bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Pulse and AC Polarography of Reserpine, Using an Aprotic Organic Solvent System
Authors: Taira Albert , Smith Donald E
Published: February 2020

Previously demonstrated advantages of aprotic organic solvent for analysis of organic pharmaceuticals have been applied to the assay of reserpine tablets. A procedure using high sensitivity electroanalytical relaxation methods was developed which is simpler and more sensitive than the USP assay. Most data were obtained with a commercial differential pulse polarograph which is widely available. However, less extensive measurements with other instruments established the general applicability of the differential pulse method, as well as various ac polarographic techniques. The results of differential pulse polarographic (DPP) and USP assays of synthetically formulated reserpine tablets compare favorably. The DPP method yields an average recovery for 0.1 mg reserpine/tablet of 100%, with a range of 97.6-102.3%. Corresponding data for 0.25 mg reserpine/ tablet are 99.3%, with a range of 97.6-100.6%. Satisfactory results also were obtained in content uniformity studies, using single 0.1 and 0.25 mg tablets.
Spectroscopic and Chromatographic Identification of Precursors, Intermediates, and Impurities of 3,4-Methylenedioxyamphetamine Synthesis
Authors: Lukaszewski Theodore
Published: February 2020

The ultraviolet, infrared, nuclear magnetic resonance, and mass spectra of a number of precursors, intermediates, and impurities of 3,4-methylenedioxyamphetamine (MDA) synthesis are presented as well as gas-liquid and thin layer chromatographic data. Test results are given on the precursors safrole, isosafrole, and piperonal; the intermediates isosafrole glycol, N-formyl-MDA, and l-(3,4-methylenedioxyphenyl)- 2-nitro-l-propene; the impurities di[l- (3,4-methylenedioxyphenyl) -2-propyl] amine, di[l - (3,4 - methylenedioxyphenyl) -2- propyl] methylamine, and 3,4-methylenedioxyphenyIpropane; and the product MDA. The data are discussed and 2 methods of MDA synthesis are summarized, in which the precursors, intermediates, and impurities are encountered.
Gas-Liquid Chromatographic Determination of Volatile Organic Acids as Benzyl Esters with Applications to Tuna, Shrimp, and Eggs
Authors: Staruszkiewicz Walter F , Fernandez-Flores Enrique , Bond John F
Published: February 2020

Volatile acids are recognized as useful indicators of decomposition in a variety of foods. A method has been developed for the rapid preparation of benzyl esters of formic, acetic, propionic, isobutyric, and butyric acids and for their quantitative determination by gas-liquid chromatography. Esters were formed by reaction with BCl3-benzyl alcohol, followed by washing with aqueous ammonia before storage. They were chromatographed, using tetradecane as an internal standard, and were separated at 140°C on columns having DC-200 and SP-1000 as liquid phases. The method offers significant advantages, especially for the determination of formic acid, over the present official AOAC method, 17.042-17.046. Recoveries of volatile acids added to steam distillates of tuna extracts were ≥ 91% with mean recoveries for the 5 volatile acids of 96—104%. Applications to the analysis of canned tuna, frozen headless shrimp, and frozen whole egg resulted in recoveries of ≥ 8 2% with mean recoveries for the 5 acids of 91—101%. The method was compatible with an automated gas chromatograph-data processing system.
Determination of Fluoride in Deboned Meat
Authors: Dolan Thomas , Legette Liston , Mcneal Jon , Malanoski Anthony J
Published: February 2020

A rapid analytical procedure was investigated for measuring the fluoride content of deboned meat, using a specific ion electrode. The method involves a defatting procedure followed by chelation with EDTA before final solubilization and measurement. Fluoride content is determined by comparison to a standard curve on 2-cycle semi-logarithmic graph paper of fluoride ion vs. millivolt readings. The method is applicable to hand and mechanically deboned pork, beef, and poultry within a range of from 0.7 to 25.0 ppm fluoride. Higher concentrations may be measured by analyzing additional standards and extending the curve into a third cycle. The curve is not linear below 0.7 ppm. Samples less than 0.7 ppm may be estimated by extrapolation. Studies with fortified samples indicate average recoveries of 92±4.2%. The standard deviation of duplicates within the laboratory is 0.5 ppm in the range stated above.
Separating Meat and Nonmeat Proteins by Using Disc Electrophoresis
Authors: Richardson Florence M
Published: February 2020

Meat and nonmeat proteins were separated by using an adaptation of the disc electrophoresis method. Milk and soy proteins, at the 3.0, 2.0, 1.0, and 0.5% levels, were incorporated into cooked sausage products. Nonmeat proteins required a denaturing treatment in the final gel preparation step. The entire process of polymerization, staining, and destaining can be completed in 1 day. Densitometer tracings of the band patterns confirmed the reproducibility of the proposed method.
Gas Chromatographic Identification of Propellants and Aerating Agents in Aerosol Whipped Toppings and Sprayed Pan Coatings
Authors: Page B Denis
Published: February 2020

A gas chromatographic procedure is described for the identification of a variety of propellants and aerating agents in aerosol whipped toppings and antistick pan coatings. The aerosol product is dispensed into a flask containing ethanol and the headspace is analyzed by gas chromatography. Carbon dioxide, nitrous oxide, chloropentafluoroethane, octafluorocyclobutane, propane, dichlorodifluoromethane, isobutane, and fluorotrichloromethane are identified by their retention times relative to ethanol.
Survey for Aflatoxin B1 in Chicken Eggs
Authors: Stoloff Leonard , Trucksess Mary W
Published: February 2020

Samples of egg products were obtained during January and July 1977 from 35 establishments located in the southern part of the United States. Of the 112 samples analyzed, aflatoxin B1 was found in 1 sample of liquid egg white at a level of 0.06 ng/g. No aflatoxin was found in 101 samples of shell eggs offered for sale to consumers in Alabama, Georgia, South Carolina, and North Carolina in the late fall of 1977.
Improved Method for Determination of Light Filth in Chocolate Products
Authors: Shostak Marie T
Published: February 2020

The recovery of rodent hairs from chocolate has been significantly improved by the introduction of an additional defatting step, substitution of 4 0% isopropanol for water, and substitution of mineral oil-heptane (85+15 ) for heptane in the trapping-off step. These changes have no adverse effect on insect fragment recovery. An average recovery of 9 5 % was obtained for rodent hairs, coefficient of variation 7.9%. Insect fragment recoveries were 100%.
Modified Method for Extracting Light Filth from Chocolate Liquor by Using 2% Igepal CO 630 as Detergent Solution: Collaborative Study
Authors: Mastrorocco Donald A , Wagner Geraldine H
Published: February 2020

A collaborative study was conducted among 3 laboratories comparing 2 detergent solutions, 2% Igepal CO 630 and the AOAC-approved 2% sodium lauryl sulfate, in the analysis of extraneous materials in chocolate liquor. Each laboratory tested a minimum of 8 samples per detergent solution. No significant differences were found between the numbers of rodent hairs and insect fragments recovered with the 2 detergent solutions and, in addition, igepal produced cleaner filter papers. The 2% Igepal CO 630 detergent solution has been adopted as a substitute for 2% sodium lauryl sulfate in 44.006(b) for chocolate liquor.
Determination of Zearalenone in Corn by High Pressure Liquid Chromatography and Fluorescence Detection
Authors: Ware George M , Thorpe Charles W
Published: February 2020

A method is reported for determining zearalenone in corn at levels as low as 10 ng/g. Samples are extracted with chloroform-water and cleaned up by liquid-liquid chromatography, and the zearalenone is detected by a fluorescence detector after separation by reverse phase high pressure liquid chromatography (HPLC). Recoveries of zearalenone added to corn at levels from 10 to 200 ng/g averaged greater than 89%. In addition, a confirmation procedure is described which involves sequential HPLC analysis of the sample and a zearalenone standard, using 4 different excitation wavelengths and comparing fluorescence responses obtained. This method was successfully applied to the analysis of 11 samples of cornmeal; zearalenone was detected in 9 of the samples at levels from 11 to 69 ng/g.
Fluorometric Determination of Indole in Shrimp
Authors: Ponder Carl
Published: February 2020

A fluorometric method is described for determining indole in shrimp. The indole is extracted with n-hexane, partitioned into a methanol- saturated sodium chloride solution ( 9 + 1 ), and determined fluoromctrically. The detection limit of the method is 0.04 μg indole/g shrimp. Quantitative analytical data are presented for indole in samples of shrimp determined by the fluorometric method and the AOAC official colorimetric and gas-liquid chromatographic procedures. The correlation coefficient between the data of the fluorometric and colorimetric methods was 0.96. Indole recovered from 25 g samples of fresh shrimp spiked with 6 and 12 μg indole/25 g ranged from 97 to 106%. The fluorescence response is linear in the range of 1 to 25 μg indole/100 ml methanol solution and no significant change is noted in solutions kept in the dark 18 hr.
Reverse Phase High Pressure Liquid Chromatographic Determination of Vitamin D in Fortified Milk
Authors: Henderson Susan K , Wickroski Alphonse F
Published: February 2020

Vitamin D was determined in commercially fortified milk, using reverse phase high pressure liquid chromatography (HPLC). The milk sample was saponified at room temperature and cleaned up on an alumina column to remove cholesterol and carotenes. The sample was then chromatographed in an HPLC system on a 0.26 × 25 cm ODS-HC-Sil-X-1 column using methanol-acetonitrile (1 + 1) as the mobile phase. For 6 milk samples, the recovery of added vitamin D using this procedure was 92%.
Calibration of Water Activity Measuring Instruments and Devices: Collaborative Study
Authors: Stoloff Leonard
Published: February 2020

A method is presented for calibration or check of suitable equipment or procedures for measuring the relative humidity generated by the commodities of interest in a closed system. The critical parameters are defined and the control limit for each parameter is established to achieve the desired sensitivity and precision of measurement. A multilaboratory, multi-instrument study of the method, applied to a cross section of commodities and reference standards, demonstrated that measurements of water activity by the described method with instruments using immobilized salt solution sensors can be made with an accuracy and precision within ± 0 . 0 1 , provided there are no commodity-instrument interactions. The study showed that commodity-instrument interactions did exist with lupini beans in brine, soy sauce, and cheese spread, but not with fudge sauce. A sampling error is distinctly evident with walnuts and is probably a component of the variance with rice. There were too few laboratories using other types of instruments than those with immobilized salt solution sensors for a valid statistical analysis of each.
Use of Mass Spectrometry for Confirmation of Animal Drug Residues
Authors: Sphon James A
Published: February 2020

Mass spectrometry is a technique capable of providing unambiguous confirmation of drug residues in edible tissues at trace levels. This has led to an increase in the number of new animal drug applications containing a mass spectrometry procedure as the confirmatory test. Written guidelines do not exist to cover the requirements to be met for acceptance of these procedures. The legal, analytical, and practical requirements to be considered in developing and submitting these procedures will be presented on current requirements and past experiences.
Trenbolone Acetate: Experiences with Bound Residues in Cattle Tissues
Authors: Ryan John Joseph , Hoffmann Bernd
Published: February 2020

Two heifers were implanted with 300 mg of the radiolabeled anabolic steroid, trenbolone acetate (TBA). After a 60 day slaughter and a 60 day removal followed by 76 day slaughter, total 3H-content in various tissues was 0.5—25 ng/g equivalents of TBA. Radioimmunoassay of the tissues showed that only 1-5% of the total residue present was TBA, its main metabolite trenbolone (TBOH), and TBOH glucuronide, plus up to 5% of other organic-soluble material. Of the radioactivity remaining about half was directly water-soluble, and the insoluble residue could be made water-soluble by treatment with the proteolytic enzymes pepsin and trypsin. These 2 portions were purified with Sephadex G-25 to give a low and high molecular weight fraction. Raney nickel reduction of sulfur bonds in either fraction released up to 50% of radioactivity into the organic phase. TLC showed that the latter contained 2 components which had characteristics similar to TBOH and its metabolites, and thus were at least partly drug-related metabolites. In vitro experiments with bovine liver also showed a small but definite protein binding. It is proposed that in dealing with these covalently bound residues, priority be given to the reactive drug intermediate and the type of binding to macromolecules rather than to the presence of the bound residue itself.
Determination of Citrinin in Corn and Barley
Authors: Marti Luz R , Wilson David M , Evans Bonnie D
Published: February 2020

A method is described for determining citrinin in corn and barley. The initial extraction uses an aqueous acidified acetonitrile solution, and the resulting solution is partially purified by several partition steps. Citrinin is determined by using either high pressure liquid chromatography (HPLC) or thin layer chromatography (TLC). For HPLC, the extract is injected on a reverse phase column, eluted with either 0.25N H3P04-methanol (45+55) or 0.25N H3P04-acetonitriIe (50+50) , and detected by fluorescence (excitation 325—385 nm, emission above 451 nm). Recovery of added citrinin from corn by this method is 60—86% at levels of 50-4000 μg/kg. For TLC, the chromatographic plates are impregnated with oxalic acid by dipping them in an oxalic acid-methanol solution before spotting and development. Recovery of added citrinin from corn, using TLC, is 40-100% at levels of 50-4000 μg-kg.
High Pressure Liquid Chromatographic Determination of Patulin in Apple Juice
Authors: Stray Helge
Published: February 2020

Patulin was extracted from apple juice with ethyl acetate and the extract was purified by elution from a silica gel column with ethyl acetate-toluene. The eluate was concentrated, and patulin was determined by reverse phase high pressure liquid chromatography using a 25 cm PartisiI-10 ODS column. The lower detection limit was 1 μg/L and the mean recovery of patulin added to apple juice was 82.6± 2.8%. The patulin content ranged from <1 to 220 μg/L for the 140 samples analyzed.
Spectrodensitometric Determination of Chloramine-T in Ice Cream
Authors: Beljaars Paul R , Rondags Theo M M
Published: February 2020

A spectrodensitometric method has been developed for the quantitative determination of chloramine-T (N-chloro-Ar-sodium-p-toluenesulfonamide) in ice cream. Chloramine-T is extracted and converted into p-toluenesulfonamide (p-TSA) followed by thin layer chromatographic separation of concentrated extracts on silica gel and quantitation of the p-TSA spots from standards and samples by direct scanning with a reflectance densitometer at 228 nm. A linear relationship was obtained between recorded peak area and concentration for 0.5–7.0 μg p-TSA/spot. The reproducibility of the complete method was 2.87% (n = 9 determinations). The detection limit of the scanning procedure was 0.5 μg p-TSA/spot, corresponding to a concentration of 4 mg chloramine-T/kg sample. The average recovery was 88±3% (P = 95%) for 10 ice cream samples spiked with chloramine-T at levels ranging from 10 to 55 mg/kg. The described method was used to assay 146 commercial ice cream and whipped cream samples for chloramine-T.
Effects of Brine Treatment on Pesticide Residues During Recycling of Pickling Brine
Authors: Fehringer Norbert V
Published: February 2020

The effects of 2 pickle brine recycling treatments on residues of selected insecticides, herbicides, and fungicides are presented. Residues were determined in raw and brined cucumbers, in untreated brine, and in brine following pasteurization or chemical (NaOH) treatment. The samples were extracted with acetone, partitioned into methylene chloride, cleaned up by gel permeation chromatography, and quantitated by gas-liquid chromatography using nitrogen/phosphorus, electron capture, and flame photometric detectors.
Evaluation of Amperometric Detector for Liquid Chromatographic Determination of 2-Phenylphenol Residues in Orange Rind
Authors: Ott Daniel E
Published: February 2020

A modular component liquid chromatograph has been assembled which has on-stream ultraviolet (UV) and amperometric detectors connected to a dual pen recorder. In this method, the commonly used UV detection technique provides a reference for direct comparisons of results from the amperometric detector. The system has been evaluated and applied to the determination of 2-phenylphenol (2PP) fortified in orange rind. The method is not tedious; before liquid chromatographic analysis, the sample is extracted with methylene chloride and cleaned up on a Florisil column. The method is sensitive to <1 ppm 2PP fortified in orange rind; there are no electrically oxidizable interferences, from control samples, in the chromatographic region of 2PP. Some background interference does appear from the same samples on the UV chromatogram. Thus, amperometric detection is more specific than UV detection for this application.
Infrared Spectrophotometric Determination of Encapsulated Famphur in Poly (lactic acid)
Authors: Giang Paul A , Jaffe Howard
Published: February 2020

A simple but specific infrared (IR) spectrophotometry method for the quantitative determination of famphur, O,O-dimethyl O-[p-(dimet hylsulf amoyl) phenyl] phosphorothioate, in a capsule sample of lactic acid-polymer material is presented. The analytical method includes the following operations: extracting the encapsulated famphur with CQ4 and heat, cooling the extract to room temperature and diluting to volume with CCl4, and, after filtering through anhydrous H2S04 , determining IR absorption of the sample, which is related by a standard curve to mg famphur/ml solution.
High Pressure Liquid Chromatographic Determination of Arprinocid in Feed
Authors: Fink David W , Fox Allen , Pivnichny James V
Published: February 2020

Arprinocid [9 - (2 - chloro - 6 - fluorophenyl-methyl)-9H-purin-6-amine ] is determined in feed by high pressure liquid chromatography with a silica column and ultraviolet detection. The drug is extracted from the feed into chloroform in the presence of pH 7 phosphate buffer, transferred to 0.1N HCL, and separated from interfering substances by partitioning with hexane. The acidic solution is neutralized, and the analyte is extracted into chloroform for injection into the chromatograph. This procedure has been applied to feeds containing 0.0030—0.0090% arprinocid with a precision of < 5% relative standard deviation at the 0.0060% formulated concentration level. The results of this chromatographic procedure also correlate with those from a colorimetric analysis.
High Pressure Liquid Chromatographic Determination of Naphthaleneacetic Acid Residues in Apples
Authors: Cochrane William P , Lanouette Monique
Published: February 2020

An ion-suppression reverse phase high pressure liquid chromatographic method is described for determining naphthaleneacetic acid (NAA) residues in apples. Samples are extracted with acidic chloroform, filtered through pre-acidified Hy-Flo Supercel, and cleaned up by acid-base partitioning. The extract can be successfully chromatographed on either a μLiChrosorb NH2 or μBondapak C18 column and quantitated by using a variable wavelength ultraviolet detector set at 220 mn, The mobile phase is acetonitrile-water (20+80) buffered to pH 3.5 (μLiChrosorb column) or pH 5.2 (μBondapak column) and flowing at 1.0—2.0 ml/min. Recoveries ranged from 86 to 98%. The minimum detectable amount was 0.5 ng, which easily permitted the quantitation of 0.01 ppm NAA in 50 g sample. A fluorometric detector was 4 times as sensitive, using an excitation wavelength of 220 mm and monitoring the emission at 340 nm. For this detector, the minimum detectable amount was 0.12 ng NAA.
High Pressure Liquid Chromatographic Determination of Ethion in Formulations: Collaborative Study
Authors: Launer James E
Published: February 2020

A simple and rapid high pressure liquid chromatographic (HPLC) method is described for determining ethion (O,O,O',0'-tetraethyl-S,S'-methylene bisphosphorodithioate) in formulations, using reverse phase columns of either μBondapak C18/Porasil or ODS Permaphase. The sample is dissolved in either methanol for μBondapak C18 or acetonitrile for ODS Permaphase; pentachloronitrobenzene is used as an internal standard. After inert materials are removed, the supernate is injected onto the HPLC column and the compound is quantitated by peak height ratios at 254 nm. Six collaborators made single determinations of 8 samples. The average coefficients of variation were 0.76% for the 2 technical samples, 0.63% for the two 50% formulations, 0.95% for the two 25% wettable powders, and 0.76% for the two 2% oil formulations. The method was adopted as official first action.
Analysis of Fat-Soluble Vitamins. XXI. High Pressure Liquid Chromatographic Assay Methods for Vitamin D in Vitamin D Concentrates1
Authors: De Vries Ellen J , Zeeman Jakob , Esser Robert J E , Borsje Ben , Mulder Frits J
Published: February 2020

Two high pressure liquid chromatographic methods, a straight and a reverse phase system, were developed and compared with the official (chemical) AOAC method for vitamin D concentrates. The effects of the systematic error and the reproducibility of using an internal or external standard were studied, as well as the effect of using peak height or peak height × retention time for calculating the potential vitamin D content. A method is given for determining the conversion factor to calculate previtamin D as vitamin D. Based on the results of the comparison, the following conditions were selected for collaborative study: straight phase, amyl alcohol-hexane mobile phase, external standard, and calculation of potency by peak height.
Automated Analysis of High Levels of Nitrogen in Liquid Fertilizers
Authors: Barbera Andrea , Bottacin Emilio , Bovolenta Luigi
Published: February 2020

A thermometric analyzer was evaluated for analysis of individual samples and for continuous monitoring of high levels of ammonia nitrogen and urea nitrogen in the production of concentrated liquid fertilizers. Levels of nitrogen determined were 7—8% ammonia nitrogen and 14—16% urea nitrogen. All coefficients of variation were <0.5%.
High Pressure Liquid Chromatographic Detection and Estimation of Furazolidone and Nitrofurazone in Animal Feeds
Authors: Cieri Ugo R
Published: February 2020

The feed sample is extracted with acetone or dimethylformamide-acetone (1 + 1) and the filtered extracts are evaporated to dryness. The residue is dissolved in chloroform and transferred to a silica gel column. The nitrofurans are eluted with methanol-chloroform (50+50). A portion of the eluate is evaporated to dryness and the residue is redissolved in a small volume of methanol. Aliquots of the methanolic solution are injected into a liquid chromatograph with a μBondapak C18 column, using 30% acetonitrile as the eluting solvent and ultraviolet detection at 365 nm. Several samples spiked with 0.5—50 ppm furazolidone or nitrofurazone and 2 commercial samples were analyzed by the proposed method.
Gas-Liquid Chromatographic Test for Honey Adulteration by High Fructose Corn Sirup
Authors: Doner Landis W , White Jonathan W , Phillips John G
Published: February 2020

A gas-liquid chromatographic (GLC) method has been developed to detect the addition to honey of high fructose corn sirup (HFCS). Samples are derivatized directly with trimethylsilane, cholestane is added as an internal standard, and the levels of maltose (includes other minor disaccharides) and isomaltose are determined after chromatography on OV-17. Domestic and imported honey samples (115) contained 2.00% maltose and 0.71% isomaltose. HFCS samples (21) contained 1.50% maltose, and 2.09% isomaltose. A discriminatory equation was developed (D = 2.73 — 5.35 (isomaltose/maltose)) and, when applied to the data for these samples and 37 adulterated samples, 81.4% of authentic honey samples and 78.4% of samples known to be adulterated with HFCS were correctly classified.
Rapid Chemical Confirmation Method for Aflatoxins B1 and G1 by Direct Acetylation on a Thin Layer Plate Before Chromatography
Authors: Cauderay Philippe
Published: February 2020

A method of acetylation of aflatoxins Bx and G1 before thin layer chromatographic (TLC) identification is described. Extracts containing anatoxin B1 and/or G1 are spotted on a silica gel TLC plate and overspotted with acetic anhydride and HCL. After reaction, the plate is developed and the Rf values of reacted anatoxin B1 and/or G1 are compared with those of authentic standards treated similarly.
Thin Layer Chromatographic Determination of Citrinin
Authors: Stubblefield Robert D
Published: February 2020

Clearly defined zones of citrinin can be obtained on thin layer chromatographic (TLC) plates and measured by fluorodensitometry. Silica gel plates were prepared as a slurry with aqueous 0.05M Na2EDTA (ethylenediaminetetraacetic acid), spread at 0.5 mm wet thickness, and activated at 105°C for 1 hr. Plates were developed in acetic acid-benzene (5+95). The limit of detection was 10 ng citrinin/zone. Densitometric analysis (365 nm excitation, 505 nm emission) revealed that a linear relationship exists for levels of 10 ng to at least 100 ng/zone wtih a coefficient of variation of ±5%.
Colorimetric Determination of Dillapiole in Wheat
Authors: Handa Swadesh K
Published: February 2020

A rapid colorimetric method has been developed for determining residues of dillapiole (3,4-methylenedioxy-5,6-dimethoxy allyl benzene) in wheat grain. Dillapiole is reacted with sulfuric acid to liberate formaldehyde which reacts with chromotropic acid to yield a pink compound with maximum absorbance at 575 nm. The method can detect 1—15 μg residue /ml.
Characterization of a Plant Constituent Interfering in the Analysis of Residues of 2,3-Dihydro-2,2-Dimethyl-3,7-Benzofurandiol, a Metabolite of Carbofuran
Authors: Holmstead Roy L , Allsup Thurman L , Fullmer Oliver H
Published: February 2020

A plant breakdown product interfering with the analysis of 2,3-dihydro-2,2-dimethy1-3,7-benzofurandiol, a major metabolite of carbofuran, is a vanillin derivative and is identified as α - (4 - hydroxy - 3 - methoxyphenyl) - ethanol (methyl-guaiacyl-carbinol). Procedures for the resolution of the interference are reported.
Pyrolytic Method for Estimation of Bound Residues of Chloroaniline Compounds in Plants
Authors: Balba Hamdy M , Still Gerald G , Mansager Eugene R
Published: February 2020

With one exception, pyrolysis in the absence of oxygen of different forms of bound [14C]-chloroaniline residues released more than 80% of the radioactivity as volatile products. Gas chromatography-mass spectrometry of the pyrolysates indicated that the major radioactive products were the chloroaniline compounds. The pyrolysates were collected, purified, and derivatized to the corresponding trifluoroacetanilides and these derivatives were analyzed by electron capture gas chromatography. Materials used as bound residues were model synthetic lignin - [14C] - chloroaniline polymers, bound residue fractions, and lignin fractions isolated from the roots of rice plants treated hydroponically with [14C]-3-chloroaniline or [14C]-3,4-dichloroaniline.
Gas-Liquid Chromatographic-Mass Fragmentographic Determination of Low Levels of Diethylcarbonate in Beverages
Authors: Lierop Ben H Van , Nootenboom Hans
Published: February 2020

Sodium chloride and ethanol (omitted for samples with >10% alcohol) are added to the beverage sample and the sample is allowed to equilibrate in a 30°C water bath. An aliquot of the headspace is injected into a gas chromatograph containing a column packed with 0.2% Carbowax 1500 on 80—100 mesh Carbopack C. During the elution of diethylcarbonate (DEC), an impurity that is present in diethylpyrocarbonate, the column effluent is vented to a mass spectrometer with a multiple ion detection system and operated in the electron impact mode. The ions at m/e 63 and 91 are monitored. Lemonade, fruit drinks, wine, and beer samples (138 total) were analyzed for DEC. Sixteen samples had >30 ppb DEC. Eight analyses of a lemonade sample gave a mean of 88 ppb with a coefficient of variation of 11 % .
Determination of Lonomycin by Reaction with Vanillin
Authors: Brown Robert L
Published: February 2020

A rapid, relatively sensitive test using the vanillin reaction is described for lonomycin, a polyether antibiotic. The method can be used with powders, fermentation broths, and samples from intermediate isolation steps. The limit of detection of the test is 10 μg/g for powders and 50 μg/g for fermentation broths, although the latter level is dependent on the volume of material extracted.
Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Pressure Liquid Chromatographic Determination of Retinyl Palmitate and β-Carotene in Oil and Margarine
Authors: Landen William O , Eitenmiller Ronald R
Published: February 2020

A high pressure liquid chromatographic method was developed using high pressure gel permeation chromatography (HP-GPC) and high pressure reverse phase chromatography (RP-HPLC) for quantitation of retinyl palmitate and β-carotene. HP-GPC was used for fractionation of vitamin A active compounds from oil preliminary to quantitation on nonaqueous RP-HPLC. HP-GPC fractionation was completed on oil and margarine dissolved in methylene chloride by 2 elution passes through 2 μStyragel (100Å) columns connected in series with methylene chloride as the mobile phase. RPHPLC separation of retinyl palmitate and β-carotene was achieved on μBondapak C18 (10 μm), using methylene chloride-acetonitrile ( 3 0 + 7 0 ) . Based on 10 repetitive analyses, recoveries of added β-carotene and retinyl palmitate from vegetable oils were 98.6±2.9 and 95.2±2.6%, respectively. The coefficients of variation were 2.9% for β-carotene and 2.7% for retinyl palmitate. The determination of vitamin A activity in 7 margarine brands with label claims of 10% U.S.RDA/serving revealed that all but one of the margarines contained at least 94% of the label claim. Vitamin A activity in the margarines ranged from 90.6 to 110.8% of the label declaration.
Determination of Crude Protein in Animal Feeds, Using Block Digestion Followed by Steam Distillation: Collaborative Study
Authors: Noel Rodney J
Published: February 2020

A method consisting of digesting animal feeds in a block digestor and determining ammonia by steam distillation followed by titration has been evaluated and compared with the official final action Kjeldahl method, 7.016. Fifteen laboratories analyzed 5 feed samples and lysine monohydrochloride. Statistical analysis showed that results from the 2 methods were comparable. The distillation technique has been adopted as official first action as an alternative technique for ammonia determination from the digest of the official final action block digestor method, 7.B11.
Laser Fluorometric Determination of Aflatoxin B1 in Corn
Authors: Diebold Gerald J , Karny Noga , Zare Richard N , Seitz Larry M
Published: February 2020

A 2-step chromatographic separation, using both thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC), in conjunction with the high sensitivity of laser fluorometry permits extension of the detection limits of aflatoxin contamination in corn to 0.1 ppb (μg/kg) with a 26% root mean square variation. Aflatoxin B1 is extracted from corn with water-methanol and cleaned up by TLC. The recovery of aflatoxin from the TLC plates was linear from 10 to 1000 pg. Aflatoxin B1 is converted to the more highly fluorescent B2A derivative by treatment with 1N HC1. Experiments with aflatoxin B1 standards establish a constant conversion to B2A over approximately 3 orders of magnitude in B1 concentration. An extract of the B2A aflatoxin derivative is injected onto a reverse phase HPLC column. A flowing droplet of eluant is irradiated by an amplitude-modulated 325 nm He-Cd ion laser beam, and fluorescence from the droplet is detected by a lock-in amplifier in phase with the laser modulation. Several chromatograms are presented that demonstrate the capability of this procedure for removing interfering components in the corn extract.
Colorimetric Determination of Boric Acid in Prawns, Shrimp, and Salted Jelly Fish by Chelate Extraction with 2-Ethyl-l,3-Hexanediol
Authors: Ogawa Shunjiro , Toyoda Masatake , Tonogai Yasuhide , Ito Yoshio , Iwaida Masahiro
Published: February 2020

Borate was directly chelate-extracted from foods with 5% 2-ethyl-l,3-hexanediol (EHD) in n-hexane–n-butyl acetate mixture (8+2), from which borate was selectively transferred into 1% NaOH, since EHD-chelated boron did not react with curcumin to develop color. Finally, an aliquot of the alkaline solution was acidified with HC1 and reacted with curcumin in a rotary evaporator. Color development was increased by heating for 8 min at 80°C under reduced pressure of 16 mm Hg. Frozen shrimp and prawns (peeled and with shells) and salted jelly fish were analyzed by the proposed method. Results were compared with the contemporary official method of Japan based on curcumin reaction on an incinerated sample. Over 90% of the boric acid was recovered by the proposed method when samples were fortified with 20 ppm boric acid. Recoveries were superior to those of the official method especially for shrimp and prawns with shells and salted jelly fish. Detection limit of boric acid is 1 ppm. Moreover, the method requires only about 1 hr for analysis of one sample, making it suitable for routine analysis.
Determination of Amprolium in Feeds: Collaborative Study
Authors: Davis E Jack
Published: February 2020

The official final action method, 42.028-42.032, for determining amprolium in feeds was modified by a change in the preparation of aluminum oxide for chromatography. A premix containing 0.5% amprolium was collaboratively studied by the modified and the official methods. Compared with the modified method, 87.7% of the drug was recovered from the premix by using the official method. The modification makes possible the assay of premixes as well as finished feeds. The official final action method has been modified to incorporate this change.
Identification of Species in Cooked Crabmeat by Thin Layer Isoelectric Focusing
Authors: Krzynowek Judith , Wiggin Kate
Published: February 2020

Thin layer polyacrylamide gel isoelectric focusing (TLIEF) is described for characterizing the species-specific, heat-denatured proteins of 8 species of crab: red (Geryon quinquedens), rock (Cancer irroratus), Jonah (Cancer borealis), blue (Callinectes sapidus), king (Paralithodes camtschatica), snow (Chionoectes spp.), European edible (Cancer pagurus), and dungeness (Cancer magister). Protein pattern differences are shown not only among species, but also between 2 modes of heat processing of the crabmeat. Individual variation within the species as to sex, size, and maturity, length of frozen storage, and body parts chosen for sampling do not alter the species banding pattern. The reproducible species-specific fingerprint obviates the need to analyze authenticated samples simultaneously with the unknown crabmeat.
Determination of Proof of Distilled Alcoholic Beverages, Using an Oscillating U-Tube Density Meter
Authors: Strunk Duane H , Hamman Jack W , Timmel Bertha M
Published: February 2020

A simple, rapid, and accurate method is described for determining the concentration of alcohol in ethanol solutions using a density meter. With this instrument, the U-tube is suctionfilled with 0.7 mL sample, and the results are displayed on a digital read-out in specific gravity units. These values are converted by tables to per cent ethanol or proof. For samples under 40° proof, the instrument is standardized on air and water. When testing samples between 40 and 193° proof, the instrument is standardized on air and an ethanol standard having a proof within ±30° of the sample tested. Thus, large corrections for the nonlinearity of the plot of the specific gravity of ethanol vs. proof are avoided. An equation is presented that corrects for this non-linearity, and the result is obtained in per cent ethanol rather than specific gravity. Proof results obtained with this instrument are in good agreement with the values obtained by a pycnometer and/or refractometer for 1–190° proof ethanol-water solutions, vodkas, whiskeys, brandies, and liqueurs.
Development of Culture Vessel for Sterility Testing of Bandages and Other Medical Devices
Authors: Quagliaro Daniel A , Spite George T , Guilfoyle Dennis E , Mestrandrea Leonard W , Stiesi Walter E
Published: February 2020

A cylindrical glass culture vessel equipped with a vented nylon closure was developed and evaluated for sterility testing. The sterility testing cylinder (STC), made in 2 sizes, accommodates 250 or 400 mL culture broth. A tightfitting, skirted nylon cap protects the upper part of the cylinder, and a membrane filter in a recessed opening allows venting during autoclaving and ensures sterility during removal and replacement of the cap. The configuration of the vessel in terms of the opening size and ratio of the horizontal to vertical cross section provides depths desirable for testing many shapes of medical devices, including elongated and narrow ones, without excessive waste of medium. They are easy to charge with medium, and to autoclave, store, inoculate, and observe for growth.
Spectrophotometric Determination of Caffeine in Coffee Products: Collaborative Study
Authors: Newton John M
Published: February 2020

An ultraviolet (UV) spectrophotometric method for determining caffeine in regular and decaffeinated coffee products has been studied collaboratively. Nine laboratories participated in this study which compares the proposed UV method with the official AOAC micro Bailey-Andrew method. Caffeine content was determined on as-is basis on 8 samples of green, roasted, and soluble coffees. The coefficients of variation for the proposed method ranged from 2.02 to 6.98% for the 8 samples studied. The results agreed well with those from the Bailey-Andrew method. The method was adopted as official first action.
IUPAC Gas Chromatographic Method for Determination of Fatty Acid Composition: Collaborative Study
Authors: Firestone David , Horwitz William
Published: February 2020

An international collaborative study of IUPAC methods II.D.19 and II.D.25 for preparation and GLC analysis of fatty acid methyl esters was begun in 1976. The IUPAC methodology, applicable to animal and vegetable oils and fats and fatty acids from all sources, contains special instructions for preparation and analysis of methyl esters of fatty acids containing 4 or more carbon atoms (analysis of milk fat). Twenty-three collaborators participated in the analysis of 5 known mixtures, 4 vegetable oils, 1 fish oil, and 2 butterfats. Several blind duplicate samples were included. The experimental data were subjected to statistical analysis to examine intra- and interlaboratory variation. Reproducibility and accuracy data for the higher fatty acid (14:0–22:1) mixtures and fish and vegetable oils were satisfactory and were in good agreement with results from an AOCS Smalley Committee check sample program involving analysis of the same samples. Typical coefficients of variation (%) at various concentrations were 15 (2% level), 8.5 (5% level), 7 (10% level), and 3 (50% level). Low recoveries and poor reproducibility were characteristic of results obtained for butyric acid in the butterfat and related known mixtures. A coefficient of variation of about 19% was found for analysis of butyric acid in butterfat, vs. coefficients of variation in the range of 4–13% for similar levels of other components in butterfat and other samples. The IUPAC methodology for GLC analysis .of fats and oils other than milk fats has been adopted by the AOAC as official first action to replace the current GLC method, 28.063-28.067.
Identification of Some Benzodiazepines of Forensic Interest
Authors: Noggle F Taylor , Clark C Randall
Published: February 2020

Ten benzodiazepines–clorazepate, nitrazepam, clonazepam, oxazepam, lorazepam, chlordiazepoxide, N-desmethyldiazepam, diazepam, prazepam, and flurazepam–in solid dosage form are identified by ultraviolet (UY) and infrared (IR) spectrophotometry and by high pressure liquid chromatography (HPLC). UV absorption data and IR spectra of the 10 benzodiazepines are provided and HPLC separation methods are described.
Charcoal Column/Thin Layer Chromatographic Method for High Fructose Corn Sirup and Spectrophotometric Method for Hydroxymethylfurfural in Honey: Collaborative Studies
Authors: White Jonathan W , Kushnir Irene , Doner Landis W
Published: February 2020

A new spectrophotometric method is described for determining hydroxymethylfurfural in honey in which interfering background absorption of honey is corrected for by use of a bisulfite-treated sample as blank. Two procedures for detecting high-fructose corn sirup (HFCS) in honey were also tested. In one, charcoal column pretreatment is used to concentrate trace oligosaccharides, followed by thin layer chromatography to differentiate those of HFCS from those of honey. The other method depends on measurement of the isomaltose/maltose ratio by gas-liquid chromatography. The charcoal/thin layer chromatographic method for HFCS has been adopted official first action. The bisulfite method for hydroxymethylfurfural has been adopted interim first action.
Some Principles of Microbiological Turbidimetric Assays of Antibiotics
Authors: Rippere Robert A
Published: February 2020

Turbidimetric methods for determining the potency of antibiotics are inherently more accurate and more precise than are comparable agar diffusion procedures, but assays conducted in liquid media are subject to degradation from less than ideal conditions to a much greater extent than are diffusion methods. The relationships between test organisms, antibiotics, and assay concentrations are discussed. A valid assay procedure must produce a linear response with an adequate slope (–0.4 to –1.2) by the test organism to increasing concentrations of drug; such linear response normally occurs over a limited range of concentrations. Criteria used to select photometers that offer the greatest advantages to analytical microbiologists are described, with guidelines for the most effective use of the chosen instrument.
Aflatoxigenic Potential of Dried Figs, Apricots, Pineapples, and Raisins
Authors: Morton S Glenn , Eadie Thomas , Llewellyn Gerald C
Published: February 2020

Spores from 3 aflatoxigenic strains were applied to the surface of dried figs, pineapple slices, apricots, and raisins. Half of the samples of each foodstuff was autoclaved (cooked) before inoculation. All 3 strains produced some toxin but not in all of the foodstuffs. No aflatoxins were found in any of the raisin cultures. The overall potential for toxin production in the dried fruit was apricot < fig < pineapple < raisin. Among the cooked substrates, the order was apricot < pineapple < fig = raisin. For the raw dried fruits, the ranking was fig < pineapple < apricot < raisin. Pineapple was considered the best broad spectrum substrate of the foodstuffs evaluated in the study.
Analysis of Foods for Iodine: Interlaboratory Study
Authors: Heckman Mary M
Published: February 2020

An accurate, reproducible method for ≤1 ppm iodine in foods is required for nutritional labeling. In order to ascertain the current status of iodine analysis in foods, 7 samples, representing different food classes, were analyzed by 8 laboratories. Six laboratories used their modifications of the Ce-As-I catalytic method preceded by alkaline dry ashing. Two laboratories used neutron activation analysis (NAA), with differing radiochemical separations. The study showed wide discrepancy in analytical results. Mean relative standard deviation for all laboratories was 77.9% between laboratories; 19.1% within-laboratories. Laboratories using NAA had only slightly better precision than did laboratories using the chemical method. The lowest level reported on the entire group of samples ranged among laboratories from 0.0089 to 0.65 ppm. Figures reported by a laboratory are, in general, consistently high or consistently low. The only differences in methodology which may possibly correlate with level of iodine obtained are the use of NAA technique and use of manual, rather than automated, colorimetry.
Reverse Phase Ion Pair High Pressure Liquid Chromatographic Determination of Ethylenediaminetetraacetic Acid in Crabmeat and Mayonnaise
Authors: Perfetti Gracia A , Warner Charles R
Published: February 2020

A method is described for the determination of ethylenediaminetetraacetic acid (EDTA) in crabmeat and mayonnaise. EDTA is extracted from the food sample with water and converted to its copper chelate, which is then quantitated by reverse phase ion pair high pressure liquid chromatography with ultraviolet detection. Maximum sensitivity is obtained with detection at about 254 nm; higher wavelengths may be used for enhanced specificity. Cleanup procedures for crabmeat and mayonnaise were improved by using a radiotracer method. Analyses of crabmeat and mayonnaise samples spiked at 3 different levels showed >90% recovery of EDTA.
Identification of Analogs of the Hallucinogen Cyclohexamine
Authors: Bailey Keith , Legault Donald
Published: February 2020

The hallucinogenic drug 1-phenylcyclohexylamine and its N-methyl-, N-ethyl-, N-propyl-, Nisopropyl-, and N-(β-phenylethyl)-derivatives are identified by spectroscopic techniques. Reference mass and infrared spectra and gas-liquid and thin layer chromatographic data are provided and discussed.
Gas-Liquid Chromatographic Determination of Bayer 73 in Fish, Aquatic Invertebrates, Mud, and Water
Authors: Luhning Charles W , Harman Paul D , Sills Joe B , Dawson Verdel K , Allen John L
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for determining residues of Bayer 73 (2-aminoethanol salt of 2’,5-dichloro-4’-nitrosalicylanilide) in fish muscle, aquatic invertebrates, mud, and water by analyzing for 2-chloro-4-nitroaniline (CNA), a hydrolysis product of Bayer 73. Bayer 73 residues are extracted from fish muscle tissue, invertebrates, and mud with acetone-formic acid (98+2), and partitioned from water samples with chloroform. After sample cleanup by solvent and acid-base partitioning, the concentrated extract is hydrolyzed with 2N NaOH and H2O2 for 10 min at 95°C. The CNA is then partitioned into hexane-ethyl ether (7+3) and determined by electron capture GLC. Average recoveries were 88% for fish, 82% for invertebrates, 82% for mud, and 98% for water at 3 or more fortification levels.
Gas-Liquid Chromatographic Determination of Thiourea in Citrus Peels
Authors: Toyoda Masatake , Ogawa Shunjiro , Ito Yoshio , Iwaida Masahiro
Published: February 2020

A gas-liquid chromatographic (GLC) method was developed for the detection and determination of thiourea in citrus peels. After the peel is extracted with ethyl ether, the ether extract is adsorbed on sodium sulfate together with water. Thiourea is recovered from both the sodium sulfate and the peel residue with ethyl acetateacetone( 2+l). The extracted mixture is cleaned on an alumina column, the eluate is concentrated under vacuum, and thiourea is extracted from the concentrate with sodium carbonate solution. GLC was carried out on the prepared benzoyl derivative of thiourea. The average recoveries of thiourea from lemon peel were 85.3, 93.1, and 97.6% at the fortification levels of 1, 10, and 100 ppm, respectively. The detection limit was as low as 0.08 ppm.