bluuebunny/crossref_metadata_2025 huggingface dataset:
Diazomethane Methylation of a Mixture of Chlorophenoxy Acids and Dinitrophenols
Authors: Howard Samuel F , Yip George
Published: February 2020

Three different methylation procedures using diazomethane were evaluated on 2,4-D, 2,4,5-T, 2,4,5-TP, 2,4-DB, 2,3,6-TBA, DNOC, DNBP, and DNOCHP: (I) diazomethane alone, (II) diazomethane and methanol, (III) diazomethane, methanol, and HC1. Evaluations were made by comparing electron capture GLC peak heights or peak areas of reacted products with those of standards. Volatility losses were observed with method I. Completeness of dinitrophenol methylation varied with the lot of methanol used with methods II and III. From the results of this study, method I was modified by the addition of isooctane to the reaction vessel to prevent the sample from evaporating to dryness and the use of a 70°C water bath to speed up the reaction. Conversion of all pesticides by the modified procedure was over 90%.
Water in Granular Triple Superphosphate
Authors: Duncan R D
Published: February 2020

The gain or loss of moisture by samples of granular triple superphosphate during grinding in preparation for analysis depends upon both the conditions of manufacture of the material and the humidity of the atmosphere in the grinding room. Care should be exercised in the preparation of superphosphate samples for analysis, and the relative humidity in the grinding room probably should be ≤40%.
Comparison of Four Extraction Procedures for Root-Translocated Dieldrin in Maize, Kale, Alfalfa, and Wheat
Authors: Caro Joseph H
Published: February 2020

Internal dieldrin residues in 5 crops were determined by gas chromatography after extraction by 4 different methods. Blending with hexane-isopropanol (2 + 1) followed by Soxhlet treatment with chloroform-methanol (1 + 1) generally extracted the most pesticide. Blending with acetonitrile-water (65 + 35) was a less tedious, satisfactory substitute procedure. Blending with acetonitrile or with hexane-isopropanol alone gave lower recovery of dieldrin. Recovery with either of these 2 solvents was especially low in crops of low moisture content.
Hybrid Assay for Trisulfapyrimidine Preparations
Authors: Banes Daniel , Riggleman Oscar H
Published: February 2020

A method is described for the assay of trisulfapyrimidines tablets and trisulfapyrimidines oral suspension. Total sulfonamides are measured colorimetrically by the Bratton-Marshall procedure, and sulfadiazine is quantitated directly by means of its specific reaction with thiobarbituric acid. Sulfamethazine is separated from its homologs by column partition chromatography and is determined by ultraviolet spectrophotometry. When applied to commercial samples of trisulfapyrimidines tablets and oral suspensions, this hybrid method yields data that are consistent with assays of the same samples by the official nitrite titration method.
Characterization of Some Lincomycin and Cyclamate Salts by Thermal Analysis and Infrared Spectroscopy
Authors: Neville G A , Ethier J C , Bright N F H , Lake R H
Published: February 2020

The relative thermal stability of lincomycin. HCl.H2O, lincomycin cyclamate, calcium cyclamate.2H2O, and sodium cyclamate was studied by differential thermal analysis and by thermogravimetric analysis. Lincomycin. HCl.H2O easily undergoes thermal degradation with the release of methyl mercaptan, but the cyclamate anion confers considerably greater thermal stability on the lincomycin moiety. Calcium cyclamate.2H2O was found to undergo a 2-step thermal dehydration analogous to that undergone by CaSO4.2H2O, including termination in the formation of CaSO4· Grating infrared spectra are reproduced for lincomycin.HCl.H2O, cyclohexylsulfamic acid (cyclamic acid), sodium cyclamate, and calcium cyclamate.2H20. Principal group frequencies are assigned with the aid of deuterium exchange studies and thermal dehydration limits. Infrared characteristics of derivatives of sulfamic acid are described for the first time and evidence is presented for the trans amide configuration in lincomycin. HCl.H2O.
Semiautomated Determination of Sulfadimethoxine in Feeds
Authors: Araujo M , De Ritter E , Osadca M
Published: February 2020

A method is described for determining sulfadimethoxine in feeds at levels of 0.00625 to 0.0125%. Colorimetry based on the Bratton-Marshall reaction is carried out by an automated procedure, using extracts prepared by manual digestion, extraction, and filtration. Of several extraction procedures tried, only alcohol extraction after digestion with ficin yielded both 100% recoveries of sulfadimethoxine and negligible readings on unmedicated feeds. After preparation of the extracts, 20 samples/hr can be assayed by the automated colorimetric method. Increased precision is achieved by automation of the colorimetry.
Determination of 1,4-Dihydroxyanthraquinone in D&C Green No. 5 and the Former External D&C Violet No. 2
Authors: Hoskins Elizabeth C
Published: February 2020

The certifiable color D&C Green No. 5 and the formerly certifiable color External D&C Violet No. 2 may contain small quantities of the intermediate quinizarin, 1,4-dihydroxy-anthraquinone. The quinizarin is separated from the color by solvent extraction and is determined spectrophotometrically. Recoveries averaged 92 and 99% for D&C Green No. 5 and former External D&C Violet No. 2, respectively.
Colorimetric Method for the Determination of Vitamin D in Fortified Whole and Partially Skim Fluid Milks
Authors: Panalaks T
Published: February 2020

Vitamin D in fortified milk was determined from a standard curve prepared from the addition of known amounts of the vitamin to unfortified milk. The usual exhaustive extractions for isolation of the unsaponifiable fraction were replaced by a labor-saving benzene partition technique. The main interfering substance, cholesterol, was removed by passing the sample extract through a column of Celite impregnated with digitonin. Other interfering substances were removed by partition and adsorption column chromatography. Oxidative deterioration of the vitamin during saponification and subsequent analytical steps was prevented by additions of antioxidants and by addition of a high boiling hydrocarbon to prevent drying. The vitamin concentration was determined colorimetrically at 500 nm after reaction with antimony trichloride, using a correction factor derived from absorbances measured at 435 and 550 nm. The use of a color inhibitor was eliminated. The method when applied to whole and partially skim milks fortified with vitamin D in the range from 22 to 44 IU/100 ml milk gave recoveries of 92 and 103%, respectively.
Effect of Cooking Utensil Composition and Contents on the Reductive Dechlorination of DDT to DDD
Authors: Deloach Hiroko K , Hemphill Delbert D
Published: February 2020

The reductive dechlorination of DDT to DDD by some cooking utensil compositions and contents is demonstrated and the identification of specific reducing agents of DDT is investigated. Iron is found to be the most active reducing agent of DDT. A progressive loss of DDT and accumulation of DDD from DDT are observed when DDT standard is boiled with double-distilled water in metal utensils (iron, stainless steel, or aluminum) or in glass utensils containing iron powder. Non-metal utensils (Teflon, glass, or enamel) by themselves do not give an accumulation of DDD from DDT despite considerable loss of DDT. Teflon-coated utensils are ineffective in the reduction of DDT and tend to adsorb pesticides on their surface. A substance (or substances) which is present in vegetables also acts as a DDT-reducing agent as shown by boiling DDT with vegetables in glass utensils.
Colorimetric Determination of Aniline Derivatives in Natural Waters
Authors: El-Dib M A
Published: February 2020

A rapid, direct, and sensitive colorimetric method has been proposed for the determination of aniline derivatives in surface waters. The method is based on diazotization of the primary aromatic amine and coupling with resorcinol or 1-naphthol. Hydroxy-azo dyes obtained have considerably high absorptivities, rendering the method sensitive enough to determine anilines at 0.1 ppm. The effects of pH, saline constituents of waters, coupling phenols, and substituents on color intensity are discussed. Coefficients of variation ranged between 6 and 0.5, according to the nature of aniline derivative and the amount determined. Precision of the method is greatly increased when the amount of the existent aniline ranges between 40 and 100 μg.
Comparison of the Official AOAC Method with Rapid Methods for the Analysis of Moisture in Meats
Authors: Cohen Edward H
Published: February 2020

Moisture studies were conducted on 4 types of meat. A method specifying 2 hr at 125-150°C in a gravity convection oven gave similar results to 24.003. Five rapid methods were also evaluated: the IR automatic moisture analyzer, the IR moisture determination balance, toluene extraction, specific gravity change, and hot plate methods. The methods were evaluated for precision and recovery of moisture as compared with the official AOAC method and for their practicability, ease of handling, and rapidity of analysis.
Determination of Added Lactose (Nonfat Dry Milk) in Meat Products. I. Colorimetric Method
Authors: Karasz A B , Gantenbein W M , Bokus L
Published: February 2020

A colorimetric method is described for the quantitative determination of lactose in meat products, based on the reaction of lactose with methylamine. After enzymatic removal of maltose and glucose, absorbance of the reaction product is measured at 540 nm. The method is applicable in the presence of corn sirup solids and is suitable for the routine surveillance of the nonfat dry milk content of processed meats. Average recovery of nonfat dry milk was 98.0%. The precision of the method is good, with a standard deviation of 0.013 for replicate analyses and a relative standard deviation of 5.5 parts/1000.
Determination of Lactose (Nonfat Dry Milk) in Meat Products. II. Automated Method
Authors: Gantenbein W M , Karasz A B , Bokus L
Published: February 2020

A rapid method for the determination of lactose in meat products has been developed. The method involves a manual extraction of the sample, purification, proportioning, mixing, and reacting the sample extract and reagents in a newly designed AutoAnalyzer system assembled from basic Technicon components. Lactose present in the sample extract is reacted with methylamine hydrochloride at 95°C in an alkaline medium to produce a red product with an absorption maximum at 540 nm. Interference due to the presence of maltose and glucose in the meat product is eliminated by enzyme hydrolysis with maltase and glucose oxidase. Slight interference from substances such as creatine, which are naturally present in meat tissue, is compensated for by preparing standard lactose solutions in a meat product extract. The method is applicable to samples containing 0.25-2.0% lactose (0.5-4.0% nonfat dry milk). Recovery of nonfat dry milk from fortified samples averaged 95.6%. Reproducibility is good, with a range of 0.09%, a standard deviation of ±0.030, and a relative standard deviation of 14.4 parts/1000. With this method, a single analyst is capable of analyzing approximately 40 samples/day for nonfat dry milk content.
Simplified Procedure for the Purification of Ochratoxin A from Extracts of Penicillium viridicatum
Authors: Scott P M , Kennedy B , Walbeek W Van
Published: February 2020

Substantial purification of ochratoxin A in chloroform extracts of Penicillium viridicatum can be achieved by column chromatography on silica gel impregnated with 5% oxalic acid dihydrate. Ochratoxin A is eluted by chloroform-acetone (99 + 1 or 98 + 2). The method is simple and rapid and has the advantage that, although further purification via sodium bicarbonate is needed, preparative thin layer chromatography is unnecessary.
Cold Vapor Atomic Absorption Determination of Mercury in Coal
Authors: Bailey B W , Lo F C
Published: February 2020

A method for the determination of mercury in coal is described. The procedure involves combustion of the coal sample in an oxygen atmosphere and collection of the mercury so liberated in an acid permanganate solution. The mercury concentration in this solution is determined by cold vapor atomic absorption.
Individual Tablet Assay Program for a Small Computer
Authors: Alber Larry L , Overton Mack W
Published: February 2020

A computer program is presented to rapidly calculate individual tablet analyses, using FOCAL-8 language in an off-line application of a small laboratory computer. The program, flow chart, and 2 examples of typical reports are included.
Recovery System for Mercury Catalyst Used in Kjeldahl Analysis
Authors: Dillon P L , Caldwell M J , Gehrt A J
Published: February 2020

A simple system has been developed for recovering mercury used as a catalyst in the Kjeldahl analysis. The equipment consists of two 55 gal. stainless steel drums connected by an overflow. Mercuric sulfide sludge settles in the first drum and the clear, essentially mercury-free effluent passes to the second drum, which is periodically discharged to the sewer. Analyses show over 99.99% removal of mercury from the effluent.
Modified Resazurin Test for Estimating Bacterial Counts in Maple Sap: Color Standards
Authors: Kissinger J C
Published: February 2020

An end point color standard based on reflectance, which can be described by the Munsell system of color notation, was developed for the modified resazurin test used to estimate bacterial counts in maple sap. In order to secure a reflected color, a sterile, nonfat milk solution was added to the clear sap-dye test solution to render it opaque. Results of tests made in accordance with this method are presented in graphic form.
Determination of Formaldehyde in Maple Sirup: Interfering Substances
Authors: Underwood J C
Published: February 2020

Three carbonyl compounds isolated from maple sirup by distillation as in the AOAC official method for formaldehyde have been identified by mass spectrometry as formaldehyde, acetone, and acetaldehyde. Acetone and acetaldehyde do not interfere with the formaldehyde determination if the procedure of the AOAC official method is followed; acetol and glyoxal also do not cause errors in the formaldehyde value. Tests run have shown the modified Nash method (31.184–31.189) adopted as official final action to be extremely specific for formaldehyde in maple sirup.
Chlortetracycline Residues in Eggs from Hens on Chlortetracycline-Supplemented Diets
Authors: Katz Stanley E , Fassbender Carol A , Dowling John J
Published: February 2020

Chlortetracycline was fed continuously to laying hens at levels of 0, 50, 100, 150, and 200 g/ton for a period of 4 months. Eggs from hens on the hasal ration showed a miniscule rate of positives, 2.1%; eggs from hens fed 50, 100, and 150 g/ton showed a positive presumptive rate of 58.3, 11.8, and 3.5% and a measurable residue rate of 11.1, 83.8, and 94.9%; and eggs from hens fed 200 g/ton had a 100% measurable rate. Preparation of eggs by several cooking procedures indicated a 30–50% retention of potency.
Rapid Method for the Determination of Proof of Alcoholic Products Containing Dissolved Solids
Authors: Strunk Duane H
Published: February 2020

A rapid and accurate method is described for determining proof of alcoholic products containing dissolved solids. Samples are distilled in a Jaulmes distillation unit and alcohol concentration is determined by a proof hydrometer. Shortened analysis time is due to the rapid distillation rate afforded by the Jaulmes unit. Recovery data and comparisons with results by a modified AOAC method are presented for 18 commercial alcoholic beverages. Results obtained, using the 2 methods, were in good agreement; a maximum difference in results of 0.4° proof was found for 2 of the 18 samples tested.
Collaborative Study of the Single Tablet Determination of Reserpine
Authors: Barkan Susan
Published: February 2020

A fluorometric single tablet determination of reserpine was subjected to collaborative study. Fourteen collaborators, divided into 2 groups, analyzed commercial 0.1 and 1 mg tablets and single tablet weights of the respective composites prepared from the same tablets. The analyses were satisfactory and the collaborators reported that the method presented no difficulties. It is recommended that the method be adopted as official first action.
Partition Chromatographic-Gravimetric Assay of Opium
Authors: Smith Edward , Sheixix Eric B , Levixe Joseph
Published: February 2020

The current AOAC method for the determination of morphine in opium, 36.031–36.035, utilizes a 3-column partition chromatographic system for the isolation of morphine, with spectrophotometric measurement of the product. The same partition system has been modified to accommodate a larger sample size to permit a gravimetric measurement of the isolated morphine as its dinitrophenyl ether. The gravimetric procedure yields values comparable to those obtained by the much shorter and simpler UV method.
Gas Chromatographic Determination of Diethylstilbestrol Dimethyl Ether in Diethylstilbestrol
Authors: Gainer F E , Chiasson W J
Published: February 2020

A GLC method is described for the determination of the dimethyl ether of diethylstilbestrol (DME) in diethylstilbestrol (DES). A 1 g sample of DES is dissolved in an aqueous solution of 0.5N NaOH and then extracted with a chloroform solution containing benefin, the internal standard. An aliquot of the chloroform layer is chromatographed and the DME peak is measured relative to the internal standard peak. The method was tested for accuracy within the 11–110 ppm range and a linear plot of detector response vs. concentration was obtained.
Human Plasma Iron Responses Following Test Doses of Iron from Known Sources
Authors: Pla Gwendolyn W , Fritz James C
Published: February 2020

A study was conducted to determine the effects of certain dietary components on iron absorption in human subjects. Iron absorption was measured by plasma iron responses following test doses of iron as ferrous sulfate or ferric pyrophosphate alone or with egg, enriched white bread, or ascorbic acid. The effects of egg on iron absorption were inconclusive. Phytates at the level present in enriched white bread had no adverse effects and 500 mg ascorbic acid proved beneficial.
Determination of Moisture in Raisins
Authors: Bolin H R , Stafford A E , Mackey B E
Published: February 2020

The official AOAC method, section 22.012, and the dried fruit moisture tester method for determining moisture in raisins have been collaboratively studied. There is good agreement between the 2 methods with less than ± 1% moisture difference being noted in the 10–20% range. Results indicate that the dried fruit moisture charts are accurate throughout their temperature range. It is recommended that the dried fruit moisture tester method be adopted as official first action for the determination of moisture in raisins.
Colorimetric Method for the Determination of Starch in Tobacco
Authors: Sensabaugh A J , Rush Kenneth L
Published: February 2020

A method is presented for extracting and determining the starch content of tobacco. Dried tobacco is ground to pass a 60 mesh screen, interfering colored materials are removed from the tobacco by a methanol-water extraction, and the starch is extracted from the tobacco by a perchloric acid treatment. Final quantitative measurement of the starch is made on a colored starch–iodine complex. The absorbance of this colored complex at 600 nm is proportional to the concentration of the starch in solution and can be related to the starch content of the original tobacco sample. Also included is a procedure for the isolation of pure tobacco starch. Such material was prepared for use as a calibration standard needed for the calculation of starch content of tobacco samples from the colorimetric data.
Collaborative Study of a New Method for the Extraction of Light Filth from Ground Coffee
Authors: Thrasher Joel J
Published: February 2020

A collaborative study has been completed on a new method for light filth in ground coffee. The sample is defatted with chloroform, dried, and boiled in water; isopropanol is added and the sample is boiled again. Light filth is trapped off with mineral oil from a hot solution. The method yields better recoveries of insect fragments and rodent hairs than the official method. Other advantages are less analytical time, cleaner filter papers, and elimination of the use of carbon tetrachloride. It is recommended that the method be adopted as official first action to replace 40.007(b) for the isolation of light filth from ground coffee and that the hydrogen peroxide bleaching technique described earlier be adopted as a procedure to replace the sodium hypochlorite technique described in 40.006.
Collaborative Study of an Improved Method for the Isolation of Filth from Starches
Authors: Gecan John S , Brickey Paris M
Published: February 2020

The official AOAC method for filth in starches, 40.056, has been modified to obtain better recovery of extraneous materials. In lieu of wet sieving on a No. 140 sieve, the modified method utilizes No. 230 wet sieving followed by an acid hydrolysis, if excessive starch material remains on the sieve. A limited collaborative study comparing the improved method with the official method resulted in higher recoveries of rodent hairs and equivalent recoveries of other spike elements by the improved method. The improved method is recommended for adoption as official first action to replace 40.056.
Collaborative Study of a Method for the Extraction of Light Filth from Bulk and Link Pork Sausage
Authors: Gecan John S
Published: February 2020

A method has been developed for extraction of light filth from bulk and link sausage. The sample is dispersed with Tergitol 7 anionic, wet sieved, defatted with chloroform, deaerated, and extracted with a mineral oil-nheptane mixture from cooled 40% isopropanol. The collaborative study resulted in good recoveries and clean extraction papers. The method is recommended for adoption as official first action.
Collaborative Study of a New Method for the Extraction of Light Filth from Black and White Ground Pepper
Authors: Dent Russell G , Brickey Paris M
Published: February 2020

In the method described, the black or white ground pepper sample is slurried with water and wet sieved. The pepper residue is defatted during the sieving step. Flotation extraction of the sieved material utilizes a combination of n-heptane-mineral oil as the oil layer over 40% isopropanol. Collaborative studies resulted in reproducible recoveries and light-to-medium laden filter papers. It is recommended that the method be adopted as official first action to replace 40.109(b).
Determination of Mercury in Biological Samples by Flameless Atomic Absorption After Combustion and Mercury-Silver Amalgamation
Authors: Okuno Iwao , Wilson Richard A , White Robert E
Published: February 2020

A method is described that combines combustion with amalgamation of mercury with silver for determining low levels of mercury by flameless atomic absorption spectrophotometry. Samples are burned with oxygen in a combustion flask and the combustion products are dissolved in dilute HCl. Mercury is extracted from solution by amalgamating on a silver wire and then volatilized into an atomic absorption cell by electrically heating the silver wire. An average recovery of 91.4% was obtained from tissue samples spiked with inorganic and organic mercury compounds at levels of 0.01 to 1.0 ppm mercury. The coefficient of variation for duplicate determinations was 14.2%. The method is relatively simple and is applicable to any material that can be burned by the combustion procedure.
Effects of Solvent Composition on the Partition of Amines: Extraction of the Free Base
Authors: Doyle Thomas D , Proctor Joseph B
Published: February 2020

Extraction constants are given for the free bases of 20 pharmaceutical amines in a water and chloroform-isooctane system. The variation of extraction with solvent composition is nonlinear and may be described by an exponential function in which the value of the exponent is related empirically to the extraction in the pure solvents.
Partition Chromatography of Barbiturates in Combinations with Salicylamide and Other Drugs
Authors: Hall Robert J , Levine Joseph
Published: February 2020

Barbiturates can be separated from salicylamide by trapping the latter on a partition chromatographic column in which ferric chloride or ferric chloride-urea is the immobile phase, and isooctane-ether mixtures are the mobile phase. Experimental conditions must be selected in accord with the partition characteristics of the individual barbiturate. Analyses are presented of commercial preparations of amobarbital, pentobarbital, and butabarbital with salicylamide together with a variety of other drugs.
Identification of Polychlorobiphenyls by High Resolution Proton Magnetic Resonance
Authors: Bartle K D
Published: February 2020

Mass spectrometry allows the number of chlorine atoms per polychlorobiphenyl molecule to be determined but not the positions of substitution. A method of identifying PCB components from high resolution proton magnetic resonance spectra is illustrated by application to 2,5,2′,5′-tetrachloro- and 2,3,4,2′,4′,- 5′-hexachlorobiphenyls separated by gas chromatography from a commercial PCB mixture.
Formation of β-Hydroxybutyric Acid in Eggs During Incubation
Authors: Salwin Harold , Staruszkiewicz Walter F , Bond John F
Published: February 2020

β-Hydroxybutyric acid was identified in incubator-reject eggs from commercial hatcheries. The circumstances relating to its occurrence were investigated in a laboratory study of incubation. The observed changes in concentration of the acid at several stages during ncubation were consistent with known metabolic processes that are operative in chicken embryos. The results indicated that analyses for β-hydroxybutyric acid are poteutialry useful for identifying incubator-reject eggs that may be diverted unlawfully into human food channels.
Vertical Plate Gel Electrophoresis for the Differentiation of Meat Species
Authors: Coduri R J , Rand A G
Published: February 2020

Polyacrylamide gel electrophoresis of fresh meat sarcoplasmic proteins by the vertical plat e technique was studied as a method for the detection and identification of pure and mixed species extracts. A single 7% Cyanogum gel containing 1M urea, in conjunction with a tris-chloride, tris-glycine discontinuous buffer system, produced satisfactory resolution of single species and mixed species muscle protein extracts. Eleetrophoretie patterns were obtained by direct analysis of meat proteins extracted with a tris-chloride-10% glucose extraction buffer at pH 6.7. Mixtures of beef and pork and beef and horse were easily identified. The possibility for a d a p t i n g t h e eleetrophoretie procedure to the analysis of cooked meat products and non-meat proteins is discussed.
Methods for the Analysis of Beer
Authors: Stone Irwin
Published: February 2020

Four new methods relating to beer were released by the American Society of Brewing Chemists (ASBC) prior to their publication in t h e forthcoming revised edition of their book of methods. Three of these methods were subm i t t e d to t h e AOAC and were adopted as official first action: (1) cuprethol alternative method for the determination of copper in beer; (2) color of laboratory wort method to replace the present methods; ami (3) caloric content of beer as calculated from analytical data . The fourth method, “Accelerated Haze After Chilling,” was regarded as outside the field of general interest to the AOAC and therefore was not submitted for adoption. The methods proposed for adoption have been adopted as official first action.
Analysis for Aflatoxins in Products Containing Alcohol
Authors: Moor Julia L
Published: February 2020

The official first action method for aflatoxins In peanuts and peanut products, Method I, 26,015-26.020, has heen modified for application to products containing 10% or more alcohol. In the modified method, the sample is extracted with chloroform and filtered, and the entire chloroform extract is evaporated and cleaned up on a silica gel column, if necessary. The extract is spotted on a TLC plate and the aflatoxin is determined by fluorescence under UV light. Seven samples of wine and duplicate samples of an iron tonic Mere spiked with aflatoxin B1; recoveries ranged from 90 to 100%. The sensitivity of this method is less than 1 µg/L. It is recommended that the method he subjected to a collahorative study.
Composition and Analysis of the Carotenoids in Marigold Petals
Authors: Quackenbush F W , Miller Sharon L
Published: February 2020

A modification of the current official first action method for carotenes and xanthophylls in dried plant materials and mixed feeds, 39.018–39.023, is presented for the analysis of the pigments in marigold petal meal and in feeds which contain it. Marigolds of different types and colors were grown locally from seed and the carotenoids of their petals were extracted, saponified, and chromalographed. Little variation in pigment distribution was observed in the different varieties and in commercial marigold petal meals. Of the 17 different pigments which were separated, lutein was preponderant; lutein plus zeaxanthin constituted 88–92% of the total. Epoxy pigments were less than 3% of the total. The wax-like nature of the xanthophyll esters in marigold petals neccssitates treatment with hot melhanolic KOH prior to chromatography. It is recommended that a collaborative study be initiated (a) to test the hot methanolic KOH treatment as an alternative procedure for all analyses, (b) to adapt the current official first action method to include the analysis of petal meal and mixed feeds containing it.
Analysis of Cyclofenil in Bovine Tissue
Authors: Crucs Robert J
Published: February 2020

An extraction and cleanup procedure is described for the analysis of cyclofenil in bovine muscle tissue. Flame ionization gas chromatography is used as the determinative step. An average recovery of 95% cyclofenil was obtained for tissue fortified with 0.5–30 μg cyclofenil/25g sample.
Identification of Canned Salmon Species by Scale Characteristics
Authors: Newton Richard T
Published: February 2020

An additional collaborative study on the identification of canned salmon species, based on the method and key published earlier, was conducted in 1971. All of the 8 collaborators were able to find usable and intact scales for mounting and identification. The overall percent correct identifications for 48 samples for the 8 collaborators was 79%. Three collaborators correctly identified all 6 samples and 3 more had only 1 of 6 samples incorrectly identified. Since the pink species was correctly identified in all cases and the chum species was correctly identified in 9 of 11 samples, the method has been adopted as official first action for the identification of these 2 species. Additional work will be done to eliminate the problems encountered with the sockeye, coho, and chinook species.
Spot Test for Detection of Urea in Foods and Feeds
Authors: Roy B R , Bosk P K
Published: February 2020

A colorimetric test for the detection of urea has been adapted as a spot test on filter paper for food and feed materials. This test is rapid and sensitive and requires no cleanup before analysis. Some degree of chromatographic separation between the color generated and interfering substances is achieved in the test. Contamination with 1% or less of urea can be detected. Samples of wheat, pulses, and wheat bran spiked with urea were subjected to this test and the recovery of added urea was good.
Collaborative Study of the Automatic Carbon, Hydrogen, and Nitrogen Determination
Authors: Scroggins La Verne H
Published: February 2020

A method for t h e simultaneous determination of per cent carbon, hydrogen, and nitrogen, employing automatic instrumentation, was tested by 10 collaborators. The samples analyzed were acetanilide, nicotinic acid, stearic acid, methyl palmitate, and ethyllaurate . Evaluation of the statistical data and overall consideration indicate satisfactory results for all types of compounds studied. The method was adopted as official first action.
Collaborative Study of Microanalytical Determination of Bromine and Chlorine by Oxygen Flask Combustion
Authors: Steyermark Al , Lalaxcette Roger A , Contreras Elise M
Published: February 2020

Twenty-six collaborators participated in the study of a specific method using oxygen flask combustion followed by mercurimetric titration of the ionic halide. With the exception of 3 collaborators, all obtained good results for bromine, although a fourth collaborator obtained borderline results. Including data from all collaborators gave: mean, 36.90%; mean–theory, -0.43%; standard deviation, 0.31; and standard deviation of the means, 1.59. Omitting results of 3 collaborators, the figures become: 37.36%, +0.03%, 0.20, and 0.20, respectively. Omitting results of 4 collaborators, the values become: 37.33%, 0.00%, 0.18, and 0.15, respectively. Similar results were obtained for chlorine. The results from all collaborators gave: mean, 20.76%; mean – theory, -0.14%; standard deviation, 0.18; and standard deviation of the means, 0.48. Omitting results of 3 collaborators (the same as those for bromine), the values are : 20.89%, -0.01%, 0.14, and 0.12, respectively. Omitting the results of a fourth collaborator was not considered necessary, because the results for chlorine were borderline, and including them still gave a good overall picture. The method was adopted as official first action as an alternative to the Carius method for the determination of bromine and chlorine in organic compounds.
Utilization of a Centrifuge for Gravimetrically Determining Phosphorus in Feeds and Fertilizers
Authors: Melton James R , Hoover William L , Howard Peggy A
Published: February 2020

The AOAC gravimetric quinolinium molybdophosphate method for the determination of P2O5 in fertilizers, 2.023–2.025, has been modified to allow centrifugation of the precipitate. Aliquots of the digested samples are placed in preweighed 16 ml centrifuge tubes, and quimociac reagent is added directly to the tubes. After formation of the precipitate, the samples are centrifuged and the supernatant is decanted. The precipitate is washed, recentrifuged, and decanted. After oven-drying, the weights of the precipitates are determined and per cent P2O5 is calculated. There were no significant differences between results of collaborative feed and fertilizer samples determined by the AOAC and the modified methods.
Sampling Bagged Fertilizers
Authors: Gehrke Charles W
Published: February 2020

Data pertaining to equipment and procedures used by 34 States in sampling bagged fertilizers are presented. All States reporting use the recommended slotted tube with solid cone tip, either as a single tube (25 States) or as a double tube (8 States). All but 2 States secure at least 10 cores. No serious sampling problems were reported. The recommended bag sampler specifications, based on the most widely used equipment, have been adopted as official first action for inclusion in 2.001(a).
Simple, Rapid Digestion Technique for the Determination of Mercury in Fish by Flameless Atomic Absorption
Authors: Holak Walter , Krinitz Benjamin , Williams John C
Published: February 2020

A simple and rapid digestion technique is described for the determination of mercury in fish by flameless atomic absorption. The sample is digested with nitric acid in a closed system in a commercially available vessel made of Teflon. A 30 min digestion at 150 °C is sufficient to convert the mercury to an inorganic form so that it can t h e n be reduced to the elemental state , aerated, and determined by atomic absorption. The proposed digestion compares favorably with the official AOAC sulfuricnitric- perchloric acid digestion.
Colorimetric Method for Estimation of Methyl Iodide Residues on Jo war (Sorghum) and Rice
Authors: Rangaswamy J R , Majumder S K , Poornima P
Published: February 2020

A new colorimetric method based on the catalytic action of iodide on oxidation of As(III) by Ce(IV) has been developed for the estimation of methyl iodide residues on grains. Methyl iodide residues, in methanolic KOH, are converted to potassium iodide which acts as a catalyst in the timed oxidation of As(III) by Ce(IV). Unreduced eerie salt is measured colorimetrically and the iodide in the sample is calculated. The method is sensitive in the range 0.01 to 0.1 μg iodide.
Gas Chromatographic Determination of Traces of Accelerants in Physical Evidence
Authors: Midkiff Charles R , Washington Willard D
Published: February 2020

Techniques developed for use with gas-liquid chromatography for the examination of evidence collected at the scene of suspected arson fires and firebombings are discussed. Both solvent extraction and vapor phase examinations are employed. Internal standards are used for the identification of specific components in actual samples to allow confirmation of hydrocarbon type, e.g., gasoline and kerosene. Operating parameters and solvent selection criteria are included. Results obtained from known materials and residual hydrocarbons in actual samples are compared.
Thin Layer Chromatography of Marihuana
Authors: Parker James M , Fiske Harold L
Published: February 2020

The various TLC methods employed in the separation and identification of Cannabis products to date are reviewed. Two solvent systems are recommended for rapid identification of marihuana: multiple development, semiquantitatiom, and wedge and loose-layer chromatographic techniques are discussed.
Thin Layer Chromatographic Identification Test for Sorbitol and Sorbitol Solution
Authors: Coles Zachary A , Upton R P
Published: February 2020

A simple, specific, and rapid method for the identification of sorbitol is described. This method is based on the thin layer chromatographic separation of sorbitol from its potential contaminants, using silica gel G treated with boric acid as the stationary phase and distilled water as the mobile solvent. The sorbitol is detected with an alkaline permanganate spray reagent and its Rf is compared with that of a sorbitol standard. The method is applicable to both crystalline and dissolved sorbitol.
A Simple Color Spot Test for Distinguishing Between Maneb, Zineb, Mancozeb, and Selected Mixtures
Authors: Stevenson A
Published: February 2020

Maneb, zineb, mancozeb, and selected fungicidal mixtures can be differentiated by a simple color spot test. Differentiation is based on the colors produced after successive application of acid dithizone, sodium hydroxide, and acid dithizone to the spot. The color depends on the type and concentration of metal present in the sample.
Neutron Activation Analysis of Mercury in Fish, Flour, and Standard Reference Orchard Leaves by Electrodeposition Radiochemistry
Authors: Heitzman M W , Simpson R E
Published: February 2020

A method for neutron activation analysis of mercury is described in which electrodeposition is used to isolate the mercury carrier in the recovery step. Although the recovery of mercury carrier is variable, the results yielded by this technique are comparable to those obtained using sulfide precipitation inneutr on activation analysis. The method was also compared to gas chromatography and atomic absorption techniques and similar results were obtained. No interferences were evident in the samples analyzed: fish, flour, and standard orchard leaves. The method can detect ppb levels of mercury.
Semia u torn ate d Method for the Analysis of Methyltestosterone Tablets and Testosterone Suspensions
Authors: Myrick James W , Page Donald P , Pfabe Yvonne H
Published: February 2020

A semiautomated analytical system has been developed to determine the amount of methyltestosterone in single tablets at a level of 5–25 mg/tablet or testosterone in suspensions. The active ingredient in an alcoholic solution was acidified and the drug was extracted into chloroform. Reaction with isonicotinic acid hydrazide produced a yellow color, which was recorded on a colorimeter. Relative standard deviations of the method did not exceed 1.38 and 1.50% for methyltestosterone tablets and testosterone suspensions, respectively.
Colorimetric Estimation of Pilocarpine in Drug Preparations
Authors: Karawya Mohamed S , Ghourab M G
Published: February 2020

The proposed method is based on oxidative cleavage of pilocarpine by benzoyl peroxide and colorimetric estimation of the formaldehyde formed after addition of chromotropic acid to the sample. The method yields comparable results with the USP hydroxylamine HC1 method for varied pilocarpine formulations and the interferences present in the latter method are removed. A thin layer chromatographic step is used to isolate pilocarpine from other drugs in the analyses of multicomponent preparations.
Improved Method for Determination of Xanthophyll in Fresh Alfalfa and Wet Fractions
Authors: Knuckles Benny E , Bickoff E M , Kohler George O
Published: February 2020

An improved method for the analysis of xanthophyll, as well as carotene, is described for fresh alfalfa. This method is also applicable t o low fiber materials such as whole juice and protein-xanthophyll concentrates. T h e method is rapid and gives xanthophyll values which are significantly higher than those by other procedures. Pigmenting xanthophylls are determined as trans-lutein equivalents.
Collaborative Study of the Gas-Liquid Chromatographic Assay for Vitamin E
Authors: Rudy B C , Mahn F P , Senkowski B Z , Sheppard A J , Hubbard W D
Published: February 2020

A collaborative study for the analysis of vitamin E in multivitamin tablets was conducted and the method was subsequently approved as official first action by the AOAC. Additional data were obtained by an extensive collaborative study sponsored by the Pharmaceutical Manufacturers Association, which verified the usefulness of GLC for the assay of α-tocopherol, α-tocopheryl acetate, and α-tocopheryI acid succinate. The mean coefficient of variation obtained from the 8 participating laboratories for duplicate samples, duplicate injections, was ±2.04, 1.75, and 2.71%, respectively. Further collaborative studies were conducted on samples of mixed tocopherol concentrate, multivitamin tablets, and multivitamin soft gelatin capsules. The mean coefficient of variation obtained from 13 collaborators was in the range of ±5%. The accumulated data demonstrate the utility of this technique for improved specificity and reliability of the analysis of vitamin E.
Gas Chromatographic Determination of Residual Hexane in Modified Hop Extract
Authors: Litchman Mark A , Turano Lewis A , Upton Ronald P
Published: February 2020

A method is described for the quantitative determination of hexane in modified hop extract by head-space gas-liquid chromatography. A sample of extract is weighed into a serum vial and water-methanol solution is added. The vial is sealed tightly and heated 1 hr in a 70°C bath. A sample of the head-space gas over the solution is injected onto a Porapak Q gas chromatographic column for determination. Recovery of 2–29 ppm hexane added to potassium isohumulone was 95.5–114.8%. The method may be applicable to other hop extracts.
Confirmation of Pesticide Residue Identity. IV. Derivative Formation in Solid Matrix for the Confirmation of α- and β-Endosulfan by Gas Chromatography
Authors: Chau Alfred S Y , Terry Ken
Published: February 2020

The new solid matrix derivation procedure has now been applied to the confirmation of endosulfan residue identity . This procedure in volves the conversion of endosulfans to the same diacetate in alumina impregnated with H2SO4 and acetic anhydride. Comparable yield of the diacetate was obtained from the present approach and from a previously reported acetylation method. The advantage of the present method over the reported procedure is also discussed.
Residues of Chlorpyrifos Insecticide in Various Crops. I. Sweep Co-Distillation Method for Extraction and Cleanup
Authors: Maini Paolo , Collina Arrigo
Published: February 2020

The sweep co-distillation technique was expanded for application to chlorpyrifos insecticide residues in various substrates. The published technique was followed without significant changes for samples of lettuce, carrot, sugar beet (leaves and roots), potato, apple, onion, cauliflower, orange (pulp and peel), corn grain, and agricultural soil. Recoveries ranged from 74.2 to 100.7% at the fortification level of 0.1 ppm. Recovery tests were carried out also at levels ranging from 0.05 to 1.0 ppm for some crop samples obtained from trial field tests, with good results. For tobacco samples, some changes in the extraction and cleanup procedure were introduced to avoid some GLC interferences, but recoveries were low. Low recoveries were also obtained from the unmodified method and from the extraction, partition, and Florisil cleanup method.
Fluorescence of Aflatoxin M Standards Stored in Solution and as Dry Films
Authors: Purchase Iain F H , Steyn Martin
Published: February 2020

Aflatoxin M standards were stored in solution in nylon, soda glass, or borosilicate glass test tubes in 4 different solvents (benzene, benzene-acetonitrile (98+2), chloroform, ethanol) or as a dry film for 24 weeks. The standards were stored under conditions which were expected to accelerate deterioration. It was found that solutions in chloroform or benzene-acetonitrile stored in borosilicate glass test tubes contained the largest amount of aflatoxin M at 6 weeks. In addition, the percentage loss of aflatoxin M was greater in tubes containing small amounts (0.18 or 0.9 μg) than in tubes containing the largest amount (9.0 μg) of aflatoxin M.
Gas Chromatographic Determination of O,O-Diethyl S-(N-Isopropylcarbamoylmethyl) Phosphorothiolothionate (Prothoate) in Technical Products and Liquid Formulations
Authors: Bazzi Brunetto , Galluzzi Guglielmo , Abruzzese Luigi
Published: February 2020

A gas chromatographic method has been developed for the analysis of O,O-diethyl S-(N-isopropylcarbamoylmethyl) phosphorothiolothionate . The acaricide or a convenient amount of an acaricidal preparation is dissolved in xylene, together with malathion as an internal standard, and analyzed by gas chromatography, using a thermal conductivity detector. The precision (P = 0.05) of the method is ±1.5% of the concentration level.
Disulfiram Determination by Proton Magnetic Resonance Spectroscopy and by Colorimetry
Authors: Sheinin Eric B , Benson Walter R , Smith Myron M
Published: February 2020

Disulfiram was determined in disulfiram drug substance and tablets by proton magnetic resonance (PMR) spectroscopy at the 100–480 mg level and by a colorimetric technique involving cuprous iodide at the 50 mg level. The tablet excipients do not interfere in the analysis. The average result for disulfiram in a tablet composite was 100.8±1.4% of label claim by PMR and 100.7±0.4% by the colorimetric method.
Collaborative Study of Improvements in the Distillation Procedure of the Official Method for Formaldehyde in Maple Sirup
Authors: Hébert Calixte
Published: February 2020

A collaborative study was conducted to show that in the quantitative extraction of formaldehyde from maple sirup by the official final action controlled distillation method, 31.184—31.189, accuracy is increased by the use of a thermostatically controlled flask heater, together with the proper insulation of the glass apparatus with asbestos cord. This eliminates undue condensation of the distillate and variations in the final and total distillation times. The modified method was tested by 9 laboratories and, from their individual results, the coefficients of variation for the total time of distillation proved that the method gave excellent control of the final operation. The changes have been adopted as official first action.