bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectrophotometric Determination of Codeine in Terpin Hydrate Elixir
Authors: Milos Charles
Published: February 2020

In the proposed method for codeine in terpin hydrate elixir, p-toluenesulfonic acid and a sample of elixir are incorporated as a stationary phase on a partition chromatogram. Elution with large quantities of ether removes everything but the codeine-p-toluenesulfonic acid complex, which is eluted with chloroform-acetic acid in four steps. The complex is passed over a column containing NaHCO3 as stationary phase, yielding the isolated codeine. Codeine is determined quantitatively from absorption at 278 mμ. The average recovery of codeine reported by the collaborators was 99%.
Determination of Dihydrocodeinone in Mixtures with Antihistamines. II. Methapyrilene
Authors: Levine Joseph , Doyle Thomas D
Published: February 2020

The official procedure for dihydrocodeinone in mixtures with antihistamines gives high results with commercial samples containing methapyrilene. Two impurities which cause this failure have been separated from commercial methapyrilene. Both are separated from dihydrocodeinone in a Celite:1N succinic acid partition column, giving quantitative recovery of pure dihydrocodeinone.
Ammonia as an Index of Decomposition in Crabmeat
Authors: Burnett James L
Published: February 2020

A method, based upon the color reaction between NH3, thymol, and bromine, uses ammonia as an index of decomposition in fresh or frozen crabmeat. The color is extracted into re-butyl alcohol and net absorbance is determined by subtracting absorbance at 475 mμ. from that at 682 mμ. Sensitivity is about 1 ppm NH3. The method is very rapid and requires no special apparatus. Samples of crabmeat decomposed under controlled conditions were examined and graded organoleptically. Ammonia content was determined and found to increase uniformly and rapidly with spoilage. Good reproducibility and low results were obtained on fresh crabmeat. Ammonia can be detected by the method before spoilage can be detected organoleptically.
Collaborative Study of the Photometric Molyb do vanadate Method for Phosphorus
Authors: Heckman Mary
Published: February 2020

Sixteen laboratories analyzed five feed samples, with phosphorus levels ranging from about 0.60 to 5.50% by the photometric molybdovanadate method studied in 1963 (This Journal, 46, 836 (1963)), and by either the volumetric method, 22.061, or the gravimetric quinoline molybdate method (ibid., 47, 170 (1964)), both of which have some official status. Eight sets of results based on the volumetric method and eight based on the gravimetric method were available. Means for all methods were in good agreement. Standard deviations and coefficients of variation were satisfactory for all methods, indicating superiority of both volumetric and gravimetric methods over the photometric method. Calculation of standard deviations for the entire range tested, however, showed the photometric method to be superior to the volumetric method and inferior to the gravimetric. The molybdovanadate method was adopted as official, first action.
Spectral-Chromatographic Procedure for Caffeine
Authors: Borker Emanuel , Sloman Katherine G
Published: February 2020

A spectral-chromatographic procedure for the determination of caffeine, based on a modification of the Levine procedure, was submitted for collaborative study. Results from eight collaborators indicate that the method is accurate for coffee products and a beverage sirup. For decaffeinated soluble coffee the method is more accurate and more precise than the Bailey-Andrew methods. However, it is not as precise as the Bailey-Andrew methods for regular soluble coffee or for roasted and ground coffee.
Vacuum Sublimation Cleanup Procedure for Pesticide Residue Analysis
Authors: Farrow Richard P , Elkins Edgar R , Beacham Lowrie M
Published: February 2020

Vacuum sublimation at pressures less than 2 μ and at a temperature of 85°C has been used as a cleanup method to prepare pesticide residue extracts for detection and estimation by gas-liquid chromatography. Most of the 35 pesticide compounds tested could be sublimed from spinach and other food product extractives in analytically useful amounts. Gas chromatographic columns used on these sublimates performed well for long periods before becoming contaminated with plant materials. Some materials can be cleaned up sufficiently for thinlayer or paper chromatography, but in most instances supplementary cleanup is required before these methods can be applied to sublimates. In two years of use on a number of sample materials, vacuum sublimation proved to be a useful addition to the selection of cleanup methods available for residue analysis.
Isolation and Determination of Aflatoxin B1 in Cottonseed Meals
Authors: Engebrecht R H , Ayres J L , Sinnhuber R O
Published: February 2020

A method for the isolation and determination of aflatoxins in commercial samples of cottonseed meal has been devised. Meal samples were defatted with hexane and the aflatoxins removed from the meal by acetone extraction. The pigments and residual lipids were removed from the acetone by nitration of the cold solution. The anatoxin was further isolated by evaporating the acetone and redissolving the residue in hot methanol. After cooling, the insolubles were discarded and the methanol-soluble materials taken up in chloroform. The chloroform solution was spotted on silicic acid thin layer chromatographic plates along with suitable anatoxin standards. After development with 9:1 (v/v) chloroform :acetone, the chromatographic plates were examined under ultraviolet light. Four of the eight cottonseed meals examined contained fluorescent material chromatographically similar to aflatoxin B1 in amounts varying from 19 to 186 parts per billion (ppb). The identity of the material in the 186 ppb sample was verified as aflatoxin by duckling bioassay. Trials using rainbow trout confirmed the chemical findings. These trout experiments will be described in detail in another report.
Collaborative Study of a Proposed Method for the Determination of Primary and Subsidiary Dye Components of D&C Red No. 21 (Tetrabromofluorescein)
Authors: Koch L
Published: February 2020

The method proposed by Hanig and Koch, This Journal, 46, 1010 (1963), was studied collaboratively. Recoveries of total dye ranged from 90.45 to 106.32%. The method will be studied further to obtain cleaner and more sharply defined color zones and to see whether fluorescence can be minimized.
Separation of Synthetic Organic Colors in Lipsticks by Thin-Layer Chromatography for Quantitative Determination
Authors: Silk Rachel S
Published: February 2020

Thin-layer chromatographic procedures have been developed by which most of the colors present in current commercial lipsticks can be separated. Most lipstick colors are separated on one plate with two solvent systems, but the presence of D&C Red No. 7 requires a slightly altered procedure. A plate with a buffered zone is added and an additional development step is used. The color recovery was determined by the analyses of 16 lipsticks from four manufacturers.
A Rapid and Specific Method for the Determination of ZnO in Various Pharmaceuticals
Authors: Romano A , Turczan J , Polito M V
Published: February 2020

A method was devised to determine ZnO polarographically. Studies were made on commercial preparations and known mixtures to determine the accuracy of the method. Recoveries from a known mixture averaged 98.1–101.2%. The method is as accurate as the official procedure, more specific, and less time-consuming.
New Colorimetric Method for the Determination of the Nitrate and Nitrite Content of Baby Foods
Authors: Kamm Len , Mckeown G G , Smith D Morison
Published: February 2020

A new method for the determination of nitrite and nitrate in foods will accurately determine concentrations as low as 1 ppm. 1-Naphthylamine is diazotized by nitrite and coupled with excess amine to give 4-(lnaphthylazo)-l-naphthylamine. The compound is extracted into CHCI3, the extract is acidified with methanol-hydrochloric acid, and absorbance is measured at 555 mµ. Nitrate is quantitatively reduced by passage through a cadmium column and determined as nitrite; nitrite passes through the column unaltered. Therefore, in samples containing both forms of nitrogen, nitrate is determined by difference. The method was applied to 194 samples of baby foods. Spinach, beets, wax beans, squash, “garden vegetables,” green beans, carrots, and “mixed vegetables” were found to contain, on the average, more than 20 ppm nitrate nitrogen.
Interlaboratory Comparison of the Official AOAC Ester Determination for Alcoholic Beverages with a Colorimetric Method
Authors: Blessinger E T , Laroe E G , Conner H A
Published: February 2020

The official AOAC ester determination, 9.030, was compared with a colorimetric method for measuring the concentration of esters in Bourbon whisky. The colorimetric procedure involves the reaction of the esters with hydroxylamine to form hydroxamic acids, which are reacted with ferric ions to form a colored complex that can be measured colorimetrically. An analysis of variance shows that the colorimetric determination is more precise than the official method. There was no significant difference in the accuracy of the two methods. Since the colorimetric procedure does not involve a hydrolysis step, it requires less time than the AOAC method.
Use of an Ion Exchange Resin in the Determination of Isoniazid (INH) in the Presence of p-Aminosalicylic Acid (PAS)
Authors: Fan M C , Wald Waltraud G
Published: February 2020

A method is proposed which removes PAS with the ion exchange resin from the PAS-INH mixture. The ingredients could then be assayed spectrophotometrically. When applied to commercial products containing buffers, this method gave results comparable to those of the AOAC method.
Pesticide Residues in Total Diet Samples
Authors: Cummings J G
Published: February 2020

Pesticide residue data are presented on a total diet sample, which was collected at Baltimore, Md. in May 1964. The analytical methods employed, which included electron capture and microcoulometric gas-liquid chromatography and thin layer chromatography, could detect more than 20 chlorinated pesticides, 7 herbicides, parathion, methyl parathion, carbaryl, and total bromides. The results parallel the findings on previous market basket samplings except that residues of the 2,4-D herbicide-type were detected for the first time.
Chemical Determination of Calcium Pantothenate
Authors: Hubbard Willard D , Hintz Mary E , Libby David A , Sutor Roger P
Published: February 2020

A chemical method for the determination of calcium pantothenate in pharmaceutical preparations is presented. The method involves a number of modifications of a method of Zappala and Simpson to make it applicable to a wide variety of materials. The pantothenate molecule is cleaved with acid, and the resultant β-alanine is treated with a chlorinating solution and then with potassium iodide. The free iodine is measured spectrophotometrically at 358 mμ. Interfering color, which cannot be eliminated by washing off the outer coating of tablets, is taken into account by the use of a sample blank. The results, obtained from many types of pharmaceutical samples, are in good agreement with the official microbiological assay. Beer's law is followed over a suitable working range, 0.25–1.50 mg.
Yeast Folate Availability to Man Determined Microbiologically on Human Bioassay Samples
Authors: Schertel Max E , Libby David A , Loy Henry W
Published: February 2020

The folate activity in the urine of male subjects has been determined microbiologically following oral intake of synthetic pteroyl-L-glutamic acid (PGA). and/or yeast products. The excretion of folates from dried brewer’s yeast shows availability to man of from 22 to 31% based on the PGA excretion pattern. Folates from a concentrate of yeast (yeast extract) were found to be only 8% available by this method. By using a differential microbiological assay on urine samples, evidence has been obtained for the systemic conversion of PGA to N5-methyltetrahydrofolic acid.
Microbiological Assays of Folic Acid Activity in Foods: Changes in Results with Variation of Experimental Conditions and Methods
Authors: Flynn Laura M
Published: February 2020

Data are presented to show the fair correlation between results of microbiological assays with L. casei and results from chick assays. The effects of autoclaving standard solutions of folic acid in phosphate buffers or in potassium ascorbate are shown to be a large decrease in L. casei activity in phosphate solutions but only a relatively small loss in potassium ascorbate. Decreased responses of S. faecalis to extracts containing large concentrations of potassium ascorbate are noted when the organism is grown in the AOAC basal medium for S. faecalis. Microbiological assay data (turbidimetric or titrimetric) should be plotted on a loglog grid to give assurance of an ample incubation period and thus insure a satisfactory assay.
An Improved Screening Method For Chlorinated and Thiophosphate Organic Insecticides in Foods and Feeds
Authors: Samuel Boyd L
Published: February 2020

Three cleanup steps can be used to screen insecticides from crops: preliminary cleanup on a 1″ multiple absorbent column, partition cleanup with hexane-CH3CN, and final cleanup on a 1″ silicic acid-Celite column. Selective elution of the silicic acid column separates the pesticides into groups: a heptachlor degradation product from heptachlor epoxide; aldrin from Kelthane; and DDT, TDE, and Perthane from each other. Test recoveries range from 75 to 100%. Good reproducibility, adequate sensitivity, and freedom from highly critical steps make the method suitable for routine analysis.
Rapid Extraction Procedure for Chlorinated Pesticide Residues in Raw Animal Tissues and Fat and Meat Products
Authors: Onley John H , Bertuzzi Patricia F
Published: February 2020

A rapid procedure has been developed for the extraction of chlorinated pesticide residues from animal tissues and from fats and meat products. The method combines the use of a mixture of acetone, methyl cellosolve, and formamide to extract the pesticide residues, with the use of calcium stearate to coagulate and hold fatty constituents. The per cent recovery ranges were as follows: lindane, 90–108; heptachlor, 80–100; aldrin, 80–100; heptachlor epoxide, 80–108; p,p′-DDT, 76–101; dieldrin, 80–100; and endrin, 80–100. Comparison of results from the described procedure with those from the Mills procedure showed good agreement.
A Gas Chromatographic Column for Pesticide Residue Analysis: Retention Times and Response Data
Authors: Burke Jerry A , Holswade Wendell
Published: February 2020

DC-200 and QF-1 have been combined as the liquid phase in a GLC column to give a different elution of pesticides from the nonpolar methyl silicones now in wide use. The column packing consists of intimately mixed, equal portions of previously coated 80/100 mesh Gas Chrom Q: one portion with 15% QF-1 and the other with 10% DC-200. Operating conditions for a 6 ft × 4 mm i.d. column are as follows: column temperature, 200°C; injection temperature, 225°C; and flow rate, 120 ml N2/min. Relative retention times and response data for electron capture and microcoulometric GLC systems are tabulated for over 85 pesticide chemicals.
Determination of Chlorbenside Residues Including Its Sulfoxide and Sulfone Oxidation Products
Authors: Shuman Harry , Cieri Ugo R
Published: February 2020

A method is presented for determining residues of chlorbenside including its sulfoxide and sulfone oxidation products. The method employs the Mills-Onley-Gaither extraction procedure. Chlorbenside and chlorbenside sulfoxide are converted to chlorbenside sulfone by a short oxidation with chromic-acetic acid solution. Chlorbenside sulfone is isolated from interfering pesticides and most oxidation products on an aluminum oxide column and determined by electron capture gas chromatography. Recoveries for mixtures of the three components added to apple samples at 0.3–5 ppm (calculated as chlorbenside) were between 92 and 110%.
Collaborative Study of a Method for Multiple Chlorinated Pesticide Residues in Nonfatty Vegetables
Authors: Krause Richard T
Published: February 2020

Five laboratories measured aldrin, DDE, and methoxychlor residues in potatoes by electron capture and thin layer chromatography. Average recoveries obtained with the GLC method were 93–103% for the three added pesticides. Each of the five laboratories identified each pesticide correctly and reported reasonable estimates for DDE and methoxychlor by the TLC method. Only one laboratory reported estimates for aldrin by the TLC method. Four laboratories did not achieve complete separation by TLC due to the masking of aldrin by the high levels of DDE.
Conductivity Value of Maple Sirups
Authors: Wendt Arthur S , Benjamin Earl J
Published: February 2020

Collaborative studies were continued on a modified version of the Conlin method for conductivity values of maple sirup. Data show the method to be rapid, precise, and accurate. The method is recommended for adoption as official, first action.
Determination of Salt in Butter
Authors: Weik Robert W
Published: February 2020

The official AOAC, 15.135, and International Dairy Federation (IDF) methods for determining the salt content of butter have been collaboratively studied. Results indicated that there was no significant difference (P > 0.05) between the method means. A highly significant difference (P < 0.001) was found between laboratory means which reflected individual differences in performing titration procedures and slight deviations from the prescribed procedure. The overall results indicated that the IDF method as studied was as accurate as the longer present official method, and the IDF method is recommended for adoption as official, first action.
Determination of Water in Molasses by the Karl Fischer Method
Authors: Epps E A
Published: February 2020

Collaborative studies were conducted in 1963, 1964, and 1965 to compare the Karl Fischer method with the vacuum drying method (29.008) for determining water in molasses. Results by the Karl Fischer method were in good agreement with known water contents in all studies, and the method is recommended for adoption as official, first action.
Extraction and Estimation of Polycyclic Aromatic Hydrocarbons in Smoked Foods. II. Benzo (a) pyrene
Authors: Howard John W , White Richard H , Fry Bert E , Turicchi Elizabeth W
Published: February 2020

The carcinogen benzo(a)pyrene has been isolated from various smoked foods by modification of the general procedure for polycyclic aromatic hydrocarbons described in Part I. Recoveries of benzo(a)pyrene, added to 75, 100, and 150 g samples of frankfurters, fish, and cheese at levels of 1–2 ppb, ranged from 73 to 100%. Positive identification of the hydrocarbon recovered from feeds at levels as low as 0.02 ppb can be made from its fluorescence spectra.
Rapid Estimation of Recoverable Oil in Citrus Juices by Bromate Titration
Authors: Scott W Clifford , Veldhuis M K
Published: February 2020

A new method has been developed for estimation of recoverable oil in citrus juices, based on quantitative combination in acid solution of d-limonene, the principal component of distilled citrus oils, with bromine. 2-Propanol is added to citrus juice, the mixture is distilled, and the distillate is acidified with HC1 and titrated with potassium bromate-bromide solution. End point is observed by disappearance of color from methyl orange indicator. The distillation requires about 3 min., and complete determination, less than 7 min. Recovery of added d-limonene was 100 ±1%, indicating a high degree of accuracy; replications seldom varied more than 0.001% oil, indicating excellent precision. Recoveries were consistently higher than by the Clevenger method.
Rapid Cleanup Techniques for Chlorinated Pesticide Residues in Milk, Fats, and Oils
Authors: Giuffrida Laura , Bostwick David C , Ives Nathan F
Published: February 2020

A cleanup procedure suitable for analysis of chlorinated hydrocarbon pesticide residues in milk, fats, and oils at the 0.01 ppm level was developed. Acetone removes the milk solids and water from milk. Pesticides are efficiently separated from milk fat and other fats and oils with a small volume of aqueous acetonitrile. The Mills, Onley, & Gaither Florisil technique is used as the final cleanup. The procedure is rapid, and recoveries from fortified samples ranged from 80 to 106%.
Rapid Screening for Some Anticholinesterase Insecticide Residues by Automated Analysis
Authors: Ott Daniel E , Gunther Francis A
Published: February 2020

Various sample preparation methods with two new modifications of a previously reported automated system are presented for the determination of anticholinesterase insecticides. An analyst may select a total set of conditions which may be used as a rapid screening test for the detection of some mammalian toxic organophosphorus pesticide residues in a wide variety of plant material substrates. Suggestions are included for obtaining some degree of specificity, when desired, for certain inhibitors of cholinesterase. Typical summary data from analysis of fortified substrate are as follows: (1) 0.25 ppm DDVP in both broccoli and cauliflower; (2) 0.04 ppm parathion (99.6%) in canned peaches after a manual bromine-water oxidation procedure; (3) 0.1 ppm technical grade parathion in canned peaches and water plants (from wildlife pond); (4) paraoxon and technical grade parathion at 0.4 and 0.5 ppm each in Valencia orange peel; and (5) phosphamidon at 0.1 ppm in both the peel and the pulp of white potatoes.
Gas Chromatographic Determination of Butylated Hydroxyanisole and Butylated Hydroxytoluene in Breakfast Cereals
Authors: Takahashi David M
Published: February 2020

The gas chromatographic method for antioxidants (butylated hydroxyanisole and butylated hydroxytoluene) in corn and rice ready-to-eat breakfast cereals was studied collaboratively. The method employs a column of 80–100 mesh acid-washed Chromosorb P, with a 20% coating of DC-200 silicone oil; an argon ionization detector with a radium source was used. Results were in the 90–110% range, when the instructions were followed exactly. Recoveries ranged between 10 and 180% under conditions deviating from the proposed method. In view of the inconclusive results, it is recommended that the written procedure be revised and that the method be restudied collaboratively.
Analysis of Sunscreens in Suntan Preparations
Authors: Davis Henry M
Published: February 2020

Detailed procedures have been reported for the analysis of 2-ethoxyethyl p-methoxycinnamate, 2-ethylhexyl salicylate, homomenthyl salicylate, and glyceryl monop-aminobenzoate in suntan preparations. Sunscreens were selectively eluted by partition chromatography and identified and determined by ultraviolet spectroscopy. Known amounts of sunscreens added to commercial suntan preparations were successfully recovered. Studies will be continued.
Apparatus for Cold Vapor Atomic Absorption of Mercury
Authors: Schachter Myron M
Published: February 2020

An assembly of optical and electronic modules has been designed to measure submicrogram quantities of mercury in the vapor phase at room temperature. The signal-to-noise ratio is greater than 100 to 1 for 10−2 microgram (5 × 10−1 nanomole) of mercury.
Chemical Determination of Folic Acid in the Presence of p-Aminobenzoic Acid or Procaine Hydrochloride
Authors: Hubbard Willard D , Hintz Mary E , Libby David A
Published: February 2020

The USP XVII chemical method for the determination of folic acid is not applicable to pharmaceutical preparations containing p-aminobenzoic acid (PABA) or procaine hydrochloride (added to intertables to reduce discomfort). PABA is often present in older folic acid injectables in which a breakdown of the folic acid has occurred on long standing. A modified method is described to eliminate interference from these compounds by diazotizing the interfering material and then converting it to the corresponding phenol. The folic acid is then cleaved to form PABA, diazotized, and coupled with the Bratton-Marshall reagent. In a comparison of the two methods using known amounts of folic acid in the presence of PABA, better recovery of folic acid was achieved with the modified method than with the USP method. The application of this modification to commercial preparations is also demonstrated.
Emulsifiers. I. Determination of Mono-, Di-, and Triglycerides in Shortenings by Column Chromatography
Authors: Distler E , Baur F J
Published: February 2020

A method for the quantitative determination of mono-, di-, and triglycerides in shortenings was studied collaboratively. Samples were adsorbed on silica gel columns and the glycerides were separated by benzene, benzene plus 10% ethyl ether, and ethyl ether alone. Eight samples can be run simultaneously with an average standard deviation of 0.1–0.5%. This method is recommended for adoption as official, first action.
Emulsifiers. II. Periodic Acid Analysis for 1-Monoglycerides
Authors: Baur F J , Distler E
Published: February 2020

Two periodic acid analytical methods have been compared for the determination of 1-monoglycerides. A revised Miner procedure is apparently faster and more precise than the official AOCS method, Cd 11-57. The AOCS procedure is recommended for adoption as official, first action. A joint AOAC-AOCS multi-methods study should be conducted to compare the Miner and AOCS procedures.
Study of Moisture, Ash, and Organic Content of Peat Samples
Authors: Thorpe Virginia A
Published: February 2020

An empirical method for determining moisture, mineral, and organic content of peat has been proposed and collaboratively compared with a method similar to that used in Federal specifications for the purchase of peat. Moisture results were significantly low by the Federal method in all cases but generally were equally precise by both methods, indicating that larger samples do not greatly improve the precision. Ash results were about the same for both methods, although the Federal method gave higher precision; ashing conditions in the proposed method appear inconsistent due either to the lower ashing temperature or to the larger sample used. It is recommended that study be continued.
Correlation of Pesticide Polarities with Efficiencies of Milk Extraction Procedures
Authors: Beroza Morton , Bowman Malcolm C
Published: February 2020

Nonpolar pesticides added to milk are adsorbed onto the cream phase and do not penetrate appreciably into the fat globule of the milk. This adsorption results in low recoveries of nonpolar pesticides in extractions with hexane-ether (1:1) carried out immediately after spiking and 5 hours later. Recoveries from raw and pasteurized homogenized milk by an extraction procedure that gives low fat recovery parallel polarities of the pesticides as judged by their extraction p-values. Recoveries by an extraction procedure that gives high fat recovery were satisfactory. With the most polar of the pesticides, recoveries by the extraction procedure giving low fat recovery consistently exceeded those by the procedure giving high fat recovery. Although the data indicate that added pesticides are adsorbed on the fat globule, the nonpolar pesticides may also be bound in the aqueous phase of the milk after removal of the cream.
Assay of Apocarotenal and Canthaxanthin in Foods
Authors: Osadca M , DeRitter E , Bunnell R H
Published: February 2020

Methods are presented for determining the carotenoids β-apo-8′-carotenaI and canthaxanthin in foods to which they have been added as colorants. They are extracted by blending or by shaking with appropriate solvents, depending on the nature of the sample, and are separated from naturally occurring pigments and other added coloring agents by selective solvent extraction and/or column chromatography. Concentration is measured by spectrophotometric reading at the absorption maximum after the system is brought to isomerization equilibrium by treatment with iodine solution. Thin layer chromatographic procedures are described for confirming the identities and completeness of separation of the carotenoids.
Analytical Methods for Diethylstilbestrol in Feeds and Premixes
Authors: Stone Loyal R
Published: February 2020

Methods are presented in which diethylstilbestrol is extracted from feeds in the Goldfisch apparatus, transferred into alkaline sodium acetate solution to avoid emulsions, and measured colorimetrically in a sodium acetate-acetic acid buffer system. The procedure is rapid, and results agree closely with those obtained by the official method. Procedures are also presented for determination of diethylstilbestrol in molasses and fat mixtures.
Single Step Chromatographic Cleanup of Chlorinated Pesticide Residues, Using High Elution Rates
Authors: Moats W A , Kotula A W
Published: February 2020

Single step chromatographic cleanup on partially inactivated Florisil columns and on carbon-Celite columns was carried out with very high elution rates. Elution rates of 250 ml/minute for partially inactivated Florisil did not adversely affect results, and recoveries of insecticides, especially endrin, were improved in some cases. Carbon-Celite columns were eluted at 100 ml/minute without affecting the results. Time required for the chromatographic step was reduced from 45 to 2 minutes for the Florisil and from 2–3 hours to 8 minutes for the carbon-Celite column.
Thin Layer Chromatography of Dinitrophenol Pesticides
Authors: Yip George , Howard Samuel F
Published: February 2020

Four dinitrophenol pesticides, DNOC, DNBP, DNAP, and DNOCHP, can be separated on cellulose thin layer plates, either as the phenols or their methyl ethers. Methyl ethers are prepared by reaction with diazomethane. Partition chromatography between an immobile phase of mineral oil and a mobile aqueous phase gives complete resolution. The compounds are revealed by spraying first with stannous chloride, then with p-dimethylaminobenzaldehyde to yield yellow-orange spots which fluoresce under UV light. The lower limit of detection in the phenolic form varies with the compound, ranging from 0.05 μg for DNOC to 0.3 μg for DNOCHP. The lower limit for the ethers is the same for all compounds, 0.1 pg.
Identification of Alkanolamides by a Methanolysis—GLC Procedure
Authors: Gross F C , Jones J H
Published: February 2020

Fatty acid alkanolamides are converted to the amine and the methyl ester of the fatty acid(s) by refluxing with hydrogen chloride in methanol. The methyl ester (s) and amine are separated by solvent extraction and subsequently identified and/or determined by GLC with the internal standard technique. Recoveries of the methyl esters are substantially quantitative; recoveries of the amines are slightly low but are adequate for positive identification. In the methanolysis of the diethanolamides, products other than the expected amine are produced in detectable amounts.
Use of Detergents in the Analysis of Fibrous Feeds. IV. Determination of Plant Cell-Wall Constituents
Authors: Soest P J Van , Wine R H
Published: February 2020

A rapid procedure for determining cellwall constituents of plants consists of the determination of the fiber insoluble in neutral detergent and is applicable to all feedstuffs. The standardization of the method is based on a nutritional concept which defines fiber as insoluble vegetable matter which is indigestible by proteolytic and diastatic enzymes and which cannot be utilized except by microbial fermentation in the digestive tracts of animals.
The Multi-Determination of Antioxidants in Lard
Authors: Mccaulley Donald F , Fazio Thomas , Howard John W , Diciurcio, Frances M , Ives Julian
Published: February 2020

A method has been developed for the multiple determination of antioxidants (BHA, BHT, Ionox-100, PG, THBP, and TDPA) in lard. The procedure consists of vacuum sublimation of the antioxidants and quantitative determination by gas chromatography. UV, IR, and mass spectrometry were used for identification and confirmation. Average recoveries of the antioxidants added to 4 g lard at 100 ppm ranged from 91 to 96%
Extraction of Lipids from Raw Beef Lean by Using Various
Solvent Systems
Authors: Hagan Susie N , Murphy Elizabeth W , Shelley Lydia M
Published: February 2020

Study shows that chloroform-methanol extraction to remove lipids from beef yielded percentages of total fat equal to or greater than those obtained by the AOAC method. The ratio of phospholipid to triglyceride was always higher in the chloroform-methanol extracted samples. Six extraction methodsolvent system combinations, three drying procedures, and two sample preparation methods were compared. Tlie extracted lipids were separated by thin layer chromatography. The ratio of phospholipid to triglyceride was calculated after the spectrophotometric determination of the ester groups present. Acid-hydrolysis-Rohrig gave the lowest yield of total lipid and of phospholipid. Sample preparation method or drying method caused few significant dif. ferenccs in the proportions of total solids and of total lipids in the beef cuts analyzed
A Study of the Net Weight and Drained Weight Relationship
of Frozen Shrimp Products
Authors: Werren J C , Johnson Arthur R , Weik R W
Published: February 2020

A collaborative study was made of a disk acrylamide gel electrophoresis method for identifying fish species through the use of characteristic protein bands. Results were generally satisfactory; 6 of 7 collaborators agreed on all samples. It is recommended that the method be adopted as official, first action
Investigations of Gas-Liquid Chromatography of Fruit Acids
Authors: Hautala Earl
Published: February 2020

Seven fruit acid standards were esterified with diazomethane and the esters were gas chromatographed at various column temperatures. AH the esters except benzoate could be seen as separate peaks but were not suitable for quantitation. Study will be continued
Determination of Aldehydes in Wines by the Direct Bisulfite
Method: American Society of Enologists—AOAC Joint Report
Authors: Guymon James F , Wright Dawson L
Published: February 2020

A collaborative study was made on the Guymon and Crowcll direct bisulfite determination of aldehydes in wine in cooperation with a committee of the American Society of Enologists. The method is based upon the reaction of the aldehydes with an excess of bisulfite solution at a neutral pH, removal of the excess bisulfite by iodine in acid medium, and direct titration with standard 0.05/V iodine of the bisulfite released in alkaline medium. The mean values for aldehydes found in 4 wines by 9 collaborators gave standard deviations of 2,7-4.5% of the mean. The method determines free aldehydes plus aldehydes bound with bisulfites existing in wines, while it excludes acetals which account for only 1-3% of the aldehydes present. The method gives a very satisfactory degree of precision and accuracy and is recommended for adoption as official, first action
Quantitative Determination of Benzaldehyde in Flavors and Cordials by Ultraviolet Spectrophotometry and 2,4-Dinitrophenylhydrazine Precipitation
Authors: Brunelle Richard L
Published: February 2020

Three sets of samples were collaboratively analyzed by the official, first action ultraviolet spectrophotometric and 2,4-dinitrophenylhydrazine precipitation methods for determining benzaldehyde in flavors and cordials. The spectrophotometric method was unchanged, except for clarification, and collaborators reported recoveries averaging nearly 100%. The gravimetric procedure using 2,4-dinitrophenylhydrazine gave unsatisfactory recoveries on the first two sets of collaborative samples. However, collaborators reported approximately 96% recovery of benzaldehyde with a modified precipitation procedure on a third set of samples. The ultraviolet spectrophotometric method and the modified 2,4-dinitrophenylhydrazine precipitation procedure are recommended for adoption as official, final action as alternative methods.
Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products
Authors: Strunk Duane H , Andreasen A A
Published: February 2020

Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.
Estimation of Afiatoxin M in Milk
Authors: Purchase I F H , Steyn M
Published: February 2020

The ability of various solvents, using a Soxhlet extractor and a mechanical shaker, to extract anatoxin M from freeze-dried milk powder was compared. Extraction is most efficient when the sample is extracted with an azcotropic mixture of acetone-chlo-roform-water in a Soxhlet apparatus.
Infrared Spectra of Carbophenothion (Trithion) and Some
of Its Possible Metabolic Products
Authors: Chen Jo-Yun T , Dority Roland W
Published: February 2020

The infrared spectra of carbophenothion and five of its possible metabolic products are interpreted and discussed in this paper. A table summarizing the characteristic infrared spectra of each compound accompanies the spectra. The infrared spectra of these six compounds are sufficiently different to serve as reference curves in the identification of organophosphorus pesticide residues
Collaborative Study of Microbiological Assay for Low
Chlortetracycline Concentrations in Final Feeds
Authors: Abbey Anthony
Published: February 2020

Two batches of commercial poultry feed containing low levels of chlortetracycline (CTC) activity (ca 10 ppm) were assayed collaboratively in 15 laboratories. The coefficients of variation for the individual batches were 10.0 and 9.2%, respectively; combining the data for both batches gave a coefficient of variation of 9.6%. The microbiological assay procedure, utilizing compensating CTC standard curves prepared with a diluent containing sodium hypochlorite- inactivated animal feed extracts, was found applicable in all 15 participating laboratories. The method is recommended for adoption as official, first action.
Evaluation of the Effects of Eleven Bleaching Agents on
Ground Cocoa Bean Tissue, Insect Fragments, and
Rodent Hairs
Authors: Gecan John S , Brickey P M
Published: February 2020

Eleven bleaching agents were used to decolorize cocoa tissues, and their effects on insect fragments and rodent hairs were studied. Gilorine bleaches, potassium permanganate, and hydrogen peroxide all result in good bleaching of ground cocoa. However, chlorine bleaches completely destroy rodent hair, and potassium permanganate is not effective for high fat products. Hydrogen peroxide decolorizes cocoa bean tissue very well and does not destroy rodent hairs nor decolorize insect fragments. A mechanical means of evaluating the amount of bleaching of cocoa bean tissues is also described. Future studies are planned on the use of hydrogen peroxide as a plant tissue bleaching agent
Uncombined Intermediates in FD&C Blue No. 1
Authors: Johnson Robert K
Published: February 2020

A collaborative study of the method derived from one proposed by Schumacher, This Journal, 48, 819-826 (1965), was sponsored by the Subcommittee on Analytical Methods, Certified Color Industry Committee. All 6 domestic manufacturers of certified food colors were represented as well as the Division of Color Certification and Evaluation, FDA, Washington, D.C. Eight collaborators analyzed 3 samples each. Intermediates were separated by column chromatography and their concentrations were estimated from ultraviolet absorption measurements. N-Ethyl-iV-(3-sulfobenzyl) sulfanilic acid (ESBSA) and mixed isomers of sulfobenzaldehyde (SB) were recovered at an average level of 98% of the amounts added. Between-laboratory standard deviations ranged from 0.014 to 0.18% when the intermediates were present at levels of 0.07-1.46%. The method is recommended for adoption as official, first action
Gas Chromatographic Determination of Residues of
Organophosphorus Pesticides with a Modified
Flame Ionization Detector
Authors: Ford Joseph H , Beroza Morton
Published: February 2020

The effect of various salt coatings, metals, and carrier gases was investigated in an attempt to improve the Giuffrida thermionic detector for residues of phosphorus-containing pesticides. As reported recently hy Giuffrida et al., the highest sensitivity to phosphorus (with insignificant response to halogen) was obtained with a potassium chloride coating. The use of helium as the carrier gas produced an 8-fold enhancement in response to phosphorus over that obtained with nitrogen, and the response to halogen remained nil. Substrate interference was very low with the KCI detector and helium carrier gas, and analyses were possible at the subnanogram level
Determination of Methimazole by Infrared Spectrophotometry
Authors: Hayden Alma L , Brannon Wilson L
Published: February 2020

A method is described in which melhimazole is separated from tablet excipients by column chromatography on Celite 545 with chloroform as the eluant and then quantitatively measured and identified by infrared spectrophotometry. This method was studied collaboratively by 10 analysts; average recoveries from two simulated and two tablet mixtures ranged from 96.6% ± 1.0 to 101.1% ± 0.9. This method is recommended for adoption as official, first action.
Stoichiometry of the Volumetric Ammonium Phosphomolybdate Method for P2O5
Authors: Barker J E
Published: February 2020

A study was made to determine the stoichiometry of this method with particular reference to solubility losses and ammonia content of the precipitate. Studies show that the recovery of ammonia by distillation from a caustic solution is depressed by the presence of molybdic acid. Recovery was reduced to as little as 99% at the stoichiometric ratio of MoO3 to IN. The mechanism of this phenomenon is unknown. However, after standardizing the method for ammonia in the presence of molybdic acid, the yellow precipitate was found to contain 99.5% of the theoretical ammonia according to the formula (NH4)3PO4:12MoO3
Cobalt Loss by Dry Ashing in Porcelain Crucibles
Authors: Mays David L , Kessler Wayne V , Chilko John A , Schall Elwyn D
Published: February 2020

The adsorption of cobalt on porcelain crucibles during dry ashing was studied. The results showed that adsorption was slight if a residue was formed in the ashing procedure and heavy when no residue was formed.
Determination of Menthol in Cigarette Tobacco Filler
Authors: Tucker Charles L , Ogg C L
Published: February 2020

A gas chromatographic and a colorimetric method for determining menthol in cigarette tobacco filler were studied collaboratively by 15 laboratories. No statistically significant differences were found in the precisions within or between laboratories. There were no significant differences between mean values for the two methods for any of the samples. Trends toward higher mean values for the colorimetric method and lower within-laboratory standard deviations for the gas chromatographic method were noted. Remarks by collaborators suggest that the accuracy and precision of the colorimetric method may be improved, and further studies are recommended.
EDTA Titration of Calcium and Magnesium
Authors: Steagall Edward F
Published: February 2020

The revised method for the EDTA titration of calcium and/or magnesium in pharmaceutical preparations and canned whole tomatoes, adopted as official, first action last year, was studied collaboratively again this year. Two simulated pharmaceutical mixtures and two samples of tomato juice were analyzed by 13 analysts in 12 laboratories. The results were easily reproducible, and the agreement between laboratories was good. The required use of a pH meter in all pH adjustments has eliminated most of the turbidity and fading end points; occasional turbidity or fading end points are due to faulty or improperly prepared resin that does not completely remove phosphates. Because the revised method gives continuing precision and low standard deviations, it is recommended for adoption as official, final action.
lAscorbic and d-Isoascorbic Acids: Quantitative Separation and Assay
Authors: Weeks Cora E , Deutsch Mike J
Published: February 2020

d-Isoascorbic (erythorbic) acid is a permissible food additive. Chemical assays do not differentiate between the additive and the vitamin, l-ascorbic acid. Chromatography on silicic acid-impregnated glass fiber paper separates the two acids in 25 minutes. They are extracted from the chromatogram and assayed by the microfluorometric method (Deutsch and Weeks, This Journal, 48, 1248-1256 (1965)). Modifications have been developed for assaying small volumes of solution. Concentrations as low as 1.8 /μg/20 μl can be successfully separated and assayed.
Gas-Liquid Chromatographic Method for the Determination of Fat-Soluble Vitamins. V. Application to Pharmaceuticals Containing Vitamin E
Authors: Pillsbury H C , Sheppard Alan J , Libby David A
Published: February 2020

Gas-liquid chromatography, using a 5% SE-30 column and a hydrogen flame detector, has been used to quantitate vitamin E in pharmaceuticals. The gas chromatographic measurements were compared with the Emmerie-Engel results obtained on the same samples. Because of total recovery, smaller standard deviation, and simplicity, the GLC method was more desirable than the Emmerie-Engle method which includes a saponification preparatory step. The GLC method is also specific for each of the tocopherol analogs measured.
Studies on the Stability of Chlortetracycline in Mixed Feeds: Epimerization of Chlortetracycline
Authors: Katz Stanley E , Fassbender Carol A
Published: February 2020

Chlortetracycline is known to degrade in aqueous solution by four pathways: anhydrochlortetracycline formation under strong acid conditions, epimerization under weakly acid conditions, isochlortetracycline formation under strongly basic conditions (usually anaerobic), and formation of a desdimethylamino chlortetracycline compound under aerobic conditions at pH values greater than 5. Studies on feeds decomposed to 50% of activity indicated that isochlortetracycline and anbydrochlortetracycline were not formed in the decomposition, while epichlortetracycline and a highly fluorescent unknown compound were formed. Epimerization occurs rapidly in feeds, reaching an equilibrium in a few hours. In several types of feed, protein, fat, fiber, moisture contents, and pH did not affect the degree of epimerization. Temperature of storage appears to be significant. Data suggest that an equilibrium is established between the chlortetracycline and epichlortetracycline followed by breakdown of either chlortetracycline or its epimer or both to as yet unidentified products.
Collaborative Study of the Determination of Ethoxyquin In Chick Tissue and Eggs
Authors: Vanderen J M , Jaworski E G
Published: February 2020

The method for determining ethoxyquin (Santoquin) in chicken muscle, liver, and egg and a procedure for fat have been studied collaboratively. Results were reproducible for individual collaborators but not between collaborators. A sensitive standard curve, i.e., one which has an instrument reading of > 50% full scale for the most concentrated ethoxyquin standard, was prepared to compare between-collaborator precision. With sensitive standard curves, the standard deviation was < 10% of the average value for sample analyses. Determinations must be made on an instrument with sufficient sensitivity. For analyses with low standard deviations, average ethoxyquin recoveries of 75% were obtained for egg yolks and chicken liver and muscle and 85% recovery for chicken fat.