bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Sodium in Alkali-Treated Cereal Straws, Lye-Peel Wastes, and Brine-Frozen Foods with an Ion Selective Electrode Compared with Atomic Absorption Spectrometry
Authors: Secor Geraldine E , McDonald Gary M , McCready Rolland M
Published: February 2020

A simple procedure is described for determining sodium in sodium hydroxide-treated rice straw and rye grass, lye-peeled potato wastes, and brine-frozen vegetables. Samples containing ≤4% sodium were extracted with 0.05M ammonium carbonate and the extracts were analyzed directly by using a sodium ion selective electrode over the range 10−4 to 10−2M sodium ion. Comparable analyses of the same extracts by atomic absorption spectrometry agreed to within 10%. Recovery of sodium added to control rice straw was 102%.
Determination of the Congeners Produced from Ethanol During Whisky Maturation
Authors: Reazin George H , Baldwin Sidney , Scales Harry S , Washington Harold W , Andreasen Arthur A
Published: February 2020

A study was made to determine which congeners are derived from ethanol during maturation of whisky. Radioactive ethanol-1-14C was added to a barrel of new bourbon whisky and the radioactivity of the major individual congeners was determined during the maturation period. During 56 months of maturation, ethanol was transformed into acetic acid, acetaldehyde, ethyl acetate, and ethanol lignin as indicated by their radioactivity. No radioactivity was found in the solids, fusel oil alcohols, or the aromatic aldehydes derived from ethanol lignin. The chemistry of maturation is discussed.
Collaborative Study of the Gas-Liquid Chromatographic Determination of Coumarin (1,2-Benzopyrone) in Wine
Authors: Dyer Randolph H , Martin Glenn E
Published: February 2020

The determination of coumarin in wine by using gas-liquid chromatography of a chloroform extract was collaboratively studied. Eleven collaborators analyzed 6 samples: 3 containing 4.0 mg coumarin/L, 2 containing 8.0, and 1 containing 0.0. When the triplicate and duplicate recoveries for the 4.0 and 8.0 levels were averaged and treated singly for the collaborators, there was no statistically significant difference in the accuracy between the 2 levels. However, the accuracy for the 4.0 level was much better than that for the 8.0 level: 100.0 vs. 105.9%. An analysis of the individual values showed no significant differences among collaborator means at the 4.0 level, while there was a significant difference among means at the 8.0 level. All collaborators were within the allowable score limits in the ranking test. The method was adopted as official first action.
Ion-Pair Extraction Method for Quantitation of a Bisquaternary Ammonium Compound, Pancuronium Bromide
Authors: Michoel Armand J , Kinget Renaat D
Published: February 2020

Pancuronium bromide (PCBr), a neuromuscular blocking agent, was determined quantitatively in aqueous solution by ion-pair extraction. Separate determination of PCBr and degradation products was possible after thin layer chromatography. The procedure was developed by using a theoretical approach. Favorable conditions were calculated from the ion-pair extraction constant. The drug was determined with bromothymol blue at pH 9.0, using one extraction in the direct procedure and 2 successive extractions in the combined elution-extraction process after thin layer chromatography. In the direct method, 0.100 mg PCBr was determined with a reproducibility of ±1.0%.
Collaborative Study of a Spectrofluorometric Assay for Rauwolfia serpentina Tablets and Powdered Root
Authors: Smith William M , Clark Charles C
Published: February 2020

Reserpine-rescinnamine group alkaloids are extracted from Rauwolfia serpentina preparations into a dimethylsulfoxide (DMSO)-methanol mixture and diluted with 0.5N H2SO4. The chloroform extract of this solution is passed through a 0.1N NaOH-Celite column and then through a silica gel column. The weakly basic alkaloids trapped on the latter column are eluted with a methanol mixture; a portion of the eluate is treated with nitrous acid and the reserpine-rescinnamine content is determined by measuring the intensity of fluorescence of the oxidation product. The following means and standard deviations (11 collaborators) were obtained for the determination of reserpine-rescinnamine group alkaloids in 4 samples of Rauwolfia serpentina (NF reference powder, 100 mg and 50 mg commercial tablets, and a 45 mg synthetic tablet formulation): 0.174%±0.0112, 0.131%±0.0047, 0.160%±0.0100, and 0.153% ±0.0083, respectively.
Collaborative Study of the Extraction of Light Filth From Canned Crabmeat
Authors: Dent Russell G , Gorham J Richard
Published: February 2020

Canned crabmeat is boiled with mineral oil in a Wildman trap flask. The trappings are transferred to a Corning percolator and cycled at least 3 times. Average recoveries from 7 collaborators were 82.7 % for rodent hairs and 98.0% for flies. The proposed method has been adopted as official first action.
Collaborative Study of a Method for the Extraction of Light Filth from Ground Mace and Ground Caraway Seed
Authors: Thrasher Joel J
Published: February 2020

A new method has been developed for the extraction of light filth from ground mace and ground caraway seed. The method uses a 2-step chloroform-isopropanol pretreatment followed by separation of the light filth from 40% isopropanol with mineral oil. The collaborative study resulted in clean filter papers with more reproducible recoveries of light filth elements than the official first action method, 44.116(b). The method has been adopted as official first action.
Collaborative Study of the Modifications of the Official AOAC Method for the Determination of Biuret in Fertilizers
Authors: Corominas Luis F
Published: February 2020

Six collaborators participated in the second part of the study of the official AOAC method for the determination of biuret in fertilizers. Four samples of fertilizers containing 1.5–3.0% biuret were analyzed by using 2 standard curves prepared from biuret obtained from 2 different sources and having different melting points. Biuret contents higher than expected were obtained from the curve prepared from the low melting biuret. This confirms the necessity of checking the purity of the standard to be used and justifies a recrystallization step.
Comparison of Wet Ash and Dry Ash Methods for the Digestion of Mineral-Mix Feeds
Authors: Hoover William L
Published: February 2020

When some mineral-mix feed samples are digested by AOAC dry ash methods, the mineral components are not dissolved. A 50% error in phosphorus values is observed when these digestion methods are used. It is suggested that the wording in AOAC dry ash methods for minerals in feeds be changed to exclude mineral-mix feeds.
Multiresidue Screening by Negative Chemical Ionization Mass Spectrometry of Organic Polychlorides
Authors: Dougherty Ralph C , Piotrowska Krystyna
Published: February 2020

A multiresidue procedure, based on negative chemical ionization (NCI) mass spectrometry, for analyzing organochlorine residues in environmental substrates is described. The procedure is capable of routinely detecting about 1 ng unknown organochlorine residues. Semiquantitative data (order of magnitude) may be obtained for pentachlorophenol and 2,4,5-trichlorophenoxyacetic acid residues by calibration with internal p-chlorobenzophenone. Lipid-rich substrates were resolved into acidic and neutral fractions, and both fractions were further purified by gel permeation chromatography (GPC) prior to NCI analysis. In spite of the fact that recoveries were often low, the overall sensitivity for residues in lipid-rich substrates appeared to be higher than when the GPC step was omitted.
Direct Potentiometric Titration of Urea with Urease
Authors: Falls J Harold , Barnacascel William R , Britt Perry W
Published: February 2020

AOAC method 2.070–2.071 for determining urea with urease was shown to yield varying results according to the analyst’s interpretation of titrating to a neutral end point. The method was modified to allow the end point of the titration to correspond to the break point of ammonium carbonate (pH 4.2), which is the compound being titrated in the urea analysis. This modified method proved to be a more accurate means of urea analysis. The AOAC method was further modified and simplified by eliminating the back-titration step. Ammonium carbonate may be titrated directly to pH 4.2 without over-acidifying to eliminate carbon dioxide.
Dicofol: Collaborative Study of the Hydrolyzable Chlorine Method
Authors: Baum Harry , Black Ronald F , Kurtz C P
Published: February 2020

A collaborative study was performed on dicofol formulations, using a hydrolyzable chlorine method with a potentiometric end point. Five laboratories each analyzed 2 samples of Kelthane technical, Kelthane MF, Kelthane EC, and Kelthane 35 in duplicate on each of 2 days. Statistical analysis indicated that the between-laboratory standard deviation of the dicofol assay, excluding outliers, was 0.47, 1.09, 0.78, and 0.99% absolute, at the 20, 39, 44, and 86% assay levels, respectively. The method has been adopted as official first action.
Test Method for Determination of Virucidal Efficacy of Liquid Surface Disinfectants
Authors: McDuff Charles R , Gaustad John W
Published: February 2020

A test method was developed incorporating AOAC use-dilution stainless steel Penicylinders and H.Ep.-2 tissue culture cells for the evaluation of disinfectants as virucides. The subsequent collaborative study using Herpes simplex and poliovirus type 1 in evaluation against a quaternary ammonium compound, phenolic, and iodiphor disinfectants indicated that the basic test procedure is sound. However, an improved virus concentration technique and a modified method for drying virus-contaminated cylinders are recommended. In addition, other types of disinfectants and test viruses should be included in order to demonstrate that the procedure is versatile as well as reproducible.
Rapid Digestion and Flameless Atomic Absorption Spectroscopy of Mercury in Fish
Authors: Dusci Leon J , Hackett Laurence P
Published: February 2020

A rapid method is described for the determination of total mercury in fish samples. The sample is digested with nitric acid-sulfuric acid-potassium permanganate, and then reduced and aerated for measurement by flameless atomic absorption spectrophotometry. The average recoveries of organic and inorganic mercury added to fish were 93 and 95%, respectively. The uniformity of mercury levels in shark tissue has also been investigated.
Modifications to the Hanus Iodine Absorption Number Method
Authors: Lewis Charles E , Croft Martin G
Published: February 2020

In using the Hanus method for determining the iodine absorption number of backfat from pigs, the blank determinations varied noticeably. Slight variations in temperature changed the volume of iodine solution dispensed, because the solvent, acetic acid, has a high temperature coefficient of expansion. For accurate, precise, and rapid determinations, the iodine solution should be measured by weight, not volume. Further modifications include the use of a stabilized indicator and a change in the dispensing of the weighed samples.
Environmental Chemistry of Substitutes for Polychlorinated Biphenyls. I. Composition and Properties of an Alkylchlorobiphenyl Product
Authors: Sundström Göran , Hutzinger Otto , Karasek Francis W , Michnowicz John
Published: February 2020

The composition of a technical alkylchlorobiphenyl mixture, proposed as a substitute for polychlorinated biphenyls, has been investigated by spectral and chromatographic methods. Gas-liquid chromatography-mass spectrometry revealed the presence of a large number of biphenyls substituted with 2–3 chlorine atoms and 0–4 isopropyl groups. The mixture was dechlorinated as a first step toward structure elucidation of the individual components. The behavior of the alkylchlorobiphenyls during analytical cleanup steps such as thin layer chromatography and chromic acid oxidation was also investigated.
Problems of Sampling and Analytical Methods
Authors: Horwitz William
Published: February 2020

The need for acceptable, reliable, and practical methods of analysis, chemical, physical, and biological, by the Food Standards Program of the Food and Agriculture Organization/World Health Organization is leading to cooperation by those organizations with the resources and experience to supply them. Methods should be shown to be workable and practicable and then validated in a properly designed international collaborative study for the efficient utilization of the time and effort of participating organizations and laboratories. The methods to be subjected to interlaboratory collaborative study should be clearly written so that the method itself is being tested without unauthorized variations. Satisfactory reference standard materials are often an essential part of the method. Uniform, international methods which have been developed through interlaboratory collaborative studies are applicable to the areas of microbiology and toxicology, as well as chemistry.
Pollution-Reduced Kjeldahl Method for Crude Protein
Authors: Rexroad Paul R , Cathey Robert D
Published: February 2020

Pollution from the Kjeldahl method for crude protein has been reduced by substituting a low level of copper (0.04 g CuSO4) for the mercury (0.7 g HgO) specified in the AOAC official method, 2.049. Adjustments were made in the salt-acid ratio so the new system could handle hard-to-digest samples in a reasonable time. The new method was rugged for lysine. HCl. It is designed to be used for crude protein in feeds or similar Kjeldahl work. Precision and accuracy were equal to or better than that for the official method in a study of 17 samples analyzed in duplicate on 3 different days. The following samples were used in the study: lysine. HCl, tryptophan, NBS standards, urea, meals, mixed feeds, grains, and forage. The average per cent nitrogen found was 9.52 by the official method and 9.53 by the copper method. The average standard deviation was 0.038 by the official method and 0.033 by the copper method, giving the corresponding relative standard deviations of 0.40 and 0.35%.
Collaborative Study of the Determination of Fat in Intermediate Moisture Pet Foods
Authors: Kuhn Gustav O
Published: February 2020

Four different semimoist pet food formulations representing a cross section of commercial products were studied collaboratively for fat content by 2 methods. Ten laboratories participated in the study. Direct petroleum ether extraction by AOAC method 7.045 yielded low and variable fat recovery. AOAC acid hydrolysis method 7.047 for fat in baked dog foods was satisfactory for semimoist pet foods. The method, with some editorial changes, was adopted as official first action for this type of pet food.
Cathodic Stripping Voltammetry of Nanogram Amounts of Selenium in Biological Material
Authors: Blades Michael W , Dalziel John A , Elson Clive M
Published: February 2020

A method is described to determine selenium in biological material, based on cathodic stripping voltammetry. Following wet ashing, the selenium was extracted into benzene as the 3′,4′-diaminophenylpiazselenol. The selenium was subsequently back-extracted into dilute acid for analysis. Analyses of NBS Bovine Liver demonstrated that the method was capable of recovering 96±9% of the selenium present. The detection limit and working range were 3 ng/g and 3–10,000 ng/g, respectively. The method was also applied to the determination of selenium in rapeseed oils and seed.
Determination of Added Blood in Ground Beef
Authors: Karasz Albert B , Andersen Ross , Pollman Roger
Published: February 2020

Blood added to ground beef is estimated from hemoglobin extracted with water. Since myoglobin is co-extracted with the hemoglobin, the 2 heme pigments are separated in one portion of the extract by precipitating the hemoglobin in an 85% (NH4)2SO4 solution. The myoglobin remaining in solution is used as the reference solution for determining the hemoglobin in another portion of the extract containing both pigments. The hemoglobin is converted to cyanomethemoglobin and quantitated by its absorbance at 422 nm.
Automated Fluorometric Method for the Determination of Total Vitamin C in Food Products
Authors: Roy Ram B , Conetta Aldo , Salpeter Jerry
Published: February 2020

A specific microfluorometric method for the determination of ascorbic acid, dehydroascorbic acid, and total vitamin C in food products has been automated. The procedure developed is an adaptation of the official AOAC method (secs. 43.056–43.062), except that N-bromosuccinimide is used instead of Norit to oxidize vitamin C. Ascorbic acid is selectively oxidized by N-bromosuccinimide before other interfering substances that may be present, so this method is a highly sensitive and specific technique with extensive applicability. The proposed automated method is simple, rapid, reliable, and sufficiently sensitive to analyze as little as 2 × 10−3 to 0.1 mg ascorbic acid/ml. Analytical results obtained for ascorbic acid, dehydroascorbic acid, and total vitamin C in a wide variety of food products are reported. The analytical system developed has the capability of analyzing 50 samples/hr.
High-Pressure Liquid Chromatography of Caffeine in Coffee
Authors: Madison Bryan L , Kozarek William J , Damo Cecilia P
Published: February 2020

A new method is described for the determination of caffeine in coffee, based on high-pressure liquid chromatography. The caffeine is extracted from the sample with water and/or methylene chloride, and then separated from interfering materials by passing an aliquot of the extract through a high-pressure column containing sulfonated cation exchange resin, using 0.01M nitric acid as the mobile phase. An ultraviolet detector measures the absorption of the solution directly. The method is rapid and eliminates the lengthy separations common to other methods. The procedure was applied successfully to decaffeinated and non-decaffeinated green, roasted, and instant coffees. This method gives a more accurate measure of the caffeine content in decaffeinated coffee samples than the micro Bailey-Andrew and modified Levine methods, with equal or better precision. This method gives results equal to those obtained by the official methods for non-decaffeinated samples.
Reference Raman Spectra of Eleven Miscellaneous Pesticides
Authors: Nicholas Mark L , Powell David L , Williams Theodore R , Thompson Robert Q , Oliver Nelson H
Published: February 2020

The Raman spectra of ICP (propham), CIPC (chlorpropham), carbaryl, EPTC (ethyl N,N-dipropyl (3-chlorophenyl) carbamate), pebulate, CDEC (2-chloroallyl diethyldithiocarbamate), thiram, maneb, zineb, ferbam, and nicotine have been recorded. These spectra are presented, along with tables giving values for the frequencies.
Comparison of Dieldrin, Lindane, and DDT Extractions from Serum, and Gas-Liquid Chromatography Using Glass Capillary Columns
Authors: Franken Josef J , Luyten Bert J M
Published: February 2020

Rats were given an oral dose of 14C-labeled chlorinated pesticides to obtain serum containing p,p′-DDT, dieldrin, or lindane. Simple hexane and formic acid-hexane extraction methods, involving pretreatment of the serum with formic acid, were compared by radiometric and by paper chromatographic and gas chromatographic analysis. In vivo binding of chlorinated pesticides to constituents of the serum does not necessarily prohibit their isolation by simple hexane extractions, provided that the extraction is very vigorous and at least 5 min long. Stable emulsions were broken by cooling in liquid nitrogen or Dry Ice-acetone. The hexane extraction method described yields quantitative recovery of the pesticides studied, whereas the formic acid-hexane method is quantitative for p,p′-DDT, 93% for dieldrin, and 89% for lindane. Gas chromatographic comparison of both methods, using human serum, shows that the hexane method extracts 16% more β-BHC, 7% more dieldrin and HCB, and 4% more p,p′-DDE from serum than does the formic acid-hexane method. The difference for p,p′-DDT is not significant. Gas chromatography with glass capillary columns and an all-glass solids injection system yielded detection limits as low as 15 fg. Data show that the use of an internal standard considerably improves the precision of quantitation.
Collaborative Study of a Modified Extraction Procedure for Lasalocid Sodium in Feeds by Microbiological Assay
Authors: Scheiner Jacob M
Published: February 2020

A collaborative study was conducted on a modified extraction technique in the microbiological determination of lasalocid sodium in finished poultry feeds. The feed is warmed briefly with pH 4.7 buffer and the drug is extracted with ethyl acetate. The extract is washed with HCl and NaOH and evaporated to dryness, and the residue is dissolved in hexane, partitioned into methanol-water (3+1), and diluted to assay range at a final alcohol concentration of 25% (v/v). Seven laboratories participated in the study. Average recoveries of lasalocid sodium added at 0.01035, 0.00863, and 0.0069% ranged from 93 to 99% for mash feeds and from 86 to 95% for pellets. The coefficients of variation averaged 11.2% for mashes and 9.8% for pellets. The modified extraction technique has been adopted as official first action.
Rapid Colorimetric Method for Carbadox in Animal Feeds
Authors: Thorpe Virginia A
Published: February 2020

The colorimetric method for carbadox in animal feeds was modified to be simpler and faster. Carbadox is extracted with dimethylformamide and separated from interferences on an alumina column in the absence of water by controlling the amount of sample extract on the column and the flow rate. The isolated carbadox is eluted into sodium hydroxide and the resultant yellow chromophor is measured spectrophotometrically at 420 nm.
Preparation and Spectral Compilation of FD&C Red No. 40 Intermediates and Subsidiary Dyes
Authors: Bell Sandra J
Published: February 2020

FD&C Red No. 40 may contain higher or lower sulfonated subsidiary dyes, depending on the purity of intermediates used. Samples of 10 possible subsidiaries were prepared and purified. They are to serve as analytical standards to aid in the identification of unknown compounds frequently appearing during the analysis of certification samples. Visible, ultraviolet, and infrared spectra as well as absorptivities and molar extinction coefficients are given for each dye.
Gas Chromatographic Determination of Micro Amounts of Cyanide Residues in Wines, Distilled Liquors, and Other Alcoholic Beverages
Authors: Bates Brian L , Buick Donald R
Published: February 2020

A gas chromatographic method for the determination of cyanide residues in alcoholic beverages has been developed from procedures previously reported for application to water samples. Quantitatively isolating HCN from alcoholic beverages presented difficulties not encountered with aqueous solutions, particularly in the presence of SO2 in the sample. HCN was liberated from the acidified sample by heating at 70°C, flushed into an NaOH absorber solution, converted to cyanogen bromide (CNBr), extracted into diisopropyl ether, chromatographed on a Porapak Q column, and detected by an electron capture detector. SO2 that is present in most wines interfered with the bromination step and caused low recoveries. This interference was eliminated by initially converting any cyanide present in the sample to the stable mercuric cyanide salt and then purging the acidified sample solution of all SO2. The Hg(CN)2 present was then dissociated by adding KI and the analysis proceeded as previously described. Mean recoveries of 80–97 % were obtained for 2–20 μg cyanide from replicate analyses of spiked samples of distilled liquors free of SO2. The relative standard deviations ranged from 6.1 to 11.1%. Mean recoveries of 65 to 91% were obtained in the same range of cyanide from replicate analyses of spiked wine samples known to contain SO2, with relative standard deviations ranging from 0.8 to 10.2%. The limit of detection was 0.2 μg HCN.
Thin Layer Chromatographic Identification of Some Sympathomimetic Amines
Authors: Shah Jitendra J , Shah Ramila J
Published: February 2020

Thin layer chromatographic behavior of some sympathomimetic amines in the presence of acids in neutral and organic solvent systems is reported. The sympathomimetic amines were dissolved in 0.1N HCl or ethanol and treated with bromocresol green or p-nitrobenzoyl chloride reagents on fiber sheets or precoated glass plates. Two-, 3-, and 4-component solvent systems were tested. Benzene-ethyl acetate gave 2 spots for each amine standard; the more polar spots were satisfactorily separated. Amines in pharmaceuticals were not separated by any solvent system tested.
High Performance Liquid Chromatographic Analysis of Supplemental Vitamin E in Feed
Authors: Shaikh Badaruddin , Huang Hsinkuang S , Zielinski Walter L
Published: February 2020

Supplemental vitamin E is extracted from feed in one step with methanol and analyzed by reverse phase partition chromatography in less than 10 min, using isocratic elution with either methanol or water-methanol as the mobile phase. Detection response (as measured by peak area) was linear between 0.5 and 3.0 μg, and the coefficients of variation for retention time and peak height on replicate analyses of the standard sample were 0.8 and 2.3%, respectively.
Determination of Pirimiphos Methyl in Formulations by High Performance Liquid Chromatography
Authors: Zehner James M , Simonaitis Richard A
Published: February 2020

A simple and rapid method for the determination of pirimiphos methyl (O-[2-(diethylamino)-6-methyl-4-pyrimidinyl] O,O-dimethyl phosphorothioate) in formulations by high performance liquid chromatography is described. The sample is dissolved in methanol, and biphenyl is added as an internal standard. Then the sample is chromatographed by reverse phase chromatography on a Zipax octadecylsilane column. A 4 μI injection containing 0.01% pirimiphos methyl produces a 50% full scale peak at the maximum absorbance at 254 nm.
High Pressure Liquid Chromatographic Determination of Uncombined Intermediates in FD&C Red No. 2
Authors: Singh Manjeet
Published: February 2020

A high pressure liquid chromatographic (HPLC) method is presented for the separation and determination of uncombined intermediates in FD&C Red No. 2 (amaranth). Samples of FD&C Red No. 2 containing 0.1—0.3% naphthionic acid, 0.1—0.4% 2-naphthol-3,6-disulfonic acid, 0.3—1.0% 2-naphthol-6,8-disulfonic acid, and 2-naphthol-3,6,8-trisulfonic acid were prepared and analyzed by HPLC. Recoveries ranged between 92 and 101%. Twenty samples of FD&C Red No. 2 were analyzed by the conventional column chromatographic method and the HPLC method. The HPLC method was superior, since it separated all the above intermediates from each other and from FD&C Red No. 2 in one quarter the time required by the conventional column chromatographic method which did not separate the individual intermediates.
Electron Impact and Chemical Ionization Mass Spectrometry of Some Butyrophenones
Authors: Leferink Jos G , Maes Robert A A
Published: February 2020

The mass spectra of some butyrophenoncs are presented. Electron impact ionization and chemical ionization with isobutane as the reagent gas are compared. The chemical ionization spectra show the quasi molecular ion (M + H)+ to be the most abundant ion. Important fragments in the electron impact spectra are discussed for easy determination of other similar compounds.
Evaluation of XAD-2 for Multiresidue Extraction of Organochlorine Pesticides and Polychlorinated Biphenyls from Natural Waters
Authors: Coburn John A , Yaldmanis Ilze A , Chau Alfred S Y
Published: February 2020

The Amberlite polymeric resin, XAD-2, was evaluated for multiresidue extraction of ng/L levels of several organochlorine pesticides and polychlorinated biphenyls (PCBs) from fortified distilled water and from fortified and unfortified natural waters.

Recoveries from 1 L distilled water samples fortified with 10—100 ng of 10 organochlorine pesticides averaged 96%. Recoveries averaged 85% for XAD-2 resin extraction of fortified natural samples collected from across Canada. Unfortified control samples contained no detectable levels of any of the pesticides used in the fortification. The resin is not suitable for extracting Mirex from natural water; only about 50% of added Mirex was recovered. Recoveries of PCBs from 2 L natural water samples, fortified with 250 ng PCBs/L and corrected for losses on the silica gel fractionation column and apparent PCB content of the control samples, ranged from 78 to 86%. Blanks for the resin extraction procedure were very low, averaging 4 ng PCBs/L.
Temperature-Programmable Furnace for Ashing of Foods in Trace Metal Analysis
Authors: Holak Walter
Published: February 2020

The use of a programmable furnace in preparing samples for determining cadmium, lead, copper, and zinc by differential pulse anodic stripping voltammetry or atomic absorption spectrophotometry is convenient and timesaving. Recovery data for these 4 metals in various foods (tuna, sardines, and milk) were 93— 96% for 0.01—1 ppm cadmium, 96—114% for 0.05—5 ppm lead, 100—108% for 2—10 ppm copper, and 97% for 10 ppm zinc.
Quantitative Determination of Spleen Added to Ground Beef
Authors: Bittel Ralph J , Graham Paul P
Published: February 2020

A method for the quantitative detection of spleen added to ground beef is presented, based on the organ specificity and insolubility of the storage iron compound hemosiderin. Soluble iron forms are removed by saline extraction and centrifugation. Iron remaining in the insoluble tissue residue is assumed to be hemosiderin iron. The retained iron is extracted by acid hydrolysis of the residue in a solution of 2% thiourea in 1N HCl, filtered, and measured colorimetrically with ferrozine and by atomic absorption spectroscopy. Weighed amounts of ground beef and a composite spleen homogenate were combined to yield products with 0, 2.5, 5, and 10% spleen. A graded series was prepared at each of 3 fat levels. The residues from unadulterated samples retained less than 4 μg Fe/g original sample. Insoluble iron increased linearly (slope = 4.83) as the level of spleen in the product increased. The fat content of the products had little effect on the determination of added spleen.
High Performance Liquid Chromatography of Aflatoxins in Cottonseed Products
Authors: Pons Walter A , Franz Anthony O
Published: February 2020

A precise and sensitive high performance liquid chromatographic (HPLC) method is proposed for determining aflatoxins in cottonseed products in 1.0—1.5 hr. After aqueous acetone extraction, lead acetate treatment, and partition of aflatoxins into methylene chloride, sample extracts are purified on a small silica gel column requiring only 125 ml solvent/sample. Aflatoxins B1 and B2 in the purified extract are resolved on a micro particulate (10 μm) silica gel column in ca 8 min, using a water-saturated chloroform - cyclohexane - acetonitrile solvent, with detection by ultraviolet absorbance at 365 nm. The resolution was highly reproducible, giving coefficients of variation of 0.2—1.0% for retention and 1.0—2.3% for quantitation. Recovery of added aflatoxins B1 and B2 was 90— 95% at levels of 5—100 μg/kg. The within-laboratory coefficients of variation of the entire method, based on repetitive assays of a cottonseed meal (34 μg B1/kg, 6 μg B2/kg), were 7.3% (B1) and 7.4% (B3). A high degree of correlation was obtained for HPLC estimation by 2 different commercial columns; for quantitation by peak height vs. electronic integration; and for quantitation by HPLC or thin layer chromatography.
Fungal Growth and Aflatoxin Production on Apiarian Substrates
Authors: Hilldrup Jo Ann L , Eadie Thomas , Llewellyn Gerald C
Published: February 2020

Unprocessed honey, Lilium longiflorium pollen, brood comb, whole larvae, and whole bees were inoculated with Aspergillus flavus NRRL 3251, A. flavus ATCC 15548, and A. parasiticus NRRL 2999. The fungi grew, sporulated, and produced various amounts of aflatoxin on all substrates except the unprocessed honey. The largest quantity of aflatoxin B1 was produced on whole larvae supporting A. flavus NRRL 3251 growth. A. parasiticus NRRL 2999 growing on whole larvae produced the most aflatoxin G1. Aflatoxins B2 and G2 were seldom detected. Apiarian substrates with the exception of honey seem capable of supporting fungal growth and resultant aflatoxin production.
Improved Procedure for Quantitative Determination of Aflatoxins in Corn and Wet Milled Corn Products
Authors: Barabolak Roman
Published: February 2020

Aflatoxins are extracted from the sample by high-speed blending with aqueous acetone, purified with ammonium sulfate, and partitioned into benzene. The benzene extract is purified on a silica gel-alumina column by washing with benzene-acetic acid and ether-hexane, and eluted with methylene chloride-acetone. The eluate is evaporated, redissolved in benzeneacetonitrile, and spotted on a thin layer chromatographic plate for resolution and quantitative determination against standards.
Determination of Urethane in Wines by Gas-Liquid Chromatography and Its Confirmation by Mass Spectrometry
Authors: Joe Frank L , Kline David A , Miletta Elaine M , Roach John A G , Roseboro Emma L , Fazio Thomas
Published: February 2020

A gas-liquid chromatographic (GLC)-mass spectral (MS) method for the determination and confirmation of urethane in wines has been developed. Analyses of domestic and imported wines indicated urethane to be present at levels ranging from 1 to 20 μg/L. Recoveries of urethane from wines fortified at 10 ppb (μg/L) ranged from 50 to 100% with an average value of 71%. GLC-MS was used to confirm the identity of urethane in wine extracts in which GLC indicated the presence of urethane.
Collaborative Study of the Colorimetric Determination of Zirconium in Antiperspirant Aerosols
Authors: Beavin Paul
Published: February 2020

A previously published method for determining zirconium in antiperspirant aerosols was collaboratively studied by 7 laboratories. The method consists of 2 procedures: a rapid dilution procedure for soluble zirconium compounds or a lengthier fusion procedure for total zirconium (soluble and insoluble compounds), followed by colorimetric determination. The collaborators were asked to perform the following: Spiking materials representing 4 levels of soluble zirconium were added to weighed portions of a zirconium-free cream base concentrate and the portions were assayed by the dilution procedure. Spiking materials representing 4 levels of zirconium in either the soluble or the insoluble form (or as a mixture) were also added to portions of the same concentrate and these portions were assayed by the fusion procedure. They were also asked to concentrate and assay, by both procedures, 2 cans each of 2 commercial aerosol antiperspirants containing zirconyl hydroxychloride. The average per cent recoveries and standard deviations for spiked samples were 99.8–100.2 and 1.69–2.71, respectively, for soluble compounds determined by the dilution procedure, and 93.8–97.4 and 3.09–4.78, respectively, for soluble and/or insoluble compounds determined by the fusion procedure. The average per cent zirconium found by the dilution procedure in the 2 commercial aerosol products was 0.751 and 0.792, respectively, with coefficients of variation of 2.94 and 2.53%, respectively. Insufficient collaborative results were received for the fusion procedure for statistical evaluation. The dilution procedure has been adopted as official first action.
Gas-Liquid Chromatographic Determination of Captan and Two Metabolites in Milk and Meat
Authors: Onley John H
Published: February 2020

A gas-liquid chromatographic (GLC) method has been developed for the determination of captan (N-trichloromethylthio-4-cyclohexene-1, 2-dicarboximide) and 2 metabolites, tetrahydrophthalimide (THPI) and tetrahydrophthalamic acid (THPMA), in milk and meat. The sample is extracted with ethyl acetate and is cleaned up by acetonitrile partition and silica gel chromatography where captan, THPI, and THPMA are separated. Captan is directly determined by GLC. THPI and THPMA are separately derivatized in an acetone solution of penta fluorobenzyl bromide. The resultant derivatives are purified separately on an Al2O3, column and quantitated by GLC, using an electron capture detector. Recoveries from milk samples fortified at 0.02–10 ppm ranged from 71 to 102%; recoveries from meat samples fortified at 0.04–10 ppm ranged from 75 to 99%.
Aluminum Oxide Cleanup of Feed Grade Fats for Residues of Dieldrin
Authors: Lane Larry G , Gray Terri C , Minyard James P
Published: February 2020

A method is described for the analysis of dieldrin in feed grade fats. Fat samples in petroleum ether are cleaned up by column chromatography on 10% deactivated aluminum oxide followed by Florisil and analyzed by electron capture gas chromatography. Fourteen laboratories tested the method for determining dieldrin in naturally contaminated feed grade fats. Recoveries averaged >90% with a coefficient of variation of 13% (0.54 ppm ± 0.07), indicating that the method is sufficiently reproducible to be used by different laboratories for detecting dieldrin in feed grade fats.
Collaborative Study of Gas-Liquid Chromatographic Method for Determining Methyl Parathion
Authors: Jackson Edwin R
Published: February 2020

Methyl parathion in technical material, 4 lb/gal. emulsifiable concentrate, and 25% wettable powder was chromatographed on a 1.5% SE-30 + 1.5% OV-210 column with p,p′-DDE as internal standard and flame ionization detection. Three matched sample pairs were analyzed by 15 collaborators using peak height measurements. Liquids were diluted to volume with p,p′-DDE internal standard solution; wettable powders were extracted with chloroform-acetone (9+1), solvent was removed, and extracts were dissolved in internal standard solution. The mean of the coefficients of variation for the 6 samples was 1.65%. The method has been adopted as official first action.
Direct Plating Versus Dilution Plating in Qualitatively Determining the Mold Flora of Dried Beans and Soybeans
Authors: Mislivec Philip B , Bruce Verneal R
Published: February 2020

Two methods presently used for examining whole foods and feeds for viable molds were evaluated for their relative effectiveness in the qualitative determination of the total number of mold species present in soybeans and dried beans: the direct plating method and the serial dilution method. Sixty-nine soybean samples and 40 dried bean samples were examined. Although the quantitative results of this study were inconclusive, the qualitative results show that the direct plating method was substantially more effective in detecting individual mold species. An average of 12.9 and 10.9 species was detected by the direct plating method in whole soybean and dried bean samples, respectively. An average of 4.4 and 2.8 species was detected by the dilution method in ground soybean and dried bean samples, respectively. A total of at least 37 mold species were found in the study, including 10 toxicogenic species. With few exceptions, detection rates of the 37 individual species were substantially greater among the samples examined by direct plating than those examined by serial dilution.
Effect of Storage in Flour and of Particle Size on the Bioavailability of Elemental Iron Powders for Rats and Humans
Authors: Verma Ramesh S , Motzok Ilary , Chen Shy-Show , Rasper Jaroslava , Ross Henry U
Published: February 2020

Elemental iron powders produced by different processes were separated by nitrogen elutriation into fractions based on particle size. The fractions containing fine particles (7–10 μm) of electrolytic iron, hydrogen (H2)- and carbon monoxide (CO)-reduced iron, and the whole sample of carbonyl iron (92% <11 μm) were blended into freshly milled wheat flour and stored at about 21°C. Storing the enriched flour up to 9 months had no effect on the relative biological value (RBV) of iron for rats from each type of iron supplement. Baking bread with flour containing electrolytic, H2-reduced, and carbonyl iron after storage for 10 months also had no effect on the RBV of the iron powders. There was no change in the RBV of iron for rats from flour enriched with electrolytic iron (200 mg/kg) and ascorbic acid (200 and 1665 mg/kg flour) after storage for 1 week and 3 months. The decreases in RBV due to increase in size of particles (7–10 vs. 20–26 μm) were significant for H2-reduced iron and CO-reduced iron but not for electrolytic iron and carbonyl iron. The RBVs of elemental iron powders for rats were similar to the values obtained with humans, based on iron absorption after an overnight fast.
Reverse Phase Analytical and Preparative High Pressure Liquid Chromatography of Aflatoxins
Authors: Stubblefield Robert D , Shotwell Odette L
Published: February 2020

Reverse phase high pressure liquid chromatography (HPLC) was investigated and found applicable for determining 6 aflatoxins. Aflatoxins M2, M1, G2, G1, and B1 were completely resolved and B2 was satisfactorily separated on a C18 (10 μm, 4 mm id × 30 cm) column with an eluting solvent of acetonitrile-water (35 + 65) and flow rate of 1.5 ml/min. Compounds were detected by ultraviolet absorbance at 350 nm. Peak height and retention time reproducibility of multiple injections was excellent with coefficients of variation of 1.0% (M1) and 1.9% (B1) when laboratory temperatures were relatively constant throughout a day ; however, coefficients of variation increased significantly when temperatures varied by 10°F. HPLC determinations of aflatoxin B1 added to uncontaminated corn extracts at 20 and 50 ppb levels were 83±14 and 92.5±8%, respectively, of those expected. Comparison of com extract assays (6–98 ppb B1) by thin layer chromatography (TLC) and HPLC revealed that HPLC values averaged 25% less than TLC values. Numerous peaks and background interferences were present in corn extracts which made interpreting chromatograms difficult. None of the cleanup procedures tried was successful in removing these interferences. Preparative HPLC was used to isolate and purify quantities of aflatoxins M1, B1, and G1 from silicic acid column mixtures of M1-M2, B1-B2, and G1-G2. Separations were achieved on C18/Porasil B (35–75 μm) columns (⅜″ od × 8′) developed with acetonitrile-water mixtures (M1, 20+80; B1, 35+65; G1, 25+75) at 9.0 ml/min. These columns permitted isolation of 40 mg aflatoxin B1 or G1 in less than 3 hr. Aflatoxin M1 required 2 HPLC steps.
High Pressure Liquid Chromatographic Determination of Aflatoxins in Wines and Other Liquid Products
Authors: Takahashi David M
Published: February 2020

A previously developed high pressure liquid chromatographic (HPLC) method was evaluated by an extensive recovery study of aflatoxins from wines and other liquid products. The HPLC column and the preliminary cleanup procedures were both modified for this study. Four aflatoxins (B1, B2, G1, and G2) were recovered at 80–116% from 28 samples of various liquid commodities spiked at the 1 μg/L (1 ppb) level. The detection limit of the proposed method for wines and fruit juices was about 0.02 ppb. A total of 53 samples were analyzed for aflatoxins during this study.
High Pressure Liquid Chromatographic Determination of Sucrose in Honey
Authors: Thean James E , Funderburk Walter C
Published: February 2020

A normal phase high pressure liquid chromatographic (HPLC) method is presented for separating and determining sucrose in honeys. This method has been successfully applied to the analysis of field samples containing sucrose (0.63–8.44 wt %). Diluted honeys are filtered through a 0.45 μm membrane filter, and injected directly into the chromatograph. Samples are eluted from a μBondapak/carbohydrate column with acetonitrile-water (83+17) and quantitated with a refractive index detector. Average recovery of sucrose is 97%.
Ultraviolet Spectrophotometric Determination of Gibberellic Acid in Product Formulations
Authors: Ealy Daniel B , Gorman Robert R , Koester Jerome L
Published: February 2020

A new procedure is described for quantitating gibberellic acid in finished product formulations. The parent compound, which shows no significant ultraviolet absorbance, is chemically converted to the methyl ether of gibberellenic acid. The reaction product absorbs strongly in the ultraviolet region and thus provides the basis for Spectrophotometric quantitation. Results obtained by the new procedure are compared with results obtained by the commonly employed fluorometric procedure.
Isomer-Specific Assay of Ester and Salt Formulations of 2,4-Dichlorophenoxyacetic Acid by Automated High Pressure Liquid Chromatography
Authors: Skelly Norman E , Stevens Timothy S , Mapes David A
Published: February 2020

An automated high pressure liquid chromatographic method is described for the assay of 2,4-dichlorophenoxyacetic acid (2,4-D) in either salt or ester herbicide formulations. The method is specific for the 2,4-D isomer, and resolves all known impurities from 2,4-D and the internal standard. Ester products are assayed similarly to salt formulations, following room temperature in situ saponification. Results are thus obtained for all products as a per cent 2,4-D acid equivalent. Compounds are separated on a reverse phase microparticulate column with acetonitrile-water (20+80), buffered at pH 3. Precision data indicate a relative standard deviation of better than 1%. The method was developed to replace the nonspecific total chlorine, titration, and saponification assay procedures.
Evaluation of Rapid Polarographic Method for Determining Tocopherols in Vegetable Oils and Oil-Based Products
Authors: Waltking Arthur E , Kiernan Mary , Bleffert George W
Published: February 2020

A polarographic procedure for the determination of the tocopherols in vegetable oils was compared to a conventional gas-liquid chromatographic procedure. The polarographic method is 2–3 times more precise and more rapid, which is an important advantage for monitoring the nutritional value of processing conditions of vegetable oil-based products. Attempts to establish the validity of apparently slightly higher values for α and γ-tocopherols obtained by polarography has implicated the gas chromatograph or derivative formation rather than the extensive prior manipulation of the sample for chromatography as the source of error. Essentially the same results were obtained for α-tocopherol, regardless of the technique used. However, more variable results which were product dependent were obtained for γ- and Δ-tocopherols when gas-liquid chromatography was used.
Modification of Canadian Food and Drug Directorate Lipoxidase Method for Polyunsaturated Fatty Acid Determination
Authors: Prosser Allan R , Sheppard Alan J , Hubbard Willard D
Published: February 2020

The Canadian FA-59 enzymatic method for determining cis,cis-methylene interrupted polyunsaturated fatty acids has been modified to meet the needs of the cholesterol and fatty acid regulations of the U.S. Food and Drug Administration. A centrifugation step has been introduced to remove palmitate and stearate interference with absorbance readings for samples containing low amounts of cis,cis-methylene interrupted polyunsaturated fatty acids. The data are calculated by using a standard curve and an equation which yields g trilinolein/100 g product rather than % linoleic acid in a given weight of sample. The standard curve was linear for 1–12 μg trilinolein. Recovery of added trilinolein was 99.5%, with 4% coefficient of variation. The modified procedure was successfully applied to a wide variety of foodstuffs.