bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Cleanup Technique for Estimation of Endosulfan Residues from Fish Tissues under Tropical Conditions
Authors: Rao Desiraju M R
Published: February 2020

A new solvent system, 1% and 2% acetone in hexane,was developed for chromatography on partially inactivatedFlorisil to facilitate the separation of isomersof endosulfan and its metabolites from fishtissues under tropical conditions. By using the colorimetricmethod of Maitlen et al. (1963), the minimumdetectable limit for each isomer of endosulfanin various fish tissues is 5 µg. With this solventsystem, the 2 isomers present in the technical materialcan be separated, so their toxicity to fish can be assessedseparately.
Spectrophotometric Determination of Chloramphenicol and Its Esters in Complex Drug Mixtures
Authors: Devani Muljibhai B , Shishoo Chamanlal J , Doshi Kokila J , Shah Ashok K
Published: February 2020

When aromatic nitro compounds are reduced with zinc and calcium chloride and reacted with trisodium pentacyanoaminoferrate they give a purple product having an absorbance maximum between 480 and 540nm. Applying this reaction, a quantitative method has been developed for the determination of chloramphenicol and its esters. Various reaction conditions have been standardized. Beer’s law is obeyed in the concentration range of 4 to 32 μg/mL reaction mixture. Average recoveries and standard deviations were 99.78 ± 0.627 and 99.90 ± 0.660; 101.06 ± 0.702; and 99.90 ± 0.880% for chloramphenicol, chloramphenicol sodium succinate, and chloramphenicol palmitate, respectively. The method has also been applied to determine chloramphenicol and its esters as well as chloramphenical in the presence of combination drugs in dosage forms. The presence of benzocaine, lignocaine, sulfadiazine, nitrofurantoin, ascorbic acid, hydrocortisone, prednisolone, streptomycin, and tetracycline does not interfere with the proposed spectrophotometric procedure. The method does not require prior separation of chloramphenicol from combination drugs.
Gas Chromatographic Determination of Cadaverine, Putrescine, and Histamine in Foods
Authors: Staruszkiewicz Walter F , Bond John F
Published: February 2020

A GLC procedure for the quantitative determination of the diamines putrescine and cadaverine has been developed, using their perfluoropropionyl derivatives. The amines were extracted from foods with methanol; an internal standard, hexanediamine, was added and a dry residue of their hydrochloride salts was prepared. The salts were derivatized with perfluoropropionic anhydride by heating for 30 min at 50°C. The reaction mixture was separated on an alumina column to remove excess reagent, and the derivatives were eluted with a solution of 30% ethyl acetate in toluene. GLC separations were performed on a 3% OV-225 column held at 180°C. The retention times were 4.3,5.7, and 7.0 min for the derivatives for putrescine, cadaverine, and the internal standard, respectively. Less than 1 μg diamine/g tissue could be quantitated, using either an electron capture detector or a nitrogen-specific detector. The procedure was applied to cheese and a variety of fishery products. An increase in the diamines correlated with the presence of decomposition in some of the products. A collaborative study of the method is planned.
Manual and Semiautomated Spectrophotometric Determination of Vitamin K3 by Reactions with Piperidine and Malononitrile
Authors: Hassan Saad S M
Published: February 2020

Simple, rapid, selective, and sensitive spectrophotometric methods are described for manual and semiautomated determination of vitamin K3. These methods are based on reactions with piperidine and malononitrile whereby intense red and blue colors with maximum absorption at 510 nm (E1%1cm 150) and 580 nm (E1%1cm 155), respectively, are developed. The reactions are sensitive enough to permit the determination of 2-100 μg vitamin K3/mL with an average recovery of 98% and a standard deviation of 1%. There is no interference from vitamins K1 and K2, and the reduced forms of K vitamins, or from many common pharmaceutical diluents and additives.
Fourth Interlaboratory Study of Methods for Determining Total Migration of Plastic Materials in Liquids Simulating Fatty Foodstuffs
Authors: Rossi Luigi
Published: February 2020

Results are reported for the fourth interlaboratory study organized by the Commission of the European Communities for the adoption of an official method for determining the total migration of plastic materials in liquids simulating fatty foodstuffs. In each method, a sample of plastic material was weighed before and after it was placed in contact with fatty simulants. The fat absorbed by the sample, extracted or dissolved by suitable solvents, was determined by gas chromatography or radiometry. The results obtained confirm the conclusions given previously. Each method was moderately satisfactory, but less so between laboratories.
Open Digestion Modification of AOAC Method for Determination of Mercury in Fish
Authors: Duve Ram N , Chandra Jeffery P , Singh Satend B
Published: February 2020

The vanadium pentoxide-catalyzed reflux method has been modified to allow open digestion of samples in preparation for determination of organic and inorganic mercury. The reflux digestion performed wilh a bunsen burner resulted in charred samples, but digestions performed in tubes in a 95-100°C water bath were satisfactory. As many as 40 digestions can be carried out simultaneously, and the technique offers a fast and simple approach to digestion, dilution, and transfer.
Modified Colorimetric Method for Determining Indole in Shrimp
Authors: Cheuk Wailun , Finne Gunnar
Published: February 2020

A modified spectrophotometry method for measuring indole in shrimp is described. The method was developed to eliminate the time-consuming steam distillation and expensive instrumentation required by the official AOAC methods. Indole is extracted with light petroleum from trichloroacetic acid-precipitated shrimp muscle. The extracted indole, soluble in light petroleum, is reacted and re-extracted with Ehrlich’s reagent; indole in the form of a rose indole complex can be determined spectrophotometrically. When shrimp at various degrees of decomposition were analyzed for indole by the modified method as well as by the official AOAC colorimetric method, the correlation coefficient between the data from the 2 methods was 0.98.
Gas-Liquid Chromatographic Determination of Terbuthylazine Technical and Its Formulations: Collaborative Study
Authors: Meier Juerg , Nowak Klaus , Suter Rolf , Tomann Andrea , Bosshardt Hans P ,   Collaborators:, Amadori A , Basters I J , Bátora V , Benoit A , Davies T , Demaurex A , Dobrat W , Gideon R P , Heegemann H , Henriet E , Hofberg A H , Laass H , Larsen M , Magallanes M , Martijn A , Müller W , Nabors J B , Nixon H , Paasivuo P , Pavel K , Povlsen H H , Reuthinger E , Rasero F Sanchez , Scheck L , Stettler J , Rossum A Van , Winsauer K
Published: February 2020

Terbuthylazine technical and its 80% wettable powder were analyzed in a CIPAC collaborative study. The content and the identity were determined by gas-liquid chromatography on a column of 3% Carbowax K20M on Gas-Chrom Q, using di-n-pentylphthalate as the internal standard. Results obtained from 27 government, university, and industrial collaborators showed within-laboratory repeatability of 1.3% for the technical and 1.0% for the wettable powder. Reproducibility was 2.1% for both samples. The method has been adopted official first action
Portable and Sensitive Detector Strips for Rapid Detection of Organophosphorus, Mercury, Copper, Cadmium, and Silver Compounds
Authors: Kumar Nanguneri V Nanda , Devi Yalavarthi Prameela
Published: February 2020

Portable and sensitive detector strips developed for rapid detection of organophosphorus, mercury, copper, cadmium, and silver compounds are inexpensive, indefinitely stable, and easy to use. The strips require mild moistening with distilled water and warming for the reaction involving cholinesterase and succinate dehydrogenase inhibition by organophosphorus and heavy metal compounds, respectively. The detector strips, designated A, B, and C, can be combined to detect heavy metals and organophosphates as their oxygen analogs at nanogram concentrations in 5-10 min with little cleanup, so the strips can be used under field conditions
High Pressure Liquid Chromatographic Determination of Sulfisoxazole in Pharmaceuticals and Separation Patterns of Other Sulfonamides
Authors: Roos Robert W
Published: February 2020

A high pressure liquid chromatographic method has been developed for the identification and determination of sulf isoxazole in tablet, liquid, and ointment dosage forms. The method specifies a µBondapak C18 column, an acetonitrile-acetic acid-water (22.5 + 1 + 76.5) mobile phase, and ultraviolet detection at 254 nm. For quantitative purposes, sulfabenzamide is used as an internal standard. Commercial preparations were analyzed by the proposed method and results were compared with those obtained by the U.S. Pharmacopeia XIX and National Formulary XIV methods; good agreement was obtained. The elution behaviors of 19 additional sulfonamides were also established to verify the specificity of the proposed method for sulfisoxazole. These elutions patterns show potential for separation and identification of all 20 sulfonamides
High Performance Liquid Chromatographic Analysis of Hydrocortisone Acetate Ointments: Interlaboratory Study
Authors: Hailey David M , Lea Anthony R
Published: February 2020

An interlaboratory study was carried out on a high performance liquid chromatographic method for determining hydrocortisone acetate in ointments. The method represents an alternative to the colorimetric procedure of the British Pharmacopoeia. Two samples of a commercially available hydrocortisone acetate ointment were analyzed by 14 laboratories. Column performance and precision of the assay were satisfactory. The total error standard deviation for the method was 3.69%.
Rapid Method for Estimation of N-Nitrosodimethylamine in Malt Beverages
Authors: Hotchkiss Joseph H , Havery Donald C , Fazio Thomas
Published: February 2020

A new, rapid column elution method is described for the estimation of N-nitrosodimethylamine in malt beverages. Recoveries for N-nitrosodimethylamine and N-nitrosodipropylamine fortified at 5 ppb averaged 90 and 91%, respectively. A study of 20 different malt beverages showed that the resuts obtained with this method compared favorably with those obtained by a direct distillation procedure.
High Performance Liquid Chromatographic Preparation of Alternariol, Alternariol Methyl Ether, and Altenuene
Authors: Chu Fun S , Bennett S Christopher
Published: February 2020

A solvent system was developed for the isolation of 3 major Alternaria mycotoxins by high performance liquid chromatography (HPLC). Alternariol (AOH), alternariol methyl ether (AME), and altenuene (ALT) were purified using either a semipreparative or a preparative HPLC column. Gram quantities of pure mycotoxins were obtained in a single preparative HPLC step. Distribution of other individual mycotoxins and metabolites in various fractions obtained from either chromatographic procedure is discussed.
Potential Mold Growth, Aflatoxin Production, and Antimycotic Activity of Selected Natural Spices and Herbs
Authors: Llewellyn Gerald C , Burkett Mary Lee , Eadie Thomas
Published: February 2020

Ground spices and herbs are evaluated as substrates for mycelial growth, sporulation, and aflatoxin production. Three toxigenic strains of Aspergilli, A. flavus ATCC 15548, A. flavus NRRL 3251, and A. parasiticus NRRL 2999, were cultured on moist, commercially packaged herbs and spices. All substrates used were ground and included thyme, celery seed, oregano, cinnamon, ginger, caraway seed, clove, mustard, sesame seed, and rosemary leaves. Following inoculation of the natural materials in sterile bottles containing sterile water, the cultures were incubated 30 days at 23 ± 4°C. Not all strains of Aspergilli grew, sporulated, or produced toxins. There were definite strain differences and definite substrate differences for the variables evaluated. Sesame seed produced toxins B1, G1, and G2, with a mean of 167 ppm for 3 strains. A. flavus ATCC 15548 was the greatest overall toxin producer followed by A. partsiticus NRRL 2999 and A. flavus NRRL 3251. Ginger and rosemary leaves were also substantial producer-substrates. Mustard, caraway seed, and celery seed were judged as intermediate-producing substrates. Absolute antimycotic substrates were cinnamon and clove. Antiaflatoxigenic substrates were thyme and oregano. Mustard also may be antimycotic. Aflatoxins B1 and G1 were the more commonly found toxins
Gas Chromatographic Determination of Trialkyl/Aryl Phosphates in Drinking Water, Following Isolation Using Macroreticular Resin
Authors: Lebel Guy L , Williams David T , Benoit Frank M
Published: February 2020

An XAD-2 screening method developed previously fororganophosphorus pesticides has been extended to determine trialkyl/aryl phosphates in drinking water at the ng/L level. Recovery studies at 1,10, and 100 ng/L levels were carried out by fortification onto XAD-2 resin and by direct on-stream fortification of drinking water. Recoveries were >70% for tri-nbutyl, tris(2-chloroethyl), tri(2-ethylhexyl), tributoxyethyl, triphenyl, and tricresyl phosphate. Triethyl phosphate recoveries were about 25%. Analysis of drinking water samples collected at 6 eastern Ontario water treatment plants revealed the presence of several trialkyl/aryl phosphates at levels ranging from 0.2 to 75 mg/L.
Ultra Trace Determination of Furazolidone in Turkey Tissues by Liquid Partitioning and High Performance Liquid Chromatography
Authors: Winterlin Wray , Hall Gregory , Mourer Charles
Published: February 2020

A simple and sensiiive procedure is presented for the I determination of furazolidone in turkey tissues, j using liquid partitioning followed by high performance liquid chromatography (HPLC). Fat, liver, kidney, skin, and muscle tissues are ground with methylene chloride in a Polytron homogenizer, followed by solvent removal, partitioning in hexane-0.01M acetic acid, and back-partitioning the 0.01M acetic acid with methylene chloride. The determination by HPLC used a reverse phase Ultrasphere- ODS 5 μm column. The method is sensitive to 0.5 ppb, with a standard deviation of 6.39% at the 2 ppb fortification level. Recovery from fortified tissues j averaged 84% from samples fortified with 0.5-10 ppb furazolidone. An alternative cleanup procedure I using a Sep-Pak C18 cartridge is also presented.
Automated Determination of Urea and Ammoniacal Nitrogen (NPN) in Animal Feeds
Authors: Wall Larry L , Gehrke Charles W
Published: February 2020

A minor modification in the automated analytical system of the official AOAC semiautomated method for determining crude protein results in an automated method for determining urea and ammoniacal nitrogen in animal feeds and their ingredients. Urease enzyme which has high activity, yields a clear solution in water, has low ammonia impurity, and is inexpensive is used in the automated method. Weights from 1 to 2.5 g feed sample are dissolved in water, and sample solutions are analyzed at the rate of 40 samples/ h. Five AAFCO feed check samples were analyzed repeatedly by the automated method, and results were compared with the grand averages from the check sample reports. The official AOAC manual urease method was used by AAFCO participants. Average recovery of urea and ammoniacal nitrogen was 100.6% by the automated method relative to the AAFCO reported averages. The range of recoveries was 98.5-102.7%. The non-protein nitrogen (NPN) concentrations, expressed as protein equivalent, ranged from 3.40 to 63.04% protein on these samples. The average relative standard deviation for the automated analyses was 0.77%, compared with 1.54% for the manual method. This method is an important adjunct to laboratories using or considering use of the semiautomated method for crude protein and needing further information on NPN.
Ammonia-Selective Electrode Determination of Nitrogen in Fertilizers
Authors: Boy Victor M , Guijosa Manuel
Published: February 2020

The official AOAC magnesium oxide method (MOM), 2.065, for determining ammoniacal nitrogen in fertilizers not containing urea was compared with an alternative ammonia-selective electrode method (ASEM-1). Likewise, the official AOAC Raney powder method (RPM), 2.063-2.064, for determining total nitrogen in fertilizers, except nitric phosphates containing nonsulfate S, was compared with an ammonia- selective electrode method (ASEM-2). Each comparison included 6 samples. For ammoniacal nitrogen determination, MOM and ASEM-1 showed equivalent precision, although significant statistical differences were obtained in average values for the majority of samples. For total nitrogen determination, RPM and ASEM-2 showed equivalent precision, although significant statistical differences were obtained in 3 samples. The AOAC official methods showed better accuracy than ASEM-1 and ASEM-2. However, the accuracy and precision of ASEM-1 for ammoniacal nitrogen is suitable for routine work.
Headspace Sampling and Gas Chromatographic Determination of Styrene Migration from Food-Contact Polystyrene Cups into Beverages and Food Simulants
Authors: Varner Sandra L , Breder Charles V
Published: February 2020

Migration studies using coffee, tea, water, and 8% ethanol were conducted with various types of foodcontact polystyrene cups. Study conditions simulated filling and storage at room temperature and hot-filling or pasteurization above 150°F (65.6°C). The quantity of styrene migrating was determined by headspace sampling and gas chromatography (GC). The GC column was 6% Carbowax 20M on Chromosorb 101 with quantitation via a flame ionization detector. Detection limits ranged from 3 to 10 ppb in various liquids. The method and results of the migration studies are presented.
Infrared Spectrophotometry Method for Methazole Formulations: Collaborative Study
Authors: Forrette John E ,   Collaborators:, Audino J B , Bennett B R , Boyd W G , Carlstrom A A , Clarke D , Cohen C J , Gale G T , Grorud R B , Looker J B , Rozek A L
Published: February 2020

An infrared method was developed for the analysis of Probe 75% wettable powder formulation for methazole content. The procedure involves an extraction of the powder by agitation with acetone. The suspension is centrifuged, and the clear supernatant liquid is measured for absorbance at 755 cm−1. A collaborative study was conducted with 10 laboratories participating. One laboratory omitted the centrifugation, which resulted in a low assay. Statistical analysis of the data showed no significant variances. The coefficient of variation for 10 laboratories analyzing 2 samples in duplicate was 1.29%. The method has been adopted interim official first action.
Correction of Bias in Collaborative Check Sample Series Reporting
Authors: Kelly Patrick C
Published: February 2020

Scores or accuracy indices used in collaborative check series to evaluate laboratory performance are influenced by factors that have nothing to do with performance. Scores based on normalized deviations are affected by the number of results reported on a given method. The average score or overall accuracy index obtained by a given laboratory is affected also by the number of results reported by that laboratory. By judicious choice of methods on which to report, a laboratory can improve its score without making a corresponding improvement in analytical performance. These effects are revealed in an examination of the statistical distribution of normalized deviations. The magnitude of these effects on laboratory rankings is obtained from modeling experiments with computer-generated random numbers. The inherent unfairness of the conventional method of calculating performance indices can be eliminated by converting normalized deviations to numbers having a normal statistical distribution. This transformation is mathematically complicated, but is not too difficult for a computer. The resulting parameters accurately reflect laboratory performance, are relatively easy to interpret, and permit the establishment of confidence intervals for laboratory rankings.
Determination of Aflatoxins, Ochratoxin A, and Zearalenone in Mixed Feeds, with Detection by Thin Layer Chromatography or High Performance Liquid Chromatography
Authors: Howell Mary V , Taylor Philip W
Published: February 2020

A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described. The feed is extracted with chloroform-water and the extract is cleaned up by using a disposable Sep-Pak silica cartridge. The procedure requires less time (15 min from sample extraction to extract preparation) and less solvent (approximately one-tenth) compared with conventional methods and is suitable for a fast, economical screen. Additional cleanup procedures, involving dialysis or extraction into base, are described for samples containing high levels of interfering compounds. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with fluorescence detection are described for identification and estimation of mycotoxins. The method has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials. The limit of detection is 1 μg/kg for all mycotoxins measured by HPLC.
Interaction Between Sample Preparation Techniques and Colorimetric Reagents in Nitrite Analysis in Meat
Authors: Fox Jay B , Zell Tatiana E , Wasserman Aaron E
Published: February 2020

The amount of nitrite measured in model and meat systems was a function of the interactions of the chloride and ascorbate concentrations with the method of sample preparation and the combination of Griess reagents used for colorimetric determination. Ascorbate caused loss of nitrite in the samples when heated and interfered in the Griess reaction, increasing the concentration of pigment formed from any given concentration of nitrite if sulfanilic acid and JV-(l-naphthyl)-ethylenediamine were used, and decreasing the amount if sulfanilamide and 1-naphthylamine were used. The interference was eliminated by both the AOAC procedure and mercuric chloride addition, although the former were less effective at higher ascorbate concentrations. Chloride increased the amount of pigment formed from a given amount of nitrite with sulfanilic acid but had no effect on the amount of sulfanilamide pigment.
Chloridometer Determination of Alien Halide Content of Iodine
Authors: Ferren William , Maltese Leonard
Published: February 2020

A coulometric method is described for measuring alien halide content (usually bromide and chloride) of iodine crystals at levels less than 50 ppm. Our method replaces the vintage visual turbidimetric (Nessler tubes) measurement of the USP and ACS methods with an accurate, precise electronic end point of a chloridometer. The limit of detection is about 1 ng chloride, with an uncertainty of about 3%. Our procedure avoids the inherent errors associated with visual comparison between sample, blank, and control systems with widely differing indifferent ion populations.
Improved 4-Aminoantipyrine Colorimetry for Detection of Residual Hydrogen Peroxide in Noodles, Fish Paste, Dried Fish, and Herring Roe
Authors: Ito Yoshio , Tonogai Yasuhide , Suzuki Hideyo , Ogawa Shunjiro , Yokoyama Tsuyoshi , Hashizume Takashi , Santo Hideyuki , Tanaka Kei-Ichi , Nishigaki Kikuyo , Iwaida Masahiro
Published: February 2020

Improved 4-aminoantipyrine (4-AA) colorimetry was developed for the detection of minute quantities of residual hydrogen peroxide in several kinds of food. Hydrogen peroxide in the sample was stabilized with potassium bromate and extracted with cold methanol. The methanol extract was diluted with phosphate buffer, protein was eliminated with zinc sulfate, and the extract was reacted with phenol, 4-AA, and peroxidase to the stable quinoneimine dye. The weak color solution was purified with Florisil column chromatography, concentrated, and determined by colorimetry. Recoveries of hydrogen peroxide from samples fortified at 0.5, 2, and 10 ppm ranged from 70.7 ± 8.9 to 98.5 ± 1.2%. Color development was linear with amount of H2O2 from 0.5 to 20 µg, corresponding to 0.05-2 ppm in samples.
Determination of Proof by Distillation: Low Results for Cocktails and Specialty Products
Authors: Mark Frances G , Vaughn Troy E
Published: February 2020

A variety of specialty products, as well as alcohol solutions containing individual ingredients of the products, were proofed according to the accepted distillation method for beverages containing >600 mg extract/100 mL. Products and solutions containing non-dairy creamer, combinations of citric acid and sugar, or acetic acid gave distillates with specific gravities corresponding to proofs 0.2-0.7° lower than expected. Low results caused by carryover of acetic acid into the distillate can be prevented by making the sample alkaline before distillation. The mechanism of apparent reduced recovery of alcohol in the other cases is still under investigation.
Gas-Liquid Chromatographic Method for the Analysis of Microencapsulated Diazinon Insecticide: Collaborative Study
Authors: Karr James J ,   Collaborators:, Audino J B , Carlstrom A A , Chenery L T , Cox L M , DiPilla E J , Ellis N D , Gentry G M , Gerken D , Ginther B E , Hodgins E , Jung P D , Kahn B , King W , Launer J E , Law M W , Linhart B , MacEachern G , Minyard J P , Moya H , Renaux B , Rivera L , Schatz W E , Shah R D , Slatner J W , Smith W J , Topping A , Torrence A K , L Ullrich , Whitaker R L , Winstead G R , Wong D L
Published: February 2020

The determination of diazinon insecticide in Knox Out 2FM formulation was studied collaboratively by 18 laboratories. Knox Out 2FM is a flowable microencapsulated insecticide formulation containing 23 wt% active ingredient. Analytical samples are first treated by grinding in a tissue grinder and then extracted in situ with acetonitrile. This preparative step breaks the capsules and allows the active ingredient to dissolve in the solvent. Single determinations on each of 2 closely matched samples were made by flame ionization gas-liquid chromatography. The standard deviation by analysts was 0.18 wt% and the coefficient of variation was 0.76%. The combined laboratory and analyst variation gave a standard deviation of 0.59 wt% and a coefficient of variation of 2.49%. The method has been adopted official first action.
Atomic Absorption Spectroscopic Determination of Dimethylpolysiloxane in Juices and Beer
Authors: Kacprzak Jurgen L
Published: February 2020

A method is described for determining dimethylpolysiloxane (DMPS), an antifoaming agent, in juices and beer. The method involves adsorbing the beverage onto Florisil (an activated porous magnesium silicate), drying, and Soxhlet extraction with chloroform. The chloroform extract is evaporated to dryness and DMPS is determined in the residue after dissolution with methyl isobutyl ketone and aspiration into a nitrous oxide-acetylene flame of an atomic absorption spectrophotometer. The detection limit is about 0.2 ppm.
Direct Spectrophotometric Determination of Arprinocid in Premixes: Collaborative Study
Authors: Fink David W ,   Collaborators:, Baker K R , Bliss W J , Brignac P G , Brunsmann P , Cannon M J , Carr K E , Davis E J , Drewery G , Fink H C , Foster C L , Fox A , George G , Hanks A R , Lawrence A A , Leseney J L , Lowie D , Martin R P , Nichols F A , Portterfield D G , Riva M , Roozen W , Sikes P J , Smallidge R L , Stringham R W , Thorpe V A
Published: February 2020

A spectrophotometric analytical method for the determination of arprinocid [9-(2-chloro-6-fluorophenylmethyl)- 9H-purin-6-amine] in premixes has been evaluated in an interlaboratory collaborative study. The samples were prepared in pairs over the concentration range 10.1-16.2% arprinocid with 2 similar materials as carriers for the drug, and were distributed to 16 laboratories. Duplicate analyses were obtained within the overall paired sample design by a protocol which obviates data censoring and allows for statistical treatment according to both Youden and Steiner guidelines. Each collaborator was requested to run 1 determination on each of 16 differently numbered samples in groups of 8 on 2 different days. In this analytical procedure, the drug is extracted into CHC13 and transferred into 0.1N HC1 for measurement at 258 nm after isolation by liquid- liquid partitioning. The means of the analyses reported by the collaborators ranged from 96.9 to 101% of the true concentration of arprinocid and were not statistically significantly different (P >0.1) from the true values. The coefficient of variation at the 12.2% formulation concentration level was 3.6%. The collaborative data were normally distributed (P ≮ 0.01) with a mean, median, and mode of 99.2, 99.2, and 100.0% recovery, respectively, and a standard deviation of 3.72%. In this distribution, 80% of the results were within the range 95.1-104.1% recovery. The systematic standard deviations of the 4 unit blocks (Sb) were each <0.4% arprinocid and the analysis of variance demonstrated that laboratory bias is not statistically significant (P >0.05). There is no statistically significant difference in either accuracy (P >0.5) or precision (P >0.05) between days, and the ruggedness test confirms that none of the 7 procedural variations which were selected for study has a significant effect on the analysis. This method has been adopted official first action.
Confirmatory Identification of Carbadox-Related Residues in Swine Liver by Gas-Liquid Chromatography/Mass Spectrometry with Selected Ion Monitoring
Authors: Lynch Martin J , Richard Bartolucci S
Published: February 2020

A confirmatory method has been developed to identify quinoxaline-2-carboxylic acid, the carbadox tissue residue, in swine liver, a target tissue, at the regulatory level of 30 μg/kg. Quinoxaline-2-carboxylic acid (QCA) is isolated from liver hydrolysates by solvent extraction and ion-exclusion chromatography, and a methyl ester derivative (CP-25,536 or QME) is identified by gas-liquid chromatography/ mass spectrometry with selected ion monitoring. The relative intensities of 3 ions: the base peak at m/z = 130, a second significant mass at m/z = 158, and the molecular ion (M+) at m/z = 188, are monitored simultaneously with a quadrupole mass spectrometer. Validation studies consisting of the analysis of liver fortified with QCA at the regulatory level and analysis of swine specimens containing physiologically incurred carbadox residues demonstrated that peak height ratios of ions in these tissue extracts corresponded to ion intensities of standards monitored at m/z = 188,158, and 130.
Electron Capture Gas-Liquid Chromatographic Determination of Morantel-Related Residues in Bovine Liver
Authors: Lynch Martin J , Bartolucci S Richard
Published: February 2020

A gas-liquid chromatographic assay has been developed to determine major residues of morantel in bovine liver, a target tissue, at levels of 0.2-0.8 ppm. The method is based on hydrolysis of the N-methyltetrahydropyrimidine portion of morantel and its metabolites to N-methyl-l,3-propanediamine, and conversion of the diamine to an N,N'-bis-(2-nitro-4-trifluoromethylphenyl) derivative. The addition of an internal standard, N-ethyl-l,3-propanediamine, to the tissue sample circumvents any potential problem that could arise from variable reaction yields, and eliminates the true recovery as a factor affecting the accuracy and precision of the procedure. The concentrations of the, derivatives are determined by pulsed electron capture gas-liquid chromatography over a linear dynamic range equivalent to 0.2-0.8 ppm morantel. The method has been evaluated at 0, 0.2,0.4, and 0.8 ppm levels in fortified bovine liver, and in a withdrawal sample containing physiologically incurred morantel residues. Mean values of 0.22 ± 0.015,0.40 ± 0.033, and 0.79 ± 0.045 ppm were found for fortified samples, 0.02 ppm for control liver, and 0.56 ± 0.050 ppm for the withdrawal sample.
Gas-Liquid Chromatographic Determination of Adipate Content of Acetylated Di-starch Adipate
Authors: Mitchell Gordon A , Vanderbist Michel J , Meert Florent F
Published: February 2020

A gas-liquid chromatographic method is described for rapid, quantitative determination of adipate content of acetylated di-starch adipate. The adipate group is very labile and, under mild alkaline conditions at ambient temperature, is easily hydrolyzed from the starch. Free adipic acid is formed by acidification of the solution with HC1, and then extracted with ethyl acetate. Ethyl acetate is removed under vacuum distillation, and a silyl derivative of the adipic acid is formed. Glutaric acid internal standard is introduced into the original starch sample before hydrolysis. An aliquot of the silylated solution is injected into a gas chromatograph fitted with a column having silicone oil as the active phase. A flame ionization detector is also incorporated. Results correlate well with the amount of adipylating reagent used. No adipic acid is detectable when a hydrolyzed, extracted sample of acetylated di-starch adipate is subjected to a second extraction. Recovery levels of adipic acid, from starches fortified with 100-500 ppm, are in the range of 97-102.5.%
Technique for Preparing Spike Elements for Study Samples of Extraneous Materials
Authors: Freeman Clarence C
Published: February 2020

A microanalytical technique was developed to prepare spike elements for samples of extraneous materials to be used in collaborative studies. The technique eliminates the tedious individual transfer of spike elements from the preparatory medium to the study sample by affixing the elements to a gelatin film for mass transfer.
Gas Chromatographic Determination of Sorbitol, Mannitol, and Xylitol in Chewing Gum and Sorbitol in Mints
Authors: Daniels Daniel H , Warner Charles R , Fazio Thomas
Published: February 2020

A method has been developed for determination of sorbitol, mannitol, and xylitol in chewing gum and sorbitol in mints. Chewing gum is partitioned between methylene chloride and water; the mint is simply dissolved in water. The aqueous extract is dried and the residue is derivatized with pyridine-acetic anhydride to form the corresponding peracetates. The derivatives are quantitated by gas chromatography using a 9 ft × 2 mm column packed with 10% Silar IOC on Chromosorb W/AW. Average recoveries of these sugar alcohols ranged from 96 to 102%.
Radioimmunoassay of Oxfendazole in Sheep Fat
Authors: Nerenberg Clinton , Tsina Irene , Matin Shaikh
Published: February 2020

Oxfendazole (methyl 5-(phenylsulfinyl)-2-benzimidazole- carbamate) is a broad spectrum anthelmintic agent designed for use in food-producing animals. A simple radioimmunoassay (RIA) for determination of oxfendazole in plasma was modified for determining oxfendazole in sheep fat. Fat tissue was enzymatically hydrolyzed to an oily residue with collagenase- hyaluronidase, and oxfendazole was then extracted into an acidified aqueous phase. An aliquot of this phase was used directly for RIA. Bound radioactivity was separated from free by using polyethylene glycol-bovine gamma globulin because oils and other components in the aqueous aliquot preclude the use of charcoal for the separation. The lower limit of sensitivity of the assay is 0.003 ppm. Accuracy experiments carried out in the range 0.01-0.5 ppm gave a regression line of y (ng/g) = 0.91x (ng/g) + 2.89, with r = 0.99. Fat tissue derived from sheep given an oral dose of 6.0 mg/kg was analyzed by this method and by a high pressure liquid chromatographic (HPLC) method. Values obtained by the 2 methods agreed well.
Effects of Particle Size and Method of Milling on Determination of Morphine in Papaver somniferum L. Straw
Authors: Engelke Beatriz Ferreira , Vincent Phillip G
Published: February 2020

Different particle sizes of blade- and ball-milled poppy straw were separated and analyzed for morphine by high pressure liquid chromatography. Morphine content varied up to 70% among the different size particles. This may account for discrepancies observed in percentages of morphine found among random aliquots. Homogenizing a carefully quartered sample of blade-milled straw by further pulverization in a percussion ball mill 2 min and taking a quartered aliquot for morphine analysis improved the reproducibility of results.
Susceptibility of Strawberries, Blackberries, and Cherries to Aspergillus Mold Growth and Aflatoxin Production
Authors: Llewellyn Gerald C , Eadie Thomas , Dashek William V
Published: February 2020

The susceptibility of blackberries, cherries, and strawberries to Aspergillus growth and aflatoxin production has been examined. Three aflatoxigenic isolates of Aspergillus, A. flavus ATCC 15548 and NRRL 3251 as well as A. parasiticus NRRL 2999, were cultured on homogenates of the fruits for 14 days at 28 ± 2°C. Percent mycelial growth and spore infestation were determined each day with a calibrated grid. At day 14 each culture was frozen at –5°C until aflatoxins were extracted with methylene chloride and water. Aflatoxins were separated by thin layer chromatography (TLC) with benzene-methanol-acetic acid (90 + 5 + 5). This extraction and solvent system provided satisfactory separations of the aflatoxins and was free of background interference on the TLC plates. Although all fruits served as substrates for both Aspergillus growth and aflatoxin production, cherries appeared to be a more favorable substrate than did blackberries, and the latter was more favorable than strawberries. Whereas A. flavus produced both B1 and G1 on all substrates, it yielded B2 and G2 only on cherries. Although A. parasiticus NRRL 2999 synthesized B1, B2, G1, and G2 on both blackberries and cherries, no aflatoxins were detected on strawberries. In contrast, A. flavus NRRL 3251 failed to produce detectable levels of aflatoxin on any substrate. All substrates supported both mycelial growth and subsequent sporulation with cherries > blackberries > strawberries.
Interaction Between Sample Preparation Techniques and Three Methods of Nitrite Determination
Authors: Fox Jay B , Doerr Robert C , Lakritz Leon
Published: February 2020

Meat samples containing nitrite and varying concentrations of ascorbate, cysteine, and sodium chloride were prepared for nitrite analysis. The methods used were the AOAC method of dilution and heating; the addition of mercuric chloride, charcoal, and Carrez reagents at 2 different pH values; and direct analysis of sample supernatants with no treatment (control). The effect of these initial conditions and preparation methods on measured nitrite was determined by using 3 different Griess reagent combinations and chemiluminescent and differential pulse polarographic techniques. Systematic variations were observed in samples treated with mercuric chloride, while the addition of Carrez reagents had little or no effect. Best results were obtained by the AOAC dilution/heating method under alkaline conditions, or by charcoal addition followed by chemiluminescent or colorimetric nitrite determination. Statistical analysis of the nitrite concentrations determined in the several samples showed that these 3 procedures were precise to about 5-6% CV, which was not significantly different from the CV value of 4% determined from replicate analyses.
Multicomponent Analysis of Meat Products by Infrared Spectrophotometry: Collaborative Study
Authors: Bjarnø Ole-Christian ,   Collaborators:, Arneth W , Noack W , Pfeiffer G
Published: February 2020

A new method for rapid multicomponent analysis of meat products based on infrared transmission was tested in a collaborative study with 4 laboratories. A series consisting of 31 samples of different meats, cooked sausage, liver sausage, and fermented sausage was distributed and analyzed at all laboratories for protein, fat, and water by the present method and by well established reference methods. There was no significant difference between the infrared method and reference methods at the 95% confidence level for determination of protein, fat, and water in meat products. There is a great
Tellurium as Catalyst in Semimicro Kjeldahl Method for Total Nitrogen Determination
Authors: Liao Christina F-H
Published: February 2020

A modified semimicro Kjeldahl procedure is described for total nitrogen determination in agricultural materials and refractory organic nitrogen compounds, in which tellurium, alone or in combination with copper, is used as a catalyst. Tellurium alone is adequate for complete recovery of nitrogen from nicotinic acid if the acid:salt ratio is carefully controlled to nearly 1. However, when a mixture of tellurium and copper is used, complete nitrogen recovery could be obtained at a higher acidrsalt ratio. Use of a mixture also reduces clearing time when compared with copper alone in the Kjeldahl digestion. For samples containing nitrate, a Devarda's alloy (Cu:Al:Zn = 10:9:1) is proposed as a reducing agent in the pretreatment procedure to convert nitrate to ammonium in 6N H2SO4, with subsequent digestion of the sample by using a mixture of K2S04-catalyst and concentrated H2SO4. The proposed method is applicable for total nitrogen determination including NO3-N in plant, soil, and fertilizer samples.
In Vitro Assay for Predicting Protein Efficiency Ratio as Measured by Rat Bioassay: Collaborative Study
Authors: Satterlee Lowell D , Kendrick James G , Marshall Henry F , Jewell Duane K , Ali Rida A , Heckman Mary M , Steinke H Fred , Larson Paul , Phillips R Dixon , Sarwar G , Slump P
Published: February 2020

Seven laboratories collaborated in testing the calculated protein efficiency ratio (C-PER and DC-PER). The collaborative study required each laboratory to analyze 6 foods and a control protein (ANRC casein) for in vitro apparent protein digestibility, amino acid composition, and PER via rat bioassay. The 6 foods or food ingredients tested were nonfat dry milk, cooked chicken muscle, protein-fortified dry breakfast cereal, textured soy protein, oat-based dry breakfast cereal, and durum wheat flour. Data obtained from the study were analyzed statistically for the intralaboratory variation for each method of analysis (i.e., amino acid analysis, PER, etc.). The ability of the C-PER to rapidly predict rat PER was also measured. The C-PER and DC-PER methods were adopted official first action.
Assessment of Quantitative Methods for Determination of Trichothecenes in Grains and Grain Products
Authors: Scott Peter M
Published: February 2020

Currently available methods for determination of trichothecenes are evaluated primarily for accuracy, precision, and limits of detection. A few of the more accurate and sensitive methods are discussed further with respect to convenience and number of trichothecenes determined. The best technique to date for quantitating trichothecenes is gas-liquid chromatography with electron capture or mass spectrometric detection, subject to available instrumentation.
Aflatoxicol and Aflatoxins B1 and M1 in the Tissues of Pigs Receiving Aflatoxin
Authors: Trucksess Mary W , Stoloff Leonard , Brumley William C , Wilson David M , Hale Otha M , Sangster Lowell T , Miller Doris M
Published: February 2020

Aflatoxicol (AFL) and aflatoxins B1 and M1 were found in tissues (kidney, liver, and muscle) of feeder pigs given an estimated LD50 oral dose of B1 (1.0 mg/kg body weight) provided as a rice culture of Aspergillus flavus and of market-weight pigs fed a naturally contaminated feed, containing aflatoxin Bi at a level of 400 ng/g from corn, for 14 days. The residues in all tissues decreased with time after treatment in both groups, with no detectable residues (approximate detection limits, ng/g, B1 0.03, M1 0.05, AFL 0.01) in pig tissues from the feeding experiment 24 h after withdrawal of aflatoxin-contaminated feed. B1 and M1, when found in the feeding experiment, were at about the same levels in all tissues except the kidney, in which M1 was the dominant aflatoxin. The level of AFL, when detected, was about 10% of the B1 level.
Liquid Chromatographic Determination of Aflatoxins in Artificially Contaminated Cocoa Beans
Authors: Hurst W Jeffrey , Lenovich Lawrence M , Martin Robert A
Published: February 2020

A high pressure liquid chromatographic method is described for the extraction and determination of aflatoxins in artificially contaminated cocoa beans. Aflatoxins were extracted by using a CB extraction, column cleanup, and chromatography on a reverse phase column with UV detection at 365 nm for aflatoxins B1 and G1 and fluorescence detection for aflatoxins B2 and G2 (365 nm excitation and 455 nm emission). Recoveries from artificially contaminated cocoa beans of various roast conditions ranged from 77.50 to 107.35%. CV values ranged from 4.87 for G1 to 7.66 for G2 (n = 8). The method can be used for cocoa beans ranging from no roast to a heavy roast (12 min at 400°F).
Colorimetric Determination of Ethambutol Hydrochloride
Authors: Shingbal Dattatray M , Naik Shailendra D
Published: February 2020

A precise colorimetric procedure is proposed for estimation of ethambutol hydrochloride, based on reaction of the drug with 2,4-dinitro-l-fluorobenzene under stipulated conditions. The yellow chromophore is quantitated spectrophotometrically at 376 ± 1 nm. The relationship between absorbance and drug concentration was linear within a range of 5-40 μg/mL. The method is suitable for the analytical control of ethambutol HCl and its formulations.
Trapping Low Levels of Methyl Bromide in Air or as Residues at Ambient and Lower Temperatures for Gas Chromatography
Authors: Dumas Theodore
Published: February 2020

Methyl bromide in air was analyzed by direct injection onto a trapping tube filled with Tenax GC and operated at 25 or 0°C. Methyl bromide amounts as low as 35 ng could be determined. Methyl bromide flushed from flasks and collected in cold traps before injection onto the trapping tube showed recoveries of 99% for 30 ng in a 60 L sample. This gas chromatographic method was also used to determine methyl bromide desorption from fumigated wheat; 0.3 ppb (10-9 g) was desorbed in 24 h from 1 g wheat aerated for 30 days.
Analytical Methods Used by Industry for Determining Lead in Processed Foods
Authors: Elkins Edgar R
Published: February 2020

Over the past 8 years, a number of food processors and can manufacturers have participated in repeated round-robin studies of lead methodology. During this period, 3 methods have been found to be comparable in a variety of foods: carbon rod atomic absorption, chelation-solvent extraction atomic absorption, and anodic stripping voltammetry. Each method is described and results are given from a number of round-robin studies. In general, the coefficient of variation at lead levels of 0.1-0.3 ppm is usually ≤20%.
Gas Chromatographic Determination of Primary and Secondary Amines as Pentafluorobenzamide Derivatives
Authors: Ripley Brian D , French Bruce J , Edgington Lloyd V
Published: February 2020

An analytical method is described for the determination of mono- and dialkylamines in foodstuffs. Amines are derivatized to their pentafluorobenzamides which may be separated by gas chromatography (GC) and determined using an N-P detector. Analysis of the derivatives by GC-mass spectrometry indicated they were all mono-substituted. The amines were isolated from foodstuffs by alkaline distillation of ≥75% sample volume. The distribution of dimethylamine (DMA) in distillate volumes indicated 2 maxima from barley and malt, which could represent 2 or more sources of DMA. DMA concentrations of 6.6-8.8 ppm in barley, 11 ppm in malt, and 1.2 ppm in beer are higher than previously reported.