bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraction and GLC Detection of Pentachlorophenol and 2,3,4,6-Tetrachlorophenol in Fats, Oils, and Fatty Acids
Authors: Higginbotham G R , Ress John , Rocke Alan
Published: February 2020

A proposed tentative method for detection of residues of pentachlorophenol and 2,3,4,6-tetrachlorophenol in fats, oils, and commercial food grade fatty acids consists of treating a 5.0 g sample with concentrated sulfuric acid and Celite, followed by a series of liquid-liquid extractions with petroleum ether, aqueous alkali, and chloroform. The residue from the final extract, after further treatment with concentrated sulfuric acid, is analyzed by electron capture GLC. Recoveries of the 2 volatile polychlorophenols were low and varied over a wide range; however, the tentative procedure appears to be satisfactory for qualitative detection at the 0.5 ppm level. Several samples of commercial oleic acids contaminated with chick edema factors were analyzed and were found to be contaminated with pentachlorophenol. Further study of the method is recommended.
Atomic Absorption Spectrophotometric Determination of Boron in Plants
Authors: Melton James R , Hoover William L , Howard Peggy A , Ayers Jo Lynn
Published: February 2020

An atomic absorption method is proposed by which boron can be analyzed in plant materials at concentrations of 3 μg/g o r greater. With the exception of fluorides, no interferences were observed. Results obtained from the proposed method compared favorably with AOAC 6.073. Recoveries of boron ranged from 93 to 107%. This method involves dry ashing the plant sample and treating the ash with 5N HCl. Boron is extracted from this solution into an organic phase of 2-ethyl-l,3-hexanediol in methyl isobutyl ketone. The organic layer is aspirated into the flame without decantation for the determination by atomic absorption.
Note on Solid State Fluorescence Emission of Ochratoxins A and B on Silica Gel
Authors: Chu Fun Sun
Published: February 2020

The fluorescence emission spectra of ochratoxins A and B on silica gel have been determined. The emission maxima for both toxins were found to be around 475 nm, with excitation maxima at 340 nm for ochratoxin A and 325 nm for ochratoxin B.
Collaborative Study of a Method for Cyclohexylamine in Cyclamates and Artificially Sweetened Beverages
Authors: Fazio T , Howard J W
Published: February 2020

A collaborative study was conducted on the method for cyclohexylamine in various artificially sweetened foods and artificial sweeteners published earlier. In this method the amine is isolated by an extraction and/or distillation technique, determined by gas chromatography, and confirmed by infrared spectroscopy. Samples of cyclamates and beverages fortified with cyclohexylamine were analyzed by 7 collaborators. Overall laboratory per cent recoveries for the cyclamates (11 ppm) and beverages (0.5 and 1.0 ppm) ranged from 89.1 to 95.4.
Method for Determining Multiple Residues of Organic Fumigants in Cereal Grains
Authors: Malone Bernadette
Published: February 2020

A method is described for determination of residues of the fumigants methyl bromide, carbon disulfide, chloroform, ethylene dichloride, carbon tetrachloride, and ethylene dibromide in cereal grains. Whole or ground grain is boiled in an acid medium, and the volatile fumigants are dried and collected in cold solvent. Residues are determined by analyzing aliquots of the collected solution by electron capture GLC. Recoveries range from 59 to 105%. Extraction appears to be complete in the 2 hr boiling period specified. An unexplained conversion of carbon tetrachloride to chloroform is described.
New Instrumental Combustion Method for the Microdetermination of Phosphorus
Authors: Handy PAul R , Macdonald Alexander
Published: February 2020

An apparatus has been designed for the determination of microgram quantities of phosphorus-containing compounds. Both inorganic and organic compounds are reduced to phosphine under a stream of hydrogen in a quartz tube at 900-1000°C. The phosphine is separated from other combustion products on sequential alumina and porous polymer bead columns with final measurement by a thermionic GLC detector. The method routinely requires microgram samples with sensitivity capabilities to the nanogram level. The analysis time per sample is less than 5 min.
Note on a Simple Solvent Vent System for the GLC-Flame Photometric Detector
Authors: Watts Randall R
Published: February 2020

A simple solvent vent system is described to prevent extinguishing the flame when 1 μ1 or more of organic solvents is injected into a gas chromatograph with a flame photometric detector. This venting system is simple and inexpensive and also provides a solvent peak for reference in measuring retention times.
Evaluation of Methods for Determination of Moisture in Distillers Process Materials
Authors: Meredith M K , Baldwin S , Andreasen A A
Published: February 2020

Four methods were compared for the determination of moisture in cereal grains and distillers by-product grains: Karl Fischer method, toluene method, vacuum oven method (95–100°C, 5 hr ), and modified vacuum oven method (60°C, 16 hr). The toluene method proved to be the most satisfactory because of its speed and accuracy.
Semiautomated Method for the Determination of Reserpine in Tablets
Authors: Page Donald P
Published: February 2020

A chloroform solution of reserpine tablets is automatically sampled, washed successively with aqueous solutions of citric acid and sodium bicarbonate, and diluted with methanol. The chloroform-methanol solution is split into 3 streams: one flows sequentially through 2 UV spectrophotometers, recording the absorbances at 268 and 295 nm; the other 2 streams are used for the colorimetric assay (addition of hydrochloric acid and sodium nitrite) and blank (hydrochloric acid only). Day-to-day relative standard deviations were 0.40–0.95%. Comparisons with Barkan’s chromatographic procedure and the USP XVII method are presented.
Rapid Fluorometric Method for Determination of Nequinate in Feeds
Authors: Cox Phillip L
Published: February 2020

The modified fluorometric procedure for nequinate in feed eliminates the need for column separation and is well suited for practical routine feed analysis. Nequinate is extracted from feed with 1% formic acid in CHCl3. The extract is filtered and diluted with CHCl3. Methanesulfonic acid is added to enhance the fluorescence of nequinate and the fluorescence is determined at a 270 nm excitation wavelength and a 372 nm emission wavelength. The average recovery of nequinate from feed is 100.5% with a standard deviation of 2.2%. In the presence of most feed additives, the method is quite specific for nequinate. Other 4-hydroxy quinoline coccidiostats presently used as feed additives produce a low level of fluorescence, but qualitative differences can be detected at low concentrations in the presence of methanesulfonic acid due to the lack of a sharp 270 nm excitation peak.
Analysis of Feeds Containing a Combination of Sulfanitran, Aklomide, and Arsanilie Acid
Authors: Morrison J L , George G M
Published: February 2020

Aklomide and sulfanitran can be determined, in the presence of arsanilie acid by removal of arsanilie acid from the methanol extract of t he feed by alumina chromatography. The column effluent is then assayed by the official AOAC colorimetric methods for aklomide and sulfanitran. Arsanilie acid is determined directly on a separate feed sample, using citric acid as the extractant. Recoveries were 94–98% for arsanilie acid, 97% for aklomide, and 95–100% for sulfanitran, with an average coefficient of variation between 3 and 4% for each drug assay.
Atomic Absorption Spectrophotometry of Iron and Aluminum in Baking Powders
Authors: Holak Walter
Published: February 2020

In an atomic absorption method for iron and aluminum in baking powders, organic matter is destroyed with a mixture of H2SO4-30% H2O2, the sample is diluted to within analytical range, and absorption of each element is measured. Concentrations are obtained from calibration curves prepared from standards diluted in the presence of H2SO4 and alarge amount of alkali; the former compensates for the matrix differences and the latter suppresses the ionization of aluminum. Recovery studies with commercially manufactured baking powders to which known amounts of the elements were added indicate that the method is free of interferences for these products. Average recovery and the relative standard deviation for iron and aluminum are 100.4±1.3% and 98.7±1.8%, respectively.
GLC and TLC Determination of Tetraethyl Pyrophosphate (TEPP) in Crops
Authors: Crossley J
Published: February 2020

Two new residue methods have been developed for tetraethyl pyrophosphate (TEPP) on crops. One method employs GLC with thermionic detection and has a limit of detectability of 0.01 ppm. This is the more accurate but less sensitive of the 2 methods. TLC and cholinesterase inhibition is used in the other procedure, giving a limit of detectability of 0.001 ppm. The correlation between the results obtained from the 2 methods is excellent. The method based on GLC was successfully applied to 18 tests on 8 field-treated crops: alfalfa, cabbage, broccoli, green beans (pods and vines), apples, peaches, blueberries, and oranges (peel and pulp). Fortification levels of 0.02 ppm yielded an average recovery in all crops of 85±12%. The TLC method was used to confirm residues found by GLC.
Note on the Extraction of 14C-DDT Residues from Soybeans
Authors: Nash R G , Beall M L
Published: February 2020

Residues of 14C-DDT were not completely removed from fresh or wetted dried soybean plants when hexane-acetone-methanol was used for Soxhlet extraction. The nonextractable 14C presumably was contained in degraded residues of DDT.
Comparison of Gas-Liquid Chromatographic and Chemical Methods For Quantitative Determination of the Menadione and Menadione Sodium Bisulfite Content of Pharmaceutical Products
Authors: Sheppard A J , Hubbard W D
Published: February 2020

A collaborative study was conducted to compare the NF XII method and a GLC method for quantitatively determining menadione in pharmaceutical products. Ten collaborating laboratories analyzed 6 Pharmaceuticals encompassing tablets, capsules, and a liquid. Menadione is extracted with diethyl ether from ground tablets; slip capsules are opened and the contents are emptied into the ether along with the capsule parts. After filtration and removal of the ether, the residue is redissolved in n-hexane. The menadione sodium bisulfite injectable is transferred to a separatory funnel and extracted with chloroform and sodium hydroxide, evaporated to dryness, and redissolved in n-hexane. Menadione is chromatographed on a 6’ × 3mm id glass column packed with 1% neopentyl glycol succinate on 100–120 mesh Gas Chrom Q and operated at 135°C. The carrier gas flow is adjusted so that menadione appears within 5.5–6.5 mhi. Because of the coefficients of variation, additional study is recommended.
GLC Determination of Nikethamide in Injections
Authors: Newton John M
Published: February 2020

A GLC method for the direct determination of nikethamide in injections uses a KC1 thermionic detector which is sensitive to nitrogencontaining compounds. As little as 1 ng nikethamide is detected. The proposed method was compared to the NF XII method on various commercially prepared samples; the results are in good agreement.
Study of the AOAC Chromatographic Procedure for Reserpine Tablets
Authors: Dow Matthew L , Grant Raymond C
Published: February 2020

The procedure developed by Barkan and Kunze was used to analyze uncoated reserpine tablets representing 108 formulations from 60 drug manufacturers. To assay certain products, changes in the original method were required because of interferences from excipients; these changes involved column and sample preparation. The standard deviations of the modified procedure were 1.54% of declared (ultraviolet assay) and 0.90% of declared (colorimetric assay) at the 0.25 mg/tablet level.
Effect of Formaldehyde on the Crude Fat Content of Ground and Diced Beef
Authors: Benson John H , Coleman Charles H , Sarnow Norbert P
Published: February 2020

Ground and diced meat, with and without added 0.5 ml formaldehyde/Lb, was tested for the effect of the preservative on the analysis for crude fat. Twenty-two collaborators each analyzed 4 samples. Statistical analysis of the results indicates that there is no difference in the Soxhlet fat analysis for preserved and unpreserved meat.
Bleaching and Staining Procedure for Microscopic Counting of Insect Fragments and Rodent Hairs in Ground Cocoa Bean Products
Authors: Brickey Paris M , Gecan John S
Published: February 2020

Ground cocoa bean tissue is decolorized with hydrogen peroxide, then stained with picric acid to make decolorized hairs visible. Hydrogen peroxide does not destroy rodent hairs or decolorize insect fragments as does sodium hypochlorite which has previously been recommended by several researchers as a plant bleaching agent.
Sensitive Microbial Assay Procedure for Chlortetracycline in Milk and Related Products
Authors: Katz Stanley E , Fassbender Carol A
Published: February 2020

A microbiological assay procedure with increased sensitivity was developed for milk and some of its products. The procedure is based on the classical cylinder-plate assay procedures with the following modifications: closer adherence to a consistent pH of 4.5, centrifugation of samples to remove the physical barriers to diffusion of the antibiotic, and use of a thin, single layer of seeded agar. Recoveries in milk by this procedure averaged 65.3% versus 37.9% for those obtained using FDA methods. Improvements in recoveries were noted with the milk products studied. Of the chlortetracycline added to milk, 25% was converted to the epimer form which has negligible microbiological inhibitory properties. Binding and/or the inability to account for the antibiotic was found to be negligible.
Gas-Liquid Chromatographic Column Preparation for Adsorptive Compounds
Authors: Ives N Fred , Giuffrida Laura
Published: February 2020

Adsorption is a major difficulty in the gasliquid chromatography of low nanogram quantities of certain organic compounds. Investigations were conducted to identify and remedy problem areas. Column support material was the greatest factor contributing to adsorption problems. Column preparation procedures are described which substantially decrease detrimental column effects.
Gas-Liquid Chromatographic Determination of Saccharin in Soft Drinks
Authors: Conacher H B S , O’Brien R C
Published: February 2020

A quantitative GLC technique has been developed and applied to the determination of saccharin in several dietetic soft drinks. The procedure involves conversion of saccharin by diazomethane to the N-methyl derivative, which is determined by GLC, using methyl stearate as internal standard. Recoveries of known amounts of saccharin added to a drink ranged between 96.0 and 102.0%. The saccharin content of the commercial drinks analyzed ranged from approximately 30 to 90 mg/10 fluid oz.
Survey of Cyclohexylamine Content of Food Products Containing Cyclamates
Authors: Fazio T , Howard J W , Haenni E O
Published: February 2020

A national survey was conducted to ascertain the relationship of the cyclohexylamine content of cyclamate-containing products to their composition, processing, and storage conditions. Cyclohexylamine was found in 174 of the 232 samples examined. The cyclohexylamine content range for each major type of food product was as follows: 0.0–8.2 ppm for carbonated beverages; 0.0–5.8 ppm for dry beverage bases; 0.0–1.5 ppm for fruit juices; 0.0–0.8 ppm for weight control foods; and 0.3–66 ppm for food sweetener preparations (liquid and dry base). No correlation between the cyclamate content of products and the cyclohexylamine present was evident. However, the findings indicate that significant hydrolysis of cyclamate can occur.
The Neutron Activation Analysis Program of the Food and Drug Administration
Authors: Tanner James T , Lambert J P F , Simpson R E
Published: February 2020

Activation analysis is a rapid and sensitive method of trace element analysis applicable to a large variety of samples. For the most part the method is nondestructive; however, for highest sensitivity, chemical separations are usually required. For about 4 years the Food and Drug Administration, utilizing the Naval Research Laboratory reactor, has applied neutron activation to various samples of foods, drugs, and biological materials. Elements such as vanadium, selenium, and mercury have been determined at the nanogram level with little interference from the matrix. Possibly more important than interest in specific element determinations themselves is utilization of the elements or element profiles as indices of required information. Thus, in several forensic applications the authenticity of drugs and food items has been evaluated through the characteristic gamma-ray spectral ”signatures.” Through neutron activation the distribution of mycotoxin contamination in batches of foodstuffs has been simulated to establish homogeneity of sample preparations. This paper presents some earlier examples of the applications of neutron activation analysis which have been made in FDA and summarizes recent work.
Estimations of Vitamin A Biopotency in Liquid Feed Supplements
Authors: Parrish D B , Aguilar Dalia
Published: February 2020

Liquid feed concentrates and supplements were analyzed for total vitamin A content, and relative biopotencies were calculated from maleic values determined on those products. The initial relative biopotencies were from 65 to 97% for concentrates and 57 to 85% for supplements. Even when total vitamin A content decreased, storage up to 47 weeks had relatively small effect on relative biopotencies. A single correction factor could not be applied to relate vitamin A analytical data to vitamin A biopotency. Small quantities of anhydroretinol, vitamin A ether, and other unidentified types of vitamin A were found in several liquid feed products. On some samples spectrophotometric determinations yielded values in the same general range as calculated values based on relative biopotencies, but in a few instances the relationship was poor.
Improved Extraction Technique for the Infrared Spectrophotometry Analysis of Dioxathion, Malathion, and Other Organophosphate Insecticides in Livestock Emulsion Dips
Authors: Czech Fred P , Evans George
Published: February 2020

Certain livestock emulsion dips of dioxathion, malathion, and other organophosphate insecticides are not amenable to complete extraction of active ingredient by previous methods employed in infrared spectrophotometric determination. Evidence is presented which indicates that the major interference is dirt or soil contributed to the emulsion by animals during dipping. An improved extraction technique is presented which obviates this difficulty; it is recommended as a standard substitute in infrared analysis of organophosphate livestock dips.
Determination of Mercury in Biological Materials
Authors: Jeffus M T , Elkins J S , Kenner C T
Published: February 2020

Mercury in biological samples is determined by digestion in nitric acid, sulfuric acid, and permanganate, followed by reduction and aeration for measurement by atomic absorption at room temperature. The average recovery is 95.8% with a standard deviation of 13.3%. The standard deviation, calculated from the difference between duplicates of 23 samples, is 0.063 μg mercury, which represents 9.4% of the average value of the samples. The method is simple and requires approximately 4 hr for completion. Mercury can be confirmed by adsorption on gold foil after maximum absorbance has been obtained during aeration.
Rapid Method for Detection and Identification of Synthetic Water-Soluble Coloring Matters in Foods and Drugs
Authors: Lehmann G , Collet P , Hahn H G , Ashworth M R F
Published: February 2020

A method is described for the rapid detection of coloring matters in foods. In this method, acid dyes from the substrate of foods (starch, pectins, sugars, and gelatin) are dissolved with ammonical alcohol, followed by acidification and adsorption of the dyes from solution onto polyamide powder. Protein-containing foods are treated with acetone to remove fat and water and to coagulate soluble protein. This yields a product which can be used as the filling in a newly designed chromatographic tube; the coloring matters can be eluted with ammoniacal alcohol and the protein remains on the column. Water-soluble forms of natural coloring matters such as chlorophyll, carmine, annatto, alkanna red, betanin, and grape juice red pigment can also be adsorbed on polyamide powder. Basic dyes are adsorbed on carboxymethyl cellulose. Since the coloring matters are eluted at room temperature, they are not expected to undergo irreversible changes during the procedure.
Rapid Screening Test for the Evaluation of Quaternary Ammonium Compounds by Triphenyltetrazolium Chloride Reduction by Microorganisms
Authors: Sitkiewicz Raymond J
Published: February 2020

A rapid screening test has been developed to determine killing dilutions of quaternary ammonium compounds. Two factors, Letheen broth as a quaternary ammonium compound neutralizer and triphenyltetrazolium chloride as a microbial growth indicator, resulted in a rapid test system for the evaluation of quaternary ammonium compounds. This rapid test system takes from 4 to 8 hr to complete as opposed to the 24 to 48 hr for other tests. A new germicide can be bacteriologically screened in one day.
Test to Determine Whether Shucked Oysters Have Been Frozen and Thawed
Authors: Gould Edith , Medler Michael J
Published: February 2020

An objective test is described that will detect whether refrigerated, shucked whole oysters have been frozen and thawed at any time. Latent forms of malic enzyme activity are solubilized by freezing and thawing and can be differentiated from the normally soluble form by their differing rates of electrophoretic migration under the conditions described in this paper. SuperchiUed (23°F) oyster meats showed the same latent malic enzyme activity as the frozen. A sharply discontinuous buffer system during the polyacrylamide gel electrophoresis and a carefully timed incubation period for the histochemical staining are essential to the test. In oyster meats stored at 34°F for up to 3 weeks, neither autolysis nor bacterial action was great enough to produce the enzymogram peculiar to oysters that have been frozen or superchilled and thawed.
Spectrophotofluorodensitometric Measurement of Ochratoxin A in Cereal Products
Authors: Chu Fun Sun , Butz Mary E
Published: February 2020

A spectrophotofluorodensitometric method for measurement of oehratoxin A on TLC plates has been described. The lower limit concentration of this method is 0.5–1.0 ng ochratoxin A/spot. A method including extraction and primary treatment for detection of ochratoxin A in cereal products has also been developed. The adequacy of this method is evident from the different recovery experiments. More than 85% of the added toxin was recovered in most analyses. The overall precision of the measurement was 3–4%. The sensitivity of this method was approximately 10–50 ppb (μg/kg).
Use of Tracheal Organ Cultures for Bioassay of Aflatoxins
Authors: Nair K P C , Colwell W M , Edds G T , Cardeilhac P T
Published: February 2020

Tracheal organ cultures from day-old chicks were used for the assay of aflatoxins. Ciliary epithelium in the organ culture was found to be highly sensitive to aflatoxins B1 and G1. Anatoxin B1, incorporated into the medium in which the organ cultures were established, readily caused distinguishable eytomorphological changes in 48 hr at a concentration of 0.2 μg/ml and complete cessation of ciliary movement at a concentration of 0.5 μg/ml. Anatoxin G1 produced the same effects, but at higher concentrations (0.5 μg/ml and 2.0–2.5μg/ml). The degree of cytomorphological changes of the ciliary epithelium in the organ cultures was proportional to the concentration of aflatoxins and the period of time exposed. A dose-response curve was developed for the period of observation. The technique is simple, reproducible, and inexpensive. The feasibility of developing this test system as a biological assay for the presence of aflatoxins and other mycotoxins in feeds and foodstuffs is being explored.
Determination of Oxygen and Carbon Dioxide in Medicinal Gas Mixtures by Gas-Solid Chromatography
Authors: Langham William S
Published: February 2020

A gas-solid chromatographic method is presented for the analysis of oxygen, oxygenhelium, and oxygen-carbon dioxide mixtures. The method utilizes a 16’ Porapak Q chromatographic column, hydrogen carrier gas, and a thermal conductivity detection system. It is applicable to the analysis of nitrogen, helium, argon, carbon monoxide, and nitrous oxide. Dry Ice conditions are required for the oxygen analysis; carbon dioxide is determined at ambient temperatures. Details for the assembly of a suitable chromatograph and a procedure for sampling gas cylinders are presented. Samples of medicinal gases were analyzed by the proposed method and by the Orsat absorption method. The results by both methods were in good agreement.
Isolation of Shigella from Foods
Authors: Fishbein Morris , Mehlman Ira J , Wentz Barry
Published: February 2020

Experiments based on adverse competitive ratios were undertaken in which minimal numbers of Shigella were inundated with high density competitive populations obtained from natural foods such as ground meat or crabmeat. The effects of oxygen tension and metabolites on Shigella growth were also examined. The limitations of the Shigella detection system were analyzed and defined and an extremely sensitive model for Shigella enumeration was devised for laboratory experimentation. By means of the new system, the study of Shigella recovery under competitive stress will be much simplified. It is recommended that the isolation procedures be studied further to improve their specificity.
6,6′-Oxybis(2-Naphthalenesulfonic Acid) in FD&C Yellow No. 6
Authors: Marmion Daniel M
Published: February 2020

6,6′-Oxybis(2-naphthalenesulfonic acid), DONS, is shown to be present in FD&C Yellow No. 6 by column chromatography and UV spectrophotometry.
Comparison of Some Cleanup Columns for Residue Analysis of Chlorinated and Phosphorus-Containing Pesticides
Authors: Versino B , van der Venne M-TH , Vissers H
Published: February 2020

A comparison is presented of 8 of the most widely used cleanup methods based on adsorption column chromatography for chlorinated and phosphorus-containing compounds and their metabolites. For chlorinated pesticides, all methods show equivalent efficiency and recovery. For phosphorus-containing compounds and metabolites, methods employing columns filled with adsorbent mixtures work better than “all-Florisii” columns.
Estimations of Vitamin A Biopotency in Dry Supplements and Premixes
Authors: Parrish D B , Aguilar Dalia
Published: February 2020

Vitamin A biopotency was estimated on 20 dry vitamin A supplements and premixes from maleic value determinations. Relative bio-potencies of most samples were 90% or higher; only one recently obtained premix and an older supplement were less than 84%. Thus, the data indicate that most of the vitamin A was in the all-trans form. The problem of true vitamin A value for the dry supplements and premixes is of less concern than for the liquid feed supplements analyzed previously, and relative biopotency calculations apparently are not needed on most samples.
Determination of Mercury in Fish by Flameless Atomic Absorption: A Collaborative Study
Authors: Munns R K , Holland D C
Published: February 2020

A collaborative study for the analysis of total mercury in fish is reported. The method is based upon a measurement of the volatilized mercury vapor by flameless atomic absorption. The fish muscle is digested with nitric-sulfuricperchloric acids. The mercury (II) is reduced with stannous chloride-hydroxylamine and then volatilized at room temperature in a stream of air. The air is pumped through a gas cell where the mercury vapor is measured by atomic absorption at 253.7 nm. Nine laboratories participated in the study. An overall mercury recovery of 83.5% and a standard deviation of 0.066 were obtained. Similar samples were analyzed by the official AOAC method. Results were erratic, with an overall mercury recovery of 46% and a range of 0 to 106%.
A Colorimetric Method for the Quantitative Determination of Total Aldehydes in Cold-Pressed Orange and Grapefruit Oils
Authors: Dougherty Marshall H , Petrus Donald R
Published: February 2020

A colorimetric method for the quantitative determination of the aldehyde content of cold-pressed orange and grapefruit oils is described. The method employs N-hydroxybenzenesulfonamide and may be conducted in conjunction with the analyses of citrus essences and juices for total aldehyde content, since the same standards and reagents are used. Data for reproducibility, standard curves, and sample analyses are given and discussed. Equations are given for conversion of results to per cent decanal.
Collaborative Study for the Determination of Nequinate in Feeds
Authors: Cox Phillip L
Published: February 2020

A collaborative study has been conducted on a previously reported method for the determination of nequinate in feeds. The drug is extracted from feed with 1% formic acid in chloroform and measured spectrofluorometrically after dilution with chloroform and the addition of methanesulfonic acid. Eight collaborators participated in the study, analyzing 7 different feeds. The average coefficient of variation for the study was 5.3%. The method is recommended for adoption as official first action.
Collaborative Study of a Gas Chromatographic Method for Ipronidazole in Feeds
Authors: De Ritter Elmer , Osadca Modest
Published: February 2020

A GLC method for ipronidazole in turkey feeds at levels of 0.0033, 0.0066, and 0.0099% was studied by 7 laboratories. Ipronidazole is extracted by shaking with warm 0.2N HCl. An aliquot of the extract is made alkaline and the ipronidazole is extracted with benzene and diluted further for GLC with an electron capture detector. The method is simple, rapid, and free from interference. Agreement between laboratories was very satisfactory; coefficients of variation were 7.1, 3.0, and 8.0%. Recoveries of ipronidazole were 97, 96, and 99%. It is recommended that the method be adopted as official first action and that the study be continued.
A Sensitive Gas Chromatographie Determination of Diethylstilbestrol in Animal Feeds
Authors: Donoho A L , Decker O D , Koester J , Koons J R
Published: February 2020

A GLC method is described for the determination of diethylstilbestrol (DES) in feeds and supplements containing 0.00022-0.0022% DES (2-20 g/ton). A 20 g sample is extracted with an ethanol-chloroform mixture and an aliquot containing 1 or 2 μg DES is taken for assay. The extract is washed with pH 10.5 carbonate buffer and the DES is partitioned into 1N NaOH. After this purification, the DES is reacted in base with dichloroacetyl chloride and the esters formed are simultaneously extracted into chloroform. The DES esters are measured by GLC, using a 5% UC W-98 column and electron affinity detection. Dioctyl tetrachlorophthalate is used as internal standard. The coefficients of variation are on the order of 5% in supplements and 10% in complete feeds.
Confirmation of Organophosphorus Pesticide Residues at Nanogram Levels by Two-Dimensional Thin Layer Chromatography
Authors: Gardner Albert M
Published: February 2020

A new 2-dimensional TLC technique is described in which organophosphorus pesticides are oxidized after 1-dimensional development on silica gel G plates before development in the second direction. This system is more specific as it involves chromatography of both the parent pesticide and the subsequent derivative. Bromine vapor is used for oxidation; horse serum cholinesterase and indoxyl acetate are used for detection. Rf values and minimum detection levels of 26 organophosphorus pesticides are tabulated. Eighteen pesticides are identified at the 0.01 ppm level in fortified crops.
Modification of the Official AOAC Method for Fat Content Determination of Dried Egg Yolk
Authors: Navarro J G , Borie F , Barrientos V , Caiozzi M
Published: February 2020

Fatty acid residues higher in weight and of different composition than those obtained by the official AOAC method, 17.011(b), are obtained when the following 2 changes are made in this method for the determination of fat in dried egg yolk: (1) the replacement of the recommended HCl (4 + 1) solution by HCl (1 + 1) solution and (2) a mild boiling of the sample-HCl mixture for 20 min instead of heating in a boiling water bath for 30 min. Each yolk fat determination was followed by a GLC fatty acid analysis.
Collaborative Study of the Extraction of Light Filth from Crude and Refined Papain
Authors: Brickey Paris M
Published: February 2020

A method for the extraction of light filth from crude and refined papain has been developed. The product is solubilized by boiling in water, followed by wet sieving. Depending upon the amount of residue remaining on the sieve, the product is either transferred directly to filter paper(s) or trapped off in a Wildman trap flask. Collaborative recoveries of spiked insect fragments and rodent hairs were 94 and 92%, respectively. The method has been adopted as official first action.
Collaborative Study of a Method for the Extraction of Light Filth from Ground Chicory
Authors: Thrasher J J
Published: February 2020

Collaborative results are presented on a new method for light filth in ground chicory. A comparison of the new method and the official method, 40.007(b), indicates that recoveries of spiked larvae and adult insects were approximately equal for the 2 methods. However, average recovery of rodent hairs by the proposed method was 86% while rodent hair recovery by the official method was 55%. The new method utilizes detergent digestion and wet sieving followed by flotation with paraffin oil from 40% isopropanol. It is less time consuming to perform and cleaner filter papers are obtained. The new method has been adopted as official first action.
Collaborative Study of a Method for the Recovery of Acid-Insoluble Residues (Soil) in Frozen Spinach and Strawberries
Authors: Winter F H
Published: February 2020

A method is described for determining soil in frozen fruits and vegetables. The frozen contents of the package are transferred to a plastic bag, thawed in warm water, removed, blended, and placed in a 2 L beaker. Water is added, the contents are swirled, and, after 3 decantations of the supernatant, the residue is collected on a filter and ashed. After HCl treatment, the residue is ashed once more and weighed. The method was applied to over 50 samples of spinach and strawberries. The standard deviation between 12 collaborators, who analyzed 4 samples each, varied from 0.0051 for spinach to 0.0087 for strawberries. The method has been adopted as official first action.
Assay of Ipecac and Its Preparations. II. Collaborative Study
Authors: Sharkey Margaret F , Smith Edward , Levine Joseph
Published: February 2020

A method for the determination of 2 major alkaloids in ipecac sirup and powdered ipecac root was subjected to collaborative study. A 4-column chromatographic procedure is used for the isolation of emetine and cephaeline, which are measured individually by UV absorption. Two commercial sirups were employed as samples. The powdered root samples were representative of the different ratios of emetine and cephaeline occurring in the different species. The collaborative results were good: Standard deviations ranged from 0.024 to 0.066 for the powdered samples and from 1.11 to 2.77 for the sirup samples. The methods have been adopted as official first action for determination of emetine and cephaeline in ipecac sirup, powdered root, and fluidextract.
Gas-Liquid Chromatographic Assay for Salicylamide, Acetaminophen, and Caffeine Mixtures, Using On-Line, Computerized Real-Time Data Acquisition
Authors: Alber Larry L , Overton Mack W , Smith Donald E
Published: February 2020

Salicylamide, acetaminophen, and caffeine in drug formulations can be separated and quantitatively measured by GLC. Amobarbital and cyclizine are used as internal standards; the 4’ GLC column contains 3% OV-17 on Gas Chrom Q. The signal from the KCl thermionic detector is amplified and fed directly into the analog-to-digital converter of a PDP 12A LINC System computer. Results by the computer are compared to manual peak height measurements for 6 commercial preparations injected in duplicate and to results obtained from a UV procedure.
Identification of Phenothiazine Derivatives and Analogs by X-Ray Diffraction. I. Examination of Pure Compounds
Authors: De Leenheer A , Heyndrickx A
Published: February 2020

X-ray diffraction data for phenothiazines and chemically related compounds have been obtained by the Debye-Scherrer powder technique with photographic recording. Classification of compounds according to their X-ray data has been made, using the “innermost line index” method. The results obtained serve as reference data with absolute specificity for identification purposes.
Missouri Automated Method for Total Nitrogen in All Fertilizers
Authors: Gehrke Charles W , Wall Larry L , Killingley John S , Inada Kazuyoshi
Published: February 2020

An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed for the analysis of nitrogen in fertilizers. The continuous digestor, which was found to effectively digest organic materials in solution after the reduction step, is coupled with an automated colorimetric system. This colorimetric system employs the ammonia-phenate-hypochlorite reaction. The fertilizer samples are reduced manually via the comprehensive nitrogen method (CNM). The sampling rate chosen is 30 cups/hr (6 reference standards included) which yields an effective analysis rate of 24 samples/hr. The impinger mixer at the exit end of the digestor helix is replaced with a jacketed double-mixing coil and an AO glass fitting for a more stable baseline and improved precision. Manganous ions at a concentration of 5.0 ppm introduced into the color development manifold as a catalyst give a significant increase in sensitivity. When commercial fertilizer samples were analyzed with the automated system, consistently low results were obtained for some samples as compared to results obtained by the AOAC CNM. However, 0.01M potassium sodium tartrate in the color development manifold provides sufficient complexing potential to eliminate the effect of interfering ions. One hundred commercial fertilizer samples including solid, liquid, and suspension fertilizers were analyzed by the Missouri automated nitrogen method. The results agreed well with the results obtained by multiple independent analyses by the AOAC CNM. Details of the automated system, sample preparation, reagent concentrations and preparation, and experimental data are given.
Effect on Eggs of Applications to Poultry of Pesticide Formulations Contaminated with Chlorinated Hydrocarbons
Authors: Thomas Ronald F , Medley Jerry G
Published: February 2020

This study shows the results of intentional contamination of 3 pesticide formulations for application to poultry. Formulations used were 1% rotenone dust with 0.005–0.3% of both DDT and dieldrin contamination, 5% carbaryl dust with 0.01–0.10% of both DDT and dieldrin contamination, and 50% malathion liquid with 0.1–0.3% chlordane contamination. The DDT and dieldrin were added as a mixture. One group of hens was treated with the rotenone dust, one group with the carbaryl dust, and a third group with the 50% malathion liquid. Residues in eggs of both DDT and dieldrin resulted from proper use of rotenone and carbaryl and were increased by doubling the amounts of dust applied to the hens. Chlordane residues, if present, were below detectable levels. Treated hens from each of the 3 groups were artificially inseminated and some eggs were incubated, but no apparent inhibition of hatchability occurred following use of the levels of contamination employed in this study.
Collaborative Study of Modified Elmore Method for Mercury in Formulations
Authors: Launer James E
Published: February 2020

The titrimetric method for mercury described by Elmore in 1946 was modified and collaboratively studied with formulations containing 6.7% phenylmercury urea in one test pair and 1% mercuric nitrate in another test pair. Mercury is determined in diluted solution, following reflux at 30 drops/min with fuming H2SO4-red fuming HNO3, by titration with standard thiocyanate solution, using ferric alum as indicator. The method is not applicable in presence of large quantities of chlorine-bearing materials. Single determinations on 4 samples by 14 collaborators showed that the standard deviation estimation of random error was 0.058 for phenylmercury urea and 0.004 for mercuric nitrate. Standard deviation estimates of systematic error were 0.048 and 0.009, respectively. The method has been adopted as official first action.
Collaborative Study of Gas Chromatographic Method for Determining Captan in Formulations
Authors: Carlstrom A A
Published: February 2020

Captan is extracted from inert substances with a solution containing dieldrin in dioxane. The GLC procedure is stated in performance requirements except to specify XE-60 packing in a glass column. The ratio of captan to HEOD peak heights is measured for the sample and compared to the same ratio calculated for standard captan. Effects of extraction, peak measuring technique, sample size variation, and captan degradation on column and in solution were investigated. Twenty chemists from 18 laboratories quantitatively measured captan content of 6 samples. The coefficient of variation for the 2 technicals was 3.67%, for the two 50% wettable powders, 2.07%, and for the 10% dusts, 5.78%. A significant amount of systematic error was detected. Submitted chromatograms of a standard injection revealed that if captan degraded, as detected by formation of tetrahydrophthalimide, answers were often outliers rejected by the Dixon test. The method has been adopted as official first action and it is recommended that the problem of captan degradation be studied further.
Comparative Efficiency of Two Methods and Two Plating Media for Isolation of Staphylococcus aureus from Foods
Authors: Tardio Joseph L , Baer Edward F
Published: February 2020

Modifications of 2 methods were compared for determination of staphylococci in foods as recommended by the International Committee on Microbiological Specifications for Foods. One method was a direct plating procedure using Baird-Parker (BP) medium. The second method was the current AOAC official first action method for isolation of Staphylococcus aureus from foods (41.018). The efficiency of Vogel and Johnson (VJ) agar and BP as plating media for the AOAC method was also compared. The presence of S. aureus (positive samples) was detected more often by the AOAC method than by the direct plating method. The use of BP as a plating medium in the AOAC method resulted in detection of 25% more positive samples than were detected with VJ agar.
Isolation and Enumeration of Staphylococcus aureus: Review and Recommendations for Revision of AOAC Method
Authors: Baer E F
Published: February 2020

The genesis of the present AOAC official first action method for isolation and enumeration of Staphylococcus is reviewed and information is supplied to support recommendations for revision of the method. It is recommended that the present method be revised by deleting instructions for preparation and use of Vogel and Johnson agar and substituting instructions for preparation and use of Baird-Parker medium. It is also recommended that a direct plating method be provided as an alternative method and that the required collaborative study of the alternative method be conducted. The recommendations have been accepted by the Association.
Comparative Efficiency of Two Enrichment and Four Plating Media for Isolation of Staphylococcus aureus
Authors: Baer E F , Gilden M M , Wienke C L , Mellitz M B
Published: February 2020

The efficiency of 2 enrichment broths and 4 plating media for detecting the presence of Staphylococcus aureus was compared in 109 food samples. Media tested were Trypticase Soy broth containing 10% NaCl (TSBS), the tellurite enrichment broth (TEB) of Giolitti and Cantoni, Vogel and Johnson agar, egg yolk 110 agar, tellurite polymyxin egg yolk agar, and Baird-Parker medium. S. aureus was detected more frequently with combinations of TSBS and the 4 plating media than with TEB combinations. We also found TEB more inconvenient to use than TSBS. The superiority of a single plating medium was not clearly demonstrated. In only 10 of 108 positive samples did one plating medium fail when all others successfully detected S. aureus, and in over 50% of these samples the organism was detected by all plating media tested.
Evaluation of a Rapid Procedure for Determining Organochlorine Insecticides in Raw and Canned Beef and Cheese Fat by Microcoulometric GLC
Authors: Iwata Y , Westlake W E , Gunther F A
Published: February 2020

The ingenious, completely column chromatographic cleanup procedure described by Wood for organochlorine pesticide residues in fats was found to be excellent for sample preparation for GLC analysis by chloride determination using a microcoulometric detector. Fortification studies on corned beef and ground beef fats (0.07–3.90 ppm) and cheese fat (0.02–0.50 ppm) with lindane, dieldrin, p,p′-DDT, and p,p′-DDE indicated recoveries no lower than 60% but generally greater than 80%. Only noninterfering trace amounts of fatty materials remained after the cleanup of 2 g fat samples.
Collaborative CIPAC Study of Titrimetric Methods for the Assay of Methylthio- and Chlorotriazines
Authors: Bosshardt H P , Nowak K , Eberle D O
Published: February 2020

Methylthiotriazines are analyzed by titration with perchloric acid, and chlorotriazines by titration with silver nitrate after condensation with morpholine. Two methylthiotriazines and 3 chlorotriazines—both technical active ingredients and wettable powder formulations—were analyzed by these methods in a CIPAC collaborative study in which 7 laboratories participated. Statistical evaluation of the results shows good reproducibility of assay values within laboratories and satisfactory agreement between laboratories. The titrimetric methods for the assay of triazines have been adopted as provisional CIPAC methods.
Determination of Iodide in Feeds and Plants by Ion-Selective Electrode Analysis
Authors: Hoover William L , Melton James R , Howard Peggy A
Published: February 2020

A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.
Determination of Carotene and Xanthophyll in Alfalfa Protein Concentrates
Authors: Knuckles B E , Witt S C , Miller R E , Bickoff E M
Published: February 2020

Methods for the determination of carotene and xanthophyll in dried protein concentrates prepared during the wet fractionation of alfalfa have been studied. The AOAC method for carotene and xanthophyll in dried forages, 39.018–39.023 (11th Ed.), proved most satisfactory for analysis of the dried whole juice. The modification of a method developed earlier in this laboratory for dried forages proved most effective for analysis of a protein concentrate, high in xanthophyll and carotene, prepared from the whole juice. The modified procedure gave significantly higher values for carotene and xanthophyll in this protein-xanthophyll concentrate than the AOAC method.