bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Detection of Clostridium perfringens: Comparison of Lactose Sulfite Broth with Tryptose-
Sulfite-Cycloserine Agar
Authors: Neut Christel , Pathak Jayant , Romond Charles , Beerens Henri 
Published: February 2020

Abstract
The lactose sulfite (LS) medium recommended for the detection and identification of Clostridium perfringens in foods was compared with a reference method using tryptose-sulfite-cycloserine (TSC) agar for the enumeration of this organism in a variety of foods and food ingredients. C. perfringens was detected and enumerated in 17 of the 54 samples examined with LS broth, but its presence could be confirmed in only 9 of the samples with TSC agar. In only 2 instances, C. perfringens was detected on TSC agar but not in LS broth. A positive response (FeS + and gas +) in LS broth incubated at 46°C always corresponded to the presence of C. perfringens; whereas the black colonies formed on TSC agar incubated at 37°C were frequently found to be Clostridium species other than C. perfringens. Thus, because of its highly selective nature, LS broth was superior to TSC agar for enumerating and confirming the small numbers of C. perfringens that were present in a majority of the samples. This was especially true when other Clostridia were also present. Besides its greater selectivity and sensitivity, LS broth had the additional advantages of requiring less work and giving confirmed results within 24-48 h compared with 3 days for the TSC agar method
Review of Chromatographic Methods for Chloramphenicol Residues in Milk, Eggs, and Tissues from Food-Producing Animals
Authors: Allen Edward H 
Published: February 2020

Abstract
Although chloramphenicol is not approved for use in food-producing animals in the United States, this broad spectrum antibiotic has been widely used to treat dieases in such animals including the lactating dairy cow. Extremely low ophthalmologic doses of chloramphenicol are known to cause aplastic anemia in humans. The residues in meat, milk, and eggs intended for human consumption cause particular public health concern because the bone marrow aplasia is not dose dependent. Furthermore, chloramphenicol, a known inhibitor of protein synthesis, also retards erythropoiesis, a condition that is dose dependent and may cause allergic hypersensitivity reactions. This paper is a review of sensitive methods that use gas, liquid, thin layer, and simple column chromatography as both determinative and cleanup steps for detecting and quantitating chloramphenicol in edible animal tissues, milk, and eggs.
Chemical Contaminants in Foods: Some Analytical Considerations
Authors: Burke Jerry A 
Published: February 2020

Abstract
Data on the incidence and levels of chemical contaminants in foods are needed for continuous assessment of the safety of the food supply and to inform the public about the safety of food. A larger share of the total analytical resource—federal and state government, private sector, and academia—could profitably be directed to collection and publication of data on the occurrence of chemical contaminants in foods. The quest for more data must be accompanied by measures to ensure data reliability and comparability and to estimate the uncertainty of measurements. Research to improve the efficiency of analysis may be the top priority for future methods improvement studies. Analytical chemistry will continue to be an essential factor in assuring a safe food supply and in communicating to the public accurate information and conclusions about food safety.
Gas Chromatographic Relative Retention Data for Pesticides on Nine Packed Columns: I. Organophosphorus Pesticides, Using Flame Photometric Detection
Authors: Prinsloo Susan M , De Beer Pieter R 
Published: February 2020

Abstract
The retention time relative to parathion, absolute retention time, concentration range, peak asymmetry factor, and peak shape class are given for each of 50 organophosphorus pesticides analyzed by gas chromatography (GC) on 9 different packed columns. The packing materials used were 3% SP-2100, 1% Dexsil-300, 3% OV-17, 1.5% OV-17 + 1.95% QF-1, 4% SE-30 + 6% QF-1,3% OV-17 + 3% OV- 210, 5% DC-200 + 7.5% QF-1,3% Carbowax 20M, and 4% Reoplex- 400. Retention data were determined at 200°C with a carrier gas flow at uopt, using a flame photometric detector. The results should be useful for choosing the most suitable column for single or multiple pesticide residue analysis.
Disposable Cartridge Extraction of Retinol and α-Tocopherol from Feedstuffs
Authors: Bourgeois Claude F , Hel Sylvie H , Belliot Jean-Pierre , George Philippe R , Slomianny Catherine A 
Published: February 2020

Abstract
Automated determination of fat-soluble vitamins by modern methods such as liquid chromatography is hampered by the initial extraction step. A simple technique is proposed that allows an appreciable increase in the actual rates of determination. Feedstuff samples are first hydrolyzed in an aqueous alcohol (mainly methanol)-potassium hydroxide solution. Instead of extracting retinol and a-tocopherol from the hydrolysis solution by an organic solvent, an aliquot of the solution is mixed with a small volume of a strong antioxidant solution (ascorbic acid) and pipetted onto a kieselguhr disposable cartridge where it is adsorbed. Retinol and a-tocopherol are eluted with isooctane at normal pressure. The proposed method has been compared with conventional techniques on many feed samples.
Liquid Chromatographic Determination of Strychnine in Stomach Contents
Authors: Hoogenboom Jacobus J L , Rammell Colin G 
Published: February 2020

Abstract
A chloroform extract of stomach contents at basic pH is concentrated and then extracted with 0.1M phosphoric acid. The acid extract is chromatographed on a 10 cm reverse phase column, using 0.005M phosphate buffer (pH 3.0)-acetonitrile-tetrahydrofuran (750 + 135 + 115) containing 0.01M octanesulfonic acid at a flow rate of 1.0 raL/ min for elution. Strychnine eluted in 7.3 min. Recoveries from spiked stomach contents averaged 92%. The method can be used without modification for other alkaloids.
Liquid Chromatographic and Gas Chromatographic Determination of N-Nitrosodiethanolamine in 2,4-D Diethanolamine Pesticide Formulations
Authors: Wigfield Yuk Y , Lanouette Monique 
Published: February 2020

Abstract
A method for the determination of N-nitrosodiethanolamine (NDE1A) in diethanolamine formulations of 2,4-D herbicide has been developed. The NDE1A fraction was isolated from the formulation by 2 disposable ion exchange columns followed by an extraction column to remove the acid and amine that might be deleterious to the analytical system and to concentrate the NDE1A solution. The isolated fraction was then further purified on a silica gel disposable column and analyzed for NDE1A by using a liquid chromatographic (LC) apparatus connected to an ultraviolet (UV) detector in series with a thermal energy analyzer (TEA) detector. NDE1A was derivatized to the trimethylsilyl (TMS) derivative, the identity of which was confirmed by gas chromatography- mass spectrometry (GC-MS) and analyzed by gas chromatography with TEA detection (GC-TEA). The limit of detection of NDE1A by LC-TEA and LC-UV is 1 ng and by GC-TEA 0.08 ng. These values correspond to 0.1 ppm relative to the active ingredient in the formulation. The recoveries for this analytical method averaged from 91 to 100% when the samples were spiked at the 0.30-3.47 ppm level. The specificity and reproducibility of these 3 methods of determination were compared; results suggest that NDE1A was not generated during cleanup or in the GC injection port.
Synthesis, Identification, and Acute Toxicity of α-Benzylphenethylamine and α-Benzyl-N-Methylphenethylamine. Contaminants in Clandestine Preparation of Amphetamine and Methamphetamine
Authors: Noggle F Taylor , Clark C Randall , Davenport Timothy W , Coker Samuel T 
Published: February 2020

Abstract
Amphetamine samples obtained from clandestine laboratories often contain other by-product amines. The most common of these are the α-benzylphenethylamine derivatives. This article reports the independent synthesis of reference samples of these amines, spectrophotometric and chromatographic methods for their identification, as well as acute toxicological studies. The utility of the analytical methods is demonstrated by the analysis of several amphetamine samples containing these α-benzylphenethylamines.
Determination of Fat in Vegetable Foods
Authors: Rosenthal Ionel , Merin Uzi , Popel Gita , Bernstein Solange 
Published: February 2020

Abstract
The fat in vegetable foods—tree nuts, peanuts, sunflower seeds, avocado, and olives—can be determined volumetrically by acid digestion of the material and separation of the fat. The assay can be performed conveniently by using the equipment developed for fat determination of milk (Gerber method). The results agree well with those obtained by Soxhlet extraction. The advantages of using the Gerber method for vegetable foods are simplicity, speed, low operation cost, and elimination of the use of inflammable solvents.
Photodegradation of Sulfa Drugs by Fluorescent Light
Authors: Parks Owen W 
Published: February 2020

Abstract
Thin layer chromatographic and liquid chromatographic procedures were used to show that sulfonamides containing a heterocyclic amine moiety and free N1 acidic hydrogen will photodegrade under fluorescent light in model systems containing riboflavin. The photodegradation product was characteristic of the drug. In-depth studies on sulfamethazine showed that the drug also photodegraded in the presence of lumichrome and flavin mononucleotide; the rate of photodegradation depended on the photosensitizer and its concentration. Crude polar liver extracts sensitized the photodegradation of sulfamethazine, but to a degree less than expected on the basis of reported riboflavin content of livers. It is recommended that procedures for quantitating sulfa drugs and their metabolites be performed in subdued lighting and/or that amber or low actinic vessels be used to prevent losses due to photochemical reactions.
Determination of Ditalimfos by Liquid Chromatography
Authors: Lesser Joseph H , Massil Solomon E , Ezra Itshak 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for the determination of ditalimfos, 0,0-diethyI phthalimidophosphonothioate, is described. Bonded phase high precision LC using a mixture of n-hexane and chloroform as eluant afforded a capacity factor (k') of 2.3 for the analyte. Ditalimfos could be detected at 0.5 ppm (signal to noise ratio &gt; 3) using ultraviolet detection at 254 nm. The detector afforded a linear response from 0.2 to 10.9 mg/mL when 10 μL of solution was injected and the coefficient of variation was ±0.5%. Structurally related fungicides and several common insecticides were successfully separated from the analyte under the chromatographic conditions of analysis.
Pesticides, Selected Elements, and Other Chemicals in Adult Total Diet Samples, October 1980-March 1982
Authors: Gartrell Marcia J , Craun John C , Podrebarac David S , Gunderson Ellis L 
Published: February 2020

Abstract
The U.S. Food and Drug Administration (FDA) conducts Total Diet Studies to determine the dietary intake of selected pesticides, industrial chemicals, and elements (including radionuclides). These studies involve the retail purchase and analysis of foods representative of the diets of infants, toddlers, and adults. The individual food items are separated into a number of food groups, each of which is analyzed as a composite. This report summarizes the results for adult Total Diet samples collected in 27 cities between October 1980 and March 1982. The average concentrations, range of concentrations, and calculated average daily intake of each chemical found are presented by food group. The average daily intakes of the chemicals are similar to those found in the several preceding years and are within acceptable limits. The results for samples collected during the same period that represent the diets of infants and toddlers are reported separately.
Evaluation of an Improved MPN Medium for Recovery of Stressed and Nonstressed Staphylococcus aureus
Authors: Lancette Gayle A , Peeler J T , Lanier John M 
Published: February 2020

Abstract
Two media used for recovery of foodborne Staphylococcus aureus were compared: trypticase soy broth with 10% salt (TSBS), used in the official AOAC method, and TSBS with 1% sodium pyruvate added (PTSB). Adding pyruvate increased recovery of 4 heat-stressed and nonstressed S. aureus foodborne strains from artificially contaminated mashed potato and ham salad substrates. The overall geometric means for the 2 media differed significantly at the α = 0.05 level. Recovery of S. aureus from 70 replicates of naturally contaminated Monterey Jack cheese was highest in PTSB. The overall geometric means/g were 63 in TSBS and 96 in PTSB.
Determination of Ethylene Dibromide in Foods and Grains by High Resolution Capillary Gas Chromatography with Electron Capture Detection
Authors: Konishi Yoshimasa , Yoshida Seisaku , Nakamura Akio 
Published: February 2020

Abstract
Ethylene dibromide (EDB) levels in food samples were determined by gas chromatography with a high-resolution capillary column and electron capture detector. The capillary column used was 3 mm id × 25 m cross-linked 5% phenylmethyl silicone. Column temperature was set at 40°C by a coolant containing carbon dioxide gas. Optimum temperatures of the injection port and detector were 200 and 350°C, respectively. The detection limit was 0.5 ppb and linear from 1 to 20 pg on the dynamic range. EDB residues in food samples were extracted with n-hexane by steam distillation. A few impurity peaks appeared near EDB on the chromatogram; however, the EDB peak was resolved. Recoveries of EDB from wheat and brown rice ranged from 66.1 to 99.6%. EDB was detected in 3 samples of imported wheat at a range of 0.74-1.70 ppb, and was not detected at all in 37 samples. The EDB remaining in EDB-fortified cookies after baking was examined. The amounts of EDB were reduced to 30 to 50% of the original amounts by kneading the dough, and to below 1.5% by baking.
Simplified Automated Procedure for Measurement of Certain Catecholamine Drugs Delivered from Aerosol Inhalation Units
Authors: Lukovits Frank S , Dombrowski Lawrence J 
Published: February 2020

Abstract
An automated colorimetric method is described for the measurement of certain catecholamine drugs, such as isoproterenol and epinephrine, in sample solutions derived from 2 metered doses delivered from the mouthpiece of aerosol inhalation units. The procedure, applicable to the expressed product, involves oxidizing the catecholamine with potassium ferricyanide at pH 6 to produce an aminochrome. This method is similar to the well known trihydroxyindole reaction procedure but differs in that the formed aminochrome is measured spectrophotometrically at 495 nm instead of being further derivatized by alkaline rearrangement to the trihydroxyindole species followed by either spectrophotometric or fluorometric measurement.
Role of Collaborative and Cooperative Studies in Evaluation of Analytical Methods
Authors: Taylor John K 
Published: February 2020

Abstract
A method proposed as a standard or for use in a regulatory process must be reliable and its typical performance characteristics should be stated and verified. Collaborative testing is the most acceptable way to accomplish the latter but its function should not be misunderstood. Such testing can verify performance characteristics and experimentally demonstrate that the methodology can be used successfully by a representative group of laboratories. It does not necessarily support the validity of any data obtained using the method because this may depend on many other factors including the expertise of the laboratory and the quality assurance aspects of its measurement process.
A Statistician’s Approach to Repeatability and Reproducibility
Authors: Hamaker H C 
Published: February 2020

Abstract
Repeatability and reproducibility are 2 concepts jointly describing the precision of tests performed according to some standard test method. The statistical principles underlying these concepts are explained in Fart I. In Part II, these principles are applied to the design, statistical analysis, and interpretation of collaborative, or interlaboratory, studies especially organized for finding numerical estimates, sr and sR, of the repeatability and reproducibility standard deviations, σr and σR.
Enzyme Immunoassay-Based Survey of Prevalence of Gentamicin in Serum of Marketed Swine
Authors: Berkowitz David B , Webert Donald W 
Published: February 2020

Abstract
Sera from 3182 swine from a national sampling were tested in the gentamicin enzyme immunoassay. Of the sera tested, 6 (0.19%) contained gentamicin. Only 1 serum may have been associated with muscle levels above the tolerance. During the survey, a single analyst processed 300 samples daily. The immunoassay survey was an effective and economical method of obtaining information on the prevalence of a residue.
Gas Chromatographic Determination of Fatty Acids and Sterols in Orange Juice
Authors: Stack Jeanette B , Joe Frank L , Cunningham David G , Fazio Thomas , Roach John A G 
Published: February 2020

Abstract
A gas chromatographic (GC) method has been developed for the simultaneous quantitation of fatty acids and sterols in orange juice, using a bonded phase fused silica capillary column of intermediate polarity, splitless automatic injection, and flame ionization detection. Sample preparation has been simplified by using 1 g C-18 adsorbent in a disposable minicolumn to extract 2 mL orange juice. Methylation of fatty acids and silylation of the sterols were carried out in the eluted extract (low polarity lipid fraction). The method precision was 7%; recoveries ranged from 83 to 113%. The precision of the injection technique was 2%. Seven major fatty acids and 5 sterols in orange juice were quantitated by the GC method and identified by GC/mass spectrometry. Quantitative data for several orange juice samples indicated that the levels of the compounds of interest were in the 1.3-72.0 mg/L range. The results demonstrate that bonded phase fused silica capillary GC has great versatility and potential for the quantitative determination of fatty acids and sterols.
Inconsistent Differences Between Neutral Detergent Fiber and Total Dietary Fiber Values of Fruits and Vegetables
Authors: Visser Frans R , Gurnsey Catherine 
Published: February 2020

Abstract
A large number of fruits and vegetables were analyzed to determine levels of neutral detergent fiber (NDF) and total dietary fiber (TDF). The results showed that the TDF method is more precise than the NDF method. Further, the NDF values are significantly higher than the TDF values for apples and for miscellaneous fruits and vegetables, and significantly lower for stonefruit. For berryfruit, the differences between the NDF and TDF data are not significant. Also, a significant interaction between sample and method (except for berryfruit) indicated that, within groups, the (TDF-NDF) values vary so much that a “group difference” does not exist; consequently, figures from one method cannot be estimated from results of the other.
Simultaneous Analysis of Grain and Grain-Based Products for Ethylene Dibromide, Carbon Tetrachloride, and Ethylene Dichloride
Authors: Alleman Thomas G , Sanders Robert A , Madison Bryan L 
Published: February 2020

Abstract
A method is described for the simultaneous measurement of parts per billion levels of the fumigants ethylene dibromide, carbon tetrachloride, and ethylene dichloride in grain and grain-based products. The fumigants are isolated by hexane co-distillation, separated by capillary gas chromatography, and detected with a mass spectrometer in the selected ion monitoring mode. Recoveries are greater than 90% and standard deviations are approximately 10% of the quantity measured. The method is free of interferences and its precision and accuracy are enhanced by the use of tetradeuterated ethylene dibromide and ethylene dichloride as internal standards.
One-Step Extraction and Cleanup Procedure for Determination of p,p'-DDT, p,p'-DDD, and p,p'-DDE in Fish
Authors: Ahmad Nazir , Marolt Robert Slobodan 
Published: February 2020

Abstract
A simplified method that combines extraction, partitioning, and cleanup in a single step for measuring p,p'-DDT and its metabolites in fish is described. Minced fish samples are emulsified with disodium hydrogen orthophosphate and trisodium citrate, ground with sodium sulfate, and eluted from a chromatographic column prepacked with alumina and silicic acid. The fats and fatty acids are solubilized and easily extracted from the tissues and retained by the column, while p,p'-DDT and its metabolites are quantitatively eluted with 40 mL n-hexane. The eluate is directly applied to a gas chromatographic column. Average recoveries of p,p'-DDT and its metabolites added to fish in vitro are 81%. The average coefficient of variation for recoveries of p,p'-DDT and its metabolites is less than 6.5% and the detection limit is 0.001 Hg/g for p,p'-DDE, thus making this method very suitable for residue analysis.
Second Derivative Spectrophotometric Determination of Acetaminophen and Phenacetin in Presence of Their Degradation Products
Authors: Korany Mohamed A , Bedair Mona , Mahgoub Hoda , Elsayed Mahmoud A 
Published: February 2020

Abstract
A rapid and accurate method for determining acetaminophen and phenacetin in presence of their degradation products is presented. Solutions of these drugs in 0.1N HC1 were analyzed by measuring their second derivative spectral response at 295 nm where the degradation products do not interfere. The mean percent recoveries for mixtures of acetaminophen and/or phenacetin with the corresponding degradation products were 100.2 ± 0.6 and 100.6 ± 1.1, respectively. The method can be used for assessing the stability of the 2 drugs. The proposed method is also applied to the determination of acetaminophen in tablets and syrups.
Thin Layer Chromatography and Densitometric Determination of Aflatoxins in Mixed Feeds Containing Citrus Pulp
Authors: Pennington Linda J 
Published: February 2020

Abstract
A method for the accurate one-dimensional thin layer chromatographic (TLC) determination of aflatoxins B1, B2, G1, and G2 in mixed feeds is presented. The aflatoxins are extracted from the sample with chloroform and purified by solvent partitioning. Each aflatoxin is separated from pulp interference by thin layer chromatography on aluminumbacked silica plates. The separated aflatoxins are detected by fluorescence densitometry. Average recoveries for samples spiked from 10 to 100 ppb B1 and G1 and from 3 to 30 ppb B2 and G2 are 82, 84, 95, and 94% for B1, B2, G1, and G2, respectively. The above recovery data, when analyzed for overall method repeatability, produced relative standard deviations of 6.8, 4.3, 6.9, and 7.6% for B1, B2, G1, and G2, respectively. Minimum detection level is less than 1 ppb for each aflatoxin. B1 is confirmed by trifluoroacetic acid derivative formation on a silica TLC plate
Use of Small Charcoal/Alumina Cleanup Columns in Determination of Trichothecene Mycotoxins in Foods and Feeds
Authors: Romer Thomas R 
Published: February 2020

Abstract
Small charcoal/alumina cleanup columns have been effectively used to remove interfering materials from grain, feed, and food extracts prior to chromatographic determination of trichothecene mycotoxins. A thin layer chromatographic method has been developed that can simultaneously detect part per billion concentrations of deoxynivalenol, fusarenon X, nivalenol, T-2 toxin, HT-2 toxin, neosolaniol, and diacetoxyscirpenol in food and feed samples. Recoveries of 90-99% can be obtained. The use of charcoal/alumina cleanup columns in conjunction with liquid chromatography and gas chromatography of trichothecenes is also discussed.