bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Chromatographic Determination of CCRL583 Perfluorinated Alcohol Fumigant Residues
Authors: Zehner James M , Simonaitis Richard A
Published: February 2020

A gas chromatographic method is described for the determination of CCRL583 (l,l,l,3,3,4,4,4-octafluoro-2-(trifluoromethyl)-2-butanol). r The sample is extracted with acetonitrile and cleaned up by liquidliquid extraction, first with a basic aqueous solution and finally with an acid aqueous solution. The final organic layer is injected into a gas chromatograph equipped with a column packed with terephthalic acidterminated Carbowax 20M. Recovery of CCRL583 from fortified wheat and peanuts was 91-108%.
Correlation of Analytical Methods and Biological Activity of Various Sulfur-Coated Urea Fertilizer Products
Authors: Mcvey George R , Horn Douglas P , Scheiderer Edwin L , Davidson Allan D
Published: February 2020

Sulfur-coated urea (SCU) has become widely accepted as a fertilizer source for turf and certain other agricultural crops. A means of assessing SCU release characteristics is the Tennessee Valley Authority (TVA) 7-day dissolution rate (DR). The AOAC-accepted method is the waterinsoluble nitrogen (WIN) determination. Data are presented which show that neither of the 2 methods can be considered optimum at predicting biological activity. When testing SCU produced by only one of the 3 coating techniques now used by industry, acceptable correlations were obtained between analytical method and biological activity. However, when testing SCU produced by different coating technologies, the correlation of biological activity with analytical methods was significantly reduced. Based on the results presented here and in the literature, it is recommended that the TVA 7-day DR method not be collaboratively studied. The AOAC WIN method should be maintained until a more suitable method can be developed that has a higher correlation with biological activity.
Liquid Chromatographic Determination of Major Alkaloids in Gum Opium
Authors: Srivastava Vinod K , Maheshwari Mohan L
Published: February 2020

An isocratic reverse phase liquid chromatographic (LC) system has been developed for qualitative and quantitative assay of morphine, codeine, thebaine, papaverine, and narcotine in gum opium. Five extractions with 2.5% aqueous acetic acid quantitatively extracted the major alkaloids. A mixture of 1% aqueous sodium acetate (pH 6.78), acetonitrile, and 1,4-dioxane (75 + 20 + 5) is used as LC mobile phase | for better resolution of alkaloid peaks, especially those of morphine and codeine. The method is suitable for routine analysis of gum opium I samples.
Liquid Chromatographic Determination of Sulfasalazine in Tablets and Bulk Powder
Authors: Egli Keith L
Published: February 2020

A liquid chromatographic method has been developed that determines I the amount of sulfasalazine in tablets and bulk powder in the presence of residual synthesis by-products and excipients. The method was tested j on crude product containing large amounts of impurities. A C-18 1 reverse phase column with water-acetonitrile-acetic acid mobile phase ! was found to effectively separate the drug on the column. Six different commercial samples of 500 mg tablets were assayed. The results varied from 92.6 to 101.8% of the declared amount. Spectrohotometric determinations, which do not discriminate between the drug and impurities, gave 95.4—101.8% of declared. One commercial sample of bulk powder j was assayed.
Capillary Gas Chromatographic Separation of Various Stimulants
Authors: Trivedi Devendra
Published: February 2020

A capillary gas chromatographic (GC) method was developed for the separation of various stimulants of forensic and pharmaceutical interest. The data consist of retention time, relative retention time, corrected retention time, and relative corrected retention time, calculated using ephedrine as reference standard.
Amino Acid Analysis of Feedstuff Hydrolysates by Cation Exchange High Performance
Liquid Chromatography
Authors: Elkin Robert G , Griffith Joseph E
Published: February 2020

Corn, peanut meal, and soybean meal samples were either untreated or oxidized with performic acid before hydrolysis; the amino acids were determined by cation exchange high performance liquid chromatography (LC) and conventional cation exchange LC using an amino acid analyzer (AAA). Reproducibility of each procedure was assessed by repeated injections of the same calibration standard solution over a period of several days. LC data were more precise with regard to coefficients of variation for amino acid retention times, but were more variable with regard to peak areas. Although some significant differences between methods were noted, feedstuff amino acid values obtained by LC and AAA compared very well. The only consistent differences observed within each feedstuff were that Phe and Tyr values were significantly lower when analyzed by LC compared with AAA. Results of this study suggest that modular LC instrumentation can be used to accurately and reproducibly analyze amino acids in feedstuff hydrolysates. Advantages of using ninhydrin derivatization for feedstuff analysis, as opposed to using o-phthalaldehyde or dansyl chloride, are discussed
Liquid Chromatographic Determination of Colchicine in Pharmaceuticals: Collaborative Study
Authors: Thompson Richard D
Published: February 2020

A liquid chromatographic (LC) method for the determination of colchicine in pharmaceutical dosage forms and the bulk drug was evaluated in an interlaboratory study which included 13 participating laboratories. The method involves extraction (or dissolution) of the active ingredient with methanol-water (1 + 1), followed by filtration of the extract and reverse phase LC using an octy lsilane bonded phase column and UV detection at 254 nm. The mobile phase consists of a methanolphosphate buffer mixture (pH = 5.5). Three commercial tablet formulations (0.5-0.6 mg colchicine/tablet), 1 synthetic injectable preparation (0.510 mg colchicine/mL), and 1 bulk drug sample were assayed in duplicate by the proposed method. The reproducibility and repeatability standard deviations based on nonpooled results for each sample ranged from 0.0062 mg/mL to 0.0147 mg/tablet and from 0.0037 mg/ mL to 0.0127 mg/tablet, respectively; the corresponding coefficients of variation ranged from 1.21 to 2.54% and from 0.73 to 2.19%, respectively. The mean recovery from the synthetic injectable formulation was 100.0%. The method has been adopted official first action
Performance Characteristics of Methods of Analysis Used for Regulatory Purposes. I. Drug Dosage Forms. E. Miscellaneous Methods
Authors: Horwitz William , Albert Richard
Published: February 2020

Precision parameters of miscellaneous methods for the analysis of drug dosage forms approved by AOAC since 1972, and not previously reviewed in this series, were recalculated on a consistent statistical basis by using the computer program FDACHEMIST. Seventeen published collaborative studies were reviewed; the studies encompassed 19 analytes in 80 different materials (dosage forms), 102 collaborative assays, approximately 10 laboratories per study, and principally direct spectrophotometric, polarographic, and spectroscopic methods, for a total of 1451 determinations. The average repeatability relative standard deviation (within-laboratories, RSD„) for the instrumental methods was 1.5%; the reproducibility relative standard deviation (among-laboratories, including within-, RSDX) was 2.6%; the ratio RSD„/RSDX of the averages was 0.57, with an average outlier rate of 2.7% of the reported determinations. The line of best fit of RSDX for the instrumental methods plotted against the negative logarithm of the concentration increases slightly with decreasing concentration, extending from an RSDX of approximately 2.0% at 100% concentration to an RSDX of 3.4% at 0.001% (10 ppm) concentration; this represents an RSDX change of approximately 0.3% (absolute) for each 10-fold decrease in concentration, independent of analyte, matrix, and method. A method for determining precipitated allergenic protein by the micro-Kjeldahl technique appeared to be outside this general relation, showing an RSDX of about 13% at a concentration of 0.015% (150 ppm) nitrogen.
Automated Methods for Determination of Fat and Moisture in Meat and Poultry Products: Collaborative Study
Authors: Bostian Marianne L , Fish, David L , Webb Neil B , Arey Judy J
Published: February 2020

A collaborative study was conducted to compare automated methods for rapid determination of fat and moisture in meat and poultry products with the official AOAC solvent extraction and forced-air oven methods, respectively. Fourteen products were tested, with fat and moisture contents ranging from 2 to 43% and 44 to 74%, respectively. Eight of the collaborating laboratories analyzed the products by using a moisture/fat analyzer; 4 laboratories used the AOAC methods. Standard deviations for within-laboratory repeatability, between-laboratory reproducibility, and bias for each product indicated that the rapid methods were acceptable. The moisture/fat analyzer methods have been adopted official first action for fat and moisture analyses in meat and poultry products.
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

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.
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

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

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

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

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

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

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

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

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

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

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

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 > 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Evaluation of Direct Saponification Method for Determination of Cholesterol in Meats
Authors: Adams Mark L , Sullivan Darryl M , Smith Randall L , Richter Earl F
Published: February 2020

A gas chromatographic (GC) method has been developed for determination of cholesterol in meats. The method involves (a) ethanolic KOH saponification of the sample material, (b) homogeneous-phase toluene extraction of the unsaponifiables, (c) derivatization of cholesterol to its trimethylsilylether, and (d) quantitation by GC-flame ionization detection using 5-α-cholestane as internal standard. This direct saponification method is compared with the current AOAC official method for determination of cholesterol in 20 different meat products. The direct saponification method eliminates the need for initial lipid extraction, thus offering a 30% savings in labor, and requires fewer solvents than the AOAC method. It produced comparable or slightly higher cholesterol results than the AOAC method in all meat samples examined. Precision, determined by assaying a turkey meat sample 16 times over 4 days, was excellent (CV = 1.74%). Average recovery of cholesterol added to meat samples was 99.8%.
Determination of Trace Elements in Foods by HCl-HNO3 Leaching and Flame Atomic Absorption Spectroscopy
Authors: Puchyr Richard F , Shapiro Rubin
Published: February 2020

Aluminum, iron, tin, zinc, calcium, magnesium, nickel, copper, chromium, cadmium, and potassium in foods can be extracted by HC1- HN03 leaching and determined quantitatively using flame atomic absorption spectroscopy (AAS), with recoveries ranging from 90 to 110%. Thirty to 40 samples of almost any type of food sample can be analyzed routinely for 2 elements in 4-5 h. In contrast, one or 2 days are required when a wet-ash or dry-ash technique is used. Extraction consists of weighing 2-10 g samples into 125 mL Erlenmeyer flasks, adding 20 mL concentrated HCI-HNO3 (9 + 1), then heating in a 82- 93°C water bath for 30 min. After cooling, samples are diluted to volume in 50 mL Nessler tubes and then filtered through No. 541 or 540 Whatman paper. The filtrate is analyzed directly by AAS.
Determination of Nivalenol and Deoxynivalenol in Cereals by Electron-Capture Gas Chromatography
Authors: Scott Peter M , Kanhere Shriniwas R , Tarter Edward J
Published: February 2020

Nivalenol (NIV) is an important Fusarium mycotoxin shown to occur naturally in grains from several countries. Extraction and cleanup procedures previously described for trichothecene analysis have been modified to give good recoveries of NIV from cereal products. The extraction solvent is methanol-water (7 + 3). The extract is treated with 10% aqueous ammonium sulfate solution and then a 10 mL aliquot is partitioned into ethyl acetate (160 mL) on a hydrophilic matrix. After evaporation, the sample extract is dissolved in methylene chloridemethanol (3 +1) for column chromatography on silica gel 60. The toxins are eluted with methylene chloride-methanol (9 + 1) following column washes with toluene and n-hexane. NIV and deoxynivalenol (DON) trimethylsilyl ethers are formed with Tri-Sil TBT and determined by gas chromatography on a 3% OV-3 packed column or DB-5 capillary column with electron-capture detection. The method has been evaluated for wheat, wheat flour, corn flour, rye flour, and barley. Recoveries averaged 89% for NTV and 106% for DON from ground cerealsand flours at a spiking level of 1 μ/g; 72% and 82%, respectively, from wheat spiked at 0.5 μ/g; and 90% and 100%, respectively, from cereals spiked at 0.2 μ/g. Heptafluorobutj rates are used for confirmation of identity; the problem of 2 derivative peaks forming with NTV on the OV-3 packed column has been overcome by using an SPB-5 or DB-5 capillary column which gave single peaks.
Instability of Some TWchothecenes in Methanol
Authors: Wei Ru-Dong , Chu Fun S
Published: February 2020

Stability of 8 trichothecenes stored in methanol at room temperature was studied by thin layer chromatography. Results indicate that the trichothecenes which bear an acetoxy group at both C3 and C4 are very susceptible to methanolysis. In the early stage, the acetoxy group at C3 is most favorable for the transesterification. All trichothecenes tested were transformed to several products after prolonged (22 days) exposure to methanol.
Rapid Analysis of Xanthophyll and Carotene in Dried Plant Materials
Authors: Livingston A Lyle
Published: February 2020

An alternative method using minimal equipment has been developed for the rapid analysis of xanthophyll and carotene in dried plant materials and mixed feeds. The method includes an ambient temperature stirring technique that may be substituted for hot extraction and saponification, thereby avoiding possible losses due to oxidation and heat isomerization. The method permits rapid analysis of xanthophyll and carotene in pigment sources including alfalfa protein concentrates, corn gluten meal, marigold concentrates, whole corn and mixed feeds containing these ingredients. The results are compared with those obtained by the official AOAC method (43.018-43.023) for xanthophyll and carotene in these ingredients. The alternative method gave the same analyses (P ≤ 0.01) for xanthophyll in alfalfa protein concentrates, marigold, whole corn, corn gluten, and mixed feeds
Titrimetric Assay of Pancreatic Lipase in Pharmaceutical Preparations
Authors: Lecat Daniel , Letavernier Jean-Francois , Bourquin Thierry , Soroste Michele , Vaucher Daniel
Published: February 2020

Lyophilized pancreas and pancreatic extracts are widely used in therapy of pancreatic exocrine function deficiencies. Among the measures for quality of the extracts, assay for lipolytic activity appears to be one of the best. However, assay precision is poor, because the specificity and mode of action of lipase requires careful optimization of the assay parameters, especially substrate and measurement conditions. In the method proposed here, substrate quality is improved by the use of sodium desoxycholate and a high-speed stirrer for more reproducible emulsions. Fatty acids are assayed by a titrimetric method, using an electronically monitored pH meter. A comparative statistical study of the U.S. Pharmacopeia method, the International Pharmaceutical Federation (FIP) method, and a modified FIP method showed the latter to have improved accuracy and reproducibility.
Liquid Chromatographic Determination of Amprolium in Chicken Tissues, Using Post-Column Reaction and Fluorometric Detection
Authors: Nagata Tomoko , Saeki Masanobu
Published: February 2020

A method is presented for determination of amprolium residues in chicken muscles by a liquid chromatographic post-column reaction system. The drug is extracted from muscles with methanol, and the extract is concentrated to 3-4 mL. This aqueous solution is rinsed with n-hexane and cleaned up by alumina column chromatography. The drug is separated from the interferences on a LiChrosorb RP-8 column, reacted with ferricyanide in alkaline solution, and quantitated by fluorometric detection at 367 nm (excitation) and 470 nm (emission). Recoveries of amprolium added to chicken muscles at levels of 0.1 and 0.2 ppm were 74.9 and 80.9%, respectively. The detection limit was 1 ng for amprolium standard and 0.01 ppm in chicken muscles.
Improved Procedure for Determining Water Activity in a High Range
Authors: Flom Walter D , Tanaka Nobumasa , Kovats Susan K , Finn Lynda M
Published: February 2020

A procedure for accurate determination of water activity (aw) in a high range (aw between 0.920 and 0.970) using a Beckman Hygroline apparatus was devised because the prescribed calibration procedure was inadequate. This new procedure uses NaCl solutions as standards and the aw values for NaCl solutions reported by Robinson as the reference scale. A quadratic calibration curve:

Recorder reading = b0 + b1aw + b2aw2

was established for each sensor. A 3-point calibration scheme, taking measurements of 0.9m (molal), 1.6m, and 2.4m NaCl solutions, was used before and after a series of aw measurements of samples to estimate b0 and verify the constancy of shape of the calibration curve. The equation was solved for aw to convert each recorder reading to an aw value on Robinson’s scale. This procedure yielded precision and accuracy levels for a single determination of 0.0009 and 0.0013 aw unit, respectively. Accuracy of 0.0009 aw unit was obtained by averaging 2 determinations on different sensors.
Liquid Chromatographic Determination of Ochratoxin A in Coffee Beans and Coffee Products
Authors: Terada Hisaya , Tsubouchi Haruo , Yamamoto Katsuhiko , Hisada Kazuo , Sakabe Yoshio
Published: February 2020

A liquid chromatographic method for the determination of ochratoxin A in coffee beans (green and roast), instant coffee, and coffee drink is described. The sample is subjected to extraction with methanol-1% aqueous sodium bicarbonate (1 + 1) and C18 cartridge cleanup. The extract is chromatographed on a Nucleosil 5C18 column with a mobile solvent of acetonitrile-water-0.2M phosphate buffer pH 7.5 (50 + 47 + 3) containing 3mM cetyltrimethylammonium bromide as an ionpair reagent. Ochratoxin A is detected with a fluoromcter (excitation 365 nm, emission 450 nm). The sensitivity was increased 20-fold by using ion-pair resolution. The detection limits corresponded to 2 μg/kg for coffee beans, 5 μg/kg for instant coffee, and 0.2 μg/kg for coffee drink. The recoveries from coffee products were generally better than 80.7% and the relative standard deviations were 3.43-5.93%. The peak coinciding with ochratoxin A can be confirmed by treatment using alcohol (methanol, ethanol, or n-propanol) and H2S04.
Simultaneous Gas Chromatographic Determination of Dibutyltin and IHbutyltin Compounds in Biological and Sediment Samples
Authors: Tsuda Taizo , Nakanishi Hiroshi , Morita Takashi , Takebayashi Junko
Published: February 2020

A method is described for the simultaneous determination of nanogram amounts of dibutyltin and tributyltin compounds in biological and sediment samples. These compounds are converted to the corresponding chlorides with HC1, extracted with ethyl acetate-hexane (3 + 2) for biological samples and with hexane for sediment samples, and hydrogenated with sodium borohydride. The corresponding hydrides, Bu2SnH2 and Bu3SnH, are detected by electron-capture gas chromatography after cleanup by silica gel column chromatography. Detection limits are 1.0-2.0 and 0.5-1.0 ng/g, respectively, for biological and sediment samples.
Purge and Trap Method for Determination of Fumigants in Whole Grains, Milled Grain Products, and Intermediate Grain-Based Foods
Authors: Heikes David L , Hopper Marvin L
Published: February 2020

A method developed for the determination of 1,2-dibromoethane in whole grains and grain-based products has been modified and expanded to include 8 other fumigants. Samples are stirred with water and purged with nitrogen for 0.5 h in a water bath at 100°C. The fumigants are collected on a trap composed of Tenax TA and XAD-4 resin, eluted with hexane, and determined by gas chromatography (GC) using electron capture detection or Hall electrolytic conductivity detection. Flame photometric detection in the sulfur mode is used to determine carbon disulfide. Thick-film, wide-bore capillary columns were used exclusively in both the determination and confirmation of the halogenated fumigants. The higher levels of fumigants are also confirmed by full scan GC/mass spectrometry. Samples are analyzed for carbon disulfide, methylene chloride, chloroform, 1,2-dichIoroethane, methyl chloroform, carbon tetrachloride, trichloroethylene, 1,2-dibromoethane, and tetrachloroethylene. A total of 25 whole grains, milled grain products, and intermediate grain-based foods analyzed by this method contained fumigant levels up to 51 ppm (carbon tetrachloride in wheat). Recoveries from fortified samples ranged from 82 to 104%. Chromatograms from this purge and trap method are clean, so that low parts per billion and sub-parts per billion levels can be quantitated for the halogenated analytes. The quantitation level for carbon disulfide is 12 ppb.
Measurement of Trace Levels of Total Aluminum in Foods by Atomic Absorption Spectrophotometry
Authors: Sullivan Darryl M , Kehoe Daniel F , Smith Randall L
Published: February 2020

A graphite furnace atomic absorption spectrophotometry method was used to determine the total aluminum content of various foods found in an average American diet. The food products were ashed in platinum dishes, and the inorganic residue was fused using a sodium carbonate-sodium borate mixture. The fusion step allowed detection of all the various forms of aluminum found in food products. A L'vov platform was used in the graphite furnace to increase the sensitivity of the assay. Care was taken throughout the analysis to avoid various sources of aluminum contamination such as glass and porcelain dishes. All reagents were ultra-pure grade and were continuously monitored for aluminum content. Sodium borate used in the fusion flux mixture had previously been extracted with 8-hydroxyquinoline in chloroform to remove any aluminum present. Both raw and cooked foods were analyzed for aluminum with this method. Average recoveries of aluminum from food products ranged from 84 to 112%. The overall coefficient of variation of this method on the food products tested was 10%.