bluuebunny/crossref_metadata_2025 huggingface dataset:
Sodium Lauryl Sulfate in Egg Whites
Authors: Wiskerchen John
Published: February 2020

A method is given for the quantitative determination of sodium lauryl sulfate in liquid, frozen, powdered, or flake-dried egg white. The egg white is dissolved in water and the protein is precipitated with ethanol and filtered off. The filtrate is evaporated, the residue is dissolved in water, and the pH is adjusted to 5.0. Total alkyl sulfates are titrated with standard benzethonium chloride solution in the presence of chloroform with bromphenol blue indicator. Results are calculated as sodium lauryl sulfate. The formation of the bromphenol bluebenzethonium chloride complex, when excess benzethonium chloride is present, is taken as the end point. The blue-green complex is soluble in the chloroform. Overall recoveries of sodium lauryl sulfate from egg whites ranged from 94 to 100%. Collaborative study of the method is recommended.
Further Collaborative Studies on Methods for Vanillin and Ethyl Vanillin in Flavoring Material
Authors: Fitelson J
Published: February 2020

A second collaborative study was conducted on two ultraviolet absorption methods for vanillin (the official, final action screening method and the official, first action modified method) and on a paper chromatographic method for the detection of vanillin and ethyl vanillin when present together. All three methods gave adequate and reproducible results. Both the modified ultraviolet method and the paper chromatographic procedure are .recommended for adoption as official, final action.
Determination of Nicotine Residues on Foods
Authors: Martin Robert J
Published: February 2020

Mustard green samples were analyzed by the official method for nicotine content. The final determinative step was made on a gas chromatograph equipped with a thermionic detector (coated with KC1). The final extract was chromatographed on a 6' X 4 mm i.d. glass column containing Gas Chrom Q coated with 10% DC-200 and maintained at 125°C. Flow rate (nitrogen) was 135 ml/niin. Amounts as low as 0.3 μg nicotine were detected. Response was linear from 0.1 to 1.0 μg. For identification, a portion of the effluent was split and 2 or 3 combined injections were trapped in petroleum ether and spotted on a TLC plate as described in This Journal, 49, 175— 179 (1966).
System for the Determination of the Potential Degradability of Urea-Aldehyde Condensates Used as Fertilizers
Authors: Katz Stanley E , Fassbender Carol A
Published: February 2020

A solution biodegradability system, based upon the biochemical oxygen demand principle, narrower fractionation of materials, and use of microbial cultures adapted to these individual fractions, was developed to determine potential availability. Urea-formaldehyde condensates were fractionated into five fractions: the 25°C water-soluble fraction, the fraction insoluble at 25°C but soluble at 50°C, the fraction insoluble at 50 °C but soluble at 75 °C, the fraction insoluble at 75°C but soluble at 100°C, and the fraction insoluble at 100°C. Mixed microbial cultures were developed to utilize the nitrogen in these fractions as a source of nitrogen. Degradation studies of these fractions showed that each fraction used 90—100% of the theoretical amount of nitrogen. Sample sizes as large as 0.2 g of ureaform can be used. When this system was applied to the urea-crotonaldehyde condensate used as a fertilizer, results showed that 90—105% of the nitrogen was utilizable. These biodegradability principles are useful in determining the potential degradability of any urea-aldehyde condensate showing agronomic potential.
Comparison of Various Carbon Adsorbents and Quantitative Elution and Separation of Forty-two Pesticides from a Carbon-Solka Floe Cleanup Column
Authors: Mcleod H A , Mendoza C , Wales P , Mckinley W P
Published: February 2020

Ten different carbons were investigated as adsorbents in a column cleanup procedure for extracts of lettuce and carrots. Organochlorine pesticides were eluted with 175 nil of 1.5% acetonitrile in hexane. The quantitative elution of 13 pesticides as a mixture with and without the presence of carrot or lettuce extract was determined by gas-liquid chromatography (GLC) with electron capture detection (ECD). The mean recovery values for each pesticide from all carbons, excluding Norit A neutral, ranged from 87 to 106% with a coefficient of variation (C) of 3 to 11. In the presence of plant extracts the individual pesticide recoveries for 6 carbons ranged from 75 lo 99% with a C of 6 to 16. All pesticides from 9 individual carbons had mean recovery values ranging from 93 to 108% with a C of 5 to 10. In the presence of plant extracts these values were 81 to 100% with a C of 8 to 12. Four carbons (Darco G60, Darco S51, Nuchar C-190N, Norit FQP) were considered satisfactory in the cleanup procedure. The procedure was applied to quantitative elution of 42 pesticides representing insecticides, fungicides, and herbicides from a Darco G60-Solka Floe cleanup column. The mean per cent recoveries (3 determinations) ranged from 82 to 112 with C from 2 to 10 for 38 compounds. The mean per cent recovery of EPN was 108 with a C of 13. The per cent recoveries of three compounds were considered low: Thimet 72, Daconil 73, and Guthion 77. Twenty of the pesticides as three mixtures containing 2, 4, and 14 compounds were added to plant extracts of carrots, potatoes, wheat, and pineapples. The mean per cent recovery values ranged from 81 to 108 with a C range of 2 to 10 for 17 compounds
A Rapid Specific Method for the Gas Chromatographic Determination of Organophosphate Pesticides in Cold Pressed Citrus Oils
Authors: Stevens Robert K
Published: February 2020

Organophosphate pesticides in cold pressed citrus oils can be determined rapidly by a method using gas chromatographic procedures and the flame photometric detector developed by Brody and Chaney. This study revealed that cold pressed citrus oils obtained from the 1965— 1966 citrus crops from Florida and California contained from 1.5 to 20 ppm thiophosphate pesticides. The analytical procedure required approximately 40 min per analysis and eliminated the need for extensive preparation of the sample prior to introduction into the gas chromatograph. The procedure is more specific and less time consuming than methods previously described
Sesquiterpene Hydrocarbons of Commercial Copaiba Balsam and American Cedarwood Oils
Authors: Wenninger John A , Yates Ronald L , Dolinsky Meyer
Published: February 2020

The sesquiterpene hydrocarbons of commercial samples of copaiba balsam and American cedarwood oils were separated by a combination of techniques including silver nitrate adduction, column chromatography on alumina, distillation, and gas chromatography. Components were identified by their infrared spectra. Of the 24 sesquiterpene hydrocarbons detected in copaiba balsam oil, 18 were identified as follows: δ-elemcne, copaene, β-cubebene, cyperene, α-bergamotene, β-elemene, caryophyllene,γ -elemene, β-farnesene, allo-aromadendrene, α-, β-humuIene, β-bisabolene, α-selinene, β-selinene, δ-cadinene, ar-curcumene, γ -cadinene, calamenene, and a-cubebene (tentatively identified). The following sesquiterpene hydrocarbons were identified in American cedarwood oil: β-eIemene, acedrene, caryophyllene, thujopsene, α-,βhumulene, "acorene," valencene, cuparene, a cuprenene, and two additional hydrocarbons (tentatively identified). Gas chromatographic retention data are reported for 27 of the sesquiterpene hydrocarbons isolated
Gas-Liquid Chromatography of Vitamin B6 (Pyridoxal, Pyridoxol, and Pyridoxamine) and Its Application to Pharmaceuticals Containing Pyridoxol
Authors: Prosser A R , Sheppard A J , Libby D A
Published: February 2020

A gas chromatographic procedure has been developed for the determination of pyridoxal, pyridoxol, and pyridoxamine. These compounds are first converted to their acetyl derivatives and then injected into the gas chromatograph. The acetyl derivatives are formed by the interaction of the vitamin B6 analogs with acetic anhydride in the presence of a catalyst, extracted with a suitable organic solvent, and separated by gas chromatographic techniques. Results were confirmed by infrared, ultraviolet, nuclear magnetic resonance, and mass spectrometry. This technique has been successfully used to quantitatively measure the pyridoxol content of pharmaceutical products
A Sensitive Method for the Detection and Determination of Reducing Substances, as Hydroquinone, in Ergocalciferol
Authors: Guttman David E
Published: February 2020

A rapid and simple method for the detection and determination of reducing substances, as hydroquinone, in ergocalciferol is based on the large difference between hydroquinone and ergocalciferol in rate of reaction with blue tetrazolium. The tetrazolium salt was found to be effectively and rapidly reduced by hydroquinone; only slight reaction occurred with ergocalciferol. The method will detect levels of hydroquinone in the vitamin as low as 0.001% (w/w) and can give a quantitative estimation of hydroquinone content. Some commercial samples of erogocalciferol were found by the proposed method to contain appreciable amounts of hydroquinone that could not be detected by the spectrophotometric method of USP XVII
Spectrographs Determination of Lead in Agricultural and Related Materials
Authors: Maclean K S , Byers D L , Brown M H
Published: February 2020

A quantitative spectrograph^ method has been developed for the determination of lead in plant tissue, soils, and biological material. Organic matter is removed by ashing, and a mixture of 20 mg sample plus 40 mg of a lithium carbonate-graphite buffer is arced in a d-c arc under atmospheric conditions. Lead standards are prepared in a silica dioxide-aluminum oxidesodium carbonate base matrix to cover the range 5—1000 ppm, with bismuth as an internal standard. Other elements do not cause serious interferences. A minimum of 0.2 ppm lead can be determined in plant tissue, 2.5 ppm in soil, and 0.05 ppm in animal livers (dry weight basis). By dilution with base material, lead concentrations of up to 16% can be determined accurately, as indicated by analysis of high grade lead ores. Results for several samples have an average relative error of 5.2%.
Survey of Polycyclic Aromatic Hydrocarbons in
Smoked Foods
Authors: Malanoski A J , Greenfield E L , Barnes C J , Worthington J M , Joe F L
Published: February 2020

A survey was conducted jointly by the Food and Drug Administration and the Department of Agriculture to ascertain the types and amounts of polycyclic aromatic hydrocarbons present in smoked foods. The samples include many varieties of meat products, poultry, fish, and other miscellaneous items. All samples were analyzed by the published methods of Howard et al. Results indicate that many smoked foods contain small amounts (0.5—7.0 ppb) of polycyclic aromatic hydrocarbons
Determination of DLTDP and Other Antioxidants by a
Modified Sublimation Technique
Authors: Fazio Thomas , Howard John W , Sandoval Armando
Published: February 2020

A method has been developed for the determination of dilaurylthiodipropionate (DLTDP) and other antioxidants in lard, using a simplified and less complex vacuum procedure than previously reported. Recoveries ranged from 93-100% for DLTDP, 91-96% for BHT, 85-105% for Ionox- 100, 90-100% for PG, and 9 1% for BHA
TLC Spotting Solvent for Aflatoxins
Authors: Stoloff L , Beckwith A C , Cushmac Mary E
Published: February 2020

Benzene is recommended as a spotting solvent for aflatoxins on silica gel thin layer plates in preference to chloroform. Based on a 12-month study of stability and practical application, aflatoxin in benzene was as stable as in chloroform; benzene was less volatile, helping insure volume integrity, and easier to manipulate than chloroform. Spots on thin layer chromatograms were more compact and uniform when dispensed from benzene than from chloroform.
Whale (Mucous) Heparin with High Anticoagulant Activity
Authors: Nagasawa Kakuma
Published: February 2020

Heparins from whale mucosa have been extracted, purified, and characterized. The analytical differences between whale and bovine heparins are described. In addition, the effects of different biological standards and length of storage of blood on the potency of whale heparins as assayed by the BP and USP methods are described.
Contamination Indexes in Degerminated Corn Products
Authors: Curtis Charles E
Published: February 2020

Insect and rodent contamination in corn milling was studied to improve current methodology and recommend new methodology. Representative whole corn processing equipment, degerminators, grading equipment, and finished products were sampled. Whole corn samples were examined visually and by X-ray techniques; all samples were examined by heavy and light filth extraction methods similar to AOAC procedures. Whenever possible, contaminant counts throughout the system were weighted for stream flow before analyzing and presenting data. WRAP (Weighted Regression Analysis Program) was used in data analysis. The least number of equivalent whole exoskeletons gave the best correlations with radiograph data (r2 values ranging from 57.1 to 69.1%) of any of three methods used to report insects of kernel interior origin recovered in cracking-flotation of whole corn samples. The second trapping in light filth extractions was valuable in recovering additional rodent hairs, insects, and insect fragments from all types of corn and mill samples.
Collaborative Studies of Rapid Methods for the Separation of Extraneous Materials from Whole and Degerminated Corn Meal, Prepared Mustard, and Soy Flour
Authors: Miller Mary T
Published: February 2020

Rapid methods based on acid hydrolysis have been developed for the separation of extraneous material from whole and degerminated corn meal, prepared mustard, and soy flour. Collaborative results by the methods were satisfactory for mustard and corn meal, and the methods are recommended for adoption as official, first action. Recovery of extraneous material from soy flour was variable and further study is needed.
Collaborative Study of Gas Chromatographic Analysis of Heptachlor Content of Formulations
Authors: Malina Marshall
Published: February 2020

A collaborative study was conducted on a gas chromatographic method for analysis of heptachlor formulations that employs a glass column filled with a nonreactive packing to minimize losses of the heptachlor during chromatography. An internal standard and a response correction factor are used to convert peak size to formulation assay. An alternative gas chromatographic (GC) method that permitted free choice of GC parameters was also studied collaboratively. Collaborative results indicate that parameters must be controlled. Results by the described method were excellent, and it is recommended for adoption as official, first action.
Use of Toe Ash as a Measure of Calcification in the Chick
Authors: Fritz James C , Roberts Talmadge
Published: February 2020

The ash content of unextracted chick toes was found to be as satisfactory as the ash content of extracted tibiae for measuring calcification of chick bones in the AOAC vitamin D assay and for studying the availability of phosphorus supplements. By choice of suitable ordinates, response curves of per cent ash of tibiae or toes were superimposable when related to graded doses of vitamin D or dietary phosphorus.
Rapid Near-Infrared Spectrophotometric Method for Determination of Meprobamate in Meprobamate Tablets
Authors: Sherken Stephen
Published: February 2020

A new rapid method is presented for the analysis of meprobamate in meprobamate tablets, in which the meprobamate is quantitatively dissolved in alcohol-free chloroform and the solution scanned on a spectrophotometer in the near-IR region. The method is rapid and shows good agreement with the official NF XII procedure. Assay of eight commercial samples ranged from 98.5 to 101.6% of labeled amount. Analysis of five authentic meprobamate powder mixtures showed an average recovery of 100.3 ± 0.73%. Collaborative recoveries on two authentic meprobamate powder mixtures averaged 104.0 and 98.7%, respectively. With a standard deviation of ± 2 % some of the collaborators reported that they had difficulty with their instruments in the near-IR region, but not with the method itself. The method was recommended for adoption as official, first action.
Chlorinated Hydrocarbons in Drugs: Chloral Hydrate
Authors: Davidson Arthur W
Published: February 2020

A specific colorimetric method for chloral hydrate, studied collaboratively by eight laboratories, is based on the reaction of chloral hydrate with quinaldine ethyl iodide to yield a cyanine dye that is determined spectrophotometrically at 605 mμ. Recoveries on solutions containing 42.00 and 173.8 mg/ml were 102 ± 2 . 5% and 100 ± 2.1%, respectively. The method is recommended for adoption as official, first action.
Determination of Menthol in Cigarette Tobacco Filler
Authors: Tucker Charles L
Published: February 2020

A gas chromatographic method and two variations of a colorimetric method for determining menthol in cigarette tobacco filler were studied collaboratively by 13 laboratories. No statistically significant differences were found in the precisions within or between laboratories. There were no significant differences between means for any two of the three methods for any sample. A trend toward higher mean values was noted for both colorimetric procedures. The colorimetric procedure that uses a nonmentholated tobacco blank gave mean values nearest to those obtained by the gas chromatographic method. It is recommended that both the gas chromatographic method and the colorimetric method that uses the nonmentholated tobacco blank be adopted as official, first action
A Polarographic Method for the Determination of Nitrates in Silage
Authors: Willett D N , Peterson H P , Moubry R J
Published: February 2020

A polarographic method has been developed for the determination of nitrates in silage. After a Florisil-Norit cleanup, the chromium (III)-glycine complex of Hamm and Withrow is used. A comparison of the results obtained by the polarographic and a colorimetric method shows that the results are valid when a high concentration of nitrates (500—5000 ppm) is present in the silages. Nitrite interference must be eliminated by sulfanilic acid; data are presented to show recoveries and destruction of nitrite
Collaborative Study of the Ethyl Acetate Extraction, Sweep Co-distillation Cleanup, and GLC Determination, Using Six Parent Organophosphate Pesticides
Authors: Storherr R W , Watts R R
Published: February 2020

Nine chemists in five laboratories collaborated in testing the combined rapid ethyl acetate extraction and sweep co-distillation cleanup method for multiple organophosphate pesticide residues in crops. Pesticides were detected by GLC with the potassium thermionic detector. The six pesticides studied were Diazinon, methyl parathion, malathion, parathion, ethion, and carbophenothion. Six crops—kale, carrots, lettuce, apples, potatoes, and strawberries—were divided into three groups, and each laboratory was selected to work with a specific group. With unknown fortification levels of 1.0 and 0.5 ppm, the collaborators obtained recoveries of 90+% at each level.
Rapid Cleanup For Carbaryl, Using Channel Layer Chromatography
Authors: Faucheux Lewis J
Published: February 2020

Channel layer chromatography is used as a rapid cleanup procedure for carbaryl residues before semiquantitative determination by thin layer chromatography. With this procedure, apples, lettuce, cabbage, rough rice, cranberries, cucumbers, bell peppers, turnips (greens and bottoms), corn meal, soybeans, hay, mustard greens, strawberries, and puree sweet potato baby food were successfully analyzed for carbaryl at 0,2 and 10 ppm levels.
Collaborative Study of the Thin Layer Chromatographic Method for Carbaryl Residues in Apples and Spinach
Authors: Palmer Nancy J , Benson Walter R
Published: February 2020

A collaborative study by eight laboratories was made of the extraction, cleanup, and semiquantitative TLC determination for 0.05—2.0 ppm carbaryl added to apples and spinach. Satisfactory results were reported by most of the collaborators at levels of 0.1 ppm and above. The comments of the eight collaborators were generally favorable. It is recommended that the method be adopted as official, first action.
Automated Analysis of Organophosphorus Insecticides by Wet Digestion-Oxidation and Colorimetric Determination of the Derived Orthophosphate
Authors: Ott Daniel E , Gunther Francis A
Published: February 2020

Adaptation of an AutoAnalyzer system to the determination of phosphorus in organic compounds now provides an automated technique generally applicable for the analysis of organophosphorus inserticides. Following automated wet digestionoxidation of the compounds (some need preliminary alkaline hydrolysis) the resulting orthophosphate is determined automatically by a colorimetric system reading a phosphomolybdenum blue color at 815 mμ. The total system handles 10 samples per hour with a precision and sensitivity readily practical for organophosphorus insecticide analysis; the insecticidal solutions tested, at concentrations of 2 μg/ml or greater, gave repeatable responses within ± 10%. Manual cleanup procedures for most crop samples are required to remove interfering noninsecticidal phosphorus compounds before the system is applicable to total residue analyses. Thimet (phorate) and phosphamidon at 0.5 ppm in fortified stripping solutions of strawberries were analyzed separately without cleanup, however. Adsorption column chromatography on Florisil has provided rapid and efficient cleanup of fortified spinach extractives prior to automated analysis of Thimet and dimethoate. Autoanalysis of individual spots from thin layer chromatograms provides considerable specificity to this nonspecific analytical system, and for some crops provides all the cleanup necessary. Thin layer "spots" can be introduced directly into the automated system.
Isolation and Determination of Chlorohydrins in Foods Fumigated with Ethylene Oxide or with Propylene Oxide
Authors: Ragelis Edward P , Fisher Barbara S , Klimeck Barbara A , Johnson Corinne
Published: February 2020

Two isolative methods, steam distillation and sweep co-distillation, in conjunction with the ether extraction method, are described for the analysis of 2-chloroethanol in ethylene oxide-treated pepper, celery seed, paprika, turmeric, and gum tragacanth and for the analysis of l-chloro-2-propanol in propylene oxide-treated cocoa, walnut meats, tapioca starch, flour, glazed cherries, and glazed citron. Gas chromatography and infrared spectrophotometry were used to determine and identify the chlorohydrin present. Except in the analysis of propylene oxide-treated tapioca starch and flour, no single isolative method mentioned was applicable at a satisfactory level of sensitivity to all the food products studied. The best attainable levels of sensitivity were 25—50 ppm for sweep co-distillation, recovery range 64—92% ; 5—10 ppm for ether extraction, recovery range 64—92 % ; and 1 ppm for steam distillation, recovery range 50— 87%. Levels of 2-chloroethanol found in five food products commercially fumigated with ethylene oxide ranged from 45 ppm for paprika to 110 ppm for pepper. Levels of l-chloro-2-propanol found in six food products commercially treated with propylene oxide ranged from 4 ppm for cocoa to 47 ppm for glazed citron.
An Enzymatic (Esterase) Method For Identification of Animal and Fish Species
Authors: Thompson Robert R
Published: February 2020

A starch-gel electrophoretic method for the separation of esterases in homogenates of animal tissues was adapted to the histochemical identification of animal species. The method was applied to skeletal muscles of various fish species and warmblooded meat animals. Significant differences were observed in the numbers and locations of esterase bands; these differences permit the identification of the animal species. The esterase method can be successfully used in conjunction with the regular electrophoretic protein identification test for law enforcement purposes.
Qualitative Identification of Chlortetracycline and Oxytetracycline in Feeds
Authors: Smith C Tyson
Published: February 2020

A microscopic method is given for the qualitative differentiation and identification of chlortetracycline and oxytetracycline in mixed feeds at levels usually encountered. Identification depends upon the colors produced by the antibiotics as they pass into solution in modified Sakaguchi reagent 1% boric acid in 70% H2S04, i.e., intense red for oxytetracycline and intense purple for chlortetracycline. Collaborative study gave excellent agreement, and the method is recommended for adoption as official, first action.
Proposed Revision of the Method for Isolating Coagulase-Positive Staphylococci from Foods
Authors: Baer Edward F
Published: February 2020

The AOAC official, first action method for isolating staphylococci from foods should be revised as follows: (a) A three-tube MPN enrichment broth series should be used in place of the present single tube enrichment broth series, and (6) "desiccated coagulase plasma, rabbit, with EDTA," or "desiccated coagulase plasma (rabbit)" to which EDTA or heparin is added should be used instead of plain coagulase plasma (rabbit). It is further proposed that the method be retained in official, first action status pending comparative evaluation of the several other methods recommended for isolation of staphylococcus from foods.
Infrared Studies of Ethylene Chlorohydrin
Authors: T Chen Jo-Yun , Gould John H
Published: February 2020

The infrared spectra of ethylene chlorohydrin as a pure liquid, as a vapor, in CS2 solution, and as a solid under pressure were obtained. The infrared spectral data obtained indicate that ethylene chlorohydrin consists of a dynamic equilibrium of two rotational isomers which are capable of interconversion by heat or pressure. In the vapor phase and dilute solution the substance consists of the gauche and trans monomers which are interchangeable by heating or cooling. In the pure liquid or in the solid state under pressure, it exists as a gauche dimer and trans tetramer. These two forms are also interchangeable by the application of either pressure or heat.
Aflatoxin B1 Hemiacetal
Authors: Borland A E , Cushmac Mary E , Andrellos P J
Published: February 2020

The acid-catalyzed addition of water to the vinyl ether double bond of aflatoxin Bx was investigated. The hemiacetal produced was biologically inactive to the chick embryo and to tissue cultures at respective concentrations 80 and 50 times the minimum lethal dose of aflatoxin B1 The structure of the hemiacetal was established and found to be identical to the hemiacetal reported as an intermediate in the total synthesis of racemic aflatoxin B1
Fluorodensitometric Measurements of Afiatoxins on TLC Plates
Authors: Pons Walter A
Published: February 2020

Eight collaborators analyzed a cottonseed meal extract spiked with known amounts of afiatoxins B1, B2, G1 and G2. Afiatoxins were resolved by TLC on silica gel-coated plates and estimated by solid state fluorescence measurements on the plates. Average recovery values were 93—99% for individual afiatoxins and 97.8% for the total amount added. Coefficients of variation ranged from 3.6 to 15.7% for individual afiatoxins and 4.9% for total afiatoxins. The technique appears to be accurate and precise. It is proposed that collaborative study be initiated
Collaborative Study of the Quantitative Determination of Fusel Oil and Ethyl Acetate by Gas-Liquid Chromatography
Authors: Brunelle Richard L
Published: February 2020

Thirteen chemists representing twelve laboratories participated in a collaborative study for the quantitative determination of ethyl acetate and fusel oil by GLC. The results on four samples containing various amounts of ethyl acetate and fusel oil were compared with the official AOAC procedures. For all samples, the standard deviations were lower with GLC. Collaborators preferred the GLC procedure because the simultaneous determination of ethyl acetate and n-propyl, iso-butyl, and isoamyl alcohols is possible. Results from preliminary work performed on the quantitative determination of acetaldehyde by GLC were encouraging. It is recommended that the proposed GLC procedure for the quantitative determination of ethyl acetate and fusel oil be adopted as official, first action, and that work be continvied on the determination of acetaldehyde by GLC.
Gas Chromatographic Determination of Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT) in Breakfast Cereals
Authors: Takahashi David M
Published: February 2020

A collaborative study was made on a revised GLC method for determination of two phenolic antioxidants, BHA and BHT, in corn and rice ready-to-eat dry breakfast cereals. The method involves extraction of the antioxidants with carbon disulfide, concentration of the extract under nitrogen, and injection into a gas chromatograph equipped with a hydrogen flame ionization detector. Di-BHA was used as the internal standard. Two GLC columns, 4.8% (w/w) Apiezon L on 80—100 mesh Gas Chrom Q and 9.1% (w/w) QF-1 silicone oil on 80 - 100 mesh Gas Chrom Q, were used. Six collaborators participated in this study. The BHA recovery was satisfactory and the BHT recovery seemed reasonable, although BHT was found to be more susceptible than BHA to loss when added to breakfast cereals. All collaborators agreed that the method was very rapid and easy. The method is recommended for adoption as official, first action.
Some Mineral Elements of Commercial Spices and Herbs as Determined by Direct Reading Emission Spectroscopy
Authors: Christensen Robert E , Beckman Robert M , Birdsall John J
Published: February 2020

Data are presented for 14 elements in 33 spices analyzed by a direct reading emission spectroscopic method. For six of the spices, seven elements were verified by atomic absorption and wet chemical methods, and two additional elements were verified by wet chemical methods only. Comparison with conventional wet chemical and atomic absorption methods shows favorable agreement
Precise Fluor ometric Micro determination of Selenium in Agricultural Materials
Authors: Hoffman I , Westerby R J , Hidiroglou M
Published: February 2020

A precise, accurate, and comparatively rapid fluorometric method for the determination of selenium in the nanogram range is described and results are presented for Youden's uniformity and ruggedness tests. The sample is digested in a nitric-sulfuricperchloric acid mixture, potential interferences are masked with disodium EDTA, and selenium is complexed with freshly-prepared 2,3-diaminonaphthalene solution and estimated fluorometrically after extraction into cyclohexane. On the basis of its performance, collaborative study of the method is recommended
Collaborative Study of Atomic Absorption Spectrophotometry Method for Determining Zinc in Foods
Authors: Rogers Grayson R
Published: February 2020

An atomic absorption method for determining zinc in foods has been studied by ten collaborators, and the method appears to be accurate and precise. The collaborative samples consisted of three sucrose solutions of known zinc content, soya meal, white flour, and whole wheat flour and ranged in zinc content from 5 to 60 ppm. Both wet and dry ashing were used as the preparatory step. Average recoveries in the collaborative study ranged from 98 to 102% with a standard deviation of 0.2-2.0 and 0.8-2.97 by wet and dry ashing, respectively. The method is recommended for adoption as official, first action
Colorimetric Determination and Thin Layer Identification of Boron as Boric Acid in Caviar
Authors: Brunstad Joan W
Published: February 2020

A quantitative colorimetric method has been developed which determines boron in caviar in the 0—5 μg range. Boron is released from caviar through sulfuric acid fuming and hydrogen peroxide oxidation. Subsequent treatment results in a dehydrated precipitate. The latter reacts with curcumin in nonaqueous acid solution to form a stable color complex. Boron is identified in the range 1—3 ng by thin layer chromatography; excess dye is separated from the boroncurcumin complex. Color change of the complex, using strong base and acid, confirms the presence of boron. It is recommended that these methods be subjected to collaborative study
Identification of Isovaleric Acid in Incubator Reject Eggs and Observation of Other Unidentified Components in Decomposed Eggs
Authors: Bethea Sammie , Wong Noble P
Published: February 2020

Analysis of eggs by the AOAC official methods demonstrated the presence of previously unreported components in decomposed eggs. Using column partition, gas chromatography, and gas chromatography with a mass spectrometer, isovaleric acid was established as one of the unknown components in incubator reject eggs.
Dursban® Determination in Milk and Body Tissues of Cattle
Authors: Claborn H V , Mann H D , Oehler D D
Published: February 2020

A procedure for cleanup and determination of Dursban® in milk and tissues of cattle is described. Extracts containing 0.05 ppm (milk) and 0.012 ppm (tissue) were successfully cleaned up, using a silicic acid or Florisil column, with detection of residues by electron capture gas chromatography. Recoveries ranged from 75 t o 100%.
GLC of Sorbitol in Bakery Products, Wines, and Vinegars. Bv Harvey K. Hundley
Authors: Hundley Harvey K
Published: February 2020

Sorbitol is extracted from bakery products with methanol. Aliquots of wines and vinegars are taken directly. Sugars and sugar alcohols are acetylated, then extracted with chloroform. The acetates are determined by gas-liquid chromatography with a flame ionization detector.
Collaborative Study of an Ultraviolet Method for Measuring Diquat Content in Formulations
Authors: Carlstrom A A
Published: February 2020

The ultraviolet method for diquat described by Yuen, Bagness, and Myles in 1967 was collaboratively studied with formulations containing 2 lb diquat/gal. A portion of the sample is diluted with an acetate buffer solution and the absorbance is measured at 310 mμ the diquat content is obtained by reference to a standard curve prepared from known diquat concentrations. Single determinations on two samples by thirteen collaborators show an overall coefficient of variation of 2.4%. The coefficient of variation for random error is 1.0%, and for systematic error 1.6%. The method is recommended for adoption as official, first action.
Chromatographic Procedure for Determination of Reserpine in Tablets. I. Comparison with USP Method
Authors: Kunze Frieda M , Barkan Susan
Published: February 2020

A column partition procedure for the analysis of reserpine in tahlets is presented. The sample formulation is triturated with dimethyl sulfoxide (DM SO), incorporated on Celite, and transferred to a column containing hase, acid, and water layers. Recovery is quantitative; no degradation of reserpine by DM SO is evidenced.
Modification of the Carbon Disulfide Evolution Method for Dithiocarbamate Residues
Authors: Keppel George E
Published: February 2020

A study was made of the analytical method for dithiocarbamate fungicide residues based on decomposition by hot mineral acids to the amine and carbon disulfide and colorimetric measurement of the carbon disulfide. Increased recoveries are obtained by the following modifications: adding a reducing agent (stannous chloride) to the sample before treatment with hot acid; svibstituting diluted sodium hydroxide for lead acetate solution to remove hydrogen sulfide and other interferences; and using boiling diluted hydrochloric acid. With these modifications, recoveries of N,N-dimethyldithiocarbamates from crops ranged from 85.3 to 103.8% (average 94.7%). Ethylenebisdithiocarbamates, with the exception of zineb (range 89.1–96.8%, average 92.0%), gave appreciably lower recoveries, indicating further study is necessary.
Studies on the Effect of Sulfuric-Fuming Nitric Acid Treatment on the Analytical Characteristics of Toxaphene
Authors: Kawano Y , Bevenue A , Beckman H , Erro F
Published: February 2020

Toxaphene and a similar compound prepared from purified camphene were used in comparative studies for the analysis of residues of this pesticide before and after treatment of the compounds with a mixture of sulfuric-fuming nitric acid. The analytical characteristics of toxaphene were not affected by the acid treatment, as shown by GLC, TLC, and IR. The technique is useful for the GLC analysis of toxaphene residues in the presence of DDT and certain other insecticide residues.
Method for the Extraction of Light Filth from Plant Gums
Authors: Roaf Andree L , Brickey Paris M
Published: February 2020

A new method has been developed for the extraction of extraneous materials from plant gums. Hydrochloric acid and autoclaving are used to break down and disperse partially insoluble gums, followed by sieving and extracting using a trap flask. Collaborative studies gave reproducible recoveries of rodent hairs and insect fragments, and the method is recommended for adoption as official first action.
Automated Quantitative Determination of Selected Nitrogen-Containing Drugs
Authors: Leaton J R
Published: February 2020

Pharmaceutical preparations and selected raw materials ar e analyzed by anautomated nitrogen analyzer for the quantitative estimation of the organo-nitrogen compound. The assay method is based on a catalytic combustion process in which the drug is decomposed to elemental nitrogen, which is measured volumetrically. Tablets, powders, liquids, and suspensions are analyzed with little or no sample preparation. Recoveries from commercial preparations ranged from 98 to 102% of theory or declared amount. Degree of selectivity and specificity is limited; the chemical composition of the drug analyzed must he known. Guidelines for operating conditions are given.
Cholinesterase Inhibition Autoanalysis of Insecticidal Organophosphates and Carbamates
Authors: Voss Günther
Published: February 2020

An automated cholinesterase inhibition method gave satisfactory results during the development of insecticidal organophosphates and carbamates. Up to 40 samples/hr were analyzed with a precision equal to that of purely chemical methods performed manually. The lower limit of detectability of the method depends primarily on the inhibition potency of the particular compound under investigation and upon whether the system is operated in a pre-inhibition (most sensitive) or simultaneous inhibition (least sensitive) mode. Monocrotophos, for example, was analyzed in the concentration ranges of 0.1–2.0, 1–20, 10–200, and 100–2000 ppm; the last two concentration ranges were analyzed in the simultaneous inhibition mode. Sensitivities better than those achieved with human plasma :holinesterase, i.e., 0.1 ppm for monocroophos, were obtained by using a more sensiive type of cholinesterase, such as peacock ilasma cholinesterase. Examples of experinents, such as determinations of the stability if formulations, rates of hydrolysis, parti timing behavior of insecticides, solubilities in vatcr, and the determination of a cholineserase-inhibiting impurity in a technical samde of phosphamidon, are also described and locumented by original AutoAnalyzer reordings.
Statistical Examination of a Rapid Method for the Determination of Chlorinated Hydrocarbon Residues in Human Blood
Authors: Bonderman D P , Choi U Y , Hetzler H L , Long K R
Published: February 2020

An orderly examination of the laboratory parameters involved in the recovery of the chlorinated hydrocarbon residue, p,p′-DDE, from human blood serum by the method of Dale, Curley, and Cueto is reported. The age of the serum, amount of hexane used for extraction, duration of mixing time, and temperature were varied; the results were examined statistically to discern the possible effects. All these factors had a statistically significant effect upon the results of the analytical quantitation performed by GLC. The aging time of these rum and the amount of hexane used for the extraction as well as the aging time and duration of mixing time were intercorrelated. Modification for use of the published procedures based upon these findings is suggested.
Collaborative Study of a Chemical Method for Calcium Pantothenate
Authors: Hubbard W D , Sheppard A J
Published: February 2020

A chemical method for determining calcium pantothenate in pharmaceutical preparations has been studied collaboratively. The pantothenate molecule is cleaved with acid, and the resulting β-alanine is treated with a chlorinating solution and then with potassium iodide. The free iodine is measured spectrophotometrically at 358 mμ. The average coefficient of variation for all samples studied collaboratively is 8.9%. The method is recommended for adoption as official first action.
Vitamin A in Liquid Feed Supplements
Authors: Parrish D B , Aguilar Dalia
Published: February 2020

Maleic values were determined on vitamin A extracts from liquid feeds so that estimates could be made of biopotency of the vitamin A; the AOAC method is not suitable for this assay. Biopotencies were 57–81% of total vitamin A found. For comparison, maleic values were determined on Vitamin A Reference Solution and on chicken, quail, and rat livers. Most vitamin A in those sources appeared to be the all-trans form. Results of bioassays of vitamin A in liquid feeds indicate that further work is required before the assays are suitable for comparative purposes with results of biopotency estimates using maleic values.
Recommended Changes in the Sugar Chapter of the Official Methods of Analysis of the Association of Official Analytical Chemists
Authors: Kviesitis Boris
Published: February 2020

Changes are recommended in the arrangement of Chapter 29, “Sugars and Sugar Products”, since the present arrangement makes it difficult to determine which of the methods are acceptable for molasses analysis. It is recommended that a new section, “Molasses and Molasses Products”, be established as part of Chapter 29.
Collaborative Study on a Potentiometric Titration of Soluble Chlorides in Feeds
Authors: Sharpe D L
Published: February 2020

In the method described, a weighed feed sample is placed in 200 ml water, 1 ml nitric acid is added, and the chlorides present are titrated with silver nitrate. The titration is performed with a potentiometer equipped with a silver-silver chloride reference electrode a nd a silver indicating electrode. Collaborative s tudy showed that the method is more precise than the official method. An arithmetic mean for the coefficients of variations was 8.0 and 4.1, respectively, for the official and the potentiometric method.
Effect of Soluble Components on Crude Fat Determination in Grains and Stock Feeds
Authors: Debecze George I
Published: February 2020

Individual and collaborative tests were made to demonstrate the differences between fat values obtained by the “washed” and “unwashed” methods and to define the crude fat method that yields the true fat values. In an individual study on 18 samples and in a collaborative test by 7 participants on 20 commercial feed samples, the fat values by the two methods were identical on many samples; the washed method yielded lower fat values on certain samples and higher values on other samples. The differences were as much as –49% or +64%. The results were statistically evaluated. Based on these results, it is recommended that a statement be included in method 22.033 for aqueous extraction of samples containing large quantities of water-soluble substances prior to the fat determination.
Infrared Determination of Dithianon
Authors: Double R C
Published: February 2020

An infrared spectrophotometric method of analysis of dithianon in concentrates and formulated powders containing zineb and sulfur has been developed. Dithianon is extracted with chloroform from the concentrate or formulation; the extract is evaporated and diluted to a specific volume with chloroform; and the dithianon present is determined from the infrared absorption at 1275 cm-1. From 20 to 80 mg dithianon in 10 ml chloroform are readily determined.
Determination of Zinc Phosphide and Its Stability in Rodent Baits
Authors: Guerrant G O , Miles J W
Published: February 2020

An improved method for determining zinc phosphide has been developed that employs liberation of phosphine by refluxing with hydrochloric acid with subsequent determination by the alkalimetric quimociac phosphorus method. Zinc phosphide was found to he relatively stable when used on apple and potato baits for rodent control, with over 70% of the activity remaining after 99-day exposure under simulated baiting conditions. Decomposition occurs more rapidly in the juices of the moist surface of freshly prepared bait than on the dried baits. Decomposition is slow in a carbon dioxide atmosphere and is accelerated by moisture.
Modifications of the Assay of Bacitracin in Feeds
Authors: Craig G H
Published: February 2020

Modifications of the official first action method for bacitracin in final feeds have been investigated. An improved petroleum ether cleanup of the feed in a Goldfisch apparatus replaces the present acetone wash in a centrifuge tube. A more sensitive assay makes it possible to assay at a final concentration of 0.04 unit/ml instead of 0.10 unit/ml. Standard curves prepared in blank extracts of several types of feed at dilutions used in assaying bacitracin in the 4–10 g/ton range were similar to simultaneously prepared curves in buffer.
Fatty Acid Composition of Cocoa Butter Oil by Urea Fractionation and Programmed Temperature Gas Chromatography
Authors: Iverson John L , Harrill P G , Weik Robert W
Published: February 2020

This proposed urea fractionation procedure concentrates esters with similar GLC retention times in separate fractions. GLC peaks of esters present in cocoa butter oil in trace amounts (0.001–0.1%), which are normally hidden under major peaks, can then be detected. By modified programmed temperature GLC techniques, it is possible to detect the short and long chain length fatty acids present in cocoa butter oil. The odd and even chain length saturated acids from C10 to C28, mono-unsaturates C16 to C24, branched acids C16 to C24, and linoleic and linolenic acids were detected.
Thin Layer and Gas-Liquid Chromatography of Cholesterol in Fats and Oils. II. Collaborative Study
Authors: Thorpe C W
Published: February 2020

A method employing TLC-GLC for detecting animal fats in vegetable fats was subjected to collaborative study. The method involves preparative TLC of unsaponifiable matter followed by GLC of the isolated sterols. The results of this study, based on GLC determination of cholesterol in the isolated sterols, indicate that low levels (2.5%) of animal fat can be detected. The possibility of obtaining false positive results is greatly reduced compared with direct GLC of unsaponifiable matter or column chromatographic fractionation of unsaponifiable matter followed by GLC analysis.
Collaborative Study of Confirmative Procedures by Single Sweep Oscillographic Polarography for the Determination of Organophosphorus Pesticide Residues in Nonfatty Foods
Authors: Gajan Raymond J
Published: February 2020

Ten laboratories collaboratively studied several single sweep oscillopolarographic methods designed to be used as confirmative procedures for several organophosphorus pesticide residues determined by GLC. Polarographic methods for the detection and determination of parathion, methyl parathion, diazinon, and/or malathion at 0.5 and 2.0 ppm in extracts of apples and lettuce were included in this study. All 10 laboratories successfully detected the organophosphorus pesticide residues and quantitative results were reported by seven laboratories. These results show that the polarographic methods can be used for rapidly confirming results obtained by the multiple detection procedures now in use.
Comparison of Ten Methods for the Analysis of Milk for Residues of Chlorinated Pesticides
Authors: Lawrence James H , Burke Jerry A
Published: February 2020

Ten methods for the analysis of milk for residues of chlorinated pesticides were used to analyze a sample of milk containing a residue of heptachlor epoxide and fortified with p,p’-TDE, 1.00 p pm fat basis. Based on the p,p’-TDE determined, average recoveries above 90% were obtained with six methods, and 89, 85, 79, and 56% recoveries, respectively, with four methods. Cleanup efficiency for determination by electron capture GLC and thin layer chromatography varied from good to poor.