bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative Study of the Recovery of Hexachlorobenzene and Mirex in Butterfat and Fish
Authors: Bong Rodney L 
Published: February 2020

Abstract
A previously published method applicable to the recovery of hexachlorobenzene (HCB) and Mirex (dodecachlorooctahydro-1,3,4-metheno-2H-cyclobuta (cd) pentalene) from fats and oils has been collaboratively studied by 8 laboratories. The method involves distribution of the fat or oil on unactivated Florisil and elution of the HCB and Mirex with acetonitrile. The 2 compounds are then partitioned into petroleum ether and eluted through activated Florisil with methylene chloride-hexane. Electron capture gas-liquid chromatography is utilized as the determinative step. In the collaborative study, samples of sablefish and butterfat were fortified at 2 different levels; each level was determined in duplicate. Average HCB recoveries of 98±7% and 95±13% at respective levels of 0.06 and 0.5 ppm were obtained from the fish sample. Mirex recoveries in the fish sample at the same levels were 85±l4% and 96±10%. The butterfat sample was fortified at a low level of 0.13 ppm for both compounds and at high levels of 0.62 and 0.66 ppm for HCB and Mirex, respectively. The low level HCB recovery was 104±6% and the high level was 99±10%. In the same order, Mirex was recovered at 104±7% and 103±6%. The method has been adopted as official first action for the determination of HCB and Mirex in fish and fatty dairy products.
Anomalous Results in the Determination of Diethylcarbonate in Wine
Authors: McCalla Mark A , Barr Garold R , Kipp William H 
Published: February 2020

Abstract
Routine analyses of some wines for the presence of diethylcarbonate, using AOAC method 11.066—11.068, show a peak with the same retention time as diethylcarbonate, although an infrared spectrum of the peak conclusively proves that diethylcarbonate is not present. Spectra of components with similar retention times have been examined but the component or components of the peak have not been identified.
Separation and Ultraviolet Absorbance Techniques for Determining Dihydrotachysterol in Pharmaceutical Preparations
Authors: Hom Foo S , Veresh Stephen A , Ebert William R 
Published: February 2020

Abstract
Three separation techniques and ultraviolet (UV) spectrophotometry are described for dihydrotachysterol (DHT). The absorbance procedure eliminates the necessity of establishing a regular baseline, which is advantageous in certain cases. The relative absorbance values obey Beer’s law in the range of 1—10 μg DHT/ml ethanol. An absorbance ratio check ensures the applicability of the method with respect to the degree of allowable interference present. The absorbance ratio values at the indicated wavelengths at this concentration range and in the absence of any interferences are relatviely constant. The UV absorbance could serve as the common final determinative step for the other techniques, either singly or in combination, for quantitating DHT in preparations that require varying degrees of cleanup through extraction, saponification, and thin layer chromatography. The respective mean per cent recoveries and their relative standard deviations for a 50 μg DHT standard sample treated by the 3 techniques are 99.6±:0.5, 98.5±1.1, and 97.3±: 3.3%. Content uniformity determination of DHT in tablets and in soft gelatin capsules is also presented, and precautions are discussed.
Specific Solvation of Ion-Pairs: Examination of Anion-Solvent Complexes by Spectral Methods
Authors: Venable Richard M , Doyle Thomas D 
Published: February 2020

Abstract
The results of experiments performed using infrared (IR) and nuclear magnetic resonance spectroscopy support the theory that chloroform associates by hydrogen bonding to the halide ion of ion-pairs. IR spectra of dextromethorphan hydrobromide in chloroform showed the same effect. This provides a definitive, albeit qualitative, demonstration of the controversial concept of specific solvation of ion-pairs, central to an understanding of solvent effects in analysis of drugs by ion-pair partition. Quantitative implications are less clear. Indications that several molecules of chloroform may be involved in complexation are presented and discussed. Results of similar experiments with methylene chloride are inconclusive.
High Performance Liquid Chromatographic Determination of Sorbic Acid in Wine
Authors: McCalla Mark A , Mark Frances G , Kipp William H 
Published: February 2020

Abstract
A method is described for the qualitative and quantitative determination of 2,4-hexadienoic acid (sorbic acid) by high performance liquid chromatography (HPLC). The results show excellent reproducibility (±2.55%) and agree well with values obtained using the official AOAC ultraviolet method for both fortified wine and commercial wines. Sorbic acid is separated by HPLC, using a strong anion exchange resin, Zipax SAX, eluted with 0.01M Na2B4O7, and detected using UV (254 nm) detector. Sodium benzoate is used as an internal standard.
Aflatoxin: Comparison of Analyses of Corn by Various Methods
Authors: Shotwell Odette L , Goulden Marion L 
Published: February 2020

Abstract
Two methods were evaluated for determining levels of aflatoxin: one developed for peanuts and peanut products (BF method) ; the other (Pons method) for cottonseed products. Both were applied to corn, and results were compared with those obtained with the official first action CB method adopted for corn. Recoveries were much lower with the BF method than with the official AOAC method. Recoveries of aflatoxin B1 with the Pons method were satisfactory in samples containing less than 50 μg aflatoxin B1/kg, but only about 50% for samples spiked at 50 and 100 μg/kg; however, no aflatoxin G was detected in naturally contaminated corn, whereas G aflatoxins were detected with the CB method. Reducing the amounts of solvents used in the official AOAC method was also studied. The extraction solvent, chloroform, could be decreased from 250 ml to 150 ml, and washing and eluting solvents for column chromatography could be reduced by half without affecting results in this study.
Butyl Ester Preparation for Gas-Liquid Chromatographic Determination of Fatty Acids in Butter
Authors: Iverson John L , Sheppard Alan J 
Published: February 2020

Abstract
Butter oil is extracted from butter with hexane, using a rolling boil technique. The resulting 10% butter oil in hexane is converted to butyl esters, using butanol in place of methanol as specified in the official final action method, 28.063–28.067. A water wash and centrifuge technique is used to remove butanol from the n-hexane-butyl ester solution. Conversions to butyl esters are quantitative by the boron trifluoride, sulfuric acid, and sodium butoxide procedures. When methyl ester methods are used, there are serious losses of the short chain volatile and water-soluble acids, making the methyl ester procedures questionable for determining the authenticity of milk fat.
Use of Three Optical Systems to Obtain a Microscopic Profile of Asbestos and Other Nonopaque Particulate Matter Larger than 5 μm in Parenteral Drugs
Authors: Auerbach Leonora 
Published: February 2020

Abstract
A comparative microscopic study of chrysotile fibers was conducted, using 3 sequential optical systems: plane polarized light (PL), phase contrast (PC), and Nomarski differential interference contrast (NDIC) for complementary image analyses. The introduction of NDIC for qualitative and quantitative analyses of particulate matter &gt;5 μm resolves the problem of diffraction halos encountered in PC microscopy. High optical contrast, the instrumental characteristic of NDIC, is particularly useful for the detection of chrysotile fibers at a magnification of 500 ×.
Occurrence and Distribution of 2-Butanol, 1-Butanol, 1-Pentanol, and 1-Hexanol in Distilled Alcoholic Beverages
Authors: Barnett John H , Einsmann Joanne R 
Published: February 2020

Abstract
A survey was made of the distribution of 2-butanol, 1-butanol, 1-pentanol, and 1-hexanol in 198 brands of distilled alcoholic beverages. The principal concern of this study was to determine the applicability of any of the 4 congeners studied to be used as parameters in alcoholic beverage characterization. 1-Pentanol has very narrow use, because it occurred significantly in only 1 brand. 1-Butanol and 2-butanol show intermediate possibilities. 1-Hexanol had wide distributions, and was judged best of the 4 as a parameter. A distinction was shown between 2 brands, similar in other parameters, on the basis of the 1-hexanol content of each. In a 7-year survey, 1-hexanol was consistently characteristic for a single brand. All analyses were done using dual columns, dual flame ionization detectors in a gas-liquid chromatographic system, employing temperature programming from 50 to 150°C. Columns contained 2% Carbowax 20M, 3% Carbowax 1500, and 1% mineral oil on 45—60 mesh Chromosorb G. In addition to the 4 congeners mentioned, the following are also separated by this procedure: acetaldehyde, methyl acetate, ethyl acetate, methanol, 1-propanol, isobutyl alcohol, isoamyl acetate, isoamyl alcohol, hexyl acetate, ethyl caprylate, and 2-furfural.
Comparison of Accuracy, Precision, and Speed of Three Methods for Determining Moisture in Milk Chocolate
Authors: Kreiser Wesley R , Martin Robert A 
Published: February 2020

Abstract
Samples of grated milk chocolate were equilibrated with moisture at increased humidity levels. In the first part of the study, the moisture content of the samples was determined by using the alternative OICC method, manual Karl Fischer titration, and azeotropic distillation. In the second part of the study, the AOAC official method (13.002), azeotropic distillation, and an automated Karl Fischer titration were used for the moisture determination. The results show that the Karl Fischer titration method is more accurate, more precise, and much faster than either of the official methods tested. The azeotropic distillation method gives results that are comparable with those obtained using the Karl Fischer titration method but it requires much more time.
Thin Layer Chromatographic Detection of Amomum subulatum Roxb in Elletaria cardamomum Maton
Authors: Sen Asit R , Sengupta Pratima , Sardar Pranab K , Roy Bidhan R 
Published: February 2020

Abstract
A thin layer chromatographic method has been developed that distinguishes and differentiates true cardamom (Elletaria cardamomum Maton) and greater cardamom (Amomum subulatum Roxb). Extracted volatile oils are chromatographed on silica gel G with n-hexanediethyl ether (80+20) solvent system and visualized with a saturated solution of antimony trichloride in chloroform. The chromatographic pattern permits the detection of adulteration of one by the other at levels as low as 5%.
Assay of Thiamine in Foods, Using Manual and Semiautomated Fluorometric and Microbiological Methods
Authors: Defibaugh Phillip W , Smith Jeffrey S , Weeks Cora E 
Published: February 2020

Abstract
Three methods for the determination of thiamine in foods were evaluated for accuracy, recovery, and precision: a manual fluorescent method, a semiautomated fluorescent method, and a Lactobacillus viridescens microbiological assay. Thiamine in the samples was destroyed with clam tissue thiaminase; a known amount of thiamine hydrochloride was then added to the extract; and the thiamine recovery was determined. For 14 commercially processed food products analyzed by the manual and semiautomated methods, the mean per cent recovery values and standard deviations were 91.2±8.92 and 99.3±3.13%, respectively. Eight of these products were analyzed by all 3 methods. The mean per cent recoveries and standard deviations for these 8 samples were 90.7±8.97, 101±2.52, and 99.9± 1.03%, respectively, for the manual, semiautomated, and microbiological methods. The microbiological method with L. viridescens gave the best results for the products tested. The concentration of vitamin which can be measured is such that samples of low label declaration present no problems. The semiautomated method offers a rapid and accurate method of thiamine assay. The chemical reactions are identical to those of the official method. The major difference between the methods is in the sample cleanup. It is postulated that the low recovery observed for the manual method is due to incomplete elution of thiamine in the column purification step.
Rapid Spectrophotometric Determination of Ascorbic Acid in Citrus Fruits
Authors: Kamangar Teymour , Fawzi Ahmad B , Maghssoudi Rostam H 
Published: February 2020

Abstract
A new spectrophotometric method has been developed for determining ascorbic acid in citrus fruits. The method is based on interaction between dimethoxydiquinone and ascorbic acid, followed by extraction with chloroform. The resulting chloroform solution gives a maximum absorption at 530 nm, a determination limit of 22.0 μg/ml, and a linear range from 22.0 to 97.5 μg/ml. The molar absorptivity of the chloroform solution was 1.62 × 103. The reaction was quantitative over the pH range from 3.0 to 7.0. Ascorbic acid in citrus fruits was successfully determined by this method. Comparison of results with those obtained by using the AOAC method showed excellent agreement; the average recovery for the analysis of orange, grapefruit, and lemon juices was 100±0.3%.
Methodology for Recognition of Invasive Potential of Escherichia coli
Authors: Mehlman Ira J , Eide Elmer L , Sanders Arvey C , Fishbein Morris , Aulisio Calvin C G 
Published: February 2020

Abstract
Surveillance for dysentery-related invasive potential in bacteria using the Sereny keratoconjunctivitis test is restricted by expense, time factor, and necessity for confirmation. Primary screening of isolates in a standardized mammalian cell culture system is recommended. Bacteria are grown 20 hr in veal infusion, washed, and resuspended in 20% heat-inactivated fetal bovine serum (FBS) supplemented with 0.12% brain heart infusion and 0.1% bile salts. The HeLa culture is grown 20 hr as a monolayer in chamber slides with 90% minimal essential medium (MEM)-10% FBS. The host culture is infected at a ratio of 10 bacteria/ mammalian cell for 3 hr at 35°C. The infection medium is replaced with MEM-FBS supplemented with 300 μg lysozyme and 5 μg gentamycin/ml. The infected monolayer is incubated 5 hr at 35°C to permit intracellular multiplication. Specimens arc washed, fixed with methanol, and stained successively with May-Grunwald and Giemsa dyes. Bacteria occur within the cytoplasm if invasion has occurred. The criterion for a positive test is that 1% of the host cells possesses at least 5 bacteria in 2 of 3 trials. Invasiveness is correlated with and possibly pre-conditioned by cytotoxic principle(s). Infectivity rates vary from 0 to 30%. The cytopathic effect is noted in 5–50% of HeLa cells. Positive results must be confirmed by the Sereny test.
Gas-Liquid Chromatographic Headspace Technique for Determination of Vinyl Chloride in Corn Oil and Three Food-Simulating Solvents
Authors: Diachenko Gregory W , Breder Charles V , Brown Margaret E , Dennison J Lawrence 
Published: February 2020

Abstract
A gas-liquid chromatographic headspace technique for the determination of vinyl chloride (VC) in com oil, 50% ethanol, 3% acetic acid, and n-heptane is described. These food-simulating solvents and the corn oil are placed in septum-sealed bottles and heated to 90°C, and aliquots of headspace vapor are injected into a gas-liquid chromatograph equipped with a flame ionization detector. VC may be quantitated at concentrations of 1 ppb or less. This technique was used to measure the migration of VC into corn oil and 50% ethanol from 2 unplasticized polyvinyl chloride sheets containing 0.28 and 0.44 ppm residual monomer.
Sensitive Silica Gel-Packed Flowcell for Fluorometric Detection of Aflatoxins by High Pressure Liquid Chromatography
Authors: Panalaks Thavil , Scott Peter M 
Published: February 2020

Abstract
Aflatoxins B1, B2, G1, and G2 were quantitatively detected by High pressure liquid chromatography on a 5 μm Lichrosorb column, using a Lichrosorb-packed flowcell in the fluorometric detector. The relationship between peak height and the amount injected was linear only up to about 2 ng but showed a linear log-log relationship. Methods for constructing and packing the flowcell are given. A guard column and venting valve were used to minimize deterioration of the analytical column and the adsorbent-packed flowcell. The method was applied to a peanut butter extract, although with the cleanup procedure used, the life expectancy of the flowcell is limited.
Collaborative Study of Modified AOAC Method of Analysis for Nitrite in Meat and Meat Products
Authors: Fiddler Rosemary Nicholas 
Published: February 2020

Abstract
A modified version of the AOAC method of analysis for nitrite in meat and meat products was tested collaboratively by 23 laboratories. Results were compared with those obtained by the official AOAC method. Recommended modifications include: (a) substitution of N-(1-naphthyl) ethylenediamine and sulfanilamide for Griess reagent, (b) separate addition and 1:10 dilution of the above reagents, (c) 20 min color development and absorbance read at 540 nm, (d) substitution of NaNO2 for AgNO2 and NaCl, (e) omission of mercuric chloride, (f) screening of filter paper for nitrite contamination, (g) more precise dilution of sample aliquot, and (h) standard curve linear up to 10 μg N/50 ml. Results were statistically treated by Youden’s technique for comparing 2 methods, using a matched pair sample scheme. The random error for the modified method was significantly lower than the random error for the official method. A t-test showed no difference in bias between the 2 methods.
Collaborative Study of Precision Characteristics of the AOAC Method for Crude Fat in Meat and Meat Products
Authors: Pettinati Julio D , Swift Clifton E 
Published: February 2020

Abstract
A collaborative study of determination of fat by AOAC method 24.005(a) or (b) was conducted to gain more knowledge regarding its characteristics of precision. Twelve analysts in meat and food industry laboratories each performed 4 determinations on 7 samples containing 3.4–48% fat. The following characteristics of precision of the method were established: Variation between duplicate determinations was 0.3% fat; within-laboratory repeatability on separate days was 0.3% fat for samples containing up to 27% fat and 0.7% for samples containing 48% fat; variation among laboratories, including variation due to laboratory-sample interaction, was 0.4% fat; and reproducibility, which includes variations of determinations on a sample by different analysts using different sets of equipment in different laboratories, was 0.6% fat. This information is especially useful for comparative evaluations of alternative methods of fat determination.
Comparison of X-Ray Fluorescence, Atomic Absorption, and Gravimetric Methods for the Determination of Lead in Glassware
Authors: Prager Manfred J , Graves Donald 
Published: February 2020

Abstract
Methods were developed for determining per cent levels of lead in glassware by atomic absorption and x-ray fluorescence spectroscopy. The procedures were evaluated by comparison with a gravimetric method, using previously analyzed commercial glass samples. For atomic absorption spectrometry, samples are dissolved in a mixture of HF and HNO3. Solutions are nebulized into an acetylene-air flame and absorption is measured at 261.4 nm, a secondary line used in order to avoid large dilutions. For x-ray fluorescence analysis, samples are fused, ground, and then pressed into pellets. The intensity of the Pb Lα line corrected for background is measured. Regression analysis of data obtained with 15 commercial glassware samples shows that there is no significant difference among x-ray fluorescence, atomic absorption, and gravimetric results. Statistical tests performed with data on 4 reference materials indicate satisfactory accuracy for both instrumental methods. The atomic absorption analysis is the fastest and simplest of the 3 methods.
Detection and Semiquantitative Estimation of Thyroxine and Diiodothyronine in Liothyronine Sodium
Authors: Cieri Ugo R , Illuminati James C 
Published: February 2020

Abstract
A method is presented for the detection and semiquantitative estimation of thyroxine and diiodothyronine in liothyronine sodium. Thyroxine is detected by thin layer chromatography, using silica gel H plates developed in butanol-acetone-ammonia (30+55+15) and sprayed with a 2,7-dichlorofluorescein solution, and estimated by comparison with standard spots. For quantitative results, a larger amount of sample is applied as a streak on a fluorescent silica gel H plate. After a 5 hr development, the band is scraped off and extracted in a small volume of 0.1N NaOH; the extract is centrifuged, transferred to a 2 cm microcell, and examined spectrophotometrically. The diiodothyronine content of liothyronine sodium is estimated by liquid chromatography on a Bondapak C18 column with 0.01N sodium perchlorate-butanol-acetonitrile (1000+62+188) as the eluting solvent.
Collaborative Study of the Determination of Moisture in Chocolate by Karl Fischer Titration
Authors: Martin Robert A 
Published: February 2020

Abstract
A collaborative study was conducted comparing the AOAC air oven method, 13.002, with the Karl Fischer titration for determining moisture in cacao products. Five samples (4 milk chocolates and 1 confectionery coating) were analyzed by 10 collaborators. The results indicate that the Karl Fischer method gives better precision than the official method. The former method has been adopted as official first action.
Evaluation of Methods for Determining Available P2O5 in Fertilizers
Authors: Johnson Frank J , Farley James A 
Published: February 2020

Abstract
The official AOAC methods for the direct and indirect determination of available P2O5 in fertilizers were compared. The quantity of water-soluble P2O5 removed prior to the citrate extraction has a significant effect on the final available P2O5 result. The quantity of water and the technique used to remove the water-soluble fraction were evaluated. The results indicate that 250 ml and an active wash are necessary to obtain acceptable values for available P2O5. The official method for direct available P2O5 was revised editorially.
Determination of Nitrate Nitrogen in Compound Fertilizers
Authors: Barbera Andrea 
Published: February 2020

Abstract
A commercial electrode is suitable for the determination of nitrate nitrogen in compound fertilizers. The reliability of the electrode was better than 2%. In samples containing from 2.16 to 4.88% nitrate nitrogen, standard deviations ranged from 0.08 to 0.05. The results obtained do not significantly differ from those provided by the Devarda method for nitrate reduction to ammonia and the Kjeldahl method for ammonia determination.
Chromatographic Methods for Analysis of Some Fluorene-9-Carboxylic Acid Derivatives (Morphactins) in Emulsifiable Concentrates and Technical Material
Authors: Cochrane William P , Singh Joginder , Grant Ralph 
Published: February 2020

Abstract
Flurenol-methyl, chloroflurenol-methyl, and dichloroflurenol-methyl in emulsifiable concentrates and technical grade material are separated and identified by thin layer (TLC), high pressure liquid (HPLC), and gas-liquid chromatography (GLC). TLC results were unsatisfactory because of interferences and also variations in the quantitation of the active ingredients. HPLC and GLC gave satisfactory results. Both Porasil C400 and Corasil II HPLC columns gave good resolution of the 3 homologs, with ultraviolet detection at 254 nm. Standard curves had correlation coefficients of 0.990 or better. Analysis by GLC was quantitative with flame ionization detection and a 5% DC-200 column. Response was linear from 200 ng to 2 μg and the coefficient of variation was 2.4%. The mass spectral analysis of the formulated product is also discussed.