bluuebunny/crossref_metadata_2025 huggingface dataset:
Thin Layer Chromatographic Test for Mammalian Urine on Wheat
Authors: Thrasher Joel J
Published: February 2020

A method has been developed for the detection of urine residues on wheat. The analysis involves acetone stripping of the wheat, ether cleanup of the extract, and detection by 2-dimensional TLC on cellulose MN 300; urea and allantoin, if present, are visible after spraying with p-dimethylaminobenzaldehyde followed by heating. The method permits differentiation between cat and rodent (rat and mouse) urine and, with only minor modifications of the general technique, appears to be applicable to other seeds and materials. It is recommended that the method be collaboratively studied.
Determination of Polychlorodibenzo-p-dioxins and Related Compounds in Commercial Chlorophenols
Authors: Firestone David , Ress John , Brown N L , Barron R P , Damico J N
Published: February 2020

Twenty-one commercial chlorophenols were examined for the presence of polychlorodibenzo- p-dioxins (chlorodioxins) and related compounds. The chlorophenols were dissolved in aqueous alkali, extracted with petroleum ether, and fractionated on an alumina column. Alumina fractions were examined by electron capture gas chromatography and combined gas chromatography-mass spectrometry. Chlorodioxin content was estimated by electron capture gas chromatography. The presence of chlorodioxins, polychlorodibenzofurans (chlorofurans), and polychlorodiphenyl ethers (chloroethers) was confirmed by combined gas chromatography-mass spectrometry. The 2,3,-7,8-tetrachlorodioxin was found in 3 of 6 samples of 2,4,5-trichlorophenol but was not detected in any of the 11 samples of tetra- and pentachlorophenol that were examined. Hexachlorodioxin was present at levels ranging from 0.17 to 39 ppm in all 8 pentachlorophenols examined. Hexa-, hepta-, and octachlorodioxins as well as a wide variety of chlorofurans and chloroethers of varying chlorine content were present in most of the tetra- and pentachlorophenols. In addition, the gas chromatographic- mass spectrometric data suggested that some of the chlorophenols contained methoxy- and dimethoxypolychlorofurans and methoxypolychloroethers as well as polychlorohy droxybiphenyl.
Derivative Method for Chemical Confirmation of Identity of Aflatoxin M1
Authors: Stack M E , Pohland A E , Dantzman J G , Nesheim S
Published: February 2020

A very sensitive chemical confirmatory test for aflatoxin M1, involving the formation of 2 derivatives, has been developed. One derivative is the acetate of M1 formed in a solution of acetic anhydride and pyridine. The other derivative is formed from the acetate, using water a n d HCl, and is probably the hemiacetal. The derivatives are detected as fluorescent spots on TLC. The derivatives have been formed and detected from 1 ng aflatoxin M1 and from M1 isolated from milk, urine, and mold culture
Assay of NF Ethylene by Gas Chromatography
Authors: Carson N Aubrey
Published: February 2020

A gas chromatographic method, utilizing a 6′ × 1/4″ Poropak R column and a thermal conductivity detector, was developed for the analysis of NF ethylene. The sample was introduced into the gas chromatograph at atmospheric pressure, using a gas sampling valve with calibrated loop. A high purity standard gas was used for comparison. With the instrument set for optimum operating conditions the precision for multiple injections of standard gas was excellent. The assay value of a sample was found to be 99.7%, when determined on 3 separate days. A collaborative study of the method is recommended.
Modification of Present Procedures for the Determination of Conjugated Estrogens (Equine) in Various Low-Dosage Forms
Authors: Allen Richard G
Published: February 2020

The presently used procedures for the colorimetric determination of conjugated estrogens (equine) have been modified for the assay of tablets, capsules, liquids, and creams of low declaration per dosage unit. Modifications in sample chromatographic column preparation and elution have provided a more efficient extraction of the steroids.
A Study of Testing Methods for the Detection of Defects in Disposable Latex and Plastic Glovse
Authors: Ballbach Ray L , Beavin Paul , Walters Stephen M
Published: February 2020

Several testing methods for the detection of holes in disposable gloves intended for medical use were investigated. An air inflation method was developed which proved to be the most sensitive and reliable. A survey of the quality of commercially available disposable latex and plastic gloves was conducted in which the air inflation method was compared with the pinhole testing procedure prescribed in the Department of Defense specifications for disposable gloves. The air inflation method gave more reliable results.
Flame Ionization Gas-Liquid Chromatographic Determination of Antioxidants in Vegetable Oil
Authors: Stoddard Ellen E
Published: February 2020

A procedure is described which is suitable for the analysis of the 2 isomers of butylated hydroxyanisole, butylated hydroxy toluene, monotert- butylhydroquinone, n-propyl gallate, and nordihydroguaiaretic acid. The method described is sensitive to 0.05 ng. The antioxidants are extracted from n-hexane with acetonitrile and 80% ethanol. Butylated hydroxytoluene is eluted from Florisil (3% deactivated) with n-hexane saturated with acetonitrile and containing 2% ethanol. Quantitation of the antioxidants is performed by gas chromatographic analysis of the trimethylsilyl derivatives, using methyl pentadecanoate as the internal standard. Identity is confirmed by thin layer chromatography, employing the 2-dimensional solvent system described by Sahasrabudhe. Recoveries range from 67 to 100%.
Campesterol and β-Sitosterol Content of Some Vegetable Oils
Authors: Thorpe Charles W
Published: February 2020

The free and total campesterol and β-sitosterol content of 48 samples of crude and refined corn, cottonseed, soybean, and peanut oils are reported. The results show that the ratio of β-sitosterol to campesterol may be used to identify an individual oil and tend to confirm that sterols are lost during refining of the crude oils. It is recommended that the official method, 28.081-28.088, modified for the analysis of campesterol and β-sitosterol be collaboratively studied.
Collaborative Study of the Babcock, Mojonnier, and Foss Milko-Tester Methods for Measuring Fat in Milk
Authors: Shipe W F
Published: February 2020

In a second collaborative study, the Milkotester was compared with the Babcock and Mojonnier methods. The standard deviations for these methods were 0.020, 0.038, and 0.053%, respectively. These deviations are based on the results of 4 laboratories that tested 6 samples in triplicate by each method. There were appreciable interlaboratory differences, whereas the intralaboratory differences were relatively small. The standard deviations of differences between the Milko-tester and Babcock, the IMilko-tester and Mojonnier, and the Babcock and Mojonnier were 0.08, 0.09, and 0.11%, respectively. The standard deviations of the results from 5 Mark II and 5 automatic Milko-testers were 0.022 and 0.013%, respectively.
Collaborative Study of Moisture in Cheese by Gas Chromatography and by Karl Fischer Titrimetry
Authors: Strange Theron E
Published: February 2020

Moisture in cheese is determined by extracting the sample in a blender with 2-propanol, followed by gas chromatography on a Porapak Q column with thermal conductivity detection, or by Karl Fischer titration. The results of a collaborative study by 5 laboratories show that both procedures give more accurate values than does 16.192, but with less precision.
Collaborative Study of a New Method for the Extraction of Light Filth from White Flour
Authors: Miller Mary T
Published: February 2020

A new method for the separation of light filth from white flour is based on an autoclave-acid hydrolysis, followed by separation of light fdth elements with mineral oil in a Corning or Kilborn separator. This method is rapid and gives clean papers and good recoveries. The method has been adopted as official first action, to replace 40.045 and 40.046 for extraction of light filth from white flour.
Malathion Absorption, Translocation, and Conversion to Malaoxon in Bean Plants
Authors: El-Refai Ali , Hopkins T L
Published: February 2020

Malathion deposits on bean plant leaves, Phaseolus vulgaris, decreased 50% in 2 days under controlled environmental conditions. The decrease was initially more rapid from leaves than from glass surfaces, due to combined evaporation and absorption, but later the cuticular residues became more persistent. Five per cent of the malathion deposit was absorbed within a few minutes after application to bean leaves and declined to 0.4% by 10 days. Malathion degradation products accumulating on both glass and leaf surfaces were similar and included small amounts of malaoxon and an unknown cholinesterase inhibitor. Malathion is not translocated to any great extent in bean plants, but penetrates from the surface into the interior of the leaf and also from a nutrient solution into the root. Small malaoxon residues also accumulated in roots and foliage.
Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Diethylcarbonate in Wine
Authors: Kahn Heinrich Wunderlich
Published: February 2020

A gas-liquid chromatographic method for diethylcarhcmate in wine was collaboratively studied in the spring of 1971. Twelve collaborators were sent 4 samples of wine in duplicate, containing 0, 1, 5, and 10 p pm diethylcarbonate . Results were obtained from 10 laboratories. Values for Sb2 were 0.83, 0.33, 0.62, a n d 4.65, respectively. The method has been adopted as official first action for t h e determination of 0-10 p pm diethylcarbonate in wine.
Collaborative Study of the Direct Bisulfite Method for the Determination of Aldehydes in Brandy and Wine Spirits: American Society of Enologists-AOAC Joint Report
Authors: Guymon James F , Wright Dawson L
Published: February 2020

The determination of free and total aldehydes in brandy and wine spirits by using the direct bisulfite titration method of Guymon and Crowell was studied collaboratively by t he Technical Projects Committee of the American Society of Enologists. Titration with standard iodine solution in alkaline medium is used to measure the released bisulfite which had been bound directly to aldehydes, therefore avoiding errors due to sulfites already present. The method distinguishes between the free forms of aldehydes and those acetalized with alcohol by a simple change in sequence of reagent additions so as to provide for a n acid hydrolysis of acetals when total aldehydes are determined. Five samples of beverage brandyor wine spirits were used for the study for which the means of total aldehydes reported ranged from 0.64 to 26.4 g/100 L. The results indicate that the method gives good accuracy and precision. The method has been adopted as official first action for the direct determination of aldehydes in brandy and wine spirits.
Proposed Technique for the Determination of Both Moisture and Fat in the Same Sample of Meat or Meat Product
Authors: Cohen Edward H , Kimmelman Charles P
Published: February 2020

The moisture content of ground meat, processed frankfurters, and uncooked pork sausage mixtures was determined within a 15-30 min time period and with a minimum of 95% recovery of moisture. Selective solvents, such as octane, nonane, toluene, xylene, ethylbenzene, and cumenc were evaluated. After removal of the moisture, the residue in the flask was sampled for the fat content . A 20 ml aliquot of the cooled total solution was removed, transferred to a tared vessel, and evaporated at its boiling point under a stream of nitrogen. The oil residue was weighed and calculated as percent fat. Recoveries of fat ranged from 95 to 100% for all solvents and meat products tested except for the uncooked pork sausage mixture. The latter product yielded 80–91% recovery of fat for all solvents. To obtain a 95–100% recovery from the uncooked pork sausage mixture required an additional 15–30 min digestion. The tim e required for fat determinations was from 15–30 min, depending upon the boiling point of the solvent.
Collaborative Study of the Determination of Phosphorus in Gelatin, Dessert Preparations, and Mixes
Authors: Burkepile Roger G
Published: February 2020

A collaborative study of the proposed method for phosphorus in gelatin, dessert preparations, and mixes has been conducted. The present AOAC method for phosphorus in fertilizers, 2.023–2.025(a), was modified for this study. Preliminary work by the Associate Referee involving 4 phosphorus standard samples compared the proposed method with the official final action AOAC method for gelatin, 23.004. Additionally, phosphorus standard spikes in gelatin at the 1 and 10 mg P2O5, levels were determined by the proposed method. The proposed method is faster and more sensitive than the official method and is as accurate. Five collaborators and the Associate Referee analyzed 4 prepared samples containing various levels of phosphorus by the proposed method. The standard deviations varied from 0.005 for a 225 Bloom gelatin containing an average of 0.273% P2O5 to 0.016 for a strawberry-flavored commercial gelatin with added lecithin containing an average of 0.110% P2O5. The proposed method has been adopted as official first action to replace 23.004, which was repealed, official first action.
Utilization of the Westöö Procedure for the Determination of Methyl Mercury in Fish by Gas-Liquid Chromatography
Authors: Kamps Laverne R , McMahon Bernadette
Published: February 2020

The procedure developed by Westöö for the determination of (mono) methyl mercury in fish is elucidated. The sample is homogenized with water and acidified with HCl and the methyl mercury chloride is partitioned into benzene. The benzene phase is partitioned with a cysteine solution to provide cleanup. The cysteine is then acidified and methyl mercury chloride is again partitioned into benzene and determined by electron capture gas-liquid chromatography. Results are corrected for incomplete partitioning. Recovery of methyl mercury chloride through the partitioning steps is shown to be reproducible. Westoo’s use of mercuric chloride to verify results is substantiated. The normal limit of detection of the method is 0.08 ppm methyl mercury chloride with provisions for detectirg as little as 0.02 ppm.
Ion Exchange Method for the Separation and Spectrophotometric Determination of Some Sympathomimetic Amines, Antihistamines, and Phenothiazines in Pharmaceuticals
Authors: Smith Donald J
Published: February 2020

An ion exchange procedure has been developed for the separation and quantitative analysis of 32 drugs in various combinations: (a) promethazine HCl with codeine phosphate and potassium guaiacolsulfonate; (b) phenylephrine or phenylpropanolamine HCl with (1) dextromethorphan HBr, potassium guaiacolsulfonate, chlorpheniramine maleate, and/or pyrilamine maleate; (2) dextromethorphan HBr, glyceryl guaiacolate, chlorpheniramine maleate, and/or pyrilamine maleate; (3) dextromethorphan HBr and potassium guaiacolsulfonate; (4) dextromethorphan HBr and glyceryl guaiacolate; (5) dextromethorphan HBr and antihistamine; (6) antihistamine and glyceryl guaiacolsulfonate; (7) antihistamine and potassium guaiacolsulfonate; (8) dextromethorphan HBr; (9) glyceryl guaiacolate; (10) potassium guaiacolsulfonate; (c) promethazine HCl with (1) codeine phosphate or (2) phenylephrine HCl; (d) codeine phosphate and potassium guaiacolsulfonate; (e) chlorpromazine HCl, promazine HCl, or promethazine HCl; (f) phenylephrine HCl; (g) codeine phosphate; (h) perphenazine HCl alone or with amitriptyline HCl; (i) ephedrine sulfate with phenobarbital, theophylline, and glyceryl guaiacolate; (j) l-epinephrine bitartrate alone or with antihistamine; (k) procaine HCl, procainamide HCl, procaine isobutyrate, or tetracaine HCl; (l) quinine sulfate with aminophylline; (m) dextromethorphan HBr with (1) terpin hydrate; (2) antihistamine; (3) potassium guaiacolsulfonate; (4) glyceryl guaiacolate; and (n) atropine sulfate or honiatropine methylbromide.

The nitrogenous bases are separated from the excipients by retention on a sulfonated polystyrene resin column. These basic compounds are eluted from the column with the appropriate concentration of HCl and are determined by UV; absorption. The organic acids are retained on the quaternary ammonium anion resin. The acidic compounds are eluted from the columns with the appropriate concentration of HCl and determined by I’V absorption. Average recoveries ranged from 98.6 to 101% in the absence of excipients and 95.8 to 102% with excipients present. The method is recommended for collaborative study.
Collaborative Study of a Method for the Determination of Commercial Sterility of Low-Acid Canned Foods
Authors: Dexxy C B
Published: February 2020

A microbiological method for examining canned foods for commercial sterility to minimize contamination by the individual laboratory worker has been developed. Previous comparative tests by 7 laboratories and an earlier collaborative test with 9 food laboratories had shown considerable laboratory contamination, but had provided useful information as to appropriate apparatus, reagents, and procedures. Simple baud washing with soap was compared with the following procedure: hand and face washing, followed by washing of hands and face with a detergent sanitizer solution, and the wearing of a disposable operating room cap. Persons with beards, mustaches, or sideburns below the ear lobe were not permitted to perform the test. Eight specially prepared commercial cans of salmon were examined by 12 collaborating laboratories; 4 were examined after the simple hand washing procedure and 4 by the double washing and head-cover technique. Results showed that 25% of the laboratories experienced laboratory contamination by using only simple hand washing as compared to 0% using the double washing and head-cover technique. The microbiological method, including the double washing and head-cover technique, has been adopted as official first action.
Comparison of Aliquot and Complete Sample Procedure for the Determination of Nicotine in Cigarette Smoke
Authors: Pillsbury H C , Bright C C
Published: February 2020

Two methods for determination of nicotine in cigarette smoke have been compared : distillation of a complete sample vs. distillation of an aliquot. For the evaluation of these methods, monitor cigarettes or cigarettes from cartons with the same packing codes purchased from a local store were used for each test set. The cigarettes were conditioned, selected, and smoked according to the official method published by the Federal Trade Commission. Because both isopropanol and dioxane are used as solvents, tests were conducted using both solvents; it was found that there was no difference in the results. Cigarettes for both methods were smoked at the same time and those from alternate ports were assayed for nicotine by the aliquot method. From the results obtained, it appears that nicotine is completely recovered when the entire pad, the quarter pad, and the extraction solution are distilled together. If an aliquot of one phase is to be used, it must be determined that the soughtafter substance is homogeneously distributed throughout all phases.
Fatty Acid Composition of Tomato Seed Oil
Authors: Tsatsaronis G C , Boskou D G
Published: February 2020

The fatty acid composition of the oil extracted from tomato seeds was determined by GLC. A urea fractionation procedure and preparative GLC were used to detect esters present in small or trace amounts. Linoleic, oleic, and palmitic acids were predominant. Odd- and even-chain length saturated acids from C12-C28 were present. Hexadecenoic, heptadecenoic, and eicosenoic acids were also detected. Minor chromatographic peaks preceding some of the saturated esters were attributed to branched acids.
Dry-Ashing Egg Shells for Determining Calcium, Magnesium, and Phosphorus Levels
Authors: Wright Fred C , Riner Jayme C
Published: February 2020

A method for the determination of calcium, magnesium, and phosphorus in a single egg shell sample is given. Egg shell samples were dry-ashed 16 hr at 700°C. The ash was dissolved in HCl. After suitable dilution, the calcium and magnesium levels were determined by atomic absorption spectrophotometry. The phosphorus level was determined by a colorimetric procedure. Average calcium, magnesium, and phosphorus levels were 365, 4.0, and 1.05 mg/g shell, respectively.
Collaborative Study of the Determination of Iron and Aluminum in Baking Powder by Atomic Absorption Spectrophotometry
Authors: Holak Walter
Published: February 2020

Commercial halting powder and samples containing added iron and aluminum were subjected to an interlaboratory study. The iron and aluminum were determined by an atomic absorption method reported earlier. The results for aluminum were satisfactory (average recoveries of 98, 99, and 107% for 3 levels) and the method has been adopted as official first action for aluminum. The iron results are somewhat erratic and study will be continued.
Amino Acid Analysis of Soybean Meal: Interlaboratory Study
Authors: Cavins J F , Kwolek W F , Inglett G E , Cowan J C
Published: February 2020

Amino acid analysis of soybean meal was studied by 5 laboratories. Between- and within-laboratory variations were significant for most amino acids, whereas variations due to hydrolysis procedure and sample mesh size in the under 30 to under 270 mesh range were significant at the 0.05 level for only 2 amino acids. The relative standard deviation was different for each amino acid with cystine, methionine, and ammonia having the highest values. Normalization of results to 95% nitrogen recovery had only a small effect on statistical analysis of the data. Values from special analytical procedures for cystine did not agree, whereas those for tryptophan agreed very well.
Collaborative Study of Methods for Free and Total Water in Fertilizer
Authors: Duncan Russell D
Published: February 2020

A collaborative study was made of the 1,4-dioxane extraction method for free water and the distillation method for total water i n fertilizer. Six laboratories participated in the analysis of 5 samples, and the results of t he extraction method were evaluated by the technique of matched pairs. The extraction method compared favorably with the official vacuum desiccation method and was adopted as official first action. While the study was in progress, the Associate Referee found that nitrate interfered with the proposed method for total water. Study of this method has been discontinued.
Methods for Determining Ronnel in Feeds and Mineral Mixtures
Authors: Gehrt Albert J
Published: February 2020

The official first action GLC method (electron capture detector) for ronnel in feeds, 38.126–38.129, is rapid and dependable but has been found to give low ronnel recoveries with stored samples. A major study was made to determine whether the low results are due to decomposition or binding of the ronnel. Ronnel and trichlorophenol (TCP) analyses were made by GLC on a feed sample stored for 9 months; results showed that 29–33% of the added ronnel and 29–54% TCP (reported as ronnel) were recovered under various conditions, accounting for 58–87% of the original ronnel. Analyses for TCP made by hydrolysis gave similar results. The ronnel not accounted for was probably lost through degradation, followed by volatilization and/or sublimation on the container walls. This study indicates conclusively that degradation of the ronnel is a major cause for the low recoveries in stored feeds. A biological (housefly killing) assay was made on another sample of the stored feed and showed 41% of the ronnel remaining. Agreement between the GLC analyses and the biological assay, plus proof of ronnel decomposition in stored samples, are convincing evidence that the first action method determines the true ronnel content of the feed. The official first action GLC method for ronnel in feeds has been adopted as official final action.
Uncombined Intermediates in FD&C Yellow No. 6
Authors: Marmion Daniel M
Published: February 2020

Ten collaborators participated in a study of the analysis of uncombined intermediates in FD&C Yellow No. 6; each collaborator analyzed 4 samples. The intermediates were separated by column chromatography and quanti-tated by ultraviolet spectrometry. Sulfanilic acid, Schaeffer’s salt, and 6,6‚-oxybis(2-naphthalenesulfonic acid) were recovered at an average level of 95% of the amounts added. Between- laboratory standard deviations ranged from 0.01 to 0.20% when the intermediates were present at levels of 0.02 to 1.47%. The method has been adopted as official first action.
Rapid Quantitative TLC Method for Determining Aflatoxins in Cottonseed Products
Authors: Pons Walter A , Cucullu Alva F , Franz Anthony O
Published: February 2020

The official AOAC method for aflatoxins in cottonseed products was modified to provide a rapid quantitative method whereby an analysis can be completed in as little as 1 hr. The method incorporates a choice of either 5 min blender or 30 min shaker extraction and either half-plate (20 min) or full-plate (50 min) TLC development to provide a flexible method to meet different analytical requirements. The rapid method was compared with the official AOAC method and the ferric gel method of Velasco for determining aflatoxins in 10 samples of cottonseed kernels and 14 samples of meals. With kernels, all 3 methods were essentially equivalent up to a contamination level of 3800 μg/kg. For quantities above this level, results by the official method were 77% of those obtained by the other 2 methods. With meals, both the rapid and official methods were equivalent for aflatoxin B1, but interferences were encountered at the Rf value of B2 on TLC plates in 3 of the 14 samples analyzed by the rapid method. With the ferric gel method, interferences at the Rf values of aflatoxin B1 or B2 were encountered in 9 of the 14 samples, and the B1 estimates by this method averaged 87% of that found for the rapid or official methods.
Quantitative Fluorodensitometric Measurements of Aflatoxin B1 with a Flying-Spot Densitometer. I. Fluorodensitometric Study of the Behavior of Aflatoxin B1 Standard Spots on Different Types of Silica Gel
Authors: Beljaars P R , Fabry F H M
Published: February 2020

TLC plates were scanned after development with a reflectance flying-spot densitometer. The procedure for routine measurements of standard B1 spots is described herein. Three different types of silica gel layers were spotted with standard aliquots of aflatoxin B1 covering a range of 0.4–20 ng. Silica gel H plates were developed with a mixture of chloroform– trichloroethylene–n-amyl alcohol–formic acid (80 + 15 + 4 + 1), while silica gel G and MNG- HR plates were developed with a mixture of chloroform-acetone (90 + 10). Sharp and defined separation patterns for anatoxins B1, B2, G1, and G2 were recorded on H and MN-G-HR plates, while unsatisfactory separation was found on G plates. The relationship between peak area and concentration was linear for II and MN-G-IIR plates, but not for G plates. Variations of ±15–20% were calculated among the fluorescence of standard B1 spots between plates with same sorbent layers. Coefficients of variation of ±5–7% for single densitometric measurements on one plate under normal routine conditions were calculated for a series of 3 or 4 standard aflatoxin B1 spots ranging from 1 to 4 ng on H and MN-GHR plates. Coefficients of variation of ±11–12% were calculated for G plates. Results obtained in this investigation are compared with those found by previous investigators.
Collaborative Study of the Determination of Aflatoxin in Corn and Soybeans
Authors: Shotwell O L , Stubblefield R D
Published: February 2020

A study was made to determine whether the procedure commonly designated as the CB method, previously recommended for determining anatoxin in peanuts and peanut products, could be applied to corn and soybeans. Both naturally contaminated and spiked corn and soybeans were extracted and analyzed by TLC. Of the 15 collaborating laboratories, 9 were equipped to measure anatoxins on TLC plates densitometrically, as well as visually. Seven collaborators used molar absorptivities to determine the concentration of anatoxins in solutions to be used for TLC standards. The official CB method has been extended to include corn and soybeans, and the rapid TLC screening technique for aflatoxin in corn has been adopted as official first action.
Methods for the Development of Latent Fingerprints
Authors: Connor Charles M
Published: February 2020

Available methods for the development of latent fingerprints and some problems that arise during fingerprint examinations that affect document examination and chemical analysis are described. It is suggested that the fingerprint and document examiners work together with the analytical chemist to develop methods which are most suitable for certain items so that an analysis conducted by one examiner will not prevent examination of the same item by analysts of other disciplines.
Automated Fluorometric Method for the Determination of Morphine in Urine
Authors: Sansur M , Buccafuri A , Morgenstern S
Published: February 2020

A sensitive and specific automated method for the fluorometric determination of morphine in urine was developed. The analysis is performed at a rate of 40 samples/hr. The method is based on the oxidation of morphine to the fluorescent pseudo-morphine dimer. Morphine is extracted from urine at pH 9.4 with a mixture of organic solvents. The organic phase is washed with a dilute buffer at pH 9.4 and is further extracted with a dilute alkaline solution. Following the third extraction step, 2 equal portions of the alkali phase are buffered to pH 9.4. Potassium ferricyanide solution is added to the sample segment and water is added to the “blank” segment. Each of these solutions enters a separate fluorometer and the fluorescence is recorded. An increment in fluorescence of the sample as compared to the blank indicates the presence of morphine. Concentrations as low as 0.2 μg free morphine/ml urine are easily detected. Five hundred subjects from a Methadone Maintenance Program have been tested. Results show excellent agreement with determinations on the same samples by thin layer chromatography.
Instability of Propyl Lactate Prepared by Boron Trifluoride-Catalyzed Esterification of Lactic Acid
Authors: Staruszkiewicz Walter F , Bond John F
Published: February 2020

The official first action gas chromatographic method for the determination of lactic, β-hydroxyhutyric, and succinic acids, 17.034–17.038, requires the formation of their propyl esters with boron trifluoride-1-propanol and extraction of the esters into an organic solvent prior to chromatography. Previously published data showed that the solutions of propyl esters were stable for as long as 4 weeks when they were extracted into chloroform and stored at 40°F. However, when ethyl ether is substituted for chloroform, propyl lactate is no longer stable during storage. The ether apparently extracts some unreacted boron trifluoride which eventually causes the hydrolysis of propyl lactate. The propyl esters of β-hydroxybutyric, levulinic, and succinic acids were stable in ether as well as in chloroform. The method has been revised to include the use of ethyl ether, if required by the gas chromatographic system, and to specify analysis of the ether solutions within 24 hr of esterification.
Colorimetric Determination of Cyclamate in Soft Drinks, Using Picryl Chloride
Authors: Saturley B A
Published: February 2020

Cyclamate is converted to cyclohexylamine, which is extracted from the soft drink sample with chloroform. The cyclohexylamine extract is then coupled with picryl chloride to produce a colored complex with a maximum absorption at 418 nm.
Neutral Blue, a New Indicator
Authors: Srivastava O P
Published: February 2020

A new indicator for acid-base titrations is reported. Neutral blue, isolated from an umbelliferous plant, is pink at pH 5.3 and below and blue at pH 7.1 and above. Just before the end point, the indicator turns purple and thins there is a clear indication of when it is being approached. Examples of titrations with strong and weak acids and bases are given.
Large, Inexpensive Oven Used to Decontaminate Glassware for Environmental Pesticide Analysis
Authors: Lamberton J G , Claeys R R
Published: February 2020

Classical methods that use strong oxidizing acids or methanol-base for cleaning glassware are frequently ineffective in removing chlorinated pesticide contaminants. The construction of a large, low-cost ($400) oven is described for the removal of interfering contamination from glassware. Contamination is reduced to insignificant levels when glassware is baked in the oven at 230°C
Infrared Studies of Dicyclohexylamine
Authors: Chen Jo-Yun T
Published: February 2020

Some physical and chemical properties of dicyclohexylamine were investigated by IR spectroscopy. The spectra of dicyclohexylamine are presented, not only of the pure liquid, but also of the solid which results from high pressures and low temperatures. The IR spectral data indicate that dicyclohexylamine exists under standard conditions as 3 rotational isomers in dynamic equilibrium. Below – 24°C, dicyclohexylamine in the crystalline state exists entirely in the axial-equatorial form. This work reveals that solid dicyclohexylamine goes through several phase transitions, depending on the temperature and/or pressure. Dicyclohexylamine has marked chemical activities, i.e., the amine group will add to double bonds such as with CS2 and CO2 and forms salts with HC1, acetic acid, and moist NaCl powder. The IR spectra of these derivatives are also presented.
Gas Chromatographic Determination of Propionic, Sorbic, and Benzoic Acids in Rye Bread and Margarine
Authors: Graveland A
Published: February 2020

A rapid and accurate method is presented for the GLC determination of propionic and sorbic acids in bakery products and benzoic acid in margarine. The acids are extracted with ether containing orthophosphoric acid, to which valeric acid is added as internal standard. The extract is injected directly into the gas chromatograph. Glass columns (2 m × 2.0 mm id) containing 5% Carbowax 20M-terephthalic acid coated on Chromosorb W (AW-DMCS) are used for analysis. The simplicity and convenience of the method make it suitable for routine determinations.
Chemical Composition of Canadian Apple Juice
Authors: Ryan J J
Published: February 2020

Twenty-one samples of authentic apple juice have been studied. Analytical values are presented for amino acids, pH, density, soluble solids, potassium, ash, individual organic acids, and individual sugars. These values are compared to those obtained from 11 samples of apple juice from local markets. It has been found that the potassium, ash, and organic acid patterns are the most useful components to characterize this juice. A facile method is also described for measuring inorganic phosphate content of fruit juice.
Analysis of Botanical Standard Reference Materials by Cathode Ray Polarography
Authors: Maienthal E June
Published: February 2020

The need for certified botanical and biological standards both in research and in industrial and field applications is leading to the development and production of a number of new Standard Reference Materials by the National Bureau of Standards. The first of these to be produced and certified is an orchard leaf standard. The determination of a number of important trace elements by cathode ray polarography was investigated and found to offer considerable advantages in sensitivity and accuracy over many other techniques. In addition, several elements may be determined simultaneously in the same solution. The methods were developed and applied to the analysis and certification of nickel, lead, bismuth, and iron in the orchard leaves. Results were also obtained for aluminum which has not yet been certified. Nickel was determined on 1 g samples after extraction with dimethylglyoxime and CHCI3. Lead and bismuth were determined concurrently on 1 g samples after a sodium diethyldithiocarbamate separation. Iron and aluminum were determined on 0.25 g samples after cupferron separations. Details of the methods are given and the results are compared with those obtained by other techniques.
Application of the Animal Hemoglobin Repletion Test to Measurement of Iron Availability in Foods
Authors: Fritz James C , Pla Gwendolyn W
Published: February 2020

The animal hemoglobin repletion test, adopted as official first action last year, was successfully applied to a number of food products. The method is applicable to foods if the concentration of iron in the sample is adequate to permit a reasonable addition of iron to the basal diet. The addition of the test food must be done in a manner to maintain protein and energy levels as nearly constant as possible. Similar bioavailability was found when the iron source was added directly (alone) to the test diet and when it was a component of a food which was then added to the test diet. The source of supplemental iron was more important for bioavailability than other diet components present. Cooking farina or baking biscuits from enriched cereal had little or no effect on bioavailability of the iron.
Argentimetric Method for Determination of Malathion in Formulations
Authors: Miles James W , Goette Mary B , Guerrant Gordon O , Churchill Frederick C
Published: February 2020

A method has been developed for the determination of malathion in technical grade products by argentimetric titration of the dimethylphosphorodithioate ion formed by alkaline cleavage of the molecule. Free dimethylphosphorodithioic acid and other polar impurities are removed by a column of cellulose powder containing 30% moisture. Malaoxon, isomalathion, and diethylmercaptosuccinate do not interfere. However, the methyl ethyl ester of malathion, if present, will titrateasmalathion . The method has been adapted to the analysis of formulations of emulsifiable concentrates, water-dispersible powders, and dusting powders. The analyses can be performed potentiometrically by titration to a fixed millivoltage, using a pH meter, or with anautomatic titrator operated in the derivative mode. When the method was applied to samples of technical grade malathion, the standard deviation varied from 0.21 to 0.42%.
GLC Determination of β-Hydroxybutyric Acid in Decomposed Eggs: Separation from a Complex Mixture Containing an Unknown Interference
Authors: Staruszkiewicz Walter F , Bond John F
Published: February 2020

A sample of frozen decomposed egg, which was analyzed by using official first action method 17.034–17.038, was found to exhibit several extraneous peaks. One of the peaks had the same retention time as β-hydroxybutyric acid, which has been previously associated with incubator-reject eggs. Since the samples were known to contain no incubator-reject eggs, gas-liquid chromatography on several columns was performed to determine whether or not the peak represented β-hydroxybutyric acid. Separations performed on 5 different columns demonstrated that the principal component of the questionable peak was not β-hydroxybutyric acid. The presence of the compound may have been the result of contamination by processing equipment or sample containers.
Analytical Studies of Di-Syston Formulations
Authors: Cavagnol J C
Published: February 2020

Di-Syston is used as the technical material and also as granular and liquid formulations. A few of the methods developed for its analysis are outlined: hydrolysis, infrared, gas chromatography, gravimetric procedure, and automated colorimetry. Some of the problems encountered in quality control are also described.
Quantitative Determination of Chlorobutanol in Milk by Gas-Liquid Chromatography
Authors: Wiskerchen John E , Weishaar Joseph
Published: February 2020

A method is described for the quantitative determination of chlorobutanol in milk by gas-liquid chromatography. The cleanup includes isolation of chlorobutanol from milk by steam distillation and extraction with ether. The chlorobutanol is quantitatively determined on a column of 5% Igepal 880 on Gas-Chrom Q with electron capture detection. Recoveries were 87–101% for milk fortified at 0.01–10 ppm levels. Collaborative study is recommended after an intralaboratory study is completed.
Collaborative Study of an Automated Method for Phosphorus in Fertilizers
Authors: Johnson Frank J
Published: February 2020

A collaborative study was made of an automated method for total and direct available phosphorus (P2O5) in comparison with the official gravimetric quimociac method, 2.023–2.025. Eight laboratories participated in the analysis of the 13 sample solutions, and the results were evaluated by the technique of closely matched pairs. The fc-test showed no difference in the means of the results of the 2 methods. The estimates of the random, systematic, and total errors of the automated method all differed significantly from those of the official method when evaluated by the F-test. Further study of the automated method for P2O5 in fertilizers is recommended.
Revised Kjeldahl Total Nitrogen Method for Feeds and Premixes
Authors: Odland Robert
Published: February 2020

A Kjeldahl method for equivalent crude protein in feeds was modified by using a smaller sample (0.25 g) and smaller amounts of reagents in order to reduce analysis time and cut costs. A 6% CuSO4 catalyst was used for the complete digestion of refractory material. Winkler’s boric acid method was modified by including a 90% pretitration to insure complete retention of ammonia so that only one standardized reagent is needed.
Rapid Gas-Liquid Chromatographic Determination of Phenethyl Alcohol in Alcoholic Distillates Division, National Distillers
Authors: Kahn J H , Conner H A
Published: February 2020

A rapid gas-liquid chromatographic method is described for the quantitative determination of phenethyl alcohol in alcoholic distillates. No prior sample preparation is required. Values are presented for 47 samples of bourbon, blended, light, Canadian, and Scotch whiskies as well as for rum, brandy, and tequila. The phenethyl alcohol concentration in these samples varies from zero to 131 g/100 L at 100° proof. The accuracy and precision of the method are demonstrated.
Analysis of Drug Residues in Guinea Pigs Treated with Dimetridazole
Authors: Allen Patricia C , Mcloughlin D K
Published: February 2020

Guinea pigs were given single oral doses of 250 mg dimetridazole/kg. At intervals after dosing, urine and plasma samples were directly subjected to polarographic analysis in which the original drug plus nitroimidazole metabolites were assayed. Kidney, liver, muscle, fat, and feces samples were extracted to recover the original drug and the extracts were assayed polarographically. The highest concentrations of dimetridazole were found in urine, plasma, muscle, and fat samples 2 hr after dosing. No drug was detected in any kidney, liver, or feces samples. A small quantity of drug was still detectable in urine 24 hr after dosing. No residues could be detected at 48 hr.
X-Ray Powder Diffraction Data for Seventeen Local Anesthetics
Authors: Owen J T R , Sithiraks Rewadee , Underwood F A
Published: February 2020

X-ray powder diffraction data for some local anesthetics have been obtained by the Debye-Scherrer technique. The data for individual local anesthetics are tabulated in terms of lattice spacings (d in Å) and the relative intensities of lines. In addition, a classification is provided of the 3 most intense lines for each of the local anesthetics, with their relative intensities arranged in descending numerical order with regard to d spacing of the most intense line from each pattern.
Direct Gas-Liquid Chromatographic Determination of Water-Soluble Vitamin K3 in Feed Premixes
Authors: Winkler Victor W , Yoder John M
Published: February 2020

A method for the quantitative determination of menadione bisulfite addition products in feed premixes is presented. The menadione bisulfite compound is extracted with methanol from the premix and is determined by gas chromatography directly without pretreatment with alkali. The principle of the method is on-column pyrolysis of menadione bisulfite and subsequent gas chromatographic analysis of the pyrolytic product, menadione.
Thin Layer Chromatographic Identification of Preservatives in Food
Authors: Tjan Gwan H , Konter Theodorus
Published: February 2020

A thin layer chromatographic method is described for the identification of benzoic, phydroxybenzoic, salicylic, and sorbic acids in foods. The preservatives are extracted from food with petroleum ether-ethyl ether (1+1); the acid preservatives are converted to their sodium salts by addition of sodium bicarbonate and the esters of p-hydrobenzoic acid remain in the organic layer. The acid preservatives are spotted on activated silica gel G plates and the plates are developed in a mobile solvent containing ammonia. The preservatives are detected by spraying with bromocresol purple. The ester preservatives are spotted on silica gel G plates with and without a fluorescent indicator; the plates are developed with benzeneethyl acetate (4+1) and then viewed under shortwave ultraviolet light or sprayed with bromocresol purple.
Confirmation of Pesticide Residue Identity. V. Alternative Procedure for Derivative Formation in Solid Matrix for the Confirmation of α- and β-Endosulfan by Gas Chromatography
Authors: Chau Alfred S Y
Published: February 2020

A quick and sensitive new method has been developed for the confirmation of α- and β- endosulfan by conversion to the same ether in a solid matrix. It seems by far to be the most sensitive method reported to date for positive identification of α- and β-endosulfan. As little as 0.005 ppm of the parent compounds in a 10 g fish or sediment extract and 0.003 ppb in a 2 L water extract can be routinely confirmed.
Determination of Matacil and Zectran by Fluorigenic Labeling, Thin Layer Chromatography, and In Situ Fluorimetry
Authors: Frei R W , Lawrence J F
Published: February 2020

The fluorigenic labeling of Matacil (4-dimethylamino- m-tolyl N-methylcarbamate) and Zectran (4-dimethylamino-3,5-xylyl Wmethylcarbamate) with dansyl chloride (1-dimethylamino- naphthalene-5-sulfonyl chloride) results in 3 fluorescent derivatives, and labeling with NBD-Cl (4-chloro-7-nitrobenzo- 2,1,3-oxadiazole) produces 2 fluorescent derivatives for each carbamate, all of which can be separated by thin layer chromatography (TLC). These derivatives are identified by nuclear magnetic resonance, infrared, and fluorescence spectroscopy, aided by TLC data. The carbamates are hydrolyzed in dilute base and the resulting amine or phenol hydrolysis products react with the labeling reagents. The derivatives are analyzed by TLC and in situ fluorimetry with a spectrophotometer in the fluorescence mode and a spectrophotofluorometer with the thin layer scanning accessory. Reactions, fluorescence phenomena, and chromatographic properties of the derivatives are investigated for evaluation of the method as a quantitative technique. A reproducibility of 3–5% relative standard deviation can be expected in the concentration range from 15 to 300 ng/spot for derivatives of the 2 labeling procedures. The dansyl derivatives are instrumentally detectable as low as 1 ng/spot while the NBD derivatives may be detected at concentrations of less than 0.5 mg/spot.