bluuebunny/crossref_metadata_2025 huggingface dataset:
Known Addition Procedure for Determining Fluoride in Feeds with an Ion-Specific Electrode
Authors: Melton James R , Hoover William L , Ayers Jo Lynn
Published: February 2020

A know addition method for determining low levels of fluoride in feeds with a solid-state fluoride electrode is described. The feed samples are reacted with hydrochloric acid, and a concentrated citrate buffer is added to maintain ionic strength and pH. The amount of fluoride in the sample is calculated from the change in potential after the addition of fluoride standard. Any interferences by ions commonly found in feeds are minimized by the known addition technique. The described method is rapid and precise, and results compare favorably with those from the AOAC method for fluoride, 25.029-25.035.
Microbiological Assay of Nystatin in Feeds
Authors: Platt Thomas B , Itkin Arthur G
Published: February 2020

A modification of the official method for nystatin in feeds was collaboratively studied. Feed is extracted into methanol and a portion of the extract is converted to a feed blank by heating 20 min at 121°C. The remaining portion of the extract is assayed vs. the standard curve prepared in feed blank. Four commercial poultry laying mashes were studied; 2 were tested as formulated, 2 were tested in both crumble and powder form, and 1 of the ground feeds was diluted with cornmeal. Each sample was prepared to contain ca 50 and 100 g nystatin/ ton. Each of 9 collaborators analyzed, in duplicate, 3 different samples. The theoretical nystatin content was established by the collaborators' assay of the premix used to prepare the samples. Recoveries of activity averaged 97.6% for the lower concentration and 100.4% for the higher concentration. The method was adopted as official first action to replace the present official first action method for feeds containing ≥ 50 g nystatin/ton, 38.200-38.203.
Rapid Spectrophotometric Method for Direct Available P2O5 in Fertilizer
Authors: Thorpe Virginia A
Published: February 2020

In the rapid spectrophotometry method described, direct available P2O5 in fertilizer is determined in the presence of ammonium citrate, meta- and polyphosphates are hydrolyzed with a simple heating step, and coloring matter (other than organic material) is destroyed with the direct addition of HN03. Direct available extracts prepared from samples containing organic phosphorus can be effectively digested by a simple technique of heating an aliquot with acid in a special decomposition vessel. The method is rapid, accurate, and precise and would be readily adapted to automated techniques.
Gas-Liquid Chromatographic Determination of Methanol, Ethanol, and Isopropanol in Cosmetics, Using the Headspace Analytical Technique
Authors: Paulus Grant Geordie L
Published: February 2020

Methanol, ethanol, and isopropanol were determined in cosmetics by the gas chromatographic analysis of the vapors in the air space above a diluted sample. This method of headspace sampling compares favorably with other methods of determining alcohols, such as direct injection and isolation by codistillation. It is not necessary to isolate the alcohols before analysis because the method avoids the injection of nonvolatile substances in the sample, which may be detrimental to the column or the detector. The determination was carried out on a 6' × ¼" column packed with Chromosorb 101 coated with 1 % Ethomeen 18/60. An appropriate internal standard is used for the analysis of each alcohol to compensate for possible errors introduced by headspace sampling. The technique is applicable to various types of cosmetic products and is useful for the analysis of samples containing as little as 0.5% alcohol.
Determination and Confirmation of Hexachlorobenzene in Fatty Samples in the Presence of Other Residual Halogenated Hydrocarbon Pesticides and Poly chlorinated Biphenyls
Authors: Van Hove Holdrinet Micheline
Published: February 2020

Hexachlorobenzene (HCB) determination and confirmation at low residual levels (parts per billion range) is hampered by the presence of electron-capturing co-extractives, other organochlorine pesticides, and polychlorinated biphenyls (PCBs). A method is described to routinely examine lipid material for residual HCB, using a column chromatographic separation system and subsequent derivatization. Following initial extraction and cleanup, organochlorines, PCBs, and HCB are successively eluted from a charcoal column. After gas chromatographic analysis of each of the fractions, the HCB fraction is subjected to caustic alkali at high temperatures, and the hydrolyzed product is methylated to yield the pentachlorophenol methyl ether derivative.
Microcoulometric Determination of Organochlorine Pesticides in Human Blood
Authors: Griffith Francis D , Blanke Robert V
Published: February 2020

Improvements in the microcoulometric halogen system allow analysis of as little as 1 ppb chlorinated pesticides with specificity and linearity. Modifications were made in the sulfuric acid method of extracting pesticides from human whole blood to obtain recovery of 24 pesticides and 7 industrial chemicals. Recovery data were tabulated. Retention time and response tables for OV-210 and SE-30/QF-1 columns were prepared for these compounds, using the microcoulometric detector.
Extraction of Chlorinated Hydrocarbon Insecticides from Soil: Collaborative Study
Authors: Woolson Edwin A
Published: February 2020

Soil premoistened with 0.2M NH4C1 was shaken with hexane-acetone (1+1) to extract chlorinated hydrocarbon insecticides. Standard AOAC methods (29.014 and 29.017) were used for cleanup and detection of residues in the extract. Seven laboratories analyzed 3 soil unknown samples which contained 6 added insecticides each (at a range of 0.24 to 6.18 ppm) and a spike-and-recovery sample which contained 10 insecticides. Recovery from the spiked sample averaged 9 1% (86-100%) of the added insecticides, with an average coefficient of variation of 13.54%. Recovery from the 3 unknown samples averaged 88% (69-118%) with a coefficient of variation of 12.84%. The method has been adopted as official first action.
Sensitivity of Brine Shrimp (Artemia salina) to Trichothecenes
Authors: Eppley Robert M
Published: February 2020

Brine shrimp larvae have been successfully used as a biological monitoring system in the isolation of 5 naturally occurring, toxic 12,13- epoxy-Δ9-trichothecenes. A simplified procedure is described for the biological confirmation of these mycotoxins. The sensitivity of the brine shrimp test described for detecting 10 of the naturally occurring 12,13-epoxy-Δ9-trichothecenes is approximately 0.04—0.4 μg/ml.
Ammoniation of Aflatoxin B1: Isolation and Identification of the Major Reaction Product
Authors: Lee Louise S , Stanley James B , Cucullu Alva F , Pons Walter A , Goldblatt Leo A
Published: February 2020

The major product formed from reacting pure aflatoxin B1 with ammonium hydroxide at 100°C under pressure was isolated in crystalline form. The compound, molecular weight 286 (mass spectra), ultraviolet (UV) absorption, λMe0H 227, 324 nm (ε 15,920, 12,440), is nonfluorescent, exhibits phenolic properties, and lacks the lactone group characteristic of aflatoxin B1. Acidification of the compound did not regenerate aflatoxin B^ Calculations made from UV absorption spectra indicate that this molecular weight 286 compound comprises about 30% of the crude ammoniation product. It is postulated that the new product, C16H14O5, arises from opening the lactone ring of aflatoxin B1 during ammoniation, formation of the ammonium salt of the resultant hydroxy acid, and loss of carbon dioxide from this β-keto acid. Because this compound arises from decarboxylation, the trivial name aflatoxin D1 is proposed.
Collaborative Study for the Development of Latent Fingerprints on a Nonporous Surface, Using Standard Brushing Method for Powders
Authors: Connor Charles M
Published: February 2020

Eight latent fingerprint experts participated in a collaborative study of the black powder brushing method for the development of latent fingerprints. Latent images were placed on glass slides by the examiner, using both male and female subjects. The standard brush method, using black powder provided by the Associate Referee, was used to develop the fingerprints. Conclusive results were obtained; 138 of the 144 images (95.8% ) were considered suitable for identification purposes. The method has been adopted as official first action.
Microscopical Characterization of Glass Fragments
Authors: McCrone Walter C
Published: February 2020

Two collaborative studies have been completed and the method for characterizing glass fragments has been finalized. Using a monochromator, hot stage apparatus, and standard liquids of known refractive index, dispersion and dn/dT matching wavelengths were measured over an appropriate range of known temperatures. Results from the second collaborative study were greatly improved over those from the first study and showed that refractive indices of a small glass fragment can be measured to within ±0.0001. This is smaller than the variation observed within most glass objects. The revised method has been adopted as official final action (suspension of the rules).
Simplified Modifications of the AOAC Method for Bacteriostatic Activity of Laundry Additives
Authors: Wilson Frederic H , Brown Claude P , Ball William
Published: February 2020

Modifications of the AOAC bacteriostatic activity of laundry additives method are described, which render it more economical and less time consuming. The arbitrary use of a minimum of 18—20 edges showing clear zones of inhibition of a test organism, when 5 fabric patches 1" square are used, is liable to misinterpretation, since faulty methods of introducing germicidal substances into fabric in the final rinse during laundering result in incomplete dispersion and uneven impregnation. Therefore, absence of a zone along more than 2 edges may indicate faulty impregnation rather than the degree of bacteriostatic activity. In the modified procedure, 5 circular fabric disks from samples submitted by laundries were used for each test. They were immersed in melted, seeded nutrient agar in 1 large Petri dish and incubated at 5 and 37°C. Clear zones completely around all 5 circumferences were chosen as the criteria for bacteriostatic activity. If all 5 disks, taken from different areas of the test sample, do not show complete inhibition, impregnation of the bacteriostat is not uniform.
Automated Chemical Determination of Methionine
Authors: Gehrke Charles W , Neuner Terry E
Published: February 2020

A rapid, accurate, and precise spectrophotometry method, based on the nitroprussidemethionine color reaction, has been developed for the determination of methionine in soybeans, mungbeans, and corn. Amino acid interference was eliminated by partial enzymatic hydrolysis of samples for 4 hr at 50 °C with papain; the samples were analyzed by an automated system. Precision and accuracy were determined by repeated independent analyses of 13 samples of corn, mungbeans, and soybeans; the data were compared to independent classical ion exchange amino acid results. The range for each set of samples varied from 0.02 to 0.04 w/w% methionine. The per cent recovery for 12 of the 13 samples compared to those from ion exchange ranged from 95.2 to 107.1% with an average of 100.2%. The standard deviation varied from 0.01 to 0.02, and the per cent relative standard deviation from 11.8% for a 0.16 w/w% sample to 2.5% for a 0.42 w/w% sample. Recovery of added methionine from corn samples ranged from 92.7 to 102.0% (96.8% average) ; from soybeans 95.0 to 112.0% (101.9% average); and from mungbeans 91.3 to 102.0% (95.8% average). A reliable automated method has been developed which is applicable to different types of biological substances; 20 samples/hr can be analyzed.
Collaborative Study of a New Method for the Extraction of Aphids, Thrips, Mites, and Flies from Frozen Green Leafy Vegetables
Authors: Miller Mary T
Published: February 2020

A method, which consisted of mixing various frozen green leafy vegetables with dilute sodium sulfate and mineral oil followed by flotation in a Wildman trap flask or Corning percolator, was tested by 12 collaborators. Satisfactory results were obtained and the method has been adopted as official first action.
Partition Chromatographic Method for Caffeine and Sodium Benzoate Injections
Authors: Weber John D
Published: February 2020

Sodium benzoate is retained on a Celite :1N sodium bicarbonate column while caffeine is eluted with ether and trapped on a second Celite: 1N H2S04 column. The sodium benzoate is recovered in the form of benzoic acid by elution with acetic acid in chloroform and the caffeine is eluted with chloroform. The concentrations in the eluates are directly measured by ultraviolet spectrophotometry.
Total Flavonoid and Rutin Content of the Different Organs of Sophora japonica L.
Authors: Balbaa Shafik I , Zaki Ashgan Y , El Shamy Ali M
Published: February 2020

The total flavonoid content of the flowers, fruits, leaves, and small branches of Sophora japonica L. was determined colorimetrically after addition of 0.lM aqueous aluminum chloride. The total flavonoid and isoflavonoid content of the fruits was determined gravimetrically. Rutin was separated by thin layer chromatography from the different organs, and determined either densitometrically or spectrophotometrically, using a modified elution technique. Rutin was recovered almost completely with an average loss of 2.5%. The percentages of flavonoids and rutin of the flower buds, pericarps, seeds, leaflets, and small branches were 24.29 and 23.5, 10.57 and 4.3, 1.75 and 0.55, 6.63 and 4.7, and 1.5 and 0.26, respectively, while the total flavonoid and isoflavonoid content of the fruits was 43%.
Modification of the AOAC Qualitative Test for the Determination of Fish Oils and Marine Oils
Authors: Schwien William G
Published: February 2020

The current AOAC test for the detection of fish oil in vegetable oils, 28.098, can be readily modified through the use of diluted bromine solution and Wijs solution. This modification allows the precipitation of octabromides, which is indicative of the presence of fish oils, to be observed more clearly. Since the precipitate can be measured, the test can be semiquantitative when known fish oil mixtures are treated in a like manner. This modification has been adopted to replace 28.098.
Estimation of Butylated Hydroxyanisole and Butylated Hydroxytoluene in Meat Products
Authors: Singh Joginder , Lapointe Michel R
Published: February 2020

A procedure is described for the estimation of butylated hydroxyanisole and butylated hydroxytoluene in meat products. It involves direct extraction of the antioxidants from the meat products by using acetonitrile as the solvent in a steel ball mill. Cleanup is carried out on a column of deactivated acidic alumina. Gas chromatography with a flame ionization detector is used for qualitative and quantitative determination of the antioxidants. Average recoveries of antioxidants added to 10 g samples of corned beef and sausages ranged from 61 to 90%.
Collaborative Study of the Gas-Liquid Chromatographic Determination of Indole in Shrimp
Authors: Staruszkiewicz Walter F
Published: February 2020

A new gas-liquid chromatographic (GLC) method for the determination of indole in decomposed shrimp was submitted to collaborative study. Five samples of shrimp were analyzed in duplicate by the collaborators. The samples included passable and decomposed frozen raw shrimp and also decomposed shrimp that had been cooked and freeze-dried. The levels of indole in the samples ranged from 0 to approximately 110 μg indole/100 g shrimp. No indole was found in any of the passable samples by any collaborator. The amounts of indole found in the decomposed samples were approximately 14, 24, and 115 μg indole/100 g shrimp. The collaborators recovered an average of 106% of the indole which had been added to a sample of passable shrimp. A set of samples was analyzed by the present AOAC colorimetric method for comparison. The GLC method will also detect 3-methylindole (skatole). The method has been adopted as official first action.
Aflatoxin M1: Analysis in Dairy Products and Distribution in Dairy Foods Made from Artificially Contaminated Milk
Authors: Stubblefield Robert D , Shannon Gail M
Published: February 2020

A published method to determine aflatoxin M1 in fluid and concentrated milks was refined to permit assays of a wider range of dairy products. Milk products that were spiked with aflatoxin Mx were processed with commercial dairy cultures, rennet, and organic acids to make several cheeses and butter. Cheeses that were representative of various curd-precipitation methods or high cooking temperatures were included. When milk was set with lactic acid cultures and small quantities of rennet to produce short-set cottage cheese or heated with lactic acid starter to prepare ricotta cheese, about 71–74% of the aflatoxin M1 was recovered in the whey fractions. Nearly equal quantities of M1 were detected in curds and whey from long-set, acidprecipitated cottage cheese and from rennetprecipitated cheeses, such as colby, cheddar, and swiss. Results were similar with queso bianco cheese products that were produced by direct addition of organic acids. According to analysis, only 16% of the available M1 was in the butter while the remainder was in the buttermilk.
Dose Response Score of AOAC Use-Dilution Test for Quality Control of Internal Standard and Products
Authors: Walter George R , Scheusner Dale L
Published: February 2020

Disinfectant products registered with the Environmental Protection Agency require efficacy substantiation by the AOAC use-dilution test. This test has a low binomial probability associated with failures in the procedure. An alternative means of recording the use-dilution test response is proposed. In it a score is presented in a form which may be treated as a continuous measurement and sequentially plotted to form a control chart showing the upper and lower control limits for a given organism.
Leuco Base Determination in the Triphenylmethane Dyes, FD&C Blue No. 1, FD&C Green No. 3, and FD&C Violet No. 1
Authors: Dantzman John , Stein Charles
Published: February 2020

The quantitative oxidation of leuco bases in FD&C triphenylmethane dyes was examined. A spectrophotometric method for determining the amount of leuco base, using molecular oxygen in the presence of cupric chloride, was studied. Leuco base recovery was found to be 90.0–103% for FD&C Blue No. 1, 97.2-101.9% for FD&C Green No. 3, and 95.4-100% for FD&C Violet No. 1.
Analysis of Carbamate and Urea Herbicides in Foods, Using Fluorogenic Labeling
Authors: Lawrence James F , Laver Gary W
Published: February 2020

A procedure using fluorogenic labeling for the analysis of carbamate and urea herbicides in several food types has been developed. Extracted herbicides are hydrolyzed to their corresponding anilines, which are then labeled with dansyl chloride (1-dimethylaminonaphthalene- 5-sulfonyl chloride). The reaction is carried out on a thin layer plate which is subsequently developed, and the separated spots are either scanned for fluorescence or are removed from the layer and quantitatively analyzed in solution by fluorometry. As low as 0.05 ppm herbicide can be detected with no interference from coextractives. Other than a single partition step from the extracting solvent no cleanup is required. The method may be used for confirmation of the identity of a number of carbamate and urea herbicides, as a quantitative analytical technique where equipment is available, or as a method for screening where only the knowledge of herbicide presence is required.
Estimation of Malaoxon in the Presence of Malathion by the Ferric Hydroxamate Method
Authors: Bhagwat Vasanti M , Ramachandran Bhikshander V
Published: February 2020

Both malathion and malaoxon are completely extractable from aqueous suspensions by benzene- isobutanol (1 + 1). Aliquots of the extract are evaporated at 110– 120°C, the residue is dissolved in methanol, and the total ferric hydroxamate color is determined. Extraction of a second aliquot with cyclohexane removes malathion and some malaoxon. Malaoxon is selectively partitioned from cyclohexane into alkaline hydroxylamine, leaving only malathion in the cyclohexane phase. After the cyclohexane phase is evaporated, the amount of malathion can be estimated by the ferric hydroxamate method. The difference in the color for the benzene-isobutanol extract and the cyclohexane extract represents that due to malaoxon; the amount of malaoxon may be calculated from a standard curve. The method, sensitive to about 0.2 μmole malaoxon, is useful for monitoring the laboratory preparation of malaoxon from malathion.
Chemical Ionization Mass Spectrometry of Organophosphorus Insecticides
Authors: Holmstead Roy L , Casida John E
Published: February 2020

The chemical ionization (CI) mass spectra of 15 important organophosphorus insecticides and 14 of their major metabolites are discussed in relation to the effect of chemical structure on fragmentation patterns. The fragments obtained with CI are sometimes quite different from those formed on electron impact and, in general, simpler spectra are obtained with CI.
Systematic Approach to the Detection of Explosive Residues. III. Commercial Dynamite
Authors: Midkiff Charles R , Washington Willard D
Published: February 2020

Tests are described for the detection and identification of suspected dynamite in bombing debris. A discussion of major categories and typical formulations of dynamite is included. Thin layer chromatographic and infrared techniques are utilized for the identification of the explosive oils nitroglycerin and ethylene glycol dinitrate, which are present in most commercial dynamites. Problems encountered with solvent extraction of these oils are discussed. Additional chemical tests performed on the debris to facilitate identification of the particular type of dynamite present in the debris are described.
Automated Enzymatic Determination of L-Lysine in Grain
Authors: Wall Larry L , Gehrke Charles W
Published: February 2020

An accurate and precise automated method has been developed for the determination of lysine in grain hydrolysates. The enzyme L-lysine decarboxylase specifically catalyzes removal of the carboxyl group from L-lysine, producing an amine and carbon dioxide. This reaction has been automated. The carbon dioxide produced was selectively dialyzed into a stream of carbonate with phenolphthalein by a dialysis block containing a carbon dioxide gas dialysis membrane. Ground samples of grain (250 mg) were hydrolyzed 20 hr in 25 ml 6N HC1 at 110°C Aliquots were evaporated to dryness under nitrogen with low heat. The samples were redissolved in carbon dioxide-free water and the enzyme was suspended in pH 6.5 phosphate buffer. Analyses were made at 30/hr with a sample-to-wash ratio of 4:1. A standard curve with a range of 0 to 90 ppm lysine was expanded to full scale on the recorder. From the comparative height of each sample peak vs. the standard curve, the per cent lysine in the original sample can be calculated. Repeated analyses on 15 samples, 5 each of corn, mungbeans, and soybeans, by the automated method showed that the precision was good, and the results were in good agreement with classical ion exchange data. The automated method for lysine in corn has been used in our laboratory to analyze 1500–2000 corn samples each year for the last 5 years.
Identification of 2-, 3-, and 4-Methoxyamphetamines and 2-, 3-, and 4-Methylamphetamines
Authors: Bailey Keith , Beckstead Harry D , Legault Donald , Verner Denise
Published: February 2020

The identity of samples of 2-, 3-, and 4-methoxyamphetamine and 2-, 3-, and 4-methylamphetamine is conclusively established by comparison of their spectra. Ultraviolet, proton magnetic resonance, and mass spectra distinguish and identify the 2 series and infrared spectra differentiate isomers; reference spectra and data are provided. Thin layer and gas-liquid chromatographic systems suitable for distinguishing these compounds are described.
Improved Method for Fat and Oil Analysis by a New Process of Extraction
Authors: Randall Edward L
Published: February 2020

Equipment and procedures have been designed for the rapid (30 ruin) and accurate extraction of fats, waxes, and oils from plant and animal tissues. A 2–5 g sample is ovendried, immersed in hot ethyl ether 10 min, raised out of the solvent, and further extracted and rinsed with solvent condensate for 20 min. The ethyl ether is removed by evaporation and the residue is weighed. Excellent replication of results and agreement with analysts using Goldfisch and Soxhlet extractors were obtained. Sr (intralaboratory) values on feed samples ranged from 0.01 to 0.06%. Sb (interlaboratory) values for the same samples ranged from 0.03 to 0.15%. The same values for meat samples, which are less homogeneous, ranged from 0.18 to 0.72%.
The Statistics of Nutrition Sampling and Analysis
Authors: Roberts Howard R
Published: February 2020

It is widely recognized that there is natural variation in the nutrient content of food products. When one attempts to measure nutrient levels, another source of variation becomes apparent—that inherent in the measurement process itself. Analytical variation is, of course, apparent when different methods are used but can also occur with the same method because of differences among laboratories and/or analysts. Both in its own right and more especially with regard to evaluating compliance with labeling regulations, method variability is of critical importance. In order to appreciate the role of analytical methodology, the nutrition labeling regulations and the procedures by which the Food and Drug Administration will assess compliance must first be thoroughly understood. This paper is directed toward that understanding.
Interlaboratory Variability in Nutrient Analyses: Two Cooperative Studies
Authors: Elkins Edgar R
Published: February 2020

Canned tomato juice and canned peas were analyzed for those nutrients that are mandatory as required by the nutrition labeling regulations. Twenty-four laboratories participated in the studies, using AOAC methods predominately. Results seem to indicate that, with the exception of the fat determination, methods for proximate analyses are satisfactory. Interlaboratory variability as measured by the coefficient of variation was quite large for the fat determination, 60% in tomato juice and 80% in peas. However, at the level present in both products, per cent fat is not significant from a nutrition labeling point of view. Rather significant levels of variability are apparent for most of the vitamin and mineral determinations which would indicate that methods need to be refined and that studies such as this need to be continued for these methods in other products that will be labeled nutritionally.
Applications of Nuclear Magnetic Resonance Spectroscopy to Antibiotics. I. Specific Identification of Penicillins and Cephalosporins
Authors: Wilson William L , Avdovich Hajro W , Hughes David W
Published: February 2020

The nuclear magnetic resonance spectra of various commercially available penicillins and cephalosporins are given. General spectral features, as well as specific resonances, are discussed and their application in the identification of these antibiotics is outlined.
Comparison of Wet Ashing and Dry Ashing for the Determination of Arsenic in Marine Organisms, Using Methylated Arsenicals for Standards
Authors: Uthe John F , Freeman Harry C , Johnston John R , Michalik Paula
Published: February 2020

A vanadium catalyzed pentoxide-sulfuric acid-nitric acid digestion procedure is described which gave higher values for total arsenic than the AOAC dry ash procedure with fish and shellfish tissue. Recoveries of added methylarsenic compounds were also lower by dry ashing procedures but essentially complete by the new ashing procedure. Arsenic levels in a variety of shellfish and fish tissues as determined by wet ashing averaged 6.3% higher than dry ash values. In lobster hepatopancreas the difference was 13.1% for a large number of samples from a number of sampling areas.
Tobacco Analysis: Sequential Differential Solvent Extractions
Authors: Steele John A
Published: February 2020

A method is described for sequential differential solvent extraction of tobacco, using petroleum ether (38-58°C), tetrahydrofuran, acetonitrile, 95% ethanol, 20% water-dioxane, and water. The method is suitable for the monitoring of tobacco fermentation, the differentiation between cigarette and cigar filler tobaccos, and the assaying of the tobacco content of cigar wrapper material or manufactured reconstituted tobacco sheets.
Quality Characteristics of Canned Salmon: Four Year Study
Authors: Throm Harold R
Published: February 2020

From 1967 to 1971, over 5000 cans of salmon were examined for various quality characteristics. Five species of salmon were included in the study. The data obtained may be helpful in formulating standards of quality for canned salmon.
Addendum to Flame Photometric Determination of Sodium in Fertilizers
Authors: Corominas Luis F
Published: February 2020

Published collaborative data obtained in studies on the determination of sodium in fertilizers have been reevaluated by using more representative formulas for the calculation of precision standard deviation and standard deviation of the systematic error. The revised values do not change the previous conclusions. The new tables are reprinted here.
Proposed Standard Methods for Ink Identification
Authors: Kelly Jerry D , Cantu Antonio A
Published: February 2020

Two methods are presented for the identification of ink, both of which are currently being used by laboratories involved in ink analysis. Both methods incorporate physical and chemical procedures. The differences are primarily in chemical methods involving spot tests and thin layer chromatographic (TLC) techniques. Furthermore, one method utilizes spectrophotometric scanning of the TLC plate whereas the other method utilizes solution spectrophotometry. It is recommended that both methods be evaluated by several laboratories.
Development of Latent Fingerprints on a Nonporous Surface, Using Standard Brushing Method for Powders: Second Collaborative Study
Authors: Connor Charles M
Published: February 2020

Twelve latent fingerprint examiners participated in a collaborative study of a modification of the official first action powder brushing method for the development of latent fingerprints. Latent images were placed on glass slides by the examiners, using male and female subjects. The standard brushing method, using black, copper, and gray powders provided by the Associate Referee, was used to develop the fingerprints at various times up to 120 hr after the images were placed on the slides. Conclusive results were obtained: 139 of the 160 images (86.9%) were considered suitable for identification purposes. The method has been adopted as official final action.
Determination of Pentachlorophenol in Toy Paints
Authors: Van Langeveld Hans E A M
Published: February 2020

A simple procedure is described for the routine determination of pentachlorophenol (PCP) in various types of toy paints. PCP can be determined in water colors, body colors, showcard paints, gouache paints, and colored inks. PCP is extracted from the sample with acetone, followed by quantitative gas chromatographic analysis of the concentrated acetone extract on stainless steel columns containing 15% Carbowax 20M on 60–80 mesh Chromosorb P (AW). As little as 1 ppm PCP can be determined with recoveries ranging from 70 to 100%, depending on the type of paint. The presence of PCP in samples is confirmed by thin layer chromatography, using dansyl chloride as a fluorescent labeling compound. By this method as little as 4 ppm can be determined. The results of PCP determinations in 65 commercial samples are presented.
Collaborative Study of the Gravimetric Method for the Determination of Mercury in Chlorinated Pesticide Formulations
Authors: Launer James E
Published: February 2020

The official first action AOAC gravimetric method for mercury, 6.C01–6.C03, and the official CIPAC titrimetric method, M2.3, were collaboratively studied by 4 CIPAC laboratories, using the same 4 samples analyzed by AOAC collaboration in 1972. Averages at the 3.7 and 3.4% level were the same by both methods whereas the CIPAC method produced, on the average, 4% higher results, all levels included. The AOAC method performs well in the presence of copper and chlorinated pesticides and is less complex to use than the present CIPAC method for mercury in these mixtures. The method has been adopted as official final action.
A Screening Method for Sulfonamides Extracted from Animal Tissues
Authors: Phillips Wendell F , Trafton John E
Published: February 2020

A screening method for the estimation of possible residues of sulfonamides in poultry tissues is described. The method utilizes thin layer chromatography (TLC) to separate Bratton-Marshall positive reactants. In the absence of interference and the identification of 1 sulfonamide by TLC, the colorimctric method is recommended for quantitation. When interferences are present, TLC should be used for both qualitative and quantitative analysis. The screening method has a sensitivity of less than 0.05 ppm and a recovery of greater than 80%.
Identification of the iV-Methylated Analogs of the Hallucinogenic Amphetamines and Some Isomers
Authors: Bailey Keith , By Arnold W , Legault Donald , Verner Denise
Published: February 2020

The drugs 2-, 3-, and 4-methoxy-iV-methylamphetamine, 3-methoxy-4,5-methyIenedioxy- JV-methylamphetamine, and 3,4-methylenedioxy- /V-methylamphetamine are identified by spectroscopic techniques. The ultraviolet and mass spectra of isomers are similar, but proton magnetic resonance and infrared spectra are distinctly different, and reference spectra and data are provided. Gas-liquid and thin layer chromatographic systems for the analysis are discussed.
Quantitative Fluorodensitometric Determination and Survey of Aflatoxins in Nutmeg
Authors: Beljaars Paul E , Schumans Jan C H M , Koken Paul J
Published: February 2020

A study is presented for the quantitative fluorodensitometric analysis of aflatoxins in spices, in particular nutmeg (Semen myristicae). Samples were extracted with chloroform, followed by silica gel column cleanup according to the AOAC official first action method, 26.019(a), and by 2-dimensional thin layer chromatography according to the antidiagonal technique. The method includes a confirmatory test for aflatoxins by hemiacetal formation. The concentrations of aflatoxins in samples were determined by measurement of the fluorescent intensities of the separated aflatoxin spots from sample and standards on the same chromatoplate with a reflectance flying-spot densitometer. With such a technique, a coefficient of variation value of 5.22±1.24% (P < 99%) was calculated for a series of 5 standard B, spots and averaged for 13 TLC plates, demonstrating the precision of the chromatographic and densitometric procedures. An average recovery of 108.4±5.8% (P < 95%) was obtained for 11 spiked nutmeg extracts (5.0–20.0 μg B1 added/kg), whereas an average recovery of 92.6±4.9 (P < 95%) was established for 13 spiked nutmeg samples (5.0–20.0 μg B1 added/kg). The coefficient of variation of the complete analytical procedure for ground nutmeg was 8.80%. In a survey on the occurrence of aflatoxins in 40 commercial nutmeg samples (covering 12 different brands) in The Netherlands, aflatoxins were detected in 30 ground samples (32 ground samples analyzed) in concentrations ranging from 1.0 to 23.2 μg B1/kg or from 2.7 to 36.5 μg B1 + B2 + G1 + G2/kg, whereas no aflatoxins were present in whole nutmeg kernels (8 samples analyzed). The lowest level of detection was 1.0 μB1/kg. In addition, 50 commercial spices consisting of 19 different types of commodities other than nutmeg were assayed for aflatoxins according to the same procedure. No aflatoxins were detected in these samples, with the exception of 1 sample of bay leaf which contained 5.1 μg B1/kg.
Quantitative Determination of FD&C Colors in Foods
Authors: Graichen Charles
Published: February 2020

A published procedure using Amberlite LA-2 (a liquid anion exchange resin) solutions to extract colors from food and the salt solution cellulose chromatographic technique to separate colors from each other were updated and submitted to collaborative study. Three batches of cookies and 4 purchased products were analyzed by 13 collaborators. The 3 batches of cookies contained different color mixtures requiring the selection of various procedures. The 4 purchased products were selected principally to include a variety of foods. Some results were partially deficient. The deficiencies reflect certain inadequacies in the directions as written rather than basic flaws in the method. Some improvements were suggested by the collaborators. The Associate Referee recommends that the method be further revised to correct the present inadequacies and to include some improvements, and that the revised method be submitted to another collaborative study.
Microbiological Assay of Patulin, Using Bacillus megaterium
Authors: Stott William T , Bullerman Lloyd B
Published: February 2020

Bacillus megaterium 1NRRL 1368 was found to be sensitive to patulin and a suitable test organism for an accurate, quantitative bioassay of the toxin. The optimum conditions for the test were determined. The response of the organism to patulin was found to be linear between 2 and 80 μg. When compared to thin layer chromatographic and spectrophotometric assay methods, the bioassay was found to be comparable in accuracy, but less sensitive. The test was found to be sensitive to 1.7 μg patulin. The assay is rapid (12–15 hr), simple, and inexpensive and can be used to verify the toxicity of samples, as well as to quantitatively measure patulin in samples of liquid media, apple juice, and corn.
Collaborative Study of a Spectrofluorometric Method for Lasalocid Sodium in Feeds
Authors: Osadca Modest , Araujo Mercedes
Published: February 2020

A collaborative study has been completed on a spectrofluorometric method for determining lasalocid sodium in finished poultry feeds. After a brief treatment of feed samples with pH 4.7 buffer, the drug is extracted with ethyl acetate. The ethyl acetate extract is further cleaned up by treatment with HCI and NaOH and quantitatively measured by spectrofluorometry. Nonspecific fluorescence is corrected for via the lasalocid-boric acid complex. The method is rapid, sensitive, and free of interference. A number of other feed additives, including monensin and ethoxyquin, do not interfere. Nine collaborators participated in the study and agreement between laboratories was satisfactory. The average recoveries of lasalocid sodium from the mash feeds added at levels of 0.0064, 0.0080, and 0.0096% were 100, 98, and 99%, respectively, and the corresponding coefficients of variation were 12.8, 8.2, and 8.0% (all results included). The method has been adopted as official first action.
Column Chromatographic Analysis of Barbiturates in Their Dosage Forms. II. Secobarbital, Amobarbital, and Pentobarbital
Authors: Cunningham Catherine G , Barkan Susan
Published: February 2020

A general method for the analysis of barbiturates, using column partition chromatography, was extended to the assay of secobarbital, amobarbital, and pentobarbital. A solution of the barbiturate constitutes the immobile phase in the chromatographic system. It is eluted with ether-isooctane (l+9) and passed onto a K3PO4 column, which retains the barbiturate while extraneous materials are washed out. The barbiturate is removed from the column with etherisooctane (3+1), extracted from the eluate with NH3, and measured spectrophotometrically.
Evaluation of a Selective Medium for Hydrogen Sulfide Production by Salmonella
Authors: Andrews Wallace H
Published: February 2020

An evaluation was made of Padron-Dockstader sulfide (PDS) agar for the rapid detection of Salmonella and Arizona microorganisms in foods. Analysts from 9 Food and Drug Administration District laboratories determined the reactions of 638 Salmonella cultures, 30 Arizona cultures, and 1754 non-Salmonella and non-Arizona cultures isolated from 157 food samples in PDS agar. The degree of positive reactions of these cultures in this agar was scored on a scale of “–” to “+ + + ”. The highest percentage of Salmonella isolates (64.1%) was in the category of +++ reactions. Progressively lower percentages of Salmonella isolates occurred in the more negative reaction categories. The highest percentage of Arizona isolates (66.7%) occurred in the intermediate ++ category. The majority of non-Salmonella and non-Arizona isolates occurred in the – (41.0%) and ± (44.8%) categories. Advantages of using the PDS agar are that it is simple to use, requires no specialized training or equipment, and alerts analysts to those Salmonella cultures which produce atypical reactions in triple sugar iron agar, particularly the lactosepositive Salmonella. However, in this study the occurrence of false-negative reactions ranged from 4.3 to 13.9% for Salmonella and from 0 to 6.7% for Arizona, according to the criteria used to interpret the reactions in PDS agar,
Microbiological Turbidimetric Analysis of Low Chlortetracycline Concentrations in Feeds
Authors: Ragheb Hussein S , Porubcan Linda S
Published: February 2020

Recovery studies in which chlortetracycline hydrochloride (CTC-HCl) standard was added to cattle and swine feed supplements at 4.09–9.99 g/ton showed lower antibiotic recovery turbidimetrically (80.6–98.7%) than by the AOAC modified standard as in 38.179(d) (91.2–98.7%) and the plain buffer as in 38.179(b) (93.8-133.0%) methods. Three feeds fortified with a commercial premix at the levels of 5.0 and 10.0 g CTC-HCl/ton showed an overall CTC-HCl recovery of 87.6–110.6% by manual turbidimetric assay. Results were 89.1–108.7% by the AOAC inactivated feed diluent standard and 95.4–125.4% by the plain buffer methods. For some sample extracts (as in cattle feed) the use of heat to stop bacterial growth in the turbidimetric method caused formation of a precipitate. Cooling of cultures to room temperature and rapid reading of sample turbidity followed by standard curve concentrations minimized this interference. The manual turbidimetric assay of low levels of CTC-HCl in feeds appears to offer advantages over other methods.
Gas-Liquid Chromatographic Determination of Nifursol in Frozen Turkey Tissues to Ten Parts Per Billion
Authors: Frahm Larry J , George Glenn M , Mcdonnell J Patrick
Published: February 2020

Nifursol (3,5-dinitrosalicylic acid (5-nitrofurfurylidene) hydrazide) is extracted into ethyl acetate from 10 g tissue in the presence of sodium sulfate. Tissue interferences are removed from the tissue extract by washing with petroleum ether after the extract has been transferred into an aqueous solution by evaporation of ethyl acetate. The drug is hydrolyzed under acid conditions to form 5-nitro-2-furaldehyde (5NF). After partition of 5NF from the aqueous phase into benzene the extract is further cleaned up on a Florisil column. The 5NF is eluted from the Florisil column with benzeneethyl acetate. Electron capture gas-liquid chromatography of a 10 μl injection of the concentrated column eluate is the determinative step. Quantitation is accomplished by comparison of the peak height of the sample to the peak height of the standard which is carried through the method simultaneously. Studies of method performance on turkey muscle, liver, kidney, and skin tissues fortified to contain 10 ppb nifursol show a recovery range of 87.4–95.0% and a coefficient of variation range of 5.7–11.2%.
Analysis of Vinyl Chloride by Mass Fragmentography
Authors: Rosen Joseph D , Morano James R , Pareles Stephen R , Giacin Jack R , Gilbert Seymour G
Published: February 2020

Vinyl chloride is analyzed by mass fragmentography by simultaneously recording its m/e 62 and 64 ions. The minimum quantity necessary for detection is 8.7 × 10-12 g/10 ml injection. At this level the coefficient of variation is 8.51%.
Photochemical Technique for the Elimination of Chlorinated Aromatic Interferences in the Gas-Liquid Chromatographic Analysis for Chlorinated Paraffins
Authors: Friedman David , Lombardo Pasquale
Published: February 2020

A method is described for eliminating chlorinated aromatic interferences in the analysis for the more volatile chlorinated paraffins. Sample extracts are irradiated in aliphatic hydrocarbon solvents with high intensity ultraviolet light prior to detection of the chlorinated paraffin by microcoulometric gas-liquid chromatography. Chlorinated aromatic and unsaturated materials, including DDT and polychlorinated biphenyls, are selectively degraded to compounds containing little or no chlorine. Cycloaliphatic pesticides such as toxaphene, chlordane, and mirex are only partially degraded. Analysis of fish fillets fortified with 1 and 5 ppm of a chlorinated paraffin gave recoveries >90%.
Determination of 4,4’-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 6
Authors: Marmion Daniel M
Published: February 2020

Gravity column chromatographic and highpressure liquid chromatographic (HPLC) methods were evaluated for the determination of 4,4’-(diazoamino)-dibenzenesulfonic acid in FD&C Yellow No. 6. HPLC proved to be the superior of the 2 techniques tested and is recommended for further study.
A Quantitative Method for Determination of Aflatoxin B1 in Roasted Corn
Authors: Shannon Gail M , Shotwell Odette L
Published: February 2020

Roasting aflatoxin-contaminated corn will reduce toxin levels. A quantitative analysis for aflatoxin in roasted corn has been developed by modifying a cleanup technique for green coffee extracts approved as official first action by the AOAC. A chloroform extract is partially purified on a Florisil column, and thin layer chromatographic (TLC) plates are developed with methylene chloride-chloroform-isoamyl alcoholformic acid (81+15+3+1). Recoveries average 101% and the sensitivity limit is 5 ppb aflatoxin B1 A 2-dimensional TLC procedure can also be used to separate the aflatoxins from background interferences.
Gas-Liquid Chromatographic Determination of Total Cholesterol in Multicomponent Foods
Authors: Punwar Jalam K
Published: February 2020

A method is described for the determination of total cholesterol in multicomponent foods and also other products such as nonfat dry milk, dried whole egg solids, and certain candy bars. The lipid is extracted from the sample by a mixed solvent and saponified. The unsaponifiable fraction which contains the cholesterol and other sterols is extracted with benzene. An aliquot is evaporated to dryness and the residue is dissolved in dimethylformamide. The sterols are derivatized to form trimethylsilyl (TMS) ethers. The TMS-cholesterol derivative is quantitatively determined by gas-liquid chromatography, using 5a-cholestane as an internal standard. Nino laboratories participated in a collaborative study of the determination of total cholesterol in deviled ham sandwich spread, vegetable beef stew, corned beef hash, frozen chicken pot pie, pizza pepperoni, fish sticks, breaded shrimp, chocolate-covered candy bars, dried whole egg solids, and nonfat dry milk and the results are reported here. The coefficient of variation ranged from 5.64 to 23.2%, with an average coefficient of variation of 14.8%.
Atomic Absorption Spectrophotometric Determination of 4-Hydroxy-3-Nitrobenzenearsonic Acid (Roxarsone) in Premixes
Authors: Frahm Larry J , Albrecht Marven E , Mcdonnell J Patrick
Published: February 2020

Roxarsone (4-hydroxy-3-nitrobenzenearsonic acid) is extracted from the premix with aqueous 1% ammonium carbonate. The extract is filtered, diluted, and analyzed by atomic absorption spectrophotometry, using an air-acetylene flame and an arsenic electrodeless discharge lamp. The instrument response of the sample is compared to that of a standard solution of arsenic trioxide. Recoveries range from 99.7 to 100.4% and coefficients of variation range from 0.35 to 0.63%.