bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Colorimetric Method for the Determination of Methyl Salicylate in Medicated Oils
Authors: Dutt M C
Published: February 2020

The well-known reaction between methyl salicylate and ferric chloride has been successfully applied to the quantitative estimation of methyl salicylate in medicated oils. An aqueous solution of ferric chloride is added to an ether solution of medicated oil dissolved in excess water. After filtering, the absorbance of the filtrate is measured at 530 m/j, and the content of methyl salicylate is determined from a calibration curve. Methyl salicylate recoveries range from 92 to 97% for concentrations between 10 and 60% in a synthetic mixture. The method is simple and rapid, and compares favorably with Wilson’s method.
Effects of Calcination Temperature and Time on the Retentive Properties of Florisil Used for Pesticide Residue Analysis
Authors: Burke Jerry A , Malone Bernadette
Published: February 2020

Nineteen samples of Florisil, calcined at times ranging from 2 to 16 hours and temperatures ranging from 1000 to 1400°F, were evaluated by checking the elution of certain chlorinated pesticides and the retention of butterfat extractives by the column. Results indicated the choice of 1250°F/ three-hour calcination as the desired “activation.” Subsequent evaluations of 22 lots calcined at these conditions over a 5-month period showed consistency in the product as obtained from the manufacturer. This material, designated 60/100 PR (Pesticide Residue) Grade, is suggested for use in certain pesticide residue methodology.
Channel Layer Chromatography (CLC) : A Cleanup Procedure For Pesticide Residue Analysis
Authors: Matherne Mederic J , Bathalter William H
Published: February 2020

The chromatographic properties of aluminum oxide G are utilized to separate pesticide residues from plant extractives. A square glass plate is prepared with recessed, discrete parallel channels; the channels are filled with aluminum oxide G, creating flat rectangular columns or strips. Plant extractives are applied to the channel layer strip and the strip is chromatographed, first with acetonitrile and tetrahydrofuran (1 + 1) and then with acetonitrile alone. As the solvent rises, plant extractives remain in place or move only part way up the column, while pesticide residues move more rapidly and stay with the solvent front. The portion of the channel layer strip containing the solvent front (and any pesticides present in the product) is mechanically removed from the plate, and the pesticides are eluted from the adsorbent. This solution is injected directly into the gas chromatograph for identification and quantitative measurement. Addition of aldrin and endrin (0.050 and 0.030 ppm each) and dieldrin and thiodan (0.050 and 0.020 ppm each) to a composite of peanuts, onions, carrots, and cabbage resulted in recoveries from 74 to 98%. Recoveries of various chlorinated pesticides from different crops were good, ranging from 78 to 118%. Recoveries of pesticides from various food crops after cleanup with the Florisil column and with CLC were comparable.
Response Characteristics of a New “Stacked” Flame Ionization Detector
Authors: Abel Kenneth , Lanneau Keith , Stevens Robert K
Published: February 2020

A modified Karmen “stacked” flame detector has been designed which has controlled specificity for phosphates and halides in the order of 100,000–200,000 to 1 over other organic species. The background current of the upper flame is controlled by electrically heating a coil coated with an alkali salt, thus enabling the investigator to optimize the parameter for his burner gas mixture without consideration of the background current. From this study, it has been observed that a burner gas mixtvire of oxygen and hydrogen reduced the response for phosphates and preferentially favored organohalides. The detector can be applied to analysis of biological tissue extracts.
Response Characteristics of a New High Temperature Electron Capture Detector
Authors: Yauger W L , Addison L M , Stevens R K
Published: February 2020

An electron capture detector, which uses Ni63 as its radioactive source and whose design features permit operation up to 300°C, has been developed and tested. This detector exhibits essentially the same electron capture characteristics as a parallel plate detector using tritium, but it does not lose its activity when operated above 200°C. Continuous operation of this detector for 6 months at 300°C did not change its response pattern to a variety of organohalide and phosphate pesticides. Maintenance of this response integrity over a 6-month span shows that this detector is a considerable improvement over existing systems for routine quantitative gas chromatography of pesticide residvies.
An Improved Enzymatic-Ultraviolet Method for Determination of Uric Acid in Flours
Authors: Sen N P , Smith D Morison
Published: February 2020

Main improvements in the enzymaticultraviolet method for uric acid in flours include elimination of the uricase precipitation by trichloroacetic acid, which was not reproducible, and destruction of uricaselike material in flour before extraction. The method is capable of measuring as low as 3.2 mg uric acid per 100 g flour and is applicable to a variety of cereal products such as rice, rye, corn and soya flours, as well as barley, oats, etc.
Radioactivity in Phosphate Animal Feed and Fertilizers
Authors: Habashi Fathi
Published: February 2020

Commercially available defluorinated phosphate and dicalcium phosphates marketed as animal feed contain 0.01-0.02% uranium. If an animal is fed 1 lb of this material, a dose of about 0.17 microcurie will be given, which is about 20 times the maximum permissible limit.
Spectrophotometric Determination of Hexachlorophene and Zinc Phenolsulfonate in Aerosol Deodorants
Authors: Will Fritz , Varsel Charles
Published: February 2020

A spectrophotometric method has been developed for the determination of hexachlorophene (HCP) and zinc phenolsulfonate (ZPS) in aerosol deodorants. An ethanolie solution containing hexachlorophene and zinc phenolsulfonate was partitioned between water and chloroform, and the zinc phenolsulfonate was determined in the water phase at 270 mμ. The chloroform phase, containing hexachlorophene, was extracted with 0.1N KOH, and the hexachlorophene was determined in the KOH phase at 320 mμ. The method has been applied successfully to commercial samples of aerosol deodorants. The relative standard deviation at the 2 sigma level is ± 3.5% for hexachlorophene and ± 2.6% for zinc phenolsulfonate.
Determination of Methylcarbamate Pesticides in the Presence of Methyl Anthranilate in Concord Grapes
Authors: Broderick E J , Bourke J B , Mattick L R , Taschenberg E F , Avens A W
Published: February 2020

For a valid infrared analysis of carbamate pesticides in ripe Concord grapes, interference from methyl anthranilate should be eliminated without altering the carbamate concentration. This is possible by extracting the samples with acetone, filtering, and partitioning into chloroform. The sample is then cleaned up by precipitation with an aqueous ammonium chloride solution, methyl anthranilate is removed with a 25% hydrochloric acid wash, and the carbamate is determined by infrared spectroscopy. This method removes 93% of the interfering methyl anthranilate, thus permitting detection of as little as 50 μg of carbamate.
Micro-Infrared Analysis of Dieldrin, Endrin, and Other Chlorinated Pesticide Residues in Complex Substrates
Authors: Payne W R , Cox William S
Published: February 2020

The combination of column and thin layer chromatography provides an effective technique for the isolation of “trace” amounts of chlorinated hydrocarbon insecticides in complex substrates. These insecticides can then be identified by micro-infrared spectroscopy. The extraction procedures, column techniques, and KBr pellet preparation for analyses of chlorinated pesticides in industrial wastes are described.
Experiments with Evaporation of Solutions of Chlorinated Pesticides
Authors: Burke Jerry A , Mills Paul A , Bostwick David C
Published: February 2020

Various experiments with evaporation techniques and equipment have shown that severe losses of pesticides may occur when solutions are concentrated to volumes of 0.5 ml or less. About 10 ml of solution can be rapidly concentrated to 0.1–0.3 ml without loss of pesticide by attaching a micro Snyder column to a K-D collection tube and evaporating on a steam bath.
Separation and Identification of Substituted Urea Herbicides by Paper Chromatography
Authors: Mitchel Lloyd C
Published: February 2020

Nine substituted urea herbicides and/or their TCA salts and TCA can be separated from one another by the use of two solvent systems, one aqueous and the other nonaqueous, with the exception of monuron and 3-(2-chlorophenyI)-l-methylurea; the latter, however, is not a commercial pesticide. The compounds are detected in the chromatogram by screening under ultraviolet light, except TCA, or by spraying with the silver nitrate-2-phenoxyethanol chromogenic agent followed by exposure to germicidal ultraviolet light, except fenuron and the fenuron moiety in fenuron TCA.
Determination of Sorbitol in Bakery Products
Authors: Hundley Harvey K , Hughes Duane D
Published: February 2020

Sorbitol is extracted from bakery products with water, and nonreducing sugars are inverted by acid hydrolysis. Carbohydrates other than the sugar alcohols are degraded in alkaline solution and reaction products are removed by ion exchange resins. Sorbitol is determined by the amount of periodate consumed in oxidation and identified by thin layer chromatography.
Quantitative Determination of Sugar Alcohols in Dietetic Foods by Gas-Liquid Partition Chromatography (GLC). I. Analysis of Dietetic Biscuits
Authors: Jones H G , Smith D M , Sahasrabudhe M
Published: February 2020

GLC has been used to quantitatively measure the amount of sugar alcohols in dietetic biscuits. The total hexitol content is estimated by analysis of the trimethylsilyl ethers (TMS) and the individual hexitols are estimated as the acetate esters. An internal standard (1,4-sorbitan) was added to the biscuit during the extraction procedure. The TMS ethers were chromatographed on an SE-30 GLC column and the acetate esters were detected on a QF-l/BDS column. Recoveries of total hexitols from biscuits baked in the laboratory were 97–100%. Analyses of various commercial biscuits were also reported.
Analysis of Sunscreens in Suntan Preparations
Authors: Davis Henry M
Published: February 2020

Amyl p-dimethylaminobenzoate in suntan preparations is isolated by partition chromatography, and identified and determined by ultraviolet spectrophotometry. Known amounts of amyl p-dimethylaminobenzoate added to prepared bases were successfully recovered.
Gas-Liquid Chromatography of Some Fatty Acid Esters and Alcohols in Lipsticks
Authors: Gross Frederick C
Published: February 2020

Gas-liquid chromatography (GLC) is used to separate and determine the lipstick ingredients: butyl stearate, oleyl alcohol, cetyl alcohol, isopropyl myristate, and isopropyl palmitate. The interfering hydrocarbons normally found in lipsticks are removed by column chromatography prior to the GLC analysis. Two columns, Triton X-405 on Fluoroport T and Carbowax 20M on Fluoroport T, are used in the procedure. Those ingredients which are not well separated on one of these columns will separate on the other. An internal standard technique is used for quantitative determination of the ingredients. Recoveries of 93–107% were obtained when known amounts of these compounds were carried through the procedure. Recoveries in the same range were obtained when the compounds were added to commercial lipsticks. The method should be applicable to the determination of these compounds in other types of cosmetics. It is recommended that study be continued.
Improved Techniques for Determining Available Phosphorus in Fertilizers
Authors: Midriff V C
Published: February 2020

The determination of available phosphorus in fertilizers by the direct available gravimetric quinoline molybdate method has been made 100% faster and considerably easier by use of a multiple-unit pipetter and other glassware similarly bound together in multiple units. Each piece of apparatus and its operation are described.
Determination of Dienestrol Diacetate in Mixed Feeds
Authors: Hill V B , Schneider E L , Martin E E
Published: February 2020

Dienestrol diacetate in broiler feeds is isolated by extraction followed by alkaline hydrolysis to yield the parent phenolic compound. Interferences are removed by partition between NaOH and chloroform, in a manner similar to the AOAC procedure for diethylstilbestrol. The dienestrol is acidified, extracted with chloroform, and measured spectrophotometrically at 610 mμ after reaction with anisaldehyde. Recovery of dienestrol diacetate from 4 feeds known to contain 23–92 ppm ranged from 93 to 107% with coefficients of variation of 7.0–16.4%. Values for blank feeds were low enough to exclude a feed blank from the analytical procedure. Amounts of colorimetric reagents, reaction time, and linearity of response were studied. Of 24 common medicaments and 6 solvents tested, only acetone interferes.
Identification of Fish Species by Agar Gel Electrophoresis
Authors: Hill Wilma S , Learson Robert J , Laxe J Perry
Published: February 2020

An electrophoretic method for the identification of fish species is described in which agar gel is used as the supporting medium. Electrophoresis takes place under constant temperature and voltage, and protein is detected by staining. The gels are fixed to glass histological slides that may be preserved indefinitely. Six determinations may be done together in less than three hours. This method has been used for species identification of fish in the fresh, frozen, freeze-dried, and precooked states.
Detection of Chick Edema Factor and Other Chlorinated Hydrocarbons in Fats and Oils by Electron Capture Gas Chromatography: Use of TLC as a Preliminary Cleanup Procedure
Authors: Huang Anita , Firestone David , Campbell A D
Published: February 2020

A thin layer chromatographic (TLC) procedure is described for detecting chick edema factor in fats and oils. A specific fraction containing chick edema factor compounds is isolated by TLC from extracted unsaponifiables and cleaned up by sulfuric acid treatment. The residue is analyzed by electron capture gas chromatography. Results on several toxic samples of fats or fatty acids were comparable to the alumina adsorption column-electron capture gas chromatographic procedure. A 1.56% reference toxic fat sample can be detected under the conditions described. Toxicity of the specific TLC fraction was verified by tissue culture and chick embryo assay. Highly chlorinated biphenyls and naphthalenes which produce characteristic symptoms of chick edema disease at higher levels than the chick edema factor were also detected.
Collaborative Comparison of Dumas and Kjeldahl Methods for Nitrogen in Feeds
Authors: Ebeling Melvin E
Published: February 2020

A collaborative study to compare the Dumas and Kjeldahl methods for nitrogen determination in agricultural feed materials has been completed. The Dumas method used the Nitrogen Analyzer II, Coleman Model 29A. The mean values of the six feed materials studied showed good agreement between the two methods. Standard deviation ranged from ±0.18 to ±0.39 for the Dumas method and from ±0.06 to ±0.40 for the Kjeldahl method. For two organic standard materials studied, the Dumas method gave better accuracy. Standard deviation for both methods on these organic standards was poorer than for the feed materials, and further study is recommended.
Detection of Adulterated Concord Grape Juice with Other
Anthocyanin-Containing Products
Authors: Mattick L R , Weirs L D , Robinson W B
Published: February 2020

A method is proposed for the detection of the adulteration of Concord grape juice with other anthocyanin-containing products. This method is.based on the aqueous separation of the monoglucosides followed by a densitometer tracing. An increase in the malvidin inonoglucoside content of the juice indicates the possibility of adulteration with the vinifera or hybrid varieties. To more specifically determine adulteration with hybrids, an evaluation of an increase in the diglucosidc content would be used as the criterion, primarily the large increase in the malvidin 3,5-diglucoside
Collaborative Study Using Atomic Absorption Spectrophotometry for the Determination of Copper in Alcoholic Products
Authors: Strunk Duane H , Andreasen A A
Published: February 2020

A collaborative study was conducted on the 'atomic absorption spectrophotometric method for measuring the concentration of copper in alcoholic products. In this method, the samples are aspirated directly into the burner of the instrument, and the absorhance values are converted to ppm copper by reference to a standard curve. Data show good precision and are comparable to those obtained by the ZDBT method. It is recommended that the atomic absorption method be adopted as official, first action.
Difference in Composition Between Crude Fiber and Acid-Detergent Fiber
Authors: Kim Jong T , Gillingham John T , Loadholt Claude B
Published: February 2020

When crude fiber content of feces, silage, and pellets was determined by the AOAC and acid-detergent methods, the ADF method invariably yielded higher results. Differences between methods varied directly with lignin content of original materials and were most pronounced in feces. Regression equations would not provide acceptable AOAC values from determined aciddetergent fiber (ADF), especially in feces. Crude fiber was isolated from above materials by both methods and analyzed for lignin, pentosans, and cellulose. ADF contained more lignin but less pentosans and cellulose than the AOAC fiber. Differences in pentosan content were smallest. Cellulose content of the fibers varied inversely with the lignin content. ADF retained virtually all lignin and cellulose bvit lost 82— 84% of original pentosans. AOAC fiber retained original cellulose but lost 60—84% of original lignin and 80—86% of original pentosans. The retention of cellulose and the loss of pentosans by both methods are not consistent with animal digestive studies.
Response of Fertilized Eggs of the Mollusk Bankia setacea to Aflatoxin
Authors: Townsley P M , Lee E G H
Published: February 2020

Aflatoxin B1 inhibits cell cleavage in fertilized mollusk eggs without preventing fertilization or nuclear division. The reaction is very dramatic and positive since fertilized eggs in the presence of aflatoxin are multinuclear, whereas the controls have multiplied to multicellular larvae. The bioassay requires a minimum of technique and training and is sensitive to concentrations of 0.05 μg/ml. Because the reaction is observed with the aid of a low-powered microscope (70X), the concentration of aflatoxin required can be reduced considerably below 0.05 μg. The test required two to four hours for completion when observing egg division and 18 hours for swimming larvae.
Method for the Detection and Estimation of Ochratoxin A in Some Cereal Products
Authors: Scott P M , Hand T B
Published: February 2020

A method for the detection and semiquantitative estimation of ochratoxin A in flour and other cereal products is described which can be used in conjunction with analysis of the foodstuff for aflatoxins. The sample is extracted with aqueous methanol and n-hexane and the toxin is partitioned on a Celite column, as in the AOAC method for determination of aflatoxins in peanut products. Ochratoxin A is separated by thin layer chromatography and estimated by the intensity of fluorescence compared with that of a reference standard. By this procedure, 0.01 μg ochratoxin A can be detected in 10 μl final sample extract, corresponding to a detection limit of about 25 μg/kg cereal foodstuff. The method is applicable to whole wheat flour, corn meal, barley cereal, and rice cereal. Recoveries of 80—100% of added ochratoxin A were obtained
Comparison of Adhesive Tapes by Neutron Activation Analysis
Authors: Scott J E , Hoffman C M , Pro M J , Schlesinger H L
Published: February 2020

Adhesive tapes were compared by nondestructive gamma-ray spectrometry. Results show that neutron activation analysis can he used to characterize tapes through their elemental composition. Differences between manufacturers as well as hatch-tobatch and in-batch variations can be measured by neutron activation analysis.
Study of Moisture, Ash, and Organic Content of Peat Samples
Authors: Thorpe Virginia A
Published: February 2020

Two simple techniques are described to measure the moisture, ash, and organic content of peat materials with the necessary accuracy and precision. Recommended changes in sample size and ashing temperatures from last year's study were incorporated, and the methods were studied collaboratively. An alternative method was also included in the study; this method provides a more stable sample when pH, nitrogen, and fiber content determinations are made on the same sample. The proposed methods, as amended, are recommended for adoption as oflicial, first action.
Comparison of Slow-Release Nitrogen and Water-Insoluble
Nitrogen Methods for Fertilizers
Authors: Holt Kenneth E
Published: February 2020

A collaborative study was made to compare AOAC method 2.057 for determination of water-insoluble organic nitrogen (WIN) with the slow-release nitrogen method adopted as official, first action in 1965. Both methods showed improvement in precision over the 1964 study. The betweenlaboratory standard deviation of the WIN method was 6.16 in the 1964 study and 1.03 in 1966; the slow-release method was 4.42 in 1964 and 0.65 in 1966. With the improved precision, the two methods will give significantly different results on some types of fertilizers. This difference will affect the calculation of the activity index of urea formaldehyde. It is recommended that both methods be retained in Official Methods of Analysis.
Collaborative Study of a Method for Multiple
Organophosphorus Pesticide Residues in Nonfatty Foods
Authors: Wessel John R
Published: February 2020

Twelve collaborators from 6 laboratories studied a multiple detection gas chromatographic method (potassium chloride thermionic plus electron capture) for ronnel, ethion, Trithion, diazinon, methyl parathion, parathion, and malathion in leafy vegetables (lettuce) and fruits (apples). Residues were present at the 0.5 and 5.0 ppm levels. Average recoveries for the 7 residues at the 0.5 ppm level were 88.7% (by thermionic) and 91.2% (by electron capture) from apples. At the 5.0 ppm level, average recoveries were 89.0% (by thermionic) and 89.4% (by electron capture) from lettuce. Residues in most instances were confirmed by TLC.
Microbiological Method for Assaying Lincomycin in Animal
Feed
Authors: Neff A W , Barbiers A R , Northam J I
Published: February 2020

Collaborative results on the assay of Iincomycin in animal feeds indicated that this antibiotic can be assayed at levels around 4 g/ton with reasonable accuracy and precision. In this study the larger of the two fortifications, which differed by only 10%, were detected 90% of the time. The method is recommended for adoption as official, first action.
Microbiological Assay of Procaine Penicillin in Feeds
Authors: Mayernik John J
Published: February 2020

A modified microbiological assay for the determination of penicillin was submitted for collaborative study. The assay is carried out by the cylinder plate method with Sarcina lutea, A.T.C.C. 9341, as the test organism. Modifications consist of extracting penicillin from the feed with bufferacetone (1 + 1) in a single step by either a mechanical shaker for 30 min. or a high speed blender for 2 min. In addition, when feeds contain < 0.1 g/lb penicillin, a 50 g sample is extracted with 200 ml bufferacetone; otherwise, smaller samples are extracted with 100 ml. Six feeds containing 1.5—1680 g/ton penicillin were extracted both by mechanical shaker and by high speed blender and were analyzed by 13 collaborators. Difference in results between methods of extraction was not statistically significant. Recoveries ranged from 93 to 102%, coefficient of variation from 4.7 to 13.7%. It is recommended that the collaborative method be adopted as official, first action.
Detection and Identification of Dehydrated Red Beets
in Capsicum Spices
Authors: Schwien William G , Miller Bob J
Published: February 2020

Dried red beet pulp used as an adulterant in capsicum spices may be detected by removing the capsicum oil with petroleum ether and isolating the red beet particles from the decolorized spice. The beet particles are identified and confirmed by microscopic examination, paper chromatography, and spectrophotometric analysis
Determination of the Freezing Point of Milk by
Thermistor Cryoscopy
Authors: Henningson R W
Published: February 2020

Specific directions for the thermistor cryoscopic method, including uniformity in cooling, degree of supercooling, seeding, and reading procedures, are proposed for the present official method. It is emphasized that the instrument must be in the proper condition for use, must be properly calibrated, and must be properly utilized by the analyst. Each analyst should individually calibrate with standards by the same uniform procedure for standards and milk samples. The precautions necessary in the determination are part of the method and must be observed if the same sample is to yield the same freezing point value for different analysts, in different laboratories, at different times
Collaborative Studies of Methods for Butterfat in
Homogenized and Chocolate Milk
Authors: Mitchell D J
Published: February 2020

The modified rapid detergent (TeSa), AOAC Roese-Gottlieb, and Babcock methods for determining butterfat were compared in a collaborative study on 8 samples of homogenized milk by 6 laboratories. The modified rapid detergent and Roese- Gottlieb methods were also compared on 4 samples of chocolate milk by the same collaborators. There was a statistically significant difference between the Roese-Gottlieb and detergent methods in 5 laboratories for homogenized milk and in 4 laboratories for chocolate milk. Additional developmental work is necessary before the detergent method can be applied to homogenized and chocolate milk
Rapid Determination of Protein in Milk by Dye Binding
Authors: Sherbon J W
Published: February 2020

A rapid test for protein content in fluid milk, developed by Udy, was studied collaboratively. The test is based on the spectrophotometric measurement of excess Acid Orange 12 remaining in solution after the dye-protein complex has been removed. The dye, at a concentration of 1.300 g/L, is carried in a 0.05M phosphate buffer; 40 ml dye is mixed with 2.24 ml milk. The mixture is shaken and filtered, and the supernatant is read in a previously calibrated spectrophotometer set at 480 mμ. A flow through cuvette of 0.3 mm path length is used. Collaborative results on 39 samples in 5—7 laboratories show a small but significant variation between laboratories. This variation is smaller than that obtained by the Kjeldahl method. Within-laboratory variation was less with the dye binding procedure than with the Kjeldahl procedure. Based on these results, it is recommended that the dye binding method be adopted as oflicial, first action
Gas Chromatographic Analysis of Heptachlor Content of
Formulations
Authors: Malina Marshall
Published: February 2020

The heptachlor content of solid or liquid formulations can be determined by gas chromatography of extracts of the formulation and calculated by relating the area of the chromatographic peak to the peak of the internal standard. Results by 6 laboratories exhibit good precision and accuracy for liquid formulations but indicate a significant negative bias for solid formulations
Sweep Co-Distillation Cleanup of Fortified Edible Oils for
Determination of Organophosphate and Chlorinated
Hydrocarbon Pesticides
Authors: Storherr R W , Murray Edward J , Klein I , Rosenberg Lynn A
Published: February 2020

The technique of sweep co-distillation developed for organophosphate pesticides in fruits and vegetables was expanded for application to organophosphate and chlorinated hydrocarbon pesticides in edible oils. A modified longer and wider Storherr tube and heating assembly was used in this work and 3 mm diameter glass beads replaced the glass wool packing used in crop work. The work on oils was performed at 248 ± 3°C with a nitrogen flow of 600 ml/min and injection of a sweeping solvent every 3 minutes for 30 minutes. Phosphate pesticides were analyzed by GLC with a potassium thermionic detector and chlorinated pesticides were determined by ECGLC, after a micro Florisil column was used to eliminate extraneous peaks. Recoveries of ten phosphate pesticides from nine edible oils ranged from 74 to 100% at fortification levels of 0.04 to 6.25 ppm; average recoveries for the individual pesticides were 90—99%. Average recoveries for the chlorinated pesticides ranged from a low of 75% for Tedion to a high of 98% for endrin and dieldrin. Sensitivity of 0.01 is readily obtainable for compounds such as parathion and heptachlor cpoxide. The sweep co-distillation method is suitable for the rapid determination of the 14 chlorinated and 10 organophosphate pesticides tested in edible oils
Method for Isolation and Detection of Dioctyl Phthalate from Milk Lipids
Authors: Cerbulis J , Ard J S
Published: February 2020

A method has been developed to isolate dioctyl phthalate (DOP, di-(2-ethyIhexyI) phthalate) from milk. Milk from an individual dairy farm was dialyzed and evaporated to dryness, and the dry residue was extracted with petroleum ether. The petroleum ether extract of dried milk was chromatographed on an alumina column as described by Hanahan. The fraction containing free fatty acids and DOP was separated by thin layer chromatography (TLC). DOP was distinguished from other phthalates by TLC and infrared spectroscopy
Chlorinated Hydrocarbons in Drugs: Chlorobutanol
Authors: Davidson Arthur W
Published: February 2020

A method for chlorobutanol, a widely used antibacterial preservative for aqueous solutions of drugs, was studied collaboratively by 8 laboratories. In the method, chlorobutanol is eluted with carbon disulfide from a Celite column and determined by infrared spectrophotometry and/or gas-liquid chromatography. Both determinative steps are specific and accurate to ± 2—3% for aqueous solutions of chlorobutanol in the 0.1—0.5% range. Recoveries on solutions containing 0.4736% chlorobutanol were 100 ± 2.2% and 98.9 ± 2.3% for the IR and GLC determinations, respectively. Recoveries on solutions containing 0.2327% chlorobutanol were 103 ± 3.1% and 102 ± 3.3% for the IR and GLC determinations, respectively. The method is recommended for adoption as official, first action.
Further Collaborative Studies on the Official, First Action Tuberculocidal Test Method
Authors: Ortenzio L F
Published: February 2020

The AOAC official, first action method was slightly revised with regard to the density of the suspension of the organism used to contaminate the porcelain carriers and the addition of gelatin to the culture before maceration in the tissue grinder. Additional collaborative studies on 2 commercial germicides and on the pure chemical phenol showed that approximately one-half of the reporting laboratories were in good agreement. The method is recommended for adoption as official, final action.
Gas-Liquid Chromatographic Method for the Determination of Fat-Soluble Vitamins. IV. Application to Vitamin K1
Authors: Libby David A , Prosser A R , Sheppard Alan J
Published: February 2020

The parameters for the detection and quantitative measurement of vitamin Ki by gas-liquid chromatography are reported. On SE-30, the most satisfactory immobile phase, the vitamin K1 peak was completely resolved from tocopherols included in test materials. Quantitatively, 0.5 and 2,/μg can be effectively measured with the hydrogen flame ionization and the beta-ionization detectors, respectively. Both detectors gave a linear response to increasing quantities of vitamin K1
Determination of Loss on Drying in Roasted Ground Coffees
Authors: Mccarron Eleanor A
Published: February 2020

Air oven (at 105°C), vacuum oven (at 80 and 100°C), and toluene distillation procedures were investigated for determining moisture in roasted ground coffees. Equilibrium conditions and concordant results were found for air oven and vacuum oven (at 100°C) procedures on "fine" grinds of coffee with about 6 hours of drying. For "coarse" grinds the air oven procedure showed a uniformly lower loss than the vacuum oven procedure.
Determination of Geographical Origin of Spices. I. Cassia and Cinnamon by Thin Layer Chromatography
Authors: Voelker William A , Skarzynski Jean N , Stahl William H
Published: February 2020

A thin layer chromatographic method has been devised to differentiate the geographical origin of cinnamons (cassias). For the one-dimensional screening method, benzene-ethyl acetate-glacial acetic acid (90: 10:1, v/v/v), was used as the solvent system. The two-dimensional system first used hexane-acetone (85:15) and then benzene- ethyl acetate (85:15). The following products were differentiated on the basis of fluorescing spots, some spots common to all and some spots unique: Saigon cassia, Batavia cassia, Korintji cassia, Ceylon cinnamon, and Seychelles cinnamon. The technique is primarily designed as a quality control tool to evaluate incoming shipments of raw materials. However, it can he used to determine composition of unknown mixtures of the ground cinnamons. The technique permits judgment within ± 2 0 % of one type in a mixture
Thin Layer Chromatography of Some Carbamate and Phenylurea Pesticides
Authors: Finocchiaro Josephine M , Benson Walter R
Published: February 2020

Nineteen carbamate pesticides and three structurally related phenylureas were examined on thin layer chromatographic plates. These compounds have been divided into 4 groups, based on their Rf values and their responses to chromogenic agents: 8 aryl N-methylcarbamates; 2 aryl N-methylcarbamates containing tertiary amines; compounds containing chlorine, i.e., 4 carbamates and 3 phenylureas; and 5 other carbamates. Two adsorbents, two solvent systems, and four chromogenic sprays were used to separate and distinguish these compounds. Some compounds qualitatively came through a cleanup procedure previously reported for carbaryl.
Determination of Niagara NIA-10242 and Its Phenol Degradation Product in Corn Silage and Milk and Determination of Other Carbamates by GLC of their Thiophosphoryl Derivatives
Authors: Bowman Malcolm C , Beroza Morton
Published: February 2020

Niagara NIA-10242 (2,3-dihydro-2,2-dimethyl- 7-benzof uranyl methylcarbamate), an insecticidal carbamate, and its phenol degradation product in corn silage were analyzed as follows: liquid chromatography on alumina to separate the two compounds, alkaline hydrolysis of the carbamate to produce the phenol, steam distillation of the phenol, coupling of the phenol with dimethyl chlorotliiophospliate, and gas chromatography of the product with the phosphorus flame photometric detector (526 m/i filter). Recoveries of residues at levels of 0.5-5.0 ppm were 88-98% for the carbamate and 74—95% for the phenol. Recoveries from milk at levels of 0.5—2.0 ppm were 9 5 - 9 9% for IVIA-10242 and 7 8 - 82% for the phenol. Response was linear over at least 3 decades of concentration. The limit of sensitivity was about 0.04 ppm/100 g corn silage and 0.02 ppm/200 g milk. The derivatization procedure (without the steam distillation step) was-applied to eight other carbamates and one phenol, and the products gas chromatographed well. Because they contained phosphorus and sulfur, these derivatives were analyzed with and found to respond to the electron capture detector and the flame photometric detector in the phosphorus and sulfur modes. The procedure seems to be sensitive and highly specific for carbamates that form the thiophosphoryl derivatives
Programmed Temperature Gas Chromatographic Technique
for Detecting Trace Amounts of Fatty Acids
Authors: Iverson John L
Published: February 2020

In the rapid procedure described here, orange juice is screened for the presence of sorbic acid by measuring the UV absorbance of iin alcoholic solution of the juice. The sorbic acid is isolated by solvent extraction, measured quantitatively by UV spectrophotometry, and finally identified by paper chromatography
Rapid Determination of Sorbic Acid in Orange Juice
Authors: Floyd Kermit M
Published: February 2020

This article presents a review of the most important methods of analysis which have been published during the last decade for the common preservatives sulfur dioxide, sorbic acid, nitrate and nitrite, and benzoic acid
Moisture Analysis of Freeze-Dehydrated Cottage Cheese
Authors: Fowler James L , Coleman Charles H
Published: February 2020

A large number of samples of dehydrated cottage cheese are received by government laboratories for moisture analysis, and the apparatus for performing the test by the prescribed method lacks adequate capacity to handle them. Therefore, an experiment was designed to test whether analysis by an alternative method making use of high capacity apparatus would give comparable results. It was concluded that the mechanical convection air oven, 100—102°C, 16—18 hr drying time, did not give results comparable to the specified vacuum oven method
Determination of Propylene Glycol in Cosmetics by Gas Chromatography
Authors: Gross Frederick C , Jones John H
Published: February 2020

Propylene glycol in cosmetics can be determined by co-distillation in water followed by GC measurement of the distilled propylene glycol on a Porapak Q column and a hydrogen flame detector. The procedure has been successfully applied to a number of commercial samples; 14 of 15 sample recoveries were between 95 and 102%, the other recovery was 92%.
Determination of Glycerol in Cosmetics by GLC. I. Development of the Method
Authors: Gross Frederick C , Jones John H
Published: February 2020

Glycerol, in the absence of water, may be determined easily and accurately by GLC on a column containing SAIB on silanized Chromosorb G. Aqueous glycerol solutions are dehydrated without loss of glycerin by adding 2-methoxyethanol and evaporating to a small volume. Procedures for determining glycerol in various cosmetic products are described; recoveries of glycerol by the proposed procedure ranged from 95 to 105%.
Determination of Anthraquinone Intermediates in D&C Violet No. 2
Authors: Stein Charles
Published: February 2020

The certifiable color D&C Violet No. 2 (l-hydroxy-4-p-toluino-anthraquinone) may contain small quantities of quinizarin (1,4- dihydroxyanthraquinone) or 1-hydroxyanthraqninone. In the method described, both intermediates are extracted from D&C Violet No. 2 and are measured spectrophotoinetrically. Recoveries of 0.2 and 0.5% of added intermediates ranged from 95 to 1 0 3 %
Spectrophotometric Determination of BHA and BHT in Vegetable Oils
Authors: Johnson D P
Published: February 2020

Improved spectrophotometric methods have been developed for separate determinations of BHA and BHT in vegetable oils. The methods are applicable in the presence of other synthetic antioxidants and are adaptable to BHA and BHT concentrations ranging from 5 to 200 ppm. BHA is nitrosated directly in the oil and the nitroso product is isolated by a combination of solvent extraction and liquid chromatographic techniques. An alkaline solution of the product is measured spectrophotometrically at 480 mμ, and the absorbance is referred to a calibration curve to determine the BHA concentration. Both the 2- and 3-isomers yield approximately the same absorptivity, and Beer's Law is obeyed from 0 to 50 μg BHA/ml final solution. BHT is determined by its ultraviolet absorption at 283 mμ. The compound is separated from the oil by direct extraction into acetonitrile. BHT is isolated from BHA and other extraneous materials by chromatography on alumina
Determination of Nonfat Dry Milk in Meat Products with a Specific Enzymatic Assay
Authors: Hankin Lester
Published: February 2020

A method based on the specificity of the enzyme galactose oxidase for galactose is proposed for the determination of nonfat dry milk in meat products. This enzyme, coupled with peroxidase and a chromogen, o-tolidine, measures the amount of galactose liberated from the nonfat dry milk in the product by HC1 hydrolysis. A standard composed of nonfat dry milk is tested concurrently, thus providing a direct assay for this material. The proposed method is not influenced by carbohydrate-containing materials, other than nonfat dry milk, which may be present in the sample. Data are presented to show the validity of the method
Simple Method for Determination of Glycine and Niacin in Drug Mixtures
Authors: Egli Keith L , Romano Anthony
Published: February 2020

A method, based on the formol titration of glycine and the ultraviolet absorption of niacin, has been developed for the determination of these compounds in drug mixtures. Neither compound requires isolation for the determination. Glycine and niacin are identified by thin layer chromatography
Gas-Liquid Chromatographic Method for the Determination
of Fat-Soluble Vitamins. VI. Application to Pharmaceuticals
Containing Menadione
Authors: Hubbard W D , Sheppard A J
Published: February 2020

Gas-liquid chromatography has been used to quantitatively determine menadione (vitamin K3) in pharmaceuticals, using a 1% neopentyl glycol succinate column and a hydrogen flame detector. The gas chromatographic measurements compare favorably with results by the National Formulary methods on the same samples.
Determination of Saturated and Unsaturated Fatty Acids:
Comparison of Gas-Liquid Chromatographic, Thiocyanogen
Number, and Lead Salt-Ether Methods
Authors: Lacroix Denis E , Prosser A R , Sheppard A J
Published: February 2020

The weight per cent composition of the C16—Cis series of fatty acids in edible vegetable oils was determined by GLC, lead salt-ether, and thiocyanogen number methods. Total saturated and unsaturated fatty acid percentages obtained by GLC and the lead salt-ether methods were in poor agreement; the lead salt-ether unsaturated fatty acid percentages tended to be higher than the GLC values. The thiocyanogen number values for unsaturation were higher than GLC values lor every fat and oil analyzed except one. The polyunsaturated fatty acid percentages obtained by the thiocyanogen number method were not similar to the GLC values for about half of the fats and oils examined.
Interferences Encountered in Determining Potassium in
Fertilizers by Atomic Absorption Spectrophotometry
Authors: Hoover William L , Reagor John C
Published: February 2020

In the development of an atomic absorption method for the analysis of potassium, several interfering materials were found that influence the absorption of 7664.9A radiation by potassium. The same interfering materials had very little effect on absorption at 4044.1A. However, high phosphorus content caused varying amounts of interference at 4044.1A, depending on the presence of other ions. Various grades of fertilizer were analyzed by the proposed atomic absorption procedure at 4044.1A. Atomic absorption analyses, even though there was a low bias, compared favorably with analyses by STPB and other procedures used by commercial laboratories. The proposed atomic absorption method has merit because of its speed and simplicity
Comparison of the Automatic Dumas (Coleman Model 29A Nitrogen Analyzer II) and Kjeldahl Methods for the Determination of Total Nitrogen in Agricultural Materials
Authors: Morris G F , Carson R B , Shearer D A , Jopkiewicz W T
Published: February 2020

A wide variety of agricultural materials were analyzed for total nitrogen by the Kjeldahl and automatic Dumas methods. The recoveries of nitrogen compared favorably by both methods when a catalystassisted combustion technique was used in the automatic Dumas method. Statistical evaluation of the experimental data, as measured by standard deviation, showed that the Kjeldahl method was generally more precise than the automatic Dumas method
Studies of Losses of Pesticides During Sample Preparation
Authors: Chiba M , Morley H V
Published: February 2020

The loss of pesticide residues during sample preparation after extraction was studied. Filtration, partitioning and washing, concentration, and evaporation were examined separately, using 14C-labeled γ- BHC, p,p'-DDT, and dieldrin as representative insecticides. Washing-out of polar solvents was also investigated, using 14Clabeled methanol, acetone, and acetonitrile. Although losses of insecticide residues during filtration and partitioning and washing are relatively small, they are cumulative and cannot be neglected. Polar solvents are not completely removed by normal washing procedures. The possible significance of the presence of these trace amounts of polar solvents in column cleanup is discussed. Evaporation to dryness caused the most significant loss; it is not recommended even in the presence of soil co-extractives because they do not completely prohibit loss. A recommended standard procedure for soil extracts is given which yields quantitative recoveries of insecticides with five different solvent systems. The procedure should also serve as a guide for plant and animal extracts.
Staining Technique to Differentiate Insect Fragments, Bird Feathers, and Rodent Hairs from Plant Tissue
Authors: Stein Richard , Eisenberg William V , Brickey Paris M
Published: February 2020

A staining method is described in which plant material is differentially stained from insect fragments, rodent hairs, and bird feather barbules. Because the colors of the stained plant tissue contrast with that of the dyed extraneous material, counting of the contaminants becomes easier, rapid, and more accurate.
Collaborative Study of a Method for Sodium Lauryl Sulfate in Egg Whites
Authors: Wiskerchen John
Published: February 2020

A colorimetric method for the quantitative determination of sodium lauryl sulfate in liquid, frozen, and powdered egg white was studied by eight collaborators. Determinations were made on flake and powdered egg white at levels of 0.05, 0.1, and 0.2% (w/w) and on liquid egg white at levels of 0.006, 0.0125, and 0.0250% (w/w) sodium lauryl sulfate. The egg white is dissolved in water, and the protein is precipitated with ethanol and removed by filtration. An aliquot of the filtrate is evaporated to dryness, and the residue is dissolved in water and acidified with sulfuric acid. The sodium lauryl sulfate is complexed with Azure A, extracted into chloroform, and determined spectrophotometrically at 637 mμ. A blank determination is made on another aliquot of the filtrate by complexing the sodium lauryl sulfate with benzethonium chloride. This is a stable colorless complex. Average recoveries in the collaborative study were 98—102% with a mean deviation of 2.8—5.4%. It is recommended that the method be adopted as official, first action.
Collaborative Study of Microbiological Assay of Oxytetracycline in Feeds
Authors: Billman D C , Clark H
Published: February 2020

A collaborative study was made of a modification of the official AOAC method for the determination of oxytetracycline in feeds. This cylinder plate method uses Bacillus cereus var. mycoides, ATCC No. 11778, as the test organism. The modification consists of using a 20 g instead of a 10 g sample, of using an extraction flask instead of a mortar and pestle or a blender, and of filtering the assay solution. The average recovery of oxytetracycline by 12 collaborators was 92.4% with an average coefficient of variation of 13.5%. Assay precision, determined by computing standard deviations on the differences between pairs of similar materials, was estimated to be 7.4% at 10 g/ton and 5.9% at 25 g/ton. The method is recommended for adoption as official, first action.