Nabil B , Amer Mohamed M 
Published: February 2020

Abstract
Polarographic and colorimetric methods for analysis of cyclophosphamide and its dosage forms were investigated. Both methods are based on the reaction of cyclophosphamide with nitrous acid. A single cathodic diffusion-controlled wave was used for dc polarographic determination of cyclophosphamide, with an accuracy of 99.98 ± 1.09%. The wave was well defined and irreversible. By differential pulse polarographic analysis, as little as 10 ppm cyclophosphamide was determined; overall accuracy at 10-60 ppm was 100.16 ± 0.99%. The linear relationship between absorbance for the lemon-yellow nitroso derivative and the concentration of cyclophosphamide was further used in colorimetric analysis; overall accuracy was 100.2 ± 0.99%.
Liquid Chromatographic Determination of Primary and Secondary Amines as 8-Quinolinesulfonyl Chloride Derivatives
Authors: Noggle F Taylor , Clark C Randall 
Published: February 2020

Abstract
The normal phase and reverse phase liquid chromatographic properties of seven 8-quinolinesulfonyl derivatives of primary and secondary amines are examined using dual wavelength ultraviolet detection. The amines are further identified by infrared spectrophotometry with emphasis on structural elucidation based on absorption bands at characteristic wavelengths.
Liquid Chromatographic Method for Quantitative Determination of Free Fatty Acids in Butter
Authors: Reed Alan W , Deeth Hilton C , Clegg Donald E 
Published: February 2020

Abstract
A liquid chromatographic method has been developed for the determination of free fatty acids in butter. The fatty acids are converted to the p-bromophenacyl esters, via a crown ether-catalyzed reaction, without separation from the other butter components. The esters are separated on a Cis-bonded silica column by using an acetonitrile-water solvent gradient and quantitated using the ester of heptadecanoic acid as internal standard. Cu, and C ,S:i co-elute in the acetonitrile-water system but are separated using an isocratic methanol-acetonitrile-water system. Limits of detection range from 7 ng for butyric acid to 45 ng for linoleic acid. The average coefficient of variation (n = 10) for 10 free fatty acids from,a butter was 5.83%.
Liquid Chromatographic Determination of Aflatoxin M1 in Milk
Authors: Tyczkowska Krystyna , Hutchins James E , Hagler Winston M 
Published: February 2020

Abstract
The official AOAC method for aflatoxin M, in milk was modified by replacing cellulose column chromatography with cartridge chromatographic cleanup and replacing thin layer chromatographic (TLC) determination with liquid chromatographic (LC) quantitation to yield a new method for bovine and porcine milk. An acetone extract of milk is treated with lead acetate and defatted with hexane, and M1 is partitioned into chloroform as in the AOAC method. Chloroform is removed by evaporation under a stream of nitrogen at 50°C. The residue is dissolved in chloroform, the vessel is rinsed with hexane, and the 2 solutions are applied in sequence to a hexane-activated silica Sep-Pak cartridge. Less polar impurities are removed with hexane-ethyl ether, and M1 is eluted with chloroform-methanol, and determined by C18 reverse phase LC using fluorescence detection. Recoveries of M, added to bovine milk at 0.25, 0.50, and 1.0 ng/mL were 90.8, 93.4, and 94.1%, respectively. The limit of detection was less than 0.1 ng M,/mL for both bovine and porcine milk.
Liquid Chromatographic Determination of Sodium Saccharin, Caffeine, Aspartame, and Sodium Benzoate in Cola Beverages
Authors: Tyler Theodore A 
Published: February 2020

Abstract
A rapid method has been developed for the determination of sodium saccharin, caffeine, aspartame, and sodium benzoate in cola beverages. The sample is degassed, diluted in water, and injected onto a C18 column. The mobile phase consists of 15% acetonitrile in triethylammonium phosphate buffer adjusted to pH 4.3 with NaOH. The total run time is less than 10 min and the active compounds are determined using absorbance detection at 214 nm.
Simple and Rapid Portable Chromatographic Method for Separation and Detection of Phenylmercuric Acetate in Seeds and Water
Authors: Devi Yalavarthy Prameela , Nanda Kumar Nanguneri V 
Published: February 2020

Abstract
Phenylmercuric acetate can be detected by horse liver acetone powder succinate dehydrogenase inhibition, using a mixture of 2-(4-iodophenyl)- 3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT), sodium succinate, and N-methylphenazonium methosulfate as the chromogenic reagent. The simple cleanup involves extraction of phenylmercuric acetate in chloroform and concentration by evaporation. In the extract, the compounds in seeds or water could be separated and identified by paper chromatography in the field or laboratory at microgram levels with an acetone-water (70 + 30) solvent system.
Monocrotophos and Dicrotophos Residues in Birds as a Result of Misuse of Organophosphates in Matagorda County, Texas
Authors: Flickinger Edward L , White Donald H , Mitchell Christine A , Lamont Thair G 
Published: February 2020

Abstract
About 1100 birds of 12 species died from organophosphate poisoning in Matagorda County on the Texas Gulf Coast in March and May 1982. Birds died from feeding on rice seed that was illegally treated with dicrotophos or monocrotophos and placed near rice fields as bait to attract and kill birds. Brain acetylcholinesterase inhibition of affected birds averaged 87% (range 82-89%), and contents of gastrointestinal tracts contained residues of dicrotophos (5.6-14 ppm) or monocrotophos (2.1-13 ppm). Rice seed collected at mortality sites contained 210 ppm dicrotophos or 950 ppm monocrotophos. Mortality from dicrotophos poisoning continued for almost 3 weeks. The practice of illegally treating rice seed with either of these 2 organophosphates appears to be infrequent but widespread at present.
Some Effects of Replacement of Metaphosphoric Acid/Acetic Acid Solvent System with Trichloroacetic Acid in Microfluorometric Determination of Vitamin C
Authors: Visser Frans R 
Published: February 2020

Abstract
Trichloroacetic acid (TCA) is suggested as a substitute for the metaphosphoric acid/acetic acid (HPO3-HOAc) solvent system in the AOAC microfluorometric determination of vitamin C. Comparative advantages of TCA are easier handling, greater stability, and the approximate 10-fold increase in sensitivity. For both solvent systems, the influence of acid concentration on fluorescence is described. TCA provides maximum fluorescence enhancement at pH 5.5-6.0.
Potassium Interferences in Flame Emission Method for Determining Sodium in Fertilizers
Authors: Corominas Luis F , Navarro Roberto A , Lopez Ruben J 
Published: February 2020

Abstract
Several sodium concentrations ranging from 5.2 to 20 ppm at K:Na ratios ranging from 0 to 40 were studied to determine potassium interferences in the AOAC official first action method, 2.147-2.150, for flame emission spectrophotometric (FES) determination of sodium in fertilizers. According to an analysis of variance performed with recoveries of sodium in solution, potassium interference is the same at low (5.2 ppm) or high (20 ppm) sodium concentrations but is different when the K:Na ratio is changed. A Duncan test showed that potassium interference is equivalent only in the adjacent ratios studied (0, 1, 2, 5, 10, 20, 40) and not for larger ranges. We obtained an average recovery of 98.8% using a calibration curve for a K:Na ratio from a preliminary determination with a calibration curve without potassium content. It is essential to know the potassium content of the sample to enable preparation of a calibration curve for correction. We recommend a collaborative study of NPK samples to determine whether to modify the FES method.
Determination of Ammoniacal and Total Nitrogen in Fertilizers by Ammonia-Selective Electrode
Authors: Navarro Roberto A , Rojas Pedro 
Published: February 2020

Abstract
A method was studied for determining ammoniacal nitrogen in fertilizers by using an ammonia-selective electrode. Recovery for the method was evaluated with synthetic samples, and the method was also compared with the magnesium oxide method by analyzing 3 Magruder Check Samples. The method was adapted to determine total nitrogen in fertilizers by using the digestion procedure of the modified comprehensive nitrogen method and eliminating metal interferences by forming soluble complexes with tartaric acid. Recovery was evaluated and a comparison with AOAC official methods was made by performing a /-test on results for 3 Magruder Check Samples. Recoveries were good for determinations of both ammoniacal and total nitrogen by the method described, and results were not significantly different from those for AOAC methods.
Recent Advances in Cleanup of Fats by Sweep Co-Distillation. Part 2. Organophosphorus Residues
Authors: Luke Barry G , Richards Jeffery C 
Published: February 2020

Abstract
This paper describes the isolation of 5 organophosphorus residues in beef fat by a commercial sweep co-distillation unit (Unitrex). The operating conditions specified 233°C and nitrogen flow at 230 niL/min. Recoveries of chlorpyriphos, monodechlorchlorpyriphos, bromophosethyl, debromobromophos-ethyl, and ethion ranged from 84 to 99%, with coefficients of variation between 3 and 5%.
Liquid Chromatographic Determination of Adulteration of Sesame Oil
Authors: Han Li Ming , Adams James M 
Published: February 2020

Abstract
A liquid chromatographic (LC) procedure is presented for quantitative determination of adulteration of sesame oil with soybean oil. A portion of the oil is dissolved in chloroform, diluted in the eluant 2-propanolacetone- methanol-acetonitrile (1 + 2 + 3 + 4), and subjected to reverse phase LC. A linear calibration curve is prepared by chromatographing known mixtures of the 2 oils and plotting the volume percent of sesame oil against the peak height ratio of a selected pair of peaks. The relative standard deviation, based on 4 determinations of each of 8 sample mixtures, is less than 2.5% and the correlation coefficient is 99%. Because the LC curve for a given vegetable oil is characteristic and reproducible, the procedure can be extended to detect the adulteration of sesame oil with oils other than, or in addition to, soybean oil. An example of adulteration with rapeseed oil, in addition to soybean oil, is discussed.
Gas Chromatographic Determination of Clopidol in Chicken Tissues
Authors: Lars-Gösta Ekström , Kuivinen Jorma 
Published: February 2020

Abstract
A method has been developed for the determination of clopidol residues in chicken tissues. After extraction and cleanup, clopidol is esterified in a 2-phase system to clopidol propionate, which is determined by gas chromatography. The 2-phase system includes, in addition to the clopidol dissolved in methanol, aqueous borax solution, hexane, propionic anhydride, and pyridine. Use of these reagents precludes the use of explosive or carcinogenic chemicals in the derivatization step, and the method is therefore suitable for routine laboratory analysis. Levels of 0.5 ppb clopidol in tissue can be determined.
Mycotoxins in Grain Dust: Method for Analysis of Aflatoxins, Ochratoxin A, Zearalenone,Vomitoxin, and Secalonic Acid D
Authors: Ehrlich Kenneth C , Lee Louise S 
Published: February 2020

Abstract
A multimycotoxin method is presented to quantitate aflatoxins, ochratoxin A, zearalenone, secalonic acid D, and vomitoxin in grain dust. Dust spiked with these mycotoxins was extracted sequentially with methylene chloride followed by acetonitrile-water (86 + 14). Vomitoxin was recovered in the latter extract and all other mycotoxins were recovered in the methylene chloride. Aflatoxins and ochratoxin were quantitated by fluorescence measurement on silica thin layer chromatographic plates. The other mycotoxins were quantitated after cleanup by reverse phase liquid chromatography and ultraviolet detection. Recoveries from dust spiked in the parts per billion (ng/g) range were approximately 80% (SD = 15-29%) for all mycotoxins. Minimum detectable amounts ranged from less than 0.5 ng/g for aflatoxins to 20 ng/g for zearalenone.
Rapid, Sensitive Liquid Chromatographic Method for Determination of Zearalenone and α- and β-Zearalenol in Wheat
Authors: Trenholm H Locksley , Warner Robert M , Fitzpatrick Dennis W 
Published: February 2020

Abstract
A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and α- and β-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanolchloroform( 2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and α-zearalenol standards on the fluorescence detector and 4 ng for β-zearaIenol on the UV detector, which is equivalent to 20 μg zearalenone and 20 μg α-zearalenol/kg, and 160 μg β-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and α-zearalenol on the fluorescence detector and 0-50 ng β-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).
Determination of Histamine in Fish by Liquid Chromatography with Post-Column Reaction and Fluorometric Detection
Authors: Walters Milda J 
Published: February 2020

Abstract
A liquid chromatographic (LC) system, using a bonded cation-exchange column, resolves histamine from histidine and other related compounds. Detection sensitivity and specificity are enhanced by introduction of a post-column reaction with o-phthalaldehyde to form a fluorescent derivative. The limit of detection is 1.5 ng histamine, and the response is linear over a range of 7-750 ng. The average histamine recovery from fortified tuna and mahimahi samples was 98.4% with a relative standard deviation of 2.18%. The results for canned tuna and mahimahi were comparable to those obtained by using the official AOAC method. The LC method requires only simple extraction of the sample before introduction into the LC system, which resolves and detects cadaverine and putrescine in addition to histamine.
Detection of Adulteration in Grated Cheese by Using Calcium, Phosphorus, Magnesium, and Lactose Indices
Authors: Pollman Roger M 
Published: February 2020

Abstract
Calcium, phosphorus, and magnesium levels and calcium/phosphorus and calcium/magnesium ratios were determined for 74 authentic cheeses. Lactose was determined for 40 authentic grating cheeses. Phosphorus was measured by an AOAC method, calcium and magnesium by a modified AOAC atomic absorption method, and lactose by liquid chromatography. The average calcium/phosphorus and calcium/magnesium ratios were 1.55 and 23.3, respectively, and were used with lactose data as criteria for evaluating grated cheese adulteration.
Improved Gas Chromatographic Method for Quantitation of Deoxynivalenol in Wheat, Corn, and Feed
Authors: Terhune Stuart J , Nguyen Nhieu V , Baxter James A , Pryde Diane H , Qureshi Saeed A 
Published: February 2020

Abstract
A gas chromatographic (GC) method is described to determine deoxynivalenol in wheat and corn at levels as low as 20 ppb. Ground samples are extracted with water, adsorbed onto a Clin Elut column, extracted with ethyl acetate, and passed through a silica gel Sep-Pak cartridge. The final extract is then derivatized with N-heptafhiorobutyrylimidazole and quantitated by GC using an electron capture detector. Recoveries are greater than 85% for spiked samples at levels of 50-1000 ppb. Results for wheat, corn, and mixed feed samples are given as well as the results of an interlaboratory study on a naturally contaminated wheat sample.
Development of a Quality Assurance Program for Determination of Ultratrace Background Levels of Lead and Cadmium in Raw Agricultural Crops by Differential Pulse Anodic Stripping Voltammetry
Authors: Satzger R Duane , Bonnin Evelyn , Fricke Fred L 
Published: February 2020

Abstract
Data on the background levels of lead and cadmium in the food supply are essential in order to establish a baseline from which to evaluate the extent of contamination in transport, processing, industrial atmospheric particulate fallout, and soil treatment (e.g., fertilizers, sewage sludge, etc.). This requires the establishment of site selection and sampling criteria as well as the development of a rigorous analytical method capable of performing routine analyses of Pb and Cd at ultratrace levels. The method used in this study, which was published previously, was designed to provide high sample throughput with minimal contamination. This involved control and measurement of blank levels and the establishment of quality control procedures to maintain confidence in the accuracy and precision of the method.
Determination of Phosphorus in Processed Cheese: Collaborative Study
Authors: Steiger Gerald , Horwitz William , Poortvliet Lambrecht J , Soderhjelm Petter 
Published: February 2020

Abstract
A second interlaboratory collaborative study of the determination of phosphorus in processed cheese products by the molybdenum blue method verifies that this method is prone to producing a laboratoryinduced systematic error. It would be useless to continue to make minor modifications in the details of the method, which will improve only the within-laboratory precision, until an accuracy control of the final measurement step is incorporated into the method.
Comparison of Carr-Price Analysis and Liquid Chromatographic Analysis for Vitamin A in Fortified Milk
Authors: Mills Robert S 
Published: February 2020

Abstract
The determination of the vitamin A concentration in fortified milk was compared using Carr-Price analysis and liquid chromatography (LC). Carr-Price analysis required saponification of the sample with alcoholic potassium hydroxide, extraction with ether, and colorimetry with antimony trichloride in chloroform. LC analysis required hexane extraction of a 71% alcohol-sample solution and centrifugation at 2000 rpm. A 100 μL aliquot of the extract was analyzed on a LiChrosorb Si-60, 5 μm column, using an ethyl ether-hexane (2 + 98) mobile phase and detection at 313 nm. Each method was statistically evaluated for precision and sample-to-sample reproducibility. The LC extraction procedure was examined for efficiency. Each LC value was divided by the Carr-Price value obtained for the same sample; an average value of 0.975 with a coefficient of variation of 6.90% was obtained. It was concluded that the procedures were statistically equivalent.
Gas Chromatographic Determination of Picloram in Fish
Authors: Rieger Allan W , Muir Derek C G , Hendzel Marilyn R 
Published: February 2020

Abstract
A simple method for determining picloram in fish is described. The sample is homogenized with ethyl acetate, acidified with IN HC1, and extracted twice more with ethyl acetate. Ethyl acetate fractions are pooled, derivatized with diazomethane, cleaned up by column chromatography, and analyzed by electron capture gas chromatography. Rainbow trout exposed to I4C-picloram were used to evaluate the efficiency of 2 methods of extraction* and to provide data on the rate of uptake and the bioconcentration factor. The detection limit for this method is 5 ng/g, using a 4 g sample
Simple Colorimetric Method for Determination of Thiamine Hydrochloride in Pharmauceuticals
Authors: Sane Ramesh T , Doshi Vipul J , Jukar Swati , Joshi Sanjay K , Sawant Satish V , Pandit Ulhas R 
Published: February 2020

Abstract
A simple colorimetric method is described for the determination of thiamine hydrochloride (vitamin B,) in dosage forms. The method is based on measurement of a yellow complex formed when thiamine HC1 is treated with /7-methylaminophenol sulfate (Metol) under alkaline conditions. Compounds such as vitamins A, B2, B6, B,2, C, D, and E, and niacinamide, citric acid, liquid glucose, calcium pantothenate, biotin, liver extract, and folic acid do not interfere in the reaction. Extracting the complex into chloroform before quantitation enhances the stability of the reaction product and removes interference of watersoluble colored constituents in syrup samples. Statistical validation shows that the method is precise and accurate. Results agree well with those obtained by other methods in the literature
Colorimetric Determination of Stanozolol in Pharmaceutical Formulations
Authors: Shingbal Dattatray M , Barad Uday G 
Published: February 2020

Abstract
In acidic medium, stanozolol reacts with phenoldisulfonic acid to form a stable yellow chromophore, which is quantitated by spectrophotometry at 385 nm. The reaction gives a linear response at concentrations from 5 to 50 μg/mL. The method is suitable for routine analytical control of stanozolol and its formulations.
Assay of Calcium Borogluconate Veterinary Medicines for Calcium Gluconate, Boric Acid, Phosphorus, and Magnesium by Using Inductively Coupled Plasma Emission Spectrometry
Authors: Lyons David J , Spann Kelvin P 
Published: February 2020

Abstract
An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are ± 1.4% (calcium), ± 1.8% (boron), ± 2.6% (phosphorus), and ± 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.
Capillary Gas Chromatographic Determination of Technical Chlordane in Emulsifiable Concentrates and Aqueous Dilutions
Authors: Stringham Rodger W , Schulz Ray P 
Published: February 2020

Abstract
Technical chlordane is extracted in acetone, diluted with hexane, and determined via capillary gas chromatography with electron capture detection. Quantitation is based on the sum of areas or heights of 6 well resolved major peaks. The method was tested for precision, linearity, recovery, and applicability to aqueous dilutions of emulsifiable concentrate formulations. Comparison of quadruplicate analysis of 5 formulations by this method with the AOAC official titrimetric method gave average relative standard deviations of 1.4 and 0.9 %, respectively. Results were comparable for the 72% formulations, but were lower using this method for the 45% samples. Linearity and recovery were excellent (regression coefficient = 0.9996, recovery = 100.7%). Application of this method to aqueous dilutions was simple and resulted in an average recovery of 97%. The method is faster, safer, and more specific than the AOAC titrimetric method.