bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Moisture and Oil Concentrations in Feedstuffs by Four Different Methods
Authors: Crook Lynn , Williams W P
Published: February 2020

The moisture content of feedstuffs was determined by 4 methods: drying (1) over sulfuric acid to constant weight and (2) in vacuo 5 hr at 95°C, and direct extraction with (3) ethyl and (4) petroleum ether, assuming that the difference between weight loss of the moist sample upon extraction and the oil recovered represented the moisture content. Statistical analysis (P <0.5) indicated that 1 > 2 > 4 ⊁ 3. The oil content of feedstuffs was determined by petroleum and ethyl ether extractions of moist samples and samples dried by 1 and 2. No significant difference existed between the corresponding petroleum and ethyl ether extractions. However, the oil extracted from samples dried by 2 was significantly less than that extracted from moist samples or samples dried by 1. The quantity of nitrogen extracted was not significantly different for petroleum and ethyl ether extractions, but may be large enough to significantly affect crude protein or amino acid analysis.
Gas-Liquid Chromatography–Mass Spectrometry Characterization of Polychlorinated Biphenyls (Aroclors) and 36Cl-Labeling of Aroclors 1248 and 1254
Authors: Stalling David L , Huckins James N
Published: February 2020

The isomer composition of the Aroclor 1200 series was characterized by GLC-MS, using temperature programming and SE-30 support-coated, open-tubular capillary columns. A method is described for the preparation and purification of 36Cl-labeled Aroclors 1248 and 1254. Neutron irradiation of the commercial material was used to prepare the 36Cl-labeled material. Purification of the irradiated product was accomplished by silicic acid column chromatography. Yields of the purified product were between 63 and 99%, with no detectable alteration of the isomer composition; 10% of the 36C1 produced was associated with the unchanged PCB isomers and the remaining radioactivity was contained in polychlorinated terphenyls. The terphenyls were produced by irradiation polymerization, and they were easily separated from the PCB components. Mass spectrometry, utilizing either temperature programmed GLC or direct probe sample introduction, was used to characterize the irradiation products. The radioactive materials are being utilized in experiments to determine uptake and metabolism of PCB by aquatic organisms.
Simultaneous Polarographic Determination of p-Nitro-2-acetamido-3-hydroxypropiophenone and 1-p-Nitrophenyl-2-amino-1,3-propanediol
Authors: Dumanović D , Volke J , Jovanović R
Published: February 2020

The reduction of p-nitro-2-acetamido-3-hydroxypropiophenone is one of the steps in the synthesis of chloramphenicol by the Parke-Davis process. A simultaneous polarographic determination of the 2 compounds in the reaction mixture after the reduction of p-nitro-2-acetamido-3-hydroxypropiophenone has been proposed. The determination can be carried out in Britton-Robinson universal buffers over the pH range from 2 to 10. The polarographic behavior of the 3 compounds is described.
Comparison of Paints by Neutron Activation Analysis. II. Colored Paints
Authors: Snow K B , Washington W D
Published: February 2020

A study of colored paints was made to determine to what extent individual paint samples can be characterized by neutron activation analysis. Approximately 300 samples of red, white, blue, and green paints from the major manufacturers in the United States were examined. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. Batch-to-batch variations between paints from the same manufacturer were observed, and it was found that in a small number of cases no differences were detected.
Fluorimetric Characteristics of Some Narcotic and Dangerous Drugs
Authors: DeZan Paul , Canaff Roger F , Bianchi Robert
Published: February 2020

Spectrophotofluorimetry is one of the most sensitive analytical techniques available to the forensic scientist. An extensive amount of data has been published regarding the use of this technique in the analysis of various drugs. The object of this paper is to compile data involving the fluorimetric analysis of narcotic and dangerous drugs. This basically includes emission and excitation maxima, solvents employed, and sensitivity.
Extraction and Microbiological Assay of Erythromycin in Feeds. II. Collaborative Study
Authors: Nyman Melvin A , Winkler Victor W
Published: February 2020

Eight laboratories participated in a collaborative study of a method for determining low levels of erythromycin in commercially prepared mash and pelleted feeds. Erythromycin was extracted from 10 or 40 g milled feed samples (100 vs. 10 and 5 g/ton, respectively) with a novel methylal-methanol-water extraction system (65 + 15 + 20, v/v/v). The extractant was diluted directly by phosphate buffer for bioassay. The average recovery values for the 5, 10, and 100 g/ton feed samples were 3.9-2.6, 8.6-8.1, and 105.8-84.1 g/ton (mash vs. pellet).
Improved Method for Determination of Chlorophenoxy Acid Residues in Total Diet Samples
Authors: Yip George
Published: February 2020

Modifications to an earlier procedure for chlorophenoxyacetic acid residues are introduced to provide better recoveries, cleaner samples, and sensitivities down to 0.02 ppm. These changes include (1) extracting with acetonitrile or CHCI3, (2) more effective methylation of the acids, (3) Florisil chromatography to separate PCP from the other herbicides, and (4) isothermal gas chromatography by electron capture or microcoulometric detection. The improved procedure was compared with the previous one, using several total diet composites at fortification levels of 0.01–0.05 ppm. Results showed that usable chromatograms were obtainable only with the improved procedure. Recovery studies were made on all commodity groups except for fats, oils, and shortenings. Microcoulometric results were good. Compounds studied were MCP, 2,4-D, 2,4,5-T, 2,4,5-TP, 2,4-DB, PCP, and 2,3,6-TBA.
Effect of Chloride: Nitrate Ratios on Total Nitrogen Determinations
Authors: Rexroad Paul R
Published: February 2020

A study is reported on the effect of various chloride: nitrate ratios on per cent nitrogen recovered. The comprehensive and Raney methods were not affected. The salicylic acid method gave decreasing recoveries with the higher ratios.
Determination of Malonaldehyde as an Index of Rancidity in Nut Meats
Authors: Holland David C
Published: February 2020

Distillation of ground walnut meats from a slightly acidified concentrated NaCl solution gives a high per cent recovery of malonaldehyde which is associated with rancidity in nut meat products. Heating an aliquot of the distillate in an acetic acid solution of 2-thiobarbituric acid yields an intense red color with a maximum absorbance at about 532 nm. As little as 0.1 μg malonaldehyde/ml can be measured. Nuts judged to be slightly rancid by a taste panel showed the presence of approximately 40 μg malonaldehyde/g nul meat. Recoveries of malonaldehyde added to samples ranged from 92 to 97%. No malonaldehyde was detected in fresh nut meats.
Sensitivity of Chicks to Ochratoxins
Authors: Chu Fun Sun , Chang Chi C
Published: February 2020

The acute toxicity of ochratoxin A and its derivatives in day-old chicks has been studied. The LD50 was 166 and 216 μg per assay for ochratoxins A and C, respectively. No toxic effect was demonstrated when chicks were fed with up to 500 μg/chick of the hydrolyzed product, i.e., dihydroisocoumarin. Based on the results reported, the day-old chick assay is valid as a confirmatory test for ochratoxin.
Quantitative Determination of Tremortins in Agricultural Commodities
Authors: Hou C T , Ciegler A , Hesseltine C W
Published: February 2020

The procedure described for the quantitative determination of tremortins in agricultural commodities involves extracting the agricultural commodity with chloroform-methanol (2 + 1), followed by thin layer chromatography and colorimetric assay. This procedure was successfully applied to the analysis of tremortin A added to grains and the production of tremortins A and B on various commodities.
Colorimetric Determination of Carbaryl Residues in Field-Treated Corn
Authors: Dhal P , Lal Rattan
Published: February 2020

The colorimetric procedure outlined by Johnson was followed with some modifications for the analysis of carbaryl residues in corn. Recoveries from fortified samples were 77.2-99.3%. Carbaryl applied as granules in furrows at planting was translocated to the leaves. Carbaryl in the root and leaf was 16.25–27.50 and 17.24–27.62 ppm, respectively, 35 days after application. When applied as a water-suspension spray, 1.04 ppm carbaryl was detected in the leaves 21 days after application. It was not detectable in grain, stover, or silk, although 0.86 ppm was found in husks. In winter, 8.57 ppm carbaryl was detected 60 days after application. It was not detected in grain, stover, silk, and inner husks, but wrapper husks contained 24.23 ppm 27 days after application.
Colorimetric Method for Estimation of Zineb
Authors: Rangaswamy J R , Poornima P , Majumder S K
Published: February 2020

Zineb can be determined colorimetrically after reaction with cupric acetate in HC1. The copper salt formed is measured at 370 nm. This method has been applied successfully to the analysis of zineb formulations and zineb on grains and peanut pods.
Chromous Chloride Reductions. VI. Derivative Formation for the Simultaneous Identification of Heptachlor and Endrin Pesticide Residues by Gas Chromatography
Authors: Chau Alfred S Y , Cochrane W P
Published: February 2020

A chromous chloride reaction followed by GLC analysis is described for the simultaneous confirmation of heptachlor and endrin residues. This procedure constitutes a convenient method for the routine confirmation of heptachlor and endrin residues as low as 0.01 and 0.04 ppm, respectively, in 10 g sample extracts. An alternative method for the confirmation of heptachlor, using zinc and acetic acid, is also described.
Microcolorimetrie Estimation of Sulfur Dioxide in Fruits and Fruit Products
Authors: Nagaraja K V , Manjrekar S P
Published: February 2020

A simple and rapid microcolorimetric method, which is based on the reduction of yellow colored peroxodisulfato titanic acid to colorless titanium oxysulfate, has been developed for the determination of sulfur dioxide in dried fruit, fruit sirups, beverages, and liquid concentrates. The reduction in intensity of the yellow color is directly proportional to the concentration of sulfur dioxide over the range of 0-30 μg/ml.
Identification of Acetic, Propionic, and Sorbic Acids in Bakery Products by Thin Layer Chromatography
Authors: Tjan G H , Jansen J Th A
Published: February 2020

A rapid and sensitive thin layer chromatographic method has been described for detecting acetic, propionic, and sorbic acids in bakery products. Acetic, propionic, and sorbic acids were steam distilled from an acidified mixture of the samples into a solution of NaOH. After concentration of the alkaline solutions, samples were spotted on a thin layer plate; the chromatoplate was developed and the acids were identified by spraying with bromcresol purple.
Analysis of Nitrite- and/or Nitrate-Processed Meats for N-Nitrosodimethylamine
Authors: Fazio T , White R H , Howard J W
Published: February 2020

A total of 51 samples of various meat products was analyzed for N-nitrosodimethylamine with a method demonstrated to be sensitive to 10 ppb. The identity of the amine in one ham sample was confirmed by mass spectrometry at the 5 ppb level, the highest quantity detected in the various samples by GLC analysis. The presence of N-nitrosodimethylamine in the other samples could not be definitely established, since the apparent levels were too low for confirmatory analysis.
Analytical Profile of Straight Bourbon Whiskies
Authors: Schoeneman Robert L , Dyer Randolph H , Earl Elaine M
Published: February 2020

In this study 162 straight bourbon whiskies representing 2-, 4-, 6-, and 8-year-old samples were characterized by both chemical and physical analyses. Determinations using official AOAC methods were made on the components commonly used in characterizing distilled spirits. In addition, sodium, potassium, calcium, and magnesium were determined by atomic absorption spectrophotometry. Certain congeners were significantly correlated with age, while others were not.
Thin Layer Chromatographic-Gravimetric Determination of O,O-Diethyl S-(N-Isopropylcarbamoylmethyl) Phosphorothiolothionate (Prothoate) in Technical Products and Liquid Formulations
Authors: Bazzi B , Fabbrini R , Radice M
Published: February 2020

A method, based on phosphorus determination after thin layer chromatographic separation, has been developed for the analysis of O,O-diethyl S-(N-isopropylcarbamoylmethyl) phosphorothiolothionate in both technical products and liquid formulations. The insecticide or a convenient amount of an insecticidal preparation is dissolved in benzene and the solution is spotted on a thin layer chromatographic plate. After the plate is developed and sprayed with the chromogenic reagent, the portion containing prothoate is scraped off and the pesticide is eluted with methanol. The quantity of the active ingredient in the eluate is obtained by estimation of phosphorus as quinoline phosphomolybdate and the concentration of prothoate in the original sample can be calculated.
Conversion of Monuron to Ethyl-N-p-chlorophenyl Carbamate by Soxhlet Extraction of Plant Tissue with Ethanol
Authors: Lee Shaw S , Fang S C
Published: February 2020

Soxhlet extraction of plant materials with alcohol converted monuron residue to carbamate. Although this conversion will not affect the accuracy of monuron determination by the Bratton-Marshall reaction, it will undoubtedly affect the accuracy if the measurement is carried out by thin layer or paper chromatography. Diuron, fenuron, and chloroxuron, which contain 1,1-dimethyl substitution, were also converted to the corresponding carbamates, while siduron, neburon, linuron, monomethyl monuron, monomethyl diuron, and p-chlorophenyl urea were not. When monuron was refluxed with other alcohols such as methanol, isopropanol, and n-butanol, monuron was also converted to other products.
Identification of Crystalline Derivatives of Butyrophenones by X-Ray Diffraction: Examination of Pure Compounds and Active Substances in Pharmaceutical Formulations
Authors: Okkerse E , Leenheer A De , Heyndrickx A
Published: February 2020

Isolation and crystallization procedures have been developed for butyrophenones as free substances and from pharmaceutical formulations, namely ampoules, coated tablets, drops, and tablets. Crystallization as free bases, picrates, picrolonates, chlorhydrates, bromates, sulfates, and phosphates was attempted for all compounds. For the crystalline derivatives, the X-ray diffraction data were obtained by the Debye-Scherrer powder technique with photographic recording. The products have been classified according to their X-ray data, using “Hanawalt’s three strongest lines index” and the “innermost line index” systems. The butyrophenones could be identified with certainty by direct comparison of the X-ray diffraction patterns of compounds isolated from dosage forms with reference patterns.
Ultraviolet Spectrophotometric Determination of Propylthiouracil in Assays and Dissolution Studies of Tablets and Capsules
Authors: Hom Foo Song , Veresh Stephen A , Miskel John J
Published: February 2020

An ultraviolet Spectrophotometric method is reported for the determination of propylthiouracil in tablets or capsules. The accuracy and precision of the method are comparable to those achieved with the official USP assay procedure for tablets. In addition, the proposed method is simpler and more rapid, consequently providing an advantage where large numbers of determinations are indicated, e.g., in the determinations of individual dose variations and in dissolution rate studies. The method presently reported is suggested as an alternative to the official USP XVIII procedure.
Thin Layer Chromatographic Separation of Two Chlorodibenzo-p-Dioxins from Some Polychlorinated Biphenyls and Organochlorine Pesticides
Authors: Williams D T , Blanchfield B J
Published: February 2020

A thin layer chromatographic procedure is described for isolating 2,3,7,8-tetrachlorodibenzo-p-dioxin and octachlorodibenzo-p-dioxin. This method separates these compounds from polychlorobiphenyls and organochlorine pesticides. After isolation by thin layer chromatography, the chlorodibenzo-p-dioxins are analyzed by using electron capture gas chromatography. The application of the method to corn oil is discussed.
Interference of Sulfur Dioxide in the Determination of Cyclamates by AOAC Method 20.128
Authors: Saturley B A
Published: February 2020

Sulfur dioxide, if present in cyclamate-free drinks, will give a positive reaction in AOAC method 20.128 for cyclamates. This communication is presented as a cautionary note.
Electron Capture Gas Chromatographic Determination of Melengestrol Acetate in Animal Feed Supplements
Authors: Davis R A , Koshy K T , Ogilvie M L , Stahl G L , Callahan W A
Published: February 2020

Gas-liquid chromatographic methods are described for the determination of melengestrol acetate (MGA) in cattle feed supplements containing 0.000011–0.000220% MGA (0.05–1.0 mg/lb). A sample is extracted with hexane in a continuous liquid-liquid extractor and, if necessary, the extract is purified by treatment with activated carbon, solvent partition from hexane into aqueous methanol and then into methylene chloride, followed by column chromatography with alumina and silica columns. MGA in liquid feed and a few dry feed supplements may be determined directly in the initial extract by GLC. MGA in most dry feed supplements may be determined using only the solvent parition cleanup step; a few samples containing a low level of MGA and a large amount of co-extracted material may require all of the cleanup steps. MGA is measured by GLC, using a 1% OV-17 column, a 63Ni electron affinity detector, and cholesteryl chloroacetate as an internal standard. Recovery of MGA averages better than 90% with a coefficient of variation on the order of 7% for the feed supplements studied.
Determination of Canthaxanthin in Concentrates and Feeds
Authors: Osadca M , Araujo M , Ritter E De
Published: February 2020

Methods are presented for determining canthaxanthin as a 10% concentrate in beadlet form as such and in feed premixes and finished feeds. Canthaxanthin is liberated from the beadlets by hot aqueous solution and extracted into an organic solvent. In the case of feeds, separation from naturally occurring carotenoids in the extract is achieved by successive column and thin layer chromatography. Canthaxanthin in the final solution is isomerized to equilibrium with iodine and measured spectrophotometrically at 480±2 nm.
Collaborative Study of a Chromatographic Method for Sodium Diphenylhydantoin in Capsules
Authors: Cunningham C G , Brunner Charlotte A , Levine Joseph
Published: February 2020

A column chromatographic method is described for the determination of sodium diphenylhydantoin in capsules. A collaborative study was performed, using a synthetic mixture and a composite of a commercial preparation as samples. The average recovery for the synthetic mixture was 100.2 ±1.6%, and the average value for the commercial preparation was 96.2±1.6% of the labeled content. It is recommended that this method be adopted as official first action.
Elution Solvent System for Florisil Column Cleanup in Organochlorine Pesticide Residue Analyses
Authors: Mills Paul A , Bong Barbara A , Kamps La Verne R , Burke Jerry A
Published: February 2020

An elution solvent system is presented which can replace the currently used mixtures of ethyl ether-petroleum ether in the Florisil column chromatographic cleanup for pesticide residue analyses. Three eluants consisting of different mixtures of methylene chloride, hexane, and acetonitrile give greatly improved cleanup for extracts of fats and oils and recover pesticide chemicals of a greater range of polarity than do the ethyl ether-petroleum ether eluants. Fifty chemicals are known to be essentially completely recovered. Data are presented on fractional elution of representative compounds and on efficiency of removal of fatty substances. The proposed system has performed satisfactorily as a replacement for the ethyl ether-petroleum ether eluants in the analyses of a variety of representative foods for organochlorine pesticides.
Method for Preparing Dehydrated Tomato Powder for Examination by the Howard Mold Count Method
Authors: Parran Hamilton M , Douglas Ruth G , Eisenberg William V
Published: February 2020

Two methods were compared for preparing dehydrated tomato powder for the Howard mold count method in a collaborative study. One method requires hand-mixing the powder with water to obtain a sample within a specific refractive index range. The other involves a standard suspension based on a weight/volume dilution prepared under specified blending conditions. Standardizing these parameters eliminates some of the variables that affect the accuracy of results. It is recommended that the blending method be adopted as official first action.
Confirmation of Pesticide Residue Identity. II. Derivative Formation in Solid Matrix for the Confirmation of DDT, DDD, Methoxychlor, Perthane, cis- and trans-Chlordane, Heptachlor, and Heptachlor Epoxide Pesticide Residues by Gas Chromatography
Authors: Y Chau Alfred S , Lanouette M
Published: February 2020

A new approach has been developed for the simultaneous confirmation of DDT-type compounds, chlordanes, heptachlor, and heptachlor epoxide. Derivatives are formed by a solid matrix derivation technique in alumina/KOH and alumina/potassium tert.-butoxide. It is compared with the previously reported solution derivation technique. The high yield and simplicity of the present procedure should be useful in routine analysis, particularly for samples with a low concentration of the parent pesticide.
An Evaluation of a Buffered Agar Method for the Assay of Neomycin Sulfate in Feeds
Authors: Williams B J , Mayerhofer H J
Published: February 2020

The AOAC method for the assay of neomycin sulfate in feeds, 38.192–38.195, was modified by buffering the base and seed agar at pH 8.0 with tris (hydroxymethyl) aminomethane and deleting calcium chloride from the medium. Commercial feeds were assayed by both the modified and official AOAC methods and results were compared. The modified method was 2.64 times more sensitive than the AOAC method. The mean concentration of neomycin sulfate estimated by the modified method was 119.7% of that estimated by the AOAC method (significant at p < 0.01). Differences in method variability were not statistically significant at the 1% level. Linear correlation between the logarithms of neomycin concentrations and zone diameters was excellent for both methods, and the slopes of their regression equations were approximately equal.
Fast Screening Method for Detection of Aflatoxin Contamination in Cottonseed Products
Authors: Cucullu Alva F , Pons Walter A , Goldblatt Leo A
Published: February 2020

The detection method incorporates a 3 min blender extraction of the sample with aqueous acetonitrile, followed by partition of aflatoxins from an aliquot of the extract into benzene to effect a 4-fold concentration of the aflatoxins. A millicolumn (4 mm id × 20 cm long) filled with zones of acidic alumina (1.5 cm) and silica gel (9 cm) is placed in a portion of the benzene extract and the column is developed 5 min in chloroform-acetonitrile-2-propanol. Aflatoxins are detected by the presence of a sharp blue fluorescent band about 1 cm above the alumina zone when the developed column is examined under longwave ultraviolet light. Total analysis time is 15 min, and sensitivity of the method is in the range of 10–20 μg total aflatoxins (B1 + B2)/kg. An indication of the approximate contamination level can be obtained from the intensity of the fluorescent aflatoxin band.
Spectrophotometric Determination of Pyrantel Tartrate in Soybean Premix and Swine Feeds
Authors: Lynch M J
Published: February 2020

Spectrophotometry methods are described for the determination of the anthelmintic agent pyrantel tartrate in soybean premix and medicated swine feeds. In each method, pyrantel is separated into chloroform as the ion pair with perchlorate or iodide anions and recovered from the solvent by extraction with O.1N HCL . The pyrantel content of this aqueousacid extract is determined by 2-component UV absorption spectrophotometry. These methods are specific for the determination of the pyrantel content of premix and feeds containing 2 potential degradation products: 1,4,5,6-tetrahydro-l-methyl-2-(cis-2-(2-thienyl)vinyl)py-rimidine and (E)-N-(3-methylaminopropyl)-2- thiopheneacrylamide. Pyrantel recoveries ranged from 96 to 101% in 8 premix blends, and 94 to 104% in 7 feed samples. Coefficients of variation ranged from 1.9 to 4.2% in premix and 1.8 to 7.6% in feed. No significant interference was encountered by unmedicated premix or feed samples.
Gas-Liquid Chromatographic Estimation of Sucrose Diacetate Hexaisobutyrate in Soft Drinks
Authors: Conacher H B S , Chadha R K
Published: February 2020

A rapid screening procedure is presented for the estimation of sucrose diacetate hexaisobutyrate (SAIB) in soft drinks. After extraction, SAIB is analyzed directly by gas-liquid chromatography, using trimyristin as internal standard. Recoveries of SAIB from drinks fortified with this compound ranged mainly between 94 and 98%, with a high of 104%. The analysis of 10 commercial citrus-based drinks showed 5 drinks to contain SAIB in the 12–14 nig/10 fluid oz range; none was detected in the other drinks.
Gas-Liquid Chromatographic Determination of Vitamins D2 and D3 in Infant Formulas and Feeding Preparations
Authors: M Touw H D , C KRöSE B M , Molenaar H M
Published: February 2020

A method is described for the isolation and quantitative GLC determination of vitamins D2 and D3 individually in infant formulas and tube feeding preparations. Saponification, elimination of sterols, extraction, and Celite column chromatography are done according to the procedure of Eisses and De Vries. However, thin layer chromatography on Adsorbosil and GLC with a 2% OV-17 column are used for cleanup and determination, respectively. The average recovery of added vitamin D3 (200%800 units/60 g solid sample) was 61.0±2.3%. When the internal standard addition technique was used, recovery improved to 101.3±6%.
IUNS-AIN Nomenclature for Vitamin E
Authors: Ames Stanley R
Published: February 2020

An improved new nomenclature system for the biologically and nutritionally important stereoisomers and mixtures of stereoisomers of vitamin K has been proposed. The term vitamin E is used as the generic descriptor for biologically active tocol and tocotrienol derivatives. α-Toeopherol, formerly (d-α-tocopherol, refers specifically to the isomer of trimethyltocol that occurs naturally, All-rac-α-tocopherol, formerly (dl-α-tocopherol, refers to the equimolar mixture of the 8 possible stereoisomers of α-toeopherol obtained by synthesis from racemic isophytol. 2DL-α-Tocopherol, also formerly (dl-α-tocopherol, refers to the equimolar mixture of the 2 C-2 diastereoisomers of a-tocopherol obtained by synthesis from natural phytol. 2L,-α-Tocopherol, formerly l-α-tocopherol, refers to the C-2 epimer of a-tocopherol. Both the General Assembly and the Gouncil of the International Union of Nutritional Sciences (IUNS) and the Council of the American Institute of Nutrition (AIN) have endorsed these proposals. The new IUNS-AIN nomenclature for vitamin E has been adopted as official first action. In addition the official first action method for α-tocopherol and α-tocopheryl acetate, 39.A01–39.A14, has been adopted as official final action.
Application of Atomic Absorption Spectroscopy to Plant Analysis. I. Comparison of Zinc and Manganese Analysis with Official AOAC Colorimetric Methods
Authors: Smith D L , W G Schrenk
Published: February 2020

A rapid and simple atomic absorption spectroscopic method has been developed for determining zinc and manganese in plants. The method has been applied to sample solutions containing 0.2–1.4 μg zinc/ml and 0.4–2.4 μg manganese/ml. Operating conditions for performing the analyses have been established for the Jarrell-Ash tri-flame burner (air-acetylene or nitrous oxide-acetylene flame) and the Beckman total consumption burner (oxygenacetylene flame). Variation of gas flow to t he burners did not significantly affect the absorption signals; however, the current applied to the hollow cathode was found to be important for zinc analysis. No significant interferences were noted from other ions present in plants when the tri-flame burner was used, but potassium, sodium, and sulfate ions caused slight decreases in the zinc absorption and t h e phosphate ion produced as much as a 20% decrease in signal for the total consumption burner. Wet- and dry-ashing techniques produced similar results, but variations in some cases were somewhat greater than desirable. Per cent recovery of added zinc (10 or 20 μg) and manganese (12 or 24 μg) ranged from 87 to 106% with most results being near 100%. A comparison of the AOAC and atomic absorption methods i n dicates that the atomic absorption method is as reliable and accurate as the official AOAC colorimetric methods. The atomic absorption method is simpler and faster than the AOAC method.
Pepsin Digestibility Method for Animal Proteins: 1971 Collaborative Study
Authors: Gehrt Albert J
Published: February 2020

The official method for pepsin digestibility of animal proteins, 7.040–7.046, was modified in 1970 by isolating the indigestible residue by filtration instead of centrifuging. The modified method was adopted as official first action in 1970 for all animal proteins except poultry byproduct meal and hydrolyzed feathers, since several collaborators encountered slow filtering and high results with the last 2 items. During the past year, meat meal, blood meal, poultry by-product meal, and hydrolyzed feathers were studied by 20 collaborators, using the first action method unchanged except for inclusion of more detailed filtering instructions. No filtration difficulties were encountered and the agreement between collaborators was good for all products tested. Several collaborators obtained high results, due either to use of pepsin NF or to low incubation temperature. Use of pepsin with a 1:10,000 activity and proper incubation temperature yielded concordant results. The modified method has been adopted as official final action for all animal proteins except poultry by-product meal and hydrolyzed feathers and as official first action for these 2 products.
Total Nitrogen in Fertilizers
Authors: Rexroad Paul R
Published: February 2020

Automation and mercury pollution are discussed with the recommendation that copper be re-evaluated as a catalyst in Kjeldahl systems. An editorial change has been made in method 2.051 to increase the alkalinity of the digestion system
Determination of Lead in Fish by Atomic Absorption Spectrophotometry and by Polarography. I. Development of the Methods
Authors: Gajan Raymond J , Larry Damon
Published: February 2020

A method for the determination of lead in fish by atomic absorption spectrophotometry and polarography is described. The samples were dry-ashed at 500°C and dissolved in IN HC1; lead was determined by either method. Good agreement between atomic absorption spectrophotometry and polarography was obtained at levels of 1.0 to 10.0 ppm. Over this range the recoveries averaged 96.1% for polarography and 93.8% for atomic absorption spectrophotometry. Twelve species of fresh and salt water fish were analyzed.
Aflatoxins M1 and M2 and Parasiticol: Thin Layer Chromatography and Physical and Chemical Properties
Authors: Stubblefield R D , Shotwell O L , Shannon G M
Published: February 2020

A survey of known anatoxin solvent systems for resolution of aflatoxins M1 and M2 on TLC plates revealed that the best system for determining aflatoxins B1, B2, G1, G2, M1, and M2 is isopropyl alcohol-acetone-chloroform (5 + 10 + 85). Substitution of various alcohols for isopropyl alcohol in this system demonstrated that maximum resolution of M1 and M2 was achieved with n-amyl alcohol-acetone-chloroform (10 + 10 + 80); however, B1, B2, G1, and G2 migrated with the solvent front. When alcohol-chloroform (5 + 95) mixtures were investigated, n-propyl, n-butyl, and tert-butyl alcohol + chloroform resolved M1 and M2 best but did not separate B1, B2, G1, or G2. Molar absorptivities of both M1 and M2 were determined in methanol, chloroform, acetonitrile, and acetonitrile-benzene (2 + 98). Relative fluorescent intensities of aflatoxins B1, M1, and M2 were compared on both developed and undeveloped TLC plates. Fluorescent intensities of B1 and M1 on silica gel were nearly equal, and the intensity of M2 was 1.4–1.5 times that of the other 2 aflatoxins. Water adducts of anatoxin M1 and parasiticol were prepared. The diacetate adducts of parasiticol were formed by treatment with acetic anhydride and concentrated HC1. Monoacetyl derivatives of M1, M2, and parasiticol were obtained by treatment with pyridine and acetic anhydride. Good resolution of the water-addition derivatives of B1, G1, parasiticol, and Mi on TLC plates was achieved with isopropyl alcoholacetone-chloroform (5 + 10 + 85).
Rapid Method for the Quantitative Measurement of Numerous Pharmaceutically Important Amines
Authors: Matthew W Richard , Browne Howard C , Weber J Bex
Published: February 2020

A simplified variation of the bromothymol blue method has been used successfully to analyze numerous pharmaceutically important amines. A single benzene extraction of the yellow amine-dye complex is made possible by buffering the dye solution at pH 7.0 and by maintaining the organic-to-aqueous ratio at not less than 3:1. This procedure not only greatly reduces the analysis time but also makes possible the analysis of numerous aromatic amines by a simple single extractiondye method. Any variation in t h e solubility of the amine-dye complex is compensated for by the simultaneous determ ination of a known standard of equal volume. Total analysis time for a dissolved sample does not exceed 15 min. These factors make the method especially useful for the routine analysis of pharmaceutical products.
Determination of Residues from Herbicide iV-(l, 1- Dimethylpropynyl)-3, 5-Dichlorobenzamide by Electron Capture Gas-Liquid Chromatography
Authors: Abler Irving L , Gordon Charles F , Haines Linwood D , Wargo Joseph P
Published: February 2020

Terminal residues of N-(l,l-dimethyrpropynyl)- 3,5-dichlorobenzamide and/or its metabolites are determined by digesting the sample with sulfuric acid and methanol to convert residues to methyl 3,5-dichlorobenzoate. This compound is codistilled from the reaction medium, purified by chromatography on Florisil, and measured by electron capture gas-liquid chromatography. The method is sensitive to 0.01 ppm. A decline pattern for residues on alfalfa is given.
Modification of AOAC Method for Determination of Soluble Solids in Tomato Products
Authors: Lamb Frank C
Published: February 2020

The official first action method for soluble solids in tomato products, 32.008–32.010, was modified to permit the optional use of an ultracentrifuge to prepare samples for readings in a refractometer. Excellent agreement was obtained between the official method which specifies filtration and the centrifugation technique. Good agreement was also obtained between 2 laboratories using the centrifugation technique. The official method was modified to include the optional use of an ultracentrifuge for sample preparation.
Systematic Approach to the Detection of Explosive Residues. I. Basic Techniques
Authors: Washington Willard D , Midkiff Charles R
Published: February 2020

An analytical scheme, in several parts, dealing with the identification of explosives and incendiary destructive devices encountered in actual cases is described. Part I is introductory and is the first step taken in the examination of bomb debris for the various types of explosives and/or incendiaries. Examples and photographs of typical bomb residues are presented.
Fiber Analysis: An Evaluation of Existing Methods
Authors: Shaler Robert C , Prichard William W
Published: February 2020

A literature search concerning methods of analysis of fibers for forensic purposes has been completed. The results suggest that combined pyrolysis-gas chromatography (PGC) meets all the requirements for use in forensic analyses. Data are presented from a collaborative study conducted by the Institute of Petroleum, Gas Chromatography Discussion Group, concerning the use of PGC for polymer analysis. Their results suggest that with standardized techniques PGC would provide interlaboratory reproducibility.
Microscopical Characterization of Glass Fragments
Authors: Mccrone Walter C
Published: February 2020

The methods described involve the double variation method of Emmons which uses the optical microscope and measures dispersion of refractive index. The refractive index of match of the glass and one of a known set of carefully standardized liquids is determined by: (1) measuring the temperature of index match of the glass-liquid combination to obtain the refractive index as a function of wavelengths; and (2) measuring the wavelength of index match of the glass-liquid combination to obtain the refractive index as a function of temperature. Method 1 utilizes a hot stage microscope and monochromator. Method 2 utilizes a hot stage microscope and dispersion staining objective. Modifications of method 1 utilize phase contrast, a Schlieren microscope, or an interference microscope to increase the sensitivity of index match.
Analysis for Crude Fatty Acids (Total Fatty Acids and Unsaponifiable Matter) in Feed Grade Fats: Report of the Joint AOAC-AOCS Committee on the Analysis of Feed Grade Fats
Authors: Quackenbush F W
Published: February 2020

A method for analysis of total fatty acids plus unsaponifiable matter that employs a newly designed liquid-liquid extraction appar at us has given satisfactory results i n a collaborative test. Seven collaborators analyzed samples of prime tallow, chicken fat, yellow grease, 2 samples of cottonseed fatty acids, and 2 samples of acidulated soap stock. The method permits removal of hexane-soluble unsaponifiable matter as a separate fraction. The 3 animal fat samples yielded results which were close to the theoretical value, 95.6, for a triglyceride with 85% C18 and 15% C16 fatty acids. The 4 samples of hydrolyzed vegetable fats gave lower values, probably because of the presence of dark insoluble material. Nevertheless, the method seems to be acceptable for analysis of such low grade samples. The method has been adopted as official first action.
Collaborative Study of Extraction Method for Paraquat Aerosols Containing Hydrocarbons
Authors: Carlstrom A A
Published: February 2020

Hydrocarbons present in aerosol formulations interfere with the colorimetric step in the official final action method for paraquat in formulations, 6.160–6.163. To eliminate this interference, the oil is partitioned into npentane, leaving the paraquat in a sodium sulfate-alcohol-water phase. The standard deviation for analysis of aerosols containing 0.22% paraquat was 0.011, based on results from 18 analysts. The official final action method for paraquat has been revised to include the method for aerosol formulations containing an oil base and the revised method has been adopted as official final action.
Automated Method for Extraction, Cleanup, and Gas Chromatographic Determination of Triazine Herbicides in Soil
Authors: Hörmann W D , Formica G , Ramsteiner K , Eberle D O
Published: February 2020

Complete automation of extraction, cleanup, and GLC determination of residue analysis of some important triazine herbicides in soils has been achieved. Manually sieved soil samples are continuously delivered to the system, which presents cleaned up extracts to an automated GLC injection system. Peak areas are calculated by a digital electronic integrator. The output of the integrator is connected to a teletype printer which generates both printed hard copy and a punched paper tape in standard ASCII code. This information is fed by a punchtape reader into a programmed Wang 700 desktop computer. Final analysis reports are printed by an attached typewriter. The system allows a 4-fold output of analytical results with half the personnel compared to manual analysis.
Tracheal Organ Cultures for the Bioassay of Nanogram Quantities of Mycotoxins
Authors: Cardeilhac P T , Nair K P C , Colwell W M
Published: February 2020

Tracheal organ cultures from day-old chicks can be used in a bioassay to detect nanogram quantities of several mycotoxins implicated in animal diseases. Mycotoxins assayed with the minimum amount detectable (ng) are as follows: anatoxins B1 (22), B2 (1367), and G1 (89); patulin (750); sporidesmin (139); sporidesmin B (163); sterigmatocystin (12); gliotoxin (85); and ochratoxin A (175). By using miniature tissue culture chambers the volume of toxin containing media bathing the explants is reduced to 0.1 ml. The test depends on a cytotoxic effect of the toxins and the 50% lethal concentration (LC50) is considered to be the minimum detectable concentration. Cytotoxic potencies of several mycotoxins vary in a manner similar to their toxicities to the intact animalas indicated by a comparison of the cytotoxic LC50 determined by bioassay to an LD50 for ducklings.
Spectroanalytical Parameters of Fungal Metabolites. I. Citrinin
Authors: Neely W C , Ellis S P , Davis N D , Diener U L
Published: February 2020

The spectral data of the fungal metabolite, citrinin, were investigated and prior work was reviewed. The analytically important concentration ranges for ultraviolet and fluorometric determinations were studied in 3 solvents. The limits of detection were also determined in the solvents as well as on thin layer chromatographic films. CHCl3 was judged to be the best medium for detection and analysis with a limit of detection of 2 × 10−9M. Ultraviolet absorption and fluorescence emission were linear functions of concentration between 1 × 10−6 and 1 × 10−3M and 4 × 10−9 and 2 × 10−5M, respectively. A quantum efficiency of fluorescence of 0.058 and a mean fluorescence lifetime of 1.52 nsec were calculated. Precautions necessary to avoid thermal decomposition and photodegradation of the sample are outlined.
Survey of Ethylenethiourea in Commercial Ethylenebisdithiocarbamate Formulations
Authors: Bontoyan W R , Bontoyan J. B. Looker , Kaiser T E , Giang P , Olive B M
Published: February 2020

Twenty-eight different ethylenebisdithiocarbamate commercial products were examined for ethylenethiourea (ETU), a degradation product of ethylenebisdithiocarbamates. All products contained ETU, which was identified by thin layer and gas-liquid chromatography, infrared spectrophotometry, and mass spectrography. The techniques and parameters for identification and quantitative measurement are described.
Colorimetric Assay of Citral and Citronellal in Volatile Oils
Authors: Karawya Mohamed S , Hashim Fayek M , Hifnawy Mohamed S
Published: February 2020

A specific colorimetric method has been devised for the determination of citral and citronellal in volatile oils in the presence of other constituents , particularly aldehydes and ketones. The method is based on the fact that the reddish color generally produced by Schiff’s reagent with aldehydes fades on t h e addition of methanolic KOH. On acidification with methanolic H2SO4, a permanent, measurable green color develops which is specific for citral and citronellal. Quantitative TLC, based on the color reaction above, was also developed for the determination of citral or citronellal in volatile oils. T h e results were compared with those obtained by the Egyptian Pharmacopoeia 1963 method.
Per Cent Fatty Acid Composition and Quality Differences of Chinook and Coho Salmon
Authors: Iverson John L
Published: February 2020

The fatty acid profiles of prime and “spent” (inferior quality) Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) have been determined. There are indications that the long chain monounsaturated acids are preferentially utilized by the migrating salmon. However, there may be larger generic and specific run variations that preclude the use of a fatty acid compositional approach to differentiate between prime and spent salmon.
Determination of Starch by Glucose Oxidase and Polarographic Measurement
Authors: Trop Moshe , Grossman Shlomo
Published: February 2020

A method for the determination of starch in foodstuffs is reported. Interferences which are sometimes encountered with titrimetric or spectrophotometric determinative steps are avoided. In the method, the starch is hydrolyzed to glucose and the glucose is selectively oxidized in the presence of glucose oxidase. The rate of oxygen absorption for the oxidation reaction is measured and related to the starch content of the foodstuff. Results are presented for wheat and potato flours, which are shown to contain 71 and 59% starch , respectively. The method is specific, accurate, simple, and rapid and is applicable to foodstuffs containing interfering substances which often preclude analysis by other means.
Determination of Iron in Low-Iron Diets by Colorimetric and Atomic Absorption Procedures
Authors: Davies Muriel I , Bush K , Motzok I
Published: February 2020

Colorimetric (sulfonated bathophenanthroline) and atomic absorption methods for the analysis of iron in low-iron diets (7–30 ppm used in the biological assay of iron) gave mean values which were not significantly different; however, the values obtained with atomic absorption were significantly more variable. Copper, phosphate, perchlorate, sulfate, and a mixture simulating some of the mineral constituents of the basal diet in concentrations occurring in digests of the basal diet did not interfere with color development.
Thin Layer Chromatographic Separation and Spectrophotofluorometric Determination of Thiabendazole Residues on and in Citrus
Authors: Norman S M , Fouse D C , Craft C C
Published: February 2020

A thin layer chromatographic (TLC)-spectrophotofluorometric method was developed for quantitative determination of thiabendazole on and in citrus. Whole citrus fruits are surface stripped with ethyl acetate and a concentrated aliquot is separated by TLC. Wholefruit blends, juice, oil, and dried citrus pulp cattle feed are extracted with ethyl acetate, partitioned into 0.1N HC1, and then partitioned into ethyl acetate-chloroform from an aqueous basic solution prior to TLC. Thiabendazole is eluted from the chromatogram with acidified methanol and the intensity of fluorescence is compared to standards similarly chromatographed and measured. The method is accurate in determining thiabendazole content ranging from 0.2 to 6 ppm. Recoveries of thiabendazole from fortified samples were 95–99% for surface strippings and 70–91% for rind and pulp extractives. No significant difference was found between residue values determined by the TLC method and by the Merck method. TLC eliminates citrus constituents which occasionally interfere with the Merck method.
Methods of Estimating Dietary Exposure of the General Population to Organochlorine Insecticide Residues: Diet Analyses 1965–1967
Authors: Mcgill A E J , Robinson J , Stein M
Published: February 2020

The amounts of organochlorine insecticides in the diet of the general population of Great Britain has been estimated by analyzing representative whole cooked meals. The methods of quantitation are briefly outlined and techniques suitable for qualitative confirmation of identity of these compounds are discussed. The estimated dietary intakes are compared with the food in other dietary surveys and, in the case of dieldrin, they are also compared with the amounts calculated from the concentrations of this compound in body fat and blood. The dietary intakes of dieldrin in 1965–1966 and 1967 were estimated to be 0.00030 and 0.00020 mg/kg/day, respectively, the difference being statistically significant. The maximum estimated intakes of total equivalent DDT were 0.0011 and 0.0014, respectively.