bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Saccharin, Sodium Benzoate, and Caffeine in Beverages by Reverse Phase High-Pressure Liquid Chromatography
Authors: Smyly Dan S , Woodward Betsy B , Conrad Edward C
Published: February 2020

A reverse phase high-pressure liquid chromatographic method is presented for the simultaneous separation and determination of saccharin, sodium benzoate, and caffeine in soft drinks, fruit juices, fruit cocktails, fruit punches, coffee, and artificial sweetener concentrates. Decarbonated soft drinks, fruit punches, and artificial sweetener concentrates are injected directly into the chromatograph. Fruit juices and coffee solutions require filtration through a 0.45 μm pore membrane filter prior to injection. Samples arc eluted from a μBondapak/C18 column with 5% glacial acetic acid and are quantitated with an ultraviolet detector. The results of saccharin, sodium benzoate, and caffeine determinations in 34 soft drinks (representing 11 manufacturers and 20 flavors); 8 fruit juices, cocktails, and punches; 7 coffees; and 6 artificial sweetener concentrates are presented. Average recoveries of saccharin, sodium benzoate, and caffeine from soft drinks are 99.0, 99.3, and 100.2%, respectively.
High-Speed Liquid Chromatographic Determination of o-Phenylphenol Residues in Citrus Products
Authors: Reeder Samuel K
Published: February 2020

A method is presented for the quantitative analysis of o-phenylphenol residues in citrus oils, encapsulated flavors, and dried meal. The method utilizes high-speed liquid chromatography for the determination after specific sample preparations for each material. These preparations include hexane extraction of acidified basic extracts or steam distillation and extraction. The limit of the analysis is <1 ppm with an analysis time of <45 min.
Reference Raman Spectra of DDT and Five Structurally Related Pesticides and of Five Pesticides Containing the Norbornene Group
Authors: Nicholas Mark L , Powell David L , Williams Theodore R , Bromund Richard H
Published: February 2020

The Raman spectra of DDT and 5 structurally related pesticides, TDE (DDD), Perthane, methoxychlor, dicofol, and tetradifon, and of 5 pesticides containing the norbornene group, heptachlor, chlordane, dieldrin, endrin, and endosulfan, have been recorded. These spectra are presented, along with tables giving values for the frequencies.
Second Collaborative Study of a Gas-Liquid Chromatographie Method for the Assay of Thiocarbamate Formulations
Authors: Barney James E
Published: February 2020

A gas-liquid chromatographic (GLC) method previously evaluated for the assay of 6 thiocarbamate herbicides in formulations has been tested on 2 new formulations containing Eptam and Sutan plus a safener. The method was tested collaboratively by 17 laboratories. The coefficient of variation for 4 formulations was 4.10%. Most of the error is systematic. It is recommended that the present method, 6.367–6.371, be continued as official first action, and that other GLC stationary phases be evaluated.
Volumetric Determination of Malathion, Using Dichlorofluorescein as Indicator
Authors: Siquiroff Miguel , Pollero Ricardo , Goyena Rodolfo
Published: February 2020

A method has been developed which is based on alkali cleavage of malathion and volumetric determination of the resulting dimethylphosphorodithioate with silver nitrate, using dichlorofluorescein as the indicator. Pure malathion standards were analyzed by the proposed method, yielding a standard deviation of 0.27. Four typical malathion formulations containing talc, wheat flour, and anionic and nonionic emulsifiers were analyzed by both the proposed method and the former official first action colorimetric method with comparable results. Potential interferences from surfactants currently employed in liquid formulations are avoided by the use of Florisil column chromatography. Malathion is eluted from the column with petroleum ether-ethyl ether with an average recovery of 92.5%.
Gas-Liquid Chromatographic Headspace Method for Vinyl Chloride in Vinegars and Alcoholic Beverages
Authors: Williams David T
Published: February 2020

Vinyl chloride (VC) is determined in vinegars and alcoholic beverages by gas-liquid chromatographic headspace analysis. The lower limit of detection is 10 ppb and confirmation by gas chromatography-mass spectrometry, single ion monitoring at m/e 62, is possible at this level. Comparison of the headspace and the direct injection methods for the determination of VC in vinegars and alcoholic beverages showed that the results obtained by the 2 methods were not significantly different (P>0.05).
Pyrolysis-Gas Chromatographic Techniques for the Analysis of Automobile Finishes: Collaborative Study
Authors: Stewart William D
Published: February 2020

Samples of 7 automobile topcoats currently used by the major American automobile manufacturers were analyzed by various pyrolysis-gas chromatographic techniques. The samples were similar shades of white paint with small differences in the organic vehicle composition. The study involved analysis of the 7 samples and identification of an unknown sample chosen from the 7. A ninth chip was also included for determination of the reproducibility of the analytical technique. The samples were analyzed by other methods of analysis, including diamond cell infrared spectroscopy and mass spectrometry. Sample sizes from 4 to 200 μg were needed for the various methods of analysis and, in all cases, the unknown sample was correctly identified.
Detection of Sulfonamides in Animal Feeds
Authors: Cieri Ugo R
Published: February 2020

The animal feed sample is extracted with ethanol or acetone and the extract is evaporated to dryness. Another portion of the same sample, spiked at the 3 ppm level with 8 sulfonamides, is similarly extracted and the extract is evaporated to dryness. The residue from each solution is dispersed with 5 ml 0.1N NaOH and, following the addition of 1 ml 1N HCl and mixing, the solution is filtered. The filtrate is mixed with Celite, transferred to a column, and eluted with ammoniacal ether. Aliquots of the concentrated sample and control eluates are spotted on a neutral Adsorbosil-1 thin layer chromatographic (TLC) plate. Following development in chloroform-methanol (95+5) and drying, the plate is sprayed with an alcoholic solution of p-dimethylaminobenzaldehyde until the control chromatogram shows 6 yellow spots which are, from top to bottom; sulfadimethoxine (SO), the combined sulfamerazine (SM)-sulfamethazine (SH)-sulfaquinoxoline (SQ) spot, sulfadiazine (SD), sulfapyridine (SP), sulfathiazole (SZ), and sulfaguanidine (SG). A spot on the sample chromatogram can be identified if the Rf is identical to one of the 5 sulfonamides not overlapping with another compound. If the Rf of the sample spot is approximately the same as that of the combined SM-SH-SQ spot, more definite identification can be obtained by using basic Adsorbosil-1 TLC plates, with chloroform-methanol (92+8) as the developing solvent.
Detection of Arsanilic Acid in Animal Feeds
Authors: Cieri Ugo R
Published: February 2020

The animal feed sample is extracted with alcohol, the extract is evaporated to a small volume, and an aliquot is spotted on a silica gel H plate. After development of the plate in chloroform-methanol (80+20), the spotting area is scraped and extracted with ethanol, which is evaporated to dryness. The residue is dissolved in 3 ml alcohol, and an aliquot is reacted with p-dimethylaminobenzaldehyde solution; another aliquot of the extract is used as a sample blank. A control is prepared by spiking another portion of the same feed with about 5 ppm arsanilic acid. The method is applicable in the presence of procaine and sulfonamides.
Collaborative Study of a Semiautomated Fluorometric Method for the Determination of Reserpine in Tablets
Authors: Kreienbaum Mary A
Published: February 2020

A semiautomated fluorometric method for the determination of resperpine in tablets was collaboratively studied by 7 laboratories. The method is a modification of the semiautomated method of Urbányi and Stober, which involves formation of a fluorogen with vanadium pentoxide. Collaborators were supplied with 3 composites, each from a different dosage level of commercial tablets. The results obtained agreed well with the AOAC manual fluorometric method; coefficients of variation ranged from 0.45 to 2.70%. The method has been adopted as official first action.
Qualitative Tests for Added Coloring Matter in Meat Products
Authors: McNeal Jon E
Published: February 2020

The rapid qualitative detection of coal tar dyes, chemicals added to color meat products, and some natural coloring materials was investigated through extraction and subsequent identification by spectrophotometric, paper chromatographic, and specific reaction techniques. These techniques will detect the presence of coal tar dyes, imidazole, histamine, histidine, cochineal, beet powder, annatto, alkanet, carotene, paprika, saffron, turmeric, and materials causing discoloration in meats.
Relationship Between the Biological Availability and Solubility Rate of Reduced Iron
Authors: Pla Gwendolyn W , Fritz James C , Rollinson Carl L
Published: February 2020

Solubility rate determinations were conducted on electrolytic iron and hydrogen reduced iron and carbonyl iron samples to study the correlation of biological availability and solubility. There was excellent correlation for the hydrogen reduced iron and electrolytic iron samples. The carbonyl iron samples showed a direct relationship between solubility and bioavailability, but these data were not numerically equivalent to data from other types.
Semiautomated Ring Carrier to Facilitate and Expedite Disinfectant Testing by the AOAC Use-Dilution Method
Authors: Walter George R , Mahl Mearl C , Sadler Colin
Published: February 2020

The AOAC use-dilution test requires the replicate examination of a number of contaminated metal rings. Ten metal rings may be tested within the 20 min structure of the test. From a statistical and economical viewpoint, it would be highly desirable to increase the number of rings examined in a single test. A semiautomated ring carrier permits testing 200 rings within a 20 min test.
Digestion of Fish Samples for Mercury Determination by Flameless Atomic Absorption Spectrophotometry
Authors: Pearce Isobel D , Brooks Robert R , Reeves Roger D
Published: February 2020

Methods of digestion of fish samples for mercury determination by flameless atomic absorption spectrophotometry have been investigated. Digestion in Teflon bombs, Kjeldahl flasks, or borosilicate test tubes gives comparable precisions and mercury recoveries. Because of their cost and effect in limiting productivity, Teflon bombs were considered unnecessary for analysis of fish samples. Experiments with cooked and uncooked fish samples have confirmed that no appreciable loss of mercury occurs during baking 30 min at 170°C.
Spectropliotometric Analysis of Alkaloids with Picrolonic Acid
Authors: Taha Aly M , Gomaa Camelia S
Published: February 2020

The spectroscopic characteristics of the interaction of alkaloids with picrolonic acid were studied. In solvents of low and intermediate polarity, the presence of alkaloids caused a red shift of the 322 nm band of nonionized picrolonic acid to 355 nm, corresponding to the anionic resonance band. There was also a considerable increase in absorptivity, which was dependent on both the basicity (pKa) and molar concentration of the alkaloid present. Arylamines, aromatic N-heterocycles, and alkaloids lacking an aliphatic amine moiety did not show observable shifts. The interaction was developed into a spectrophotometric assay for the following alkaloids in pharmaceutical preparations: atropine, ephedrine, codeine, emetine, quinine, and strychnine. The method is sensitive to 2 μg alkaloid/ml, with an accuracy of ±1.5% and a standard deviation of ±1.05—1.31%.
High-Speed Liquid Chromatographie Determination of Phenothiazine in Commercial Pesticide Formulations
Authors: Byrne Martin J
Published: February 2020

Phenothiazine (thiodiphenylamine) in commercial pesticide formulations is analyzed by high-speed liquid chromatography and ultraviolet absorption detection. Phenothiazine is extracted from the formulation with methanol and injected into the liquid chromatograph. Methanol-water (1+1) is the mobile phase. The amount of phenothiazine is calculated from peak height ratios. The liquid chromatographic procedure is much faster than the infrared or colorimetric method and yields values in close agreement with both of these methods.
Chemical Composition of Technical Chlordane
Authors: Cochrane William P , Greenhalgh Roy
Published: February 2020

Technical chlordane, a multicomponent organochlorine insecticide, was separated into 26 peaks by temperature-programmed gas chromatography, using a 3% OV-17 column. Peaks were identified by using combined gas chromatography-mass spectrometry (GLC-MS) and, where individual standards were available, by comparing retention times on various columns. Technical chlordane constituents were also investigated by GLC-MS, using a Dexsil 300 column; 19–20 peaks were observed. Quantitation studies indicated differences in the per cent contributions of the constituents, particularly for heptachlor and trans-chlordane, in 2 different technical chlordane reference standards. For the same reference standard higher results were obtained by using 63Ni electron capture detection than by using flame ionization detection. By using a combination of 4 GLC columns to overcome peak overlap, we determined that the 11 known constitutents of technical chlordane constituted approximately 40%.
Ultraviolet and Infrared Analysis of Rotenone: Effect of Other Rotenoids
Authors: Delfel Norman E
Published: February 2020

Biases evidenced by past collaborative trials of ultraviolet (UV) and infrared (IR) methods for rotenone can be caused by interference from other rotenoids that occur in extracts of cubé and derris. In the UV analysis, sumatrol, rotenolone, and deguelin cause positive errors of decreasing magnitude; elliptone, toxicarol, tephrosin, dehydrodeguelin, and dehydrorotenone produce negative biases of increasing magnitude. In the IR analysis, error depends on rotenoid concentration relative to rotenone concentration. At equal proportions, bias is positive with toxicarol and deguelin and negative with other rotenoids. The baseline version of the IR method has an inherent positive bias of approximately 8% but is superior to the base point version because of greater insensitivity to deguelin. The official first action UV method for the determination of rotenone in derris and cubé powder, 6.162–6.163, has been deleted, and the IR method, 6.164–6.165, has been revised to exclude derris products.
Gas-Liquid Chromatographic Determination of Pentachloronitrobenzene in Pesticide Formulations
Authors: Hanks Alan R , Cramer Christine W
Published: February 2020

A gas-liquid chromatographic method has been developed to determine pentachloronitrobenzene (PCNB) in pesticide formulations including dusts, powders, granules, liquids, and fertilizers. Captan, disulfoton, and Terrazole do not interfere. Samples are extracted with chloroform, and an aliquot is mixed with an equal volume of internal standard solution containing o-terphenyl. PCNB is chromatographed on a 5% SE-30 column and quantitated by peak height ratios. The method has been subjected to a ruggedness test which indicates little sensitivity to changes in extraction and chromatographic conditions.
Derivatization Procedure for Identification of Aflatoxin M1 on a Thin Layer Chromatogram
Authors: Trucksess Mary W
Published: February 2020

A commodity extract containing presumptive aflatoxin is placed on an origin spot of a thin layer chromatographic plate and overspotted with trifluoroacetic acid. The mixture is held in the dark 30 min at ambient temperature and then 30 min at 55°C. The plate is developed with CHCl3-acetone-2-propanol (85+10+7). The Rf values of reacted and unreacted aflatoxin M1 are compared with authentic similarly treated for identification. The lowest concentration that has been identified is 0.1 μg/kg.
Culture Method for Detection of Salmonella in Dried Active Yeast: Collaborative Study
Authors: Poelma Paul L , Romero Aida , Wilson Clyde R , Andrews Wallace H
Published: February 2020

A method for detecting Salmonella in dried active yeast was subjected to collaborative study. This method employs trypticase soy broth as the pre-enrichment medium, a sample-to-broth ratio of 1:10, and subsequent transfers to lauryl sulfate tryptose broth and tetrathionate before streaking onto selective agars. Each collaborating analyst received ten 25 g samples of dried active yeast. Duplicate 25 g samples were each inoculated with Salmonella Oranienburg at a low level (28 cells) and a high level (107 cells). Similarly, duplicate 25 g samples were each inoculated with S. senftenberg at a low level (30 cells) and a high level (114 cells). The remaining 2 of 10 samples were not inoculated. Results from 12 of 13 collaborators were evaluated. Only 2 (8.2%) of the 24 low level S. oranienburg samples were reported incorrectly as negative. Twelve of the analysts detected S. senftenberg at both levels and S. Oranienburg at the high level in the inoculated samples. Results from 12 collaborators used in the final evaluation show that 117 of 119 (98.3%) collaborative determinations are in agreement. The official final action method for the detection and identification of Salmonella, 46.013–46.026, has been revised official first action to include applicability to dried active yeast.
Gas-Liquid Chromatography and Infrared Spectroscopy of Resmethrin in Nonaqueous Aerosols
Authors: Law Mark W , Bontoyan Warren R , Looker Jack B
Published: February 2020

Two rapid and precise methods have been developed for the determination of resmethrin in nonaqueous aerosol formulations. The propellents are evaporated, the residue is dissolved in carbon disulfide, and the resulting solution is analyzed by gas-liquid chromatography or infrared spectroscopy. The accuracies of the methods were confirmed by a collaborative study.
Nitrite in Meat Products Determined by Fluorescence Quenching of p-Aminobenzoate Ion
Authors: Coppola Elia D , Wickroski Alphonse F , Hanna J Gordon
Published: February 2020

A direct fluorometric method is presented for determining nitrites in meat products by means of quenching. The extracted sodium nitrite is consumed in a diazotization reaction with a measured excess of the fluorescent reagent p-aminobenzoic acid (PABA) in boiling water and at pH ≤1.4. The amount of decrease in fluorescence (quenching) of PABA, in alkaline medium (pH 11.0) with excitation at 265 nm and fluorescence at 339 nm, is directly related to the amount of nitrite present. The slope for the standard curve is 1 % decrease in relative fluorescence intensity per 2.76 ppm NaNO2. Results obtained for a series of 20 meat samples analyzed by this fluorometric method are in good agreement with results obtained by a colorimetric method with an average difference of ±6.1 ppm NaNO2.
Colorimetric Determination of Aconitine in Galenicals and in Biological Samples
Authors: Karawya Mohamed S , Sharaf Abdel-Aziz A , Diab Aly M
Published: February 2020

A sensitive method is presented for determining aconitine. Aconitine is complexed with Co2+, the aconitine-cobalt complex is extracted with chloroform, and the absorbance is measured at 320 nm. The sensitivity of the method ranged between 0.06 and 3 mg/25 ml, and the color was stable for 6 hr. The method was successfully applied for the quantitative determination of aconitine in animal tissues.
High-Pressure Liquid Chromatography of 4,4′-Diazoaminobis-(5-methoxy-2-methylbenzenesulfonic Acid) in FD&C Red No. 40
Authors: Marmion Daniel M
Published: February 2020

Ten analysts representing 7 laboratories participated in the evaluation of a high-pressure liquid chromatographic procedure for the determination of 4,4′-diazoaminobis(5-methoxy-2-methylbenzenesulfonic acid) (DMMA) in FD&C Red No. 40; each collaborator analyzed 7 samples. Between-laboratory standard deviations ranged from 0.0015 to 0.0033% for samples nominally containing 0–0.05% DMMA. The stability of DMMA vs. pH was also studied. It is recommended that the high-pressure liquid chromatographic method be further studied.
Gas-Liquid Chromatographic Analysis of N-(4-Chlorophenyl-N′-2,6-difluorobenzoyl)urea Insecticide After Chemical Derivatization
Authors: Lawrence James F , Sundaram Kanth M S
Published: February 2020

The gas-liquid chromatographic analysis of TH 6040 (N-(4-chlorophenyl)-N′-(2,6-difluorobenzoyl)urea) was carried out after the insecticide was converted to its N,N′-dimethyl analog (N-methyl-N-(4-chlorophenyl)-N′-methyl-N′-(2, 6-difluorobenzoyl)urea). The methylation was accomplished in DMSO with sodium hydride and methyl iodide. The derivative was thermally stable and chromatographed as a single peak on 3% OV-1 at 235°C. Support for the structure of the product was given by mass spectrometry. The sensitivity of the product to electrolytic conductivity detection was approximately 50 ng for 50% full-scale deflection in the nitrogen mode and 70 ng for the same response in the chloride (reductive) mode. About 0.25 ng was required for 50% full-scale deflection by electron capture (at 1 × 10−9 amp standing current). Foliage samples were analyzed for TH 6040, using the proposed method.
Collaborative Study of Accelerated Development of Latent Fingerprint Images on Paper by Application of Steam
Authors: Connor Charles M
Published: February 2020

Nine latent fingerprint examiners participated in a collaborative study in the use of a steam iron to accelerate chemical development of latent images on bond and newsprint papers treated with a 0.5% solution of ninhydrin in acetone. Four latent images were placed on each paper by the Associate Referee during an 8 hr period. The papers were paired and numbered 1, 2, and 3. Three pairs were mailed to each collaborator who treated Pair 1 by dipping, Pair 2 by brushing or swabbing, and Pair 3 by spraying. After air-drying, the papers were subjected to heat and steam from a household steam iron until the images developed. The average time for developing all images was 5.8 min/paper. Of the total images available, 92.1% were developed to some degree; 47.9% of these images or 43.5% of all images were identified by the collaborators. The method has been adopted as official first action.
Applications of Mass Spectrometry to the Analysis of Mycotoxins
Authors: Kingston David G I
Published: February 2020

Methods of identifying mycotoxins by mass spectrometry are reviewed, with special reference to the value of a complete listing of known fungal metabolites, arranged by molecular weight. Such a list is applied to the identification of various mycotoxins, and mass spectrometry is applied to the structural elucidation of dimethylnidurufin and ostreogrycin A.
Review of the Metabolism and Mode of Action of Cyclophosphamide
Authors: Fenselau Catherine
Published: February 2020

A review of recent studies of the pharmacology of cyclophosphamide is presented. Particular attention is paid to the use of mass spectrometry in the identification of the active compound phosphoramide mustard as a circulating human metabolite of cyclophosphamide, the development of an assay method for cyclophosphamide, phosphoramide mustard, and nornitrogen mustard, and a demonstration that alkylation by phosphoramide mustard proceeds through a symmetrical aziridinium ion.
Gas-Liquid Chromatography and Mass Spectrometric Ion Selective Detection of Sterigmatocystin in Grains
Authors: Salhab Abdulazim S , Russell Gerald F , Coughlin James R , Hsieh Dennis P H
Published: February 2020

A method was developed for direct gas-liquid chromatographic-mass spectrometric (GLC-MS) analysis of nonderivatized sterigmatocystin in wheat, rice, barley, and corn. Sterigmatocystin was extracted from spiked grain samples by 2 methods, both of which yielded high recoveries of 14C-labeled sterigmatocystin (>90%). Extracts were cleaned up by gel permeation chromatography on polystyrene with tetrahydrofuran as the eluant. Chromatography of relabeled compound indicated good recoveries (>90%). The GLC-MS system was modified to give an all-glass chromatographic pathway to the ion source. Short glass or quartz columns packed with silicone liquid phase on inert supports gave the best results. Trace levels of sterigmatocystin were very labile in all gas chromatographic systems and levels below 5 ppb in grains were detected only with great difficulty. The GLC-MS system was utilized in the mass fragmentography mode, with selective ion monitoring of the m/e 295, 306, and 324 peaks. These ions were present in only trace levels in all control grain samples, indicating minimal interference from other compounds. The limit of accurate detectability (20 ng) on spiked grain samples was lower than previously reported. Lower levels of sterigmatocystin (1 ppb or 4 ng on column) could be detected in grains by using the mass fragmentography mode, but these levels could not be measured accurately.
High-Performance Liquid Chromatographic Determination of L-Aspartyl-L-Phenylalanine Methyl Ester in Various Food Products and Formulations
Authors: Fox Lew , Anthony Gaylord D , Lau Edward P K
Published: February 2020

A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures <1000 psig, an analysis can be performed in <15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are ≤2.5%.
Monomolecular Film Method for Determining Microquantities of Fat in Egg Albumen
Authors: Taber Lawrence E
Published: February 2020

A very small amount of egg yolk (0.04–0.05%) in egg albumen interferes with the performance of the latter in the baking of angel food cakes. For many years no practical chemical test was available that would adequately determine these small amounts. In the proposed method, lipids are extracted from a sample of albumen, using a form of alkaline hydrolysis, and extracted again with petroleum ether. A known aliquot is expelled on a film of oxidized oil which has been suspended on the surface of distilled water. The resulting spot is measured by tracing its outline and measuring the area with a compensating planimeter.
Ion Selective Electrode for 2,4-Dichlorophenoxyacetic Acid
Authors: Hazemoto Norio , Kamo Naoki , Kobatake Yonosuke
Published: February 2020

An electrode responsive to 2,4-D (2,4-dichlorophenoxy acetic acid) was constructed by dissolving tetrazolium derivatives as an ion exchanger in a liquid membrane. The electrode exhibited rapid and Nernstian response to solutions of 2,4-D over the concentration range 10−1 to 10−4M. The presence of diverse substances such as acetate, benzoate, and 3-indoleacetate showed no appreciable effect on the electromotive force of the electrode.
High-Pressure Liquid Chromatographie Determination of Resmethrin and Ratios of the cis-trans Isomers
Authors: Zehner James M , Simonaitis Richard A
Published: February 2020

Total resmethrin ((5-benzyl-3-furyl)methyl cis, trans-(±)-2,2-dimethyl-3-(2-methylpropenyl)cyclopropanecarboxylate) in formulations and cis-trans ratios were determined by high-pressure liquid chromatography on a column of octadecylsilane on Zipax with methanol-water liquid phase. Pentachlorobenzene was the internal standard. The cis-trans ratio can be determined directly without hydrolysis to chrysanthemumic acid as in some other methods.
Improved Microbiological Procedure for Determining Bacitracin in Premixes and Mixed Feeds
Authors: Fassbender Carol A , Katz Stanley E
Published: February 2020

An improved microbiological procedure is presented for determining bacitracin in premixes and mixed feeds. Premixes are extracted with acidic 50% aqueous methanol, and mixed feeds are extracted with 50% dimethylformamide after washing with acetone to remove fats and pigments. Extracts are diluted with pH 6.0 phosphate buffer and assayed by using a 2-point assay system with Micrococcus flavus as the test organism. The simpler extraction coupled with the 2-point assay system measured bacitracin levels as low as 10 g/ton. Accuracy and repeatability of the 2-point system were at least equivalent to those for official AOAC methods.
Collaborative Study of the Determination of Sodium in Dietetic Foods by the Sodium Ion Electrode Method
Authors: McNerney Francis G
Published: February 2020

The dietetic food sample is diluted with total ionic strength adjusted buffer. The electrode potential of the sample is measured, known increments of sodium are added, and the electrode potential is measured after each addition. The mv readings obtained are plotted on Gran’s paper and the concentration of sodium in the sample is found from the intercept of the extrapolated straight line. Seven processed dietetic vegetables and 2 spiked samples were sent to 7 collaborators. There was a 95.8% agreement between the results from the 7 collaborators and the Associate Referee for the unfortified samples. Recoveries of 98.5 and 95.1% were obtained on fortified samples, based on results from 5 collaborators. The statistical analysis indicates minimal bias and adequate precision for determination of sodium in dietetic food at the current regulatory requirements. The method has been adopted as official first action.
Electron Capture Gas-Liquid Chromatographic Determination of Acetone in Butter
Authors: Love John L , Donnelly R Grant C
Published: February 2020

A method has been developed for the rapid, routine determination of acetone (2-propanone) at the mg/kg level in butter by electron capture gas-liquid chromatography of the 2,4-dinitrophenylhydrazone derivative. The method has potential for wider application to other carbonyls in food oils and fats.
Collaborative Study of Methods for the Determination of Chloride, Citrate, and Phosphate in Processed Cheese
Authors: Brzenk Henry R , Krett O Joseph
Published: February 2020

A collaborative study was conducted to compare the International Dairy Federation (IDF)/International Organization for Standardization (ISO)/Association of Official Analytical Chemists (AOAC) proposed methods for the determination of chloride and citrate in processed cheese with the corresponding current AOAC methods. Since there is no current AOAC method for phosphate, only the IDF/ISO/AOAC method was used. Five samples of processed cheese were prepared with varying added amounts of the anions of interest. The samples were analyzed in duplicate by 7 collaborating laboratories. For chloride, both methods are comparable, but since the IDF/ISO/AOAC method is simpler and faster it has been adopted as official first action to replace the current AOAC method, 16.224. For citrate, the colorimetric IDF/ISO/AOAC method is more rapid and simpler than the current AOAC gravimetric method. However, the AOAC method is more precise. Therefore, the proposed method has been adopted as official first action as an alternative to 16.237. For phosphate, 2 of the 7 laboratories were outliers by the Youden ranking test but the results by the remaining laboratories appear satisfactory. The phosphate method should receive further study to reduce the between-laboratory error component.
Sensitive Colorimetric Determination of Cholesterol in Dairy Products
Authors: Bachman Kermit C , Lin Jan-Hai , Wilcox Charles J
Published: February 2020

Cholesterol can be determined colorimetrically in dairy products at levels of ≥10 μg (coefficient of variation = 5.3%) with an o-phthalaldehyde reagent when non-cholesterol lipids arc eliminated prior to color development. Absorbance for 2 mg tripalmitin was found to be equivalent to about 20 μg cholesterol. Saponification followed by hexane extraction removed interfering lipids. Using the described procedure, 238 individual raw milk samples were found to contain 144.4±37.9 μg cholesterol/ml, while their skim milk portions had 26.5±6.4 μg cholesterol/ml (mean ± standard deviation). The o-phthalaldehyde cholesterol estimates agreed with those obtained by a gas-liquid chromatographic procedure when cheese and ice cream were analyzed by the colorimetric procedure with and without prior fat extraction.
Spectrophotometric Determination of Ferric, Ferrous, and Total Iron in Drugs by Reaction with α,α′-Dipyridyl
Authors: Sullivan Daniel J
Published: February 2020

The drug sample is dissolved in 0.2N HCl to yield a final concentration of 30 μg Fe/ml, an aliquot is reacted with α,α′-dipyridyl, and the pH is adjusted with an acetate buffer. For Fe(II), the color intensity is measured at 523 nm. For total iron, ascorbic acid is added to a separate aliquot of the sample solution, reducing all the iron present to Fe(II), which is then reacted with α,α′-dipyridyl, diluted to volume, and read at 523 nm. The Fe(III) content is determined by subtracting Fe(II) from total iron. This method is applicable to iron-containing drugs and drug dosage forms.
Extraction and Partition Chromatography of Tolbutamide as Ion-Pairs with Quaternary Ammonium Cations
Authors: Doyle Thomas D , Barkan Susan
Published: February 2020

The partition of tolbutamide (1-butyl-3-(p-tolylsulfonyl) urea) as ion-pairs with homologous tetraalkyl ammonium cations was studied. The determination of experimental extraction constants permitted quantitative calculation of distribution ratios, in agreement with theoretical relationships, over a continuous range of about one billion. The nature and the concentration of the counter-ion and solvent composition were the variables studied. Based on the theoretical results, a rapid partition chromatographic procedure was devised. A solution of tolbutamide sample in 10% aqueous tetraethyl ammonium hydroxide is incorporated in the system as the immobile phase in the partition column. A 1 + 1 mixture of chloroform and isooctane removes extraneous materials; then chloroform elutes the tolbutamide-tetraethyl ammonium ion-pair, which is converted to the free acid by passing the eluate through a phosphoric acid segment, and tolbutamide is determined spectrophotometrically without further treatment. Standard recoveries averaged 100.5 ± 0.70%; commercial tablets assayed 100.5 ± 0.85%.
Solvent Effects in the Partition of Phenols as Ion-Pairs with Tetrabutyl Ammonium Cations
Authors: Doyle Thomas D , Proctor Joseph B
Published: February 2020

The extraction of phenols as ion-pairs with tetrabutyl ammonium cations was studied with respect to variation of distribution as a function of solvent composition. The large solvent effect observed for 12 phenols gave quantitative agreement with an exponential relationship previously developed for other classes of ion-pairs and had approximately the same magnitude. An exception was noted for phenols substituted at the ortho position by nonpolar groups; decrease of the exponential value in these cases provided support for the controversial concept of specific solvation. Ortho substitution by polar groups led to a pronounced increase of extraction constants; this was explained in terms of delocalization of the anionic charge. Formylation via the Reimer-Tiemann reaction was observed as a complication in the extraction of some of the phenols.
Rapid Gas-Liquid Chromatographic Method for Determining Residues of Ethephon (2-Chloroethyl Phosphonic Acid) in Tomatoes
Authors: Ernst George F , Anderegg Marcia J P T
Published: February 2020

A rapid method is described for the determination of the growth regulator ethephon (2-chloroethyl phosphonic acid) in tomatoes. Samples are extracted with ethyl acetate. The extract is methylated, decolorized with carbon, and analyzed by gas-liquid chromatography on a column packed with 15% QF-1/10% DC-200 on Chromosorb W (HP). A flame photometric detector is used. Recoveries from tomatoes fortified with 0.1–11.0 ppm ethephon were 78—98%. The sensitivity of this method is about 0.1 ppm.
Thin Layer Chromatographic Determination of Sterigmatocystin in Cereal Grains and Soybeans
Authors: Shannon Gail M , Shotwell Odette L
Published: February 2020

A method has been developed for determining sterigmatocystin in yellow and white com, barley, oats, rye, sorghum, brown and wild rice, and soybeans. A partition column packed with activated magnesium silicate was used for cleanup. Averaged recoveries are 104% in white corn, 114% in rye, 100% in oats, 134% in brown rice, 96% in barley, 105% in sorghum and wild rice, and 92% in soybeans. The limit of sensitivity is 50 μg/kg for any of these commodities.
Microbiological Assay with Lactobacillus plantarum for Detection of Adulteration in Orange Juice
Authors: Vandercook Carl E , Smolensky Dora C
Published: February 2020

A microbiological assay has been developed io help detect adulteration in orange juice. Under standard assay conditions with diluted orange juice, the growth of Lactobacillus plantarum is proportional to the concentration of juice in the assay mixture. Imitation orange beverages did not support growth. Growth was also independent of the normal levels of common beverage ingredients such as sugar, acids, butylated hydroxyanisole, and orange oil. Commercial orange juices reconstituted from concentrates from various sources were assayed by the microbiological procedure, and the variability of results (coefficient of variation 24%) was about the same as or slightly lower than that for many of the other constituents used to estimate adulteration.
Gas-Liquid Chromatographic Determination of Methyl Anthranilate in Wine
Authors: Nelson Richard R , Acree Terry E , Lee Chang Y , Butts Robert M
Published: February 2020

A method is described for the gas-liquid chromatographic determination of methyl anthranilate in wine. Methyl anthranilate is extracted with Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane), concentrated, and quantitated by comparing the peak area with that of an internal standard (p-di-n-butoxybenzene). A synthetic wine solution (12% ethanol in water) as well as White Riesling and Concord wines containing various concentrations of added methyl anthranilate were analyzed. Recovery of methyl anthranilate in the range of 0.1–10 mg/L averaged 100.26% with an average relative error of 3.94%. The method is both rapid and reliable.
Infrared Spectrophotometric Analysis of Medicinal Gases for Trace Impurities
Authors: Brannon Wilson L , Benson Walter R , Schwartzman George
Published: February 2020

The feasibility of examining medicinal gases for trace impurities, using an infrared spectrophotometer in conjunction with a 10 m gas cell, was investigated. Many of the impurities for which the USP includes limits were detected and measured at concentrations at or below those permitted by the USP; these include sulfur dioxide, carbon dioxide, carbon monoxide, and water. However, others (hydrogen sulfide, nitric oxide, and nitrogen dioxide) were not detected at these levels by this technique. Methane was found at low levels in some samples.
Pilocarpine Hydrochloride in Ophthalmic Solutions: Modification of a High-Pressure Liquid Chromatographic Determination and Survey
Authors: Weber John D
Published: February 2020

Pilocarpine undergoes 2 important reactions in solutions, epimerization to isopilocarpine and hydrolysis to pilocarpic acid. There is no official USP limit for isopilocarpine or pilocarpic acid in pilocarpine hydrochloride ophthalmic solutions. An existing high-pressure liquid chromatographic (HPLC) method was modified by changing the buffer system to permit its use with constant-pressure as well as constant-volume instruments. The procedure separates all 3 components on a cation exchange resin ; pilocarpine and isopilocarpine are determined directly and pilocarpic acid indirectly. Ophthalmic solutions and drug substances were obtained from substantially all the United States marketers of pilocarpine opthalmic solutions and were analyzed by the modified HPLC method. Results of the survey show that isopilocarpine is present to the extent of 0.4–3% and pilocarpic acid at levels of 0.6–7% of total alkaloid.
Extractable Color of Capsicums and Oleoresin Paprika
Authors: Woodbury James E
Published: February 2020

A collaborative study of the method for extractable color in capsicums and oleoresin paprika was conducted to determine if the NBS neutral glass filter standard is superior to the chemical standard now used as a spectrophotometer check. For a 1000 ASTA (American Spice Trade Association) color value sample, the reproducibility standard deviation was 49 with the chemical standard compared with 14 with the NBS filter. The repeatability standard deviations were 9.0 and 8.9, respectively. For a 2000 ASTA color value sample, the reproducibility standard deviation was 162 with the chemical standard compared with 44 with the NBS filter. The repeatability standard deviations were 12.9 and 10.1, respectively. The study also indicated that 16 hr in acetone extracted 8.0% more of a capsicum than the 4 hr in the present AOAC method. The repeatability standard deviations for 4 hr vs. 16 hr were 2.1 and 1.6. The method has been adopted as official first action.
Collaborative Study of a Modified Method for the Extraction of Light Filth from Ground White Pepper, Cardamom, Celery Seed, Coriander, and Ginger
Authors: Dent Russell G
Published: February 2020

An improved method has been developed for the extraction of light filth from 5 ground spices, ginger, white pepper, coriander, celery seed, and cardamom. The method, a modification of 44.120, utilizes a cold isopropanol defatting, followed by wet sieving and flotation of light filth from 40% isopropanol with HCl and mineral oil-heptane (85+15). Collaborative results show that the proposed method is more rapid to perform than the present official first action methods, 44.116 and 44.120, and yields better recoveries. The method has been adopted as official first action.
Semiautomated Method for the Fluorometric Determination of Total Vitamin C in Food Products
Authors: Egberg David C , Potter Richard H , Heroff John C
Published: February 2020

A simple method employing simultaneous extraction and oxidation has been developed for the semiautomated determination of ascorbic and dehydroascorbic acids in food products. Recovery studies were conducted on ready-to-eat breakfast cereals and both fresh and canned fruits and vegetables, with average recoveries of 101, 100, and 102%, respectively. Reproducibility data were generated showing a relative standard deviation of 3.5%. The automated method was compared with the manual AOAC fluorometric method and with indophenol titration ; correlation coefficients were 0.9960 and 0.9926, respectively. The hydrolysis product of dehydroascorbic acid, 2,3-diketoguIonic acid, a reported interference in this method, was prepared and shown not to form an interfering fluorescent derivative.
Hydroxylamine Hydrochloride in Automated and Manual Methods for Riboflavin Determination
Authors: Jacobson Barabara S
Published: February 2020

The AOAC method for riboflavin determination has been modified to improve the precision of the manual method and greatly simplify its automation. In the AOAC method, permanganate oxidation is used for sample cleanup, and hydrogen peroxide is used to reduce excess permanganate. By substituting hydroxylamine. HCl for the hydrogen peroxide, the generation of oxygen gas, which can be troublesome, is eliminated without otherwise changing the assay. The resulting manual assay has a relative standard deviation of 1% as opposed to 2.5% for the same assay with hydrogen peroxide. This method is simple to automate, using a continuous flow system. The automated system performs 40 determinations per hour with a 1% relative standard deviation and results agree with those from the AOAC method at the 98% confidence level.
Gas-Liquid Chromatographic-Mass Spectrometric Detection and Identification of Ambergris
Authors: Governo Thomas F , Alessandro Rocco T , Prager Manfred J
Published: February 2020

A gas-liquid chromatographic-mass spectrometric method for the detection and identification of ambergris in its natural state or in perfume preparations is described. Solid samples are extracted; liquid samples are concentrated. Ambrein, a major component of ambergris, is separated by gas-liquid chromatography on an OV-17 capillary column, detected by flame ionization, and identified by mass spectrometry. Sample retention times and mass spectra were compared with those of purified material isolated from reference ambergris samples. Several types of perfume-related samples were tested. This method was satisfactory for samples of high concentration such as ambergris extracts and also for samples of low ambrein concentration typical of perfume formulations.
High Pressure Liquid Chromatographic Determination of 4,4′-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 6
Authors: Marmion Daniel M
Published: February 2020

Fourteen analysts from 9 laboratories evaluated a high pressure liquid chromatographic procedure for the determination of 4,4′-(diazoamino)-dibenzenesulfonic acid (DAADBSA) in FD&C Yellow No. 6. Each collaborator analyzed 5 samples nominally containing 0—0.050% DAADBSA. The repeatability and reproducibility of the method are estimated to be 0.003% and 0.020%, respectively. The method has been adopted as official first action.
Collaborative Study of Turbidimetric Microbiological Assay of Monensin in Chicken Rations
Authors: Breunig H Latham , Scroggs Robert E , Tonkinson Lealon V , Bikin Henry
Published: February 2020

A turbidimetric microbiological assay method for monensin in chicken rations was submitted in a modified form to 8 collaborating laboratories along with randomized and coded samples. Three laboratories used the manual method and 5 used the automated method. Other factors in the experimental design were ration types (broiler starter, broiler finisher, and pullet grower), feed form (meal vs. pellets), and potency level (90 and 110 g/ton) for one ration. Average recoveries for the ration types over all laboratories and feed forms were 87.7—93.13% of label, while mean recoveries in 2 feed forms were 91.7% for meal and 87.6% for pellets. Average recoveries in the 8 laboratories ranged from 84.6 to 106.64% of label for 90 g/ton rations and 87.1 to 106.6% for 110 g/ton rations. There was no significant difference between the manual and the automated methods. The collaborators’ assays were uniform with respect to within-laboratory variation. Relative standard deviations ranged from 4.51 to 10.76% with a median of 6.04%. Agreement with the plate assay is quite good. The turbidimetric method for monensin has been adopted as official first action.
Collaborative Study of the Recovery of Hexachlorobenzene and Mirex in Butterfat and Fish
Authors: Bong Rodney L
Published: February 2020

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