bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroanalytical Parameters of Fungal Metabolites. II. Luminescence of Griseofulvin
Authors: Neely W C , Mcduffie J R 
Published: February 2020

Abstract
I n this study of the luminescence characteristics of griseofulvin we report corrected ambient temperature fluorescence excitation and emission spectra. The uncorrected fluorescence excitation and emission spectra on thin layer chromatographic plates are also reported. The quantum efficiency of fluorescence is calculated to be 0.108 and the mean phosphorescence lifetime determined to be 0.11 sec. The fluorescence lifetime is calculated to be 0.663 nsec. It appears t h a t phosphorescence emission may be the most sensitive spectral parameter; measurable phosphorescence can be obtained from solutions as dilute as 10-8M. No photodecomposition is apparent under reasonable conditions of light exposure.
Quantitative Fluorodensitometric Measurement of Aflatoxin B1 with a Flying-Spot Densitometer. II. Comparative Study of B1 Measurements in Spiked and Naturally Contaminated Peanut Products
Authors: Beljaars P R , Fabry F H M , Pickott M M A , Peeters M J 
Published: February 2020

Abstract
Peanut butter extracts and samples spiked with 5-40 μg anatoxin B1/kg were analyzed, together with naturally contaminated peanut products, by 3 extraction procedures: the official Dutch method (KB), he Liem et al. method (methanol), and the IUPAC method. The last procedure was selected as a reference method, since it has international application. KB extracts were separated on silica gel G plates with a mixture of chloroform-acetone (90 + 10), whereas IUPAC extracts were separated similarly on MN-G-HR plates. Methanol extracts were resolved on silica gel II plates, using chloroform-trichloroethylene-n-amyl alcohol-formic acid (80 + 15 + 4 + 1) as the developing solvent. After development, plates were scanned with a reflectance flying-spot densitometer. With such techniques, average recoveries for spiked peanut butter extracts ranged from 99 to 105%, with variation values of 11-12%. Recovery values of 69% (KB method) and 84% (methanol and IUPAC methods) were obtained for spiked peanut butter samples. Coefficients of variation ranged from 13 to 15% for fluorodensitometric measurements. Innaturally contaminated peanuts and peanut products , precision values were 13.6% for fluorodensitometric measurements compared to 36% for visual estimations . Both the methanol and IUPAC methods yield extracts suitable for densitometric analysis after spotting on TLC plates; the analytical results obtained are comparable. Extracts from the KB method contained more interfering fluorescent material than the other 2 methods
Determination of Submicrogram Amounts of Mercury in Standard Reference Materials by Flameless Atomic Absorption Spectrometry
Authors: Rains Theodore C , Menis Oscar 
Published: February 2020

Abstract
In a study of the flameless atomic absorption method for the determination of nanogram amounts of mercury in organic materials, the technique was improved to provide greater precision and accuracy. The loss of mercury during the digestion of organic materials with nitric, sulfuric, and perchloric acids is prevented by controlled heating and a packed refluxing column. The reduction and absorption system was simplified by using a heated absorption cell which alleviates the interference of volatile vapors. This method has been applied to the determination of mercury in NBS Standard Reference Materials of orchard leaves, liver, and coal, and the results were compared with results obtained with 2 other analytical methods.
Microbiological Assay of Oxytetracycline in Liquid Supplements
Authors: Clarke Donald W 
Published: February 2020

Abstract
The extraction procedure of the official final action method for the determination of oxytetracycline in dry feeds, 38.208–38.213, has been modified for the analysis of liquid supplements. Ten g samples were extracted with 50 ml acid-methanol and diluted to 100 ml with the same solvent. Aliquots of the extract prepared according to the modified extraction procedure were assayed by the present official method and gave an average recovery of 100.6% and a coefficient of variation of 6.2% at a medication level of 500 mg/lb. Assays performed on liquid supplements containing oxytetracycline stored for an average of 26 days at 37 and 21°C, and for 37 days at – 4°C showed potency retentions of 21, 80, and 97%, respectively, indicating a need for low-temperature storage prior to analysis.
Sulfuric Acid for the Cleanup of Animal Tissues for Analysis of Acid-Stable Chlorinated Hydrocarbon Residues
Authors: Murphy Philip G 
Published: February 2020

Abstract
Biological substances interfering with pesticide residue analysis are removed from hexane extracts of animal tissues by shaking them with concentrated H2SO4. Recoveries are reported for several chlorinated hydrocarbon pesticides and polychlorinated biphenyls (PCB) from fish extracts. This treatment destroys dieldrin and organophosphate pesticides, but affords a rapid, efficient, and economical cleanup of animal tissues for the analysis of DDT, PCB, and other acid-stable chlorinated hydrocarbon residues.
Application of a Laboratory Analog-Digital Computer System to Data Acquisition and Reduction for Quantitative Analyses
Authors: John Matt K , Van Laerhoven Cornelis J 
Published: February 2020

Abstract
A flexible, general purpose program for a laboratory data acquisition and reduction system employing a minicomputer for off-line processing of digitized data readings from electroanalytical instrumentation was developed. Instrument data from the on-line operation of a hard-wired analog-to-digital data acquisition subsystem in conjunction with an atomic absorption instrument, a colorimeter, or a pH/millivolt meter for speeific-ion electrode determinations, are transformed into concentration units by using a linear interpolation method. The relationship between instrument measurements and quantitative data is approximated by several straight-line segments between the graphical coordinates associated with each of the reference standards analyzed. The coordinates are determined by calibrating readings and known concentrations. Routines are included to edit incorrect raw readings and to make corrections to compensate for unavoidable deviations from standard analytical procedure. The FOCAL-8 language program, therefore, permits unattended processing of sequentially read paper tape input. The results punched on paper tape are easily transferred to a large computer for more sophisticated data analysis and storage.
Emission Photometric Determination of Boron in Unboronated Fertilizers, Using the Nitrous Oxide-Hydrogen Flame
Authors: Pickett Edward E , Pau Jimmy C-M 
Published: February 2020

Abstract
The analysis of boronated fertilizers by extraction of acid-soluble boron with 2-ethyl-l,3-hexanediol in chloroform, with determination of boron by emission flame photometry, has been modified so that it may be applied to unboronated fertilizers. The very hot but non-reducing nitrous oxide-hydrogen flame provides a detection limit of 0.05 ppm in the extract or 0.5 ppm in the sample. Fluoride is the only major interference and this is eliminated by addition of zirconium ions. The range of boron content found in 8 samples of mixed fertilizers was 28.8 to 202 ppm.
Gas-Liquid Chromatographic Determination of Chloroanisoles in Soy Oil and Other Vegetable Oils
Authors: Williams D T 
Published: February 2020

Abstract
A method for the detection of chloroanisoles in soy oil utilizes partitioning between petroleum ether and acetonitrile followed by column chromatography on activated alumina. The eluate from the column, after treatment with concentrated sulfuric acid, is analyzed by electron capture gas-liquid chromatography. Recoveries from a 2 g sample of soy oil fortified at 0.01–1.0 ppm were 85–103% for pentachloroanisole, 82–99% for 2,3,4,6-tetrachloroanisole, and 75–96% for 2,4,6-trichloroanisole. Recoveries from samples fortified at 0.1–1.0 ppm were 83–99% for 2,4,5-trichloroanisole, 67–85% for 2,6-dichloroanisole, and 78–99% for 2,4-dichloroanisole.
Gas-Liquid Chromatographic Determination of Methyl Isothiocyanate in Soils
Authors: Sirons George J 
Published: February 2020

Abstract
Residues of methyl isothiocyanate in soils are extracted with diethyl ether containing 5% ethanol, concentrated in a Kuderna-Danish concentrator, and subjected to gas-liquid chromatography without further cleanup. A 6% Carbowax 20M column is used in conjunction with either conductivity (nitrogen mode) or flame photometric (sulfur mode) detection systems. The method is rapid and capable of determining methyl isothiocyanate residues in soils at a level as low as 0.01 ppm.
Oxytetracycline Residues in Tissue, Organs, and Eggs of Poultry Fed Supplemented Rations
Authors: Katz Stanley E , Fassbender Carol A , Dowling John J 
Published: February 2020

Abstract
Oxytetracycline was fed continuously to broilers at 25 to 200 g/ton from the age of 1 day to 11 weeks. Residues in the muscle tissue at 11 weeks ranged from trace quantities at 25 g/ton to 0.20 μg/g at 200 g/ton; liver residues ranged from not detectable to 0.29 μg/g at 200 g/ton; kidney levels ranged from 0.09 to 0.78 μg/g at 200 g/ton. Tissue, blood, liver, kidney, and intestinal contents were negative 24 hr after withdrawal from the drug. Cooking destroyed all residues in muscle tissue but livers retained 50% of the uncooked levels. Eggs from hens fed up to 400 g/ton contained no measurable residues.
Comparative Studies of Thin Layer Chromatographic Systems for the Separation and Identification of Photoalteration Products of Parathion
Authors: Joiner Ronald L , Baetcke Karl P 
Published: February 2020

Abstract
Twelve thin layer chromatographic systems were compared for the separation of photoalteration products of parathion. Rf values for each component in each system are presented. Infrared spectra confirmed the identity of separated components. The following 4 systems were designated superior and gave excellent separation of the components: petroleum ether-ethyl ether-glacial acetic acid (80+15+5 and 50+45+5), methanol-chloroform-ammonium hydroxide (24+75+3.5), and methanol-chloroform-petroleum ether (10+20+70).
Collaborative Study of the Ultraviolet Spectrophotometric and Gas-Liquid Chromatographic Methods for the Determination of Trifluralin and Benefin in Formulations
Authors: Hambleton Larry G 
Published: February 2020

Abstract
Fourteen collaborators participated in a study of an ultraviolet (UV) Spectrophotometric and a gas-liquid (GLC) method for the determination of trifluralin and benefin. In the UV method, trifluralin or benefin is extracted from the solid carrier or dissolved in n-hexane, if the formulation is liquid, purified by chromatography on Florisil, and determined by UV spectrometry at 376 nm. In the GLC method, the compound is extracted from the solid carrier or dissolved in acetone, if liquid, and determined by flame ionization GLC, using a column containing 5% DC-200 on 80–100 mesh Chromosorb W (HP). A statistical evaluation of the data by the technique of closely matched pairs is presented. The data show good correlation between the 2 methods and the methods seem to be reasonably accurate and precise. The ultraviolet and gas chromatographic methods have been adopted as official first action.
Collaborative Study of a Gravimetric Method for Mercury in Formulations Containing Chlorinated Pesticides
Authors: Launer James E 
Published: February 2020

Abstract
A gravimetric method for mercury was modified and collaboratively studied with formulations containing ~6% phenylmercuric urea and ~7% captan in one test pair and ~2% phenylmercuric urea and 30% lindane in another test pair. Mercury is determined by precipitation and weighing cupric propylene mercury iodide (Cu pn2HgI4), following refluxing with dilute HI-H2SO4 solution containing I2. Single determinations on 4 samples by 11 collaborators showed that the standard deviation estimation of random error was 0.063 for the captan pair and 0.034 for the lindane pair. Standard deviation estimates of systematic error were 0.061 and 0.013, respectively. In the preliminary study, the method showed close agreement with other accepted methods for 15 formulations. Lindane, captan, dieldrin, heptachlor, and zineb do not interfere; however, the method is not applicable to chloro- or nitrophenolic compounds nor to materials not decomposed by the digestion mixture. The method has been adopted as official first action.
Collaborative Study of a Gas-Liquid Chromatographic Method for the Analysis of Ametryne, Prometone, and Terbutryn
Authors: Hofberg Arthur H , Murphy Robert T 
Published: February 2020

Abstract
A gas chromatographic method for the determination of ametryne and terbutryn in wettable powder formulations containing about 80% active ingredient and prometone in liquid formulations containing about 25% active ingredient was collaboratively studied, using a matched pair scheme. The ametryne was extracted from the powder with chloroform containing dieldrin as an internal standard and chromatographed on Carbowax 20M, using a flame ionization detector; the same method was used for terbutryn. The sample containing prometone was dissolved in chloroform containing dieldrin and chromatographed in the same manner. Two samples of each pesticide were analyzed, using peak height measurements, with the following results: ametryne (14 collaborators)—1.63% overall coefficient of variation, 0.68% coefficient of variation for the random error, and 1.05% systematic error; prometone (15 collaborators)—2.27, 1.47, and 1.21%; and terbutryn (15 collaborators)—0.95, 0.51, and 0.56%, respectively. The method has been adopted as official first action.
Detection of Turmeric in Foods by Rapid Fluorometric Method and by Improved Spot Test
Authors: Karasz Albert B , De Cocco Frank , Bokus Linda 
Published: February 2020

Abstract
The rapid test for turmeric is based on the fluorescence of curcumin, the principal pigment of turmeric. In a water-saturated n-butanol solution, its excitation maximum is 435 nm and the emission maximum is 520 nm. In the test described, which was applied to pickles, salad dressings, and baked goods, a sample is shaken with the butanol solvent and the filtered extract is scanned for a 520 nm peak on a spectrophotofluorometer that has been adjusted to give 100% scale deflection for a standard curcumin solution. Extracts of pickles and salad dressings are scanned directly. Extracts of enriched baked goods are treated to remove riboflavin fluorescence by partitioning both riboflavin and curcumin from butanol into a solution of 0.1N NaOH-15% NaCl, acidifying the latter with CH3COOH, reducing the riboflavin with Na2S2O4, and reextracting curcumin from acid solution into butanol for fluorometric scanning. No interference is caused by annatto, carotene, tartrazine, or egg yolk solids. A spot test may be performed on the butanol extract. The solution is evaporated to dryness, the residue is dissolved in a few drops of ethanol, and the spot test is performed with a boric acid reagent of considerably improved sensitivity.
Collaborative Study of a Colorimetric Determination of Benztropine Mesylate in Tablets and Injections
Authors: Stricklin Marshall C 
Published: February 2020

Abstract
A collaborative study was conducted on simulated tablet and injection preparations at 2 concentration levels each and a 20 tablet composite of a tablet simulating presently marketed dosage forms of benztropine mesylate. Analysis involves the extraction of benztropine from 0.2N H2SO4 with bromophenol blue in CHCl3. Absorbance of the dye complex formed is measured at about 410 nm. Average recoveries and standard deviations submitted were: 98.9±2.54 and 99.2±2.58, 100.1±2.78 and 100.0±2.19, and 100.1±2.23%, respectively. The method has been adopted as official first action.
Collaborative Study of the Recovery and Gas Chromatographic Quantitation of Polychlorinated Biphenyls in Chicken Fat and Polychlorinated Biphenyl–DDT Combinations in Fish
Authors: Sawyer Leon D 
Published: February 2020

Abstract
Nine laboratories collaborated on the analyses of PCBs in chicken fat and DDT-PCB combinations in fish. Existing AOAC multipesticide methodology with GLC quantitation was employed. One solution containing a mixture of Aroclors 1254 and 1260 was analyzed by GLC only. The fish samples were subjected to a published silicic acid procedure for separating the DDT-PCB mixtures. The DDT analogs were quantitated before and after the separation. The PCB content was quantitated by total peak height and total area comparisons against appropriate Aroclor(s), using electron capture GLC, and additionally in 6 laboratories by total area comparisons, using halogen-specific detection. The electron capture GLC data demonstrated better accuracy and precision. The following PCB recoveries were obtained by using total peak height comparisons: 5 ppm mixed Aroclor solution, 100±4%; 8 ppm Aroclor 1242-fortified chicken fat, 101±13%; 7.5 ppm Aroclor 1248-fortified chicken fat, 96±9%; incurred Aroclor 1242 chicken fat, 9.2 ppm±8%; 6 ppm Aroclor 1254-fortified fish, 75±14%; 6 ppm Aroclor 1260-fortified fish, 75±15%; and an environmentally incurred residue in fish, 4.5 ppm±20%. The 2 Aroclor-fortified fish samples were concurrently spiked with the p,p′-isomers of DDE, TDE, and DDT at levels of 4, 1, and 3 ppm, respectively. After silicic acid separation the combined recoveries for these 2 samples were: DDE, 86±13%; TDE, 89±20%; and DDT, 84±17%. Environmentally incurred-DDT residues were recovered at 4.1 ppm±14% for p,p′-DDE, 0.7 ppm±24% for o,p′-DDT, and 2.7 ppm±17% for p,p′-DDT. The DDT values calculated before the silicic acid separation compared favorably with those summarized. The multiresidue method for chlorinated pesticides, 29.001–29.027, has been adopted official first action to include polychlorinated biphenyls in poultry fat and fish.
Modifications of the Technique for Differentiating Cultures Isolated by the Official AOAC Salmonella Method
Authors: Poelma Paul L , Romero Aida 
Published: February 2020

Abstract
Modifications are suggested for the official AOAC Salmonella method, 41.024–41.040, by which all colonies picked from selective plates are subcultured in both triple sugar and lysine iron agars. The techniques will detect Salmonella and Arizona cultures which might have been discarded. The revisions have been incorporated into the official method.
Modified Method for the Determination of Mycotoxins in Cocoa Beans
Authors: Scott Peter M 
Published: February 2020

Abstract
Method 26.026–26.030 was modified for the analysis of cocoa beans for aflatoxins by inclusion of 3% silver nitrate solution in the extraction solvent mixture. Recoveries of aflatoxins and ochratoxin A added at levels of 5–45 and 20–300 μg/kg, respectively, were satisfactory.
Collaborative Study of Acid-Detergent Fiber and Lignin
Authors: Van Soest Peter J 
Published: February 2020

Abstract
A second collaborative study on acid-detergent fiber and lignin has been completed involving 10 laboratories and 6 samples including timothy, alfalfa, soybean meal, barley straw, orchardgrass, and wheat straw. Results from 7 laboratories appeared normal according to the Youden collaborative test and yielded a mean duplicate error of 0.40±0.31, a standard error between laboratories of 0.40, and a coefficient of variation of 1.02%. The duplicate error for lignin was 0.23±0.31, the standard error between laboratories, 0.28, and the coefficient of variation, 4.26%. Results indicate problems with filtering, handling fritted glass crucibles in a uniform weighing procedure, and reliably preparing asbestos used in the preparation of lignin. Modifications of the previously published method include reduction of sample size to 1 g, elimination of the use of decalin, rigorous definition of filtration and weighing procedures, use of P2O5 or Mg(ClO4)2 as desiccant, and determination of a lignin blank. Problems in filtration can be overcome by not using more vacuum than is necessary, making all additions with vacuum off, and allowing 15–30 sec settling before applying suction. The modified acid-detergent fiber and lignin method has been adopted as official first action.
Improved Method for the Thin Layer Chromatographic Determination of Patulin in Apple Juice
Authors: Scott Peter M , Kennedy Barry P C 
Published: February 2020

Abstract
Apple juice from a freshly opened container is extracted 3 times with ethyl acetate. The extract is dried, concentrated, diluted with benzene, and added to a silica gel column. Patulin is eluted by benzene-ethyl acetate (75+25) and detected by thin layer chromatography, using a 3-methyl-2-benzothiazolinone hydrazone hydrochloride solution as the spray reagent. Satisfactory recoveries were obtained for patulin added to apple juice at levels of 25–400 μg/L.
Analysis of Ochratoxins A and B and Their Esters in Barley, Using Partition and Thin Layer Chromatography. I. Development of the Method
Authors: Nesheim Stanley , Hardin Nicole F , Francis Octave J , Langham William S 
Published: February 2020

Abstract
A convenient, specific, rapid method, developed for the determination of ochratoxin in barley, involves initial extraction of the sample with water-chloroform (1+9), followed by chromatography of the extract on an aqueous sodium bicarbonate-diatomaceous earth column. The ochratoxin esters are removed from the column with hexane-chloroform. Elution of the column with formic acid-chloroform (1+99) yields ochratoxins A and B. The ochratoxin esters are purified further on an aqueous sodium bicarbonate-methanol-diatomaceous earth column. The extracts are then quantitated on TLC plates by measuring fluorescence intensity. The presence of ochratoxins A and B is confirmed through formation of the corresponding ethyl ester derivatives. In an intralaboratory study, in which samples spiked at 25, 50, and 100 μg/kg levels were analyzed by 4 analysts, the average recovery for ochratoxin A was 81.2% with a lower detection limit of 12 μg/kg.
Prevention of Selenium Interference with Measurement of Phosphate as Its Molybdenum (V–VI) Complex
Authors: Milham Paul J , Short Colin C 
Published: February 2020

Abstract
Selenium used as a catalyst in Kjeldahl digests of plant samples was found to interfere with an automated molybdenum blue technique for determination of phosphate. Interference was prevented by formation of selenocyanate in the presence of excess cyanide. No modification of the apparatus was required and the rate of analysis was unchanged from 40 samples/hr. Reproducibility of the modified technique was good and results were not significantly different (P = 0.01) from those obtained by a manual molybdovanadate procedure.
Collaborative Study of the Microanalytical Determination of Phosphorus in Organic Compounds
Authors: Lalancette Roger A , Steyermark Al , Lee Ruth Ann , Lukaszewski Donna M 
Published: February 2020

Abstract
Sixteen collaborators participated in the study of the determination of phosphorus in organic compounds. Two samples were analyzed by the methods currently in use in the collaborators’ respective laboratories. Samples were combusted by oxygen flask, peroxide fusion, and wet digestion with acid(s). The resulting phosphoric acid was determined either gravimetrically, colorimetrically by the heteropoly blue method, or colorimetrically by the molybdenum yellow method. The various combustion methods were not compared, since there were not enough data to warrant this. The determinative steps were compared, but the data showed no significant difference in either precision or accuracy for any variation. A statistical evaluation of the data showed that the overall mean for the colorimetric heteropoly blue determination of triphenylphosphine (11.81% P) for 4 collaborators is 11.72%; for the colorimetric molybdenum yellow determination for 5 collaborators, 11.70%; and for the gravimetric determination for 3 collaborators, 11.93%. For phenylmethylphosphinic acid (19.97% P), the corresponding values are 19.64, 19.80, and 19.95%.