bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Chromatographic Determination of Protein Acid Hydrolysate Content in Blended Soy Sauce
Authors: Yeh-Chen Shih-Ling , Hsu Chin-Tan
Published: February 2020

Five methods were investigated for the determination of levulinic acid in soy sauce to determine the addition of protein hydrolysate, mainly acid hydrolysate of defatted soybeans. Best results were obtained by using liquid chromatography (LC) with 0.004M HC104 as the mobile phase and bromcresol purple as a post-column reagent. An innovative LC method with 0.1% H3PO4 as eluant was developed for determination of levulinic acid at 280 nm in soy sauce. This was the most timesaving method.
Volatile Oil Analysis Of Cassia Bark (Cinnamon): Investigation Of Systematic Errors
Authors: Way Raymond M
Published: February 2020

Results of these studies demonstrate that steam-distillable volatile oil within a lot of cassia bark is heterogeneously distributed; that sample preparation can contribute a significant part of the overall analytical error; and that the latter error can be reduced by specifying that the sample be ground to pass a U.S. 20 mesh screen rather than a U.S. 40 mesh screen. An F-distribution value of 6.7 was calculated for the data, from 6 laboratories, used for statistical analysis. The critical F-distribution is 5.05, suggesting a significant difference in the means of the U.S. 20 mesh data and the U.S. 40 mesh data. The problem of sampling segregated materials where the functional form of the quality distribution is not known is briefly discussed.
Liquid Chromatographic Determination of Tenuazonic Acid and Alternariol Methyl Ether in Tomatoes and Tomato Products
Authors: Stack Michael E , Mislivec Philip B , Roach John A G , Pohland Albert E
Published: February 2020

A liquid chromatographic (LC) method for determining tenuazonic acid (TA) and alternariol methyl ether (AME) in tomatoes and tomato products is described. The Alternaria metabolites are extracted from a water slurry of the sample with CHCL3, the mixture is centrifuged, and the extract is fractionated on a silica gel column. Reverse phase LC with an ultraviolet detector (for TA) and a fluorescence detector (for AME) connected in series is used for final separation and determination. The limit of determination for TA and AME is 25 and 3 ng/g, respectively, with average recoveries from catsup of 83 and 68%, respectively. The LC method also detects alternariol, but interfering peaks in some samples prevent accurate quantitation. Chemical ionization mass spectrometry (CI MS) is used to confirm TA. Samples (142) of tomatoes collected from commercial processing lines were analyzed; TA was found in 73 samples (0.4-70 μg/g).
Determination of Total Dietary Fiber in Foods and Food Products: Collaborative Study
Authors: Prosky Leon , Asp Nils-Georg , Furda Ivan , Devries Jonathan W , Schweizer Thomas F , Harland Barbara F
Published: February 2020

A collaborative study was conducted to determine the total dietary fiber (TDF) content of food and food products, using a combination of enzymatic and gravimetric procedures. The method was basically the same as published earlier (/. Assoc. Off. Anal. Chem. (1984) 67,1044- 1052), with changes in the concentration of alcohol and buffers, time of incubation, sample preparation, and some explanatory notes, all with the intent of decreasing the coefficient of variation (CV) of the method. Duplicate blind samples of soy isolate, white wheat flour, rye i bread, potatoes, rice, wheat bran, oats, corn bran, and whole wheat Sour were analyzed by 9 collaborators. TDF was calculated as the weight of the residue minus the weight of protein and ash. CV values of the data from all laboratories for 7 of the samples ranged from 1.56 to 9.80%. The rice and soy isolate samples had CV values of 53.71% and66.25%, respectively; however, each sample contained only about 1% TDF. The enzymatic-gravimetric method for determining TDF has been adopted official first action.
Sampling Barrel Cheese For Moisture Analysis: Comparison Of Methods
Authors: Blattner Thomas M , Olson Norman F , Wichern Dean W
Published: February 2020

Fifty-four steel and 18 fiber barrels of cheese were sampled by the conventional plug method and the samples were analyzed for moisture. These same barrels were sliced vertically through the center, and 72 samples were taken from one exposed surface and analyzed. Finally, all of the remaining cheese from the barrel was ground, blended, and sampled for moisture analysis. Results on the 72 samples obtained from the exposed surface of the sliced cheese were used to create a moisture profile of the barrel cheese. The blended samples were used to establish the "true" moisture content of the cheese. Statistical analysis of the data revealed a bias in the conventional plug sample values compared with the true moisture values. Computer simulation experiments conducted on the profile data suggested an alternative sampling site that could provide measurements with less bias. A verification study was conducted with 40 steel and 12 fiber barrels. These barrels were sampled by the conventional plug method, a new method, and the blending method used previously. Statistical evaluation of the data revealed a potential reduction in bias of 1.7 and 0.5% for steel and fiber barrels, respectively.
Determination of Ethylenethiourea in Grapes and Wine
Authors: Chovancova Jana , Matisova Eva , Batora Vojtech
Published: February 2020

Residues of ethylenethiourea (ETU) in grapes and wine were deter- [ mined by capillary gas chromatography and paper chromatography, without a cleanup step, and after derivatization to 5-benzyl-ETU. The ! detection limit was 0.0002 mg/kg for flame ionization detection, 0.008 mg/kg for paper chromatography with photodensitometric evaluation of the detected spot. Results were compared with a generally used GC method specifying electron capture detection of trifluoroacetylated S- benzyl-ETU. The recoveries of ETU in grapes and wine at different j concentration levels were determined. ETU residues were determined J in treated grapes but no residues were detected in wine
Improved Codistillation Method for Determination of Carbon Tetrachloride, Ethylene Dichloride, and Ethylene Dibromide in Grain and Grain-Based Products
Authors: Devries Jonathan W , Larson Paul A , Bowers Raymond H , Keating Joyce A , Broge James M , Wehling Paul S , Patel Hasmukh H , Zurawski James W
Published: February 2020

A method is described for the determination of the common fumigants carbon tetrachloride (CC14), ethylene dichloride (EDC), and ethylene dibromide (EDB) in grain and grain-based products. A properly prepared sample is mixed with water and hexane, an internal standard mixture of 1,2-dichloropropane (DCP) and 1,2-dibromopropane (DBP) is added, and the fumigants are codistilled with the hexane into an appropriate receiver. After the hexane solution is dried over sodium sulfate, the quantities of fumigants present are quantitated on a gas chromatograph (GC) equipped with an electron capture detector (ECD). For the matrices investigated, the relative standard deviation of the method was 6.0,9.7, and 23.1% for CC14, EDC, and EDB, respectively. Recoveries of added fumigants were 107, 95, and 101%, respectively. Comparison with an acetone-water soak extraction method gave a correlation of 0.967 between methods for EDB with odds of a difference between methods of 35%.
New FDA Migration Cell Used to Study Migration of Styrene from Polystyrene into Various
Solvents
Authors: Snyder Roger C , Breder Charles V
Published: February 2020

A new cell was evaluated for studying the migration of components of plastic food packaging materials into various food simulating solvents. Data obtained using this cell to study the migration of styrene from polystyrene at 40 and 70°C are presented. Food simulating solvents tested were: water; 3% acetic acid; 8, 20, 50, and 100% ethanol; corn oil; HB-307; heptane; hexadecane; and decanol. An iterative Basic computer program is described that fits the migration vs time data obtained to mathematical models, based on Ficks' law, yielding migrant/ polymer diffusion coefficients (£>p). Dp values determined for styrene migration from polystyrene at 40 and 70°C were 3 X 1013 and 4 x 1012 sq. cm/s, respectively.
Liquid Chromatographic Determination of Quinine, Hydroquinine, Saccharin, and Sodium Benzoate in Quinine Beverages
Authors: Valenti Leonard P
Published: February 2020

A liquid chromatographic (LC) method is described for the determination of quinine, hydroquinine, sodium saccharin, and sodium benzoate in soft drinks. The method involves simple sample preparation, direct injection onto an octadecylsilane column, and elution with a methanol-acetonitrile-water-acetic acid (20 + 10 + 70 + 1) mobile phase. Eluted constituents are measured spectrophotometrically at 254 nm. The relationship between peak height and concentration was linear between 20 and 120 μg/mL for quinine. A relative standard deviation of 0.82% was obtained for commercial samples spiked with quinine, and the average recovery was 100.3%. The proposed procedure is accurate and rapid and can also detect hydroquinine (a natural contaminant of quinine), sodium saccharin, and sodium benzoate. Linear responses ranged from 0.45 to 20 (xg/mL for hydroquinine, from 54.8 to 219 μg/mL for sodium saccharin, and from 10.1 to 145.1 (ig/mL for sodium benzoate. The reproducibility of the LC method was evaluated with standard solutions of hydroquinine, sodium saccharin, and sodium benzoate, which produced relative standard deviations of 0.42, 0.46, and 1.13%, respectively. The average recoveries for sodium saccharin and sodium benzoate from spiked samples were 99.4 and 100.2%, respectively.
Advances in Automated Analysis of Soil Phosphorus, Potassium, Calcium, and Magnesium Through Use of a Microprocessor
Authors: Markus Denes K , Shaw Richard K , Buccafuri Anthony F
Published: February 2020

The use of an automated system equipped with a microprocessor-based controller and data handler is presented for the analysis of soil extracts for P, K, Ca, and Mg. With the aid of drift, gain, and carryover correction features, the system has the potential to improve accuracy and precision of analytical results. Moreover, the system allows the use of faster sampling rates in its operation. Accuracy and precision are evaluated for P, K, Ca, and Mg analyses, determined in standard solutions with the automated system at 50, 85, 120 and 155 hourly sampling rates. Results of P, K, Ca, and Mg analyses in 3 extracts of 50 soil samples, determined with the new system at the 120 hourly sampling rate, are also presented. Analyses performed by the microprocessor- based automated system are compared with those obtained using different nonautomated techniques.
Spectrophotometric Analysis of Mixtures of Acetaminophen, Salicylamide, and Codeine
Phosphate in Tablets
Authors: El Kheir Afaf Abou , Belal Saied F , El Shanwani Abdulla
Published: February 2020

A simple and accurate spectrophotometric procedure for the analysis of a mixture of acetaminophen, salicylamide, and codeine phosphate is described. Determination of the first 2 components depends on pHinduced differential spectral changes of their nitroso derivatives. The third component is assayed by the acid dye method. The proposed procedure was successfully applied to the analysis of laboratory-made and commercial tablets containing the ternary drug mixture
Use of 7,7,8,8-Tetracyanoquinodimethane in the Colorimetric Determination of Some
Antihistamines
Authors: Abdel-Khalek Magdi M , Abdel-Hamid Mohamed E , Mahrous Mohamed S
Published: February 2020

A precise colorimetric method is described for the estimation of phenyltoloxamine dihydrogen citrate, diphenhydramine hydrochloride, and chlorpheniramine maleate. The method is based on the interaction of these drugs as n-electron donors with 7,7,8,8-tetracyanoquinodimethane as π-acceptor to give a highly colored radical anion. This is corroborated by electron spin resonance spectroscopy. The colored product is quantitated spectrophotometrically at 843 nm. Beer's law is obeyed in the concentration range 2-6 µg/mL for each drug. Optimization of the experimental conditions is described. The proposed method was applied to the analysis of these drugs in tablet form, and results were in good agreement with those obtained by the official method
Occurrence of Mycotoxins in Cereals and Animal Feedstuffs in Natal, South Africa
Authors: Dutton Michael F , Westlake Kenneth
Published: February 2020

During the period 1982-1983, just under 800 samples of agricultural commodities, comprising cereals, compound feeds, hay, and silage, were examined for molds and mycotoxins. Aflatoxin Bi showed the highest incidence rate; it occurred in over 27% of all samples analyzed, the highest levels being found in peanut meal at 1500 ppb. Other mycotoxins detected were patulin and a number of trichothecene toxins at incidence rates in all commodities of 5.6 and 3.1%, respectively. The commodities at highest risk were oil seeds, excluding soya bean; the latter was found to be fairly free from contamination with mycotoxins. The most prevalent fungi were Aspergillus flavus and parasiticus, which were found in over 22% of all samples, whereas Penicillium spp. showed the lowest incidence of genera, specifically identified in 8.3% of all samples examined. This latter finding explains in part the low incidence of Penicillium mycotoxins
Problems and Results of Trace Analysis of 2,3,7,8-Tetrachlorodibenzo-P-dioxin in 2,4,5-THchIorophenoxyacetic Acid and Its Esters
Authors: Weeren Rolf D , Asshauer Jurgen
Published: February 2020

Quantitative analysis of tetrachlorodibenzo-p-dioxins (TCDDs) has gained increasing importance in the public domain. The analytical problem is complex because of the large number of interfering isomers and the extremely low limit of determination enforced by legislation. DAPA elaborated a procedure based on the latest published methods and on the existing experience of the collaborators. This procedure involves preseparation of the original sample on a silica column and cleanup by liquid chromatography (LC) on alumina. Alkaline saponification of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) esters seems to create artificial dioxins in the organic extract. Final determination is performed by capillary gas chromatography (GC)-low resolution mass spectrometry (MS). Final international collaborative work was carried out on 4 samples. Results were reported by 13 of 20 laboratories. Mean values ranged from 3.5 to 8.7 μg/kg. The interlaboratory reproducibilities ranged from 3.4 to 8.2 μg/kg (about 100% of the mean value).
Liquid Chromatographic Determination of Benzo[a]pyrene in Total Particulate Matter of Cigarette Smoke
Authors: Tomkins Bruce A , Jenkins Roger A , Griest Wayne H , Reagan Roberta R , Holladay Susan K
Published: February 2020

The benzo[a]pyrene (BaP) delivery of reference and commercially 1 available tobacco cigarettes, as well as reference and placebo marijuana cigarettes, is determined using a sequential liquid chromatographic liquid chromatographic procedure. The total particulate matter of sample cigarette smoke is collected using a Cambridge filter pad, which isultrasonically extracted with acetone. The resulting extract is filtered, then fractionated using semipreparative-scale normal phase liquid chromatography (LC). Quantitative determination is achieved using analytical-scale reverse phase LC equipped with a fluorescence detector. The method is precise (± 10-15% relative standard deviation) and yields 85% or better BaP recovery at the μg/cig. level. A single , pad may be analyzed in 8 person-hours, while a more typical lot of 12 pads (6 pads each for 2 cigarette brands) may be analyzed in 10 person days.
Liquid Chromatographic Determination of Polycyclic Aromatic Hydrocarbons in Fish and Shellfish
Authors: Takatsuki Keigo , Suzuki Shigeru , Sato Nobutoshi , Ushizawa Isamu
Published: February 2020

A simple and accurate analytical method for determination of polycyclic aromatic hydrocarbons (PAHs) in fish and shellfish is presented, which is considered to be useful for routine analyses and for screening purposes. The procedure involves alkaline digestion, extraction with n-hexane, silica gel column chromatography, and liquid chromatographic (LC) determination with fluorometric detection. During development of the analytical method for determination of PAHs, it was found that benzo[a]pyrene, a representative PAH, was decomposed easily by the analytical procedure, and this tendency was investigated for the experimental conditions used. Benzo[a]pyrene was decomposed by the coexistence of alkaline conditions, light, and oxygen; by peroxides in aged ethyl ether; and by oxygen when adsorbed on silica gel. Thus, to obtain good recoveries and precise analytical results, these decomposition conditions must be avoided. The following precautions are recommended: protection from light through all analytical steps; addition of Na2S to alkaline digestion mixture as an antioxidant; complete removal of peroxides from ethyl ether just before use; quick column chromatography on silica gel; and prevention of air from contact with adsorbent. When this simple method was applied to fish and shellfish samples, very good recoveries of PAHs from fortified fish samples were obtained, and no serious interferences were observed in fish and shellfish extracts
Normal Phase Liquid Chromatographic Determination of Pyrethrins in Formulations
Authors: Bushway Rodney J
Published: February 2020

A liquid chromatographic method has been developed to quantitate pyrethrins in pesticide formulations. Samples were dissolved in tetrahydrofuran (THF) and injected onto an amino column with a solvent system of hexane-nonstabilized THF (90 + 10) at a flow rate of 1.5 mL/min. Detection was monitored at 240 nm and 0.4 AUFS. Total elution time was 7 min. Twelve products varying in concentration from 0.05 to 3.75% and formulated with numerous other ingredients were analyzed. Percent coefficients of variation ranged from 1.39 to 9.68 with the majority less than 5.00. Although piperonyl butoxide and Noctyl bicycloheptene dicarboximide (MGK 264) were not quantitated, neither interfered with the pyrethrin analysis
Comparison of Ether and Chloroform for Soxhlet Extraction of Freeze-Dried Animal Tissues
Authors: Firth Nigel L , Ross Deborah A , Thonney Michael L
Published: February 2020

Chloroform was a satisfactory replacement for ether in solvent extraction for lipid determination in freeze-dried animal tissues, although values obtained were not identical. Fat content of tissues used in this study ranged from less than 10 to more than 95%. Chloroform has the great advantage of being fireproof, but proper fume hoods should be used. An antifoaming agent should be added to chloroform, both in the Soxhlet apparatus and when it is redistilled.
Re-Evaluation of Selectivity of Malachite Green Test for Presence of Sulfite in Mechanically Deboned Poultry
Authors: Mallinson Edward T , Curry Kevin A , Corrao Paul A
Published: February 2020

A study was undertaken to determine whether free chlorine or sulfide anions could yield positive results for the malachite green test in meat samples when sulfite was not present. Malachite green solution was added to a mechanically deboned poultry (MDP) sample spiked with either chlorine or sulfide ions. The presence of chlorine in MDP samples at any concentration tested did not yield a positive reaction for the malachite green test. When sulfide ions were introduced into MDP samples, positive results were observed at 40 μg sulfide ion/g MDP and above. Because aqueous solutions of sulfide at the levels mentioned have a relatively high pH, it was necessary to determine whether the pH or the presence of the sulfide ions had caused this positive reaction to the malachite green test. After a comparison of a solution of sulfide, and a solution of a matching pH, it was observed that the sulfide present caused the positive reaction to the malachite green test.
Liquid Chromatographic Method for Perphenazine and Its Sulfoxide in Pharmaceutical Dosage Forms for Determination of Stability
Authors: Beaulieu Normand , Lovering Edward G
Published: February 2020

A liquid chromatographic method is described for determination of perphenazine and perphenazine sulfoxide in representative dosage forms. Sulfoxide levels were nondetectable or less than 1% in tablets and in an injectable product. Sulfoxide levels increase with time in some syrup formulations and may be as high as 11% in syrup formulations before their expiration date.
Liquid Chromatographic Determination of Levodopa, Levodopa-Carbidopa, and Related Impurities in Solid Dosage Forms
Authors: Ting Susan
Published: February 2020

A rapid reverse phase liquid chromatographic method was developed for the determination of levodopa and levodopa-carbidopa in tablets and capsules. The method also separates these drugs from 3-(3,4,6- trihydroxyphenyl)alanine and methoxytyrosine, impurities of levodopa, and from methyldopa and 3-O-methylcarbidopa, impurities of carbidopa. The mobile phase was 3% acetic acid and the detection wavelength was 280 nm. The method was linear over the concentration range 0.05-0.40 mg levodopa/mL, 0.01-0.06 mg carbidopa/mL, 0.9- 12.8 μg 3-(3,4,6-trihydroxyphenyl)alanine/mL, 0.7-3.1 μg methyldopa/ mL, 5-20 μg methoxytyrosine/mL, and 0.5-3.3 μg 3-O-methylcarbidopa/ mL. Mean recoveries (%) for spiked commercial tablets were: levodopa 100.3, carbidopa 100.4, 3-(3,4,6-trihydroxyphenyl) alanine 99.1, methoxytyrosine 100.0, methyldopa 100.0, and 3-O-methylcarbidopa 99.4.
Analysis of Pharmaceutical Dosage Forms for Oxfendazole: I. Reverse Phase Liquid Chromatographic Determination of Oxfendazole in Swine Premix
Authors: Fleitman Jeffrey , Neu Daniel , Visor Gary
Published: February 2020

A reverse phase liquid chromatographic (LC) procedure is described for quantitating oxfendazole (2-(methoxycarbonylamino)-5-phenyIsuIfinylbenzimidazole)) in swine premix. Sample preparation consists of extracting oxfendazole with an acetone-methanol mixture. An aliquot of the extract is then centrifuged to separate undissolved premix excipients. Internal standard is added to the supernate and the sample is further diluted with water-acetonitrile-phosphoric acid (80 + 20 + 1). Oxfendazole is quantitatively determined using a Partisil-5-ODS-3 column with acetonitrile-O.OlM phosphate buffer (pH 6.0) as the mobile phase. The method is stability specific and yields a mean recovery of 101.1 ± 0.4% for the 1.35% premix formulation. The dependence of chromatographic performance characteristics on mobile phase organic content, pH, and buffer concentration is also reported.
Simultaneous Determination of Vitamins B2 (Riboflavin) and B6 (Pyridoxine) in Infant Formula Products by Reverse Phase Liquid Chromatography
Authors: Ayi Benjamin K , Yuhas David A , Deangelis Nicholas J
Published: February 2020

An ion pair liquid chromatographic (LC) method is described for the simultaneous determination of vitamins B2 and B6 in infant formula products. The method eliminates many of the UV absorbing ingredients present in the infant formulations. The method involves extraction of the vitamins with distilled water followed by a filtration step and the subsequent analysis of the filtrate by LC. Vitamins B2 and B6 and their vitamers are separated from each other as well as from ingredients in the sample matrix on a 5 µm Spherisorb ODS column. The mobile phase consists of 85% 0.04M triethylammonium phosphate (pH 3.0), 10% methanol, 5% acetonitrile, and the counter ion, octane sulfonic acid sodium salt. The method is reproducible for both vitamins with relative standard deviations (RSD) ranging from ± 0.3 to ± 2.6% depending on the infant formula product. The recoveries of the vitamins from various infant formula products are greater than 97%. The analysis for vitamins B2 and B6 in various lots of infant formula compared well with the official AOAC methods.
Liquid Chromatographic Determination of Basic Nitrogen-Containing Polynuclear Aromatic Hydrocarbons in Smoked Foods
Authors: Joe Frank L , Salemme Jean , Fazio Thomas
Published: February 2020

Several smoked foods were analyzed for basic nitrogen-containing polynuclear aromatic hydrocarbon (NPAH) content by a relatively rapid liquid chromatographic (LC) technique. The analyzed products included both domestic and imported market basket commodities. Nanogram quantities of NPAH standards were detected by UV and fluorescence detectors connected in series. The NPAHs were extracted from basic aqueous ethanolic solution into cyclohexane, extracted from cyclohexane into 6N HC1, and extracted back into cyclohexane after neutralization of the acid. The NPAHs were then purified by filtering the extract through deactivated basic alumina. The eluate from this step was concentrated to dryness, and the residue was dissolved in 95% ethanol and analyzed by LC, using a Vydac C-18 column and acetonitrile-water (9 + 1) as the mobile phase. Recoveries of 3 NPAHs, 5,7-dimethylbenz(a)acridine, dibenz(aj)acridine, and dibenz(a,h)acridine, each added to salmon and sausage at the 5 ppb level, ranged from 62 to 101% by fluorescence measurement and from 64 to 106% by UV measurement. None of the NPAHs used as standards were found by either fluorescence or UV detection at levels ≥5 ppb in any of the foods analyzed.
Fluoroacetate Residues in Ground Squirrel and Coyote Tissues Due to Primary or Secondary 1080 Poisoning
Authors: Casper Howard H , Mount Michael E , Marsh Rex E , Schmidt Robert H
Published: February 2020

Fluoroacetate residues in various tissues of 1080-poisoned ground squirrels and coyotes are listed. The tissues (excluding the stomach) of squirrels poisoned with an average of 0.8 mg 1080/kg (low dose) contained from 182 to 1309 ppb fluoroacetate. In squirrels poisoned with an average of 4.8 mg 1080/kg (high dose), the tissue residues ranged from 535 to 9754 ppb fluoroacetate. Tissues from coyotes which died after consuming 1080-poisoned ground squirrels were also analyzed for fluoroacetate residues. Residues in these coyote kidneys and livers ranged from less than 10 ppb to 95 ppb fluoroacetate. The residue findings in this research indicate that a diagnostic assay for 1080 in tissues must be reliable at 10 ppb (or less) fluoroacetate
Determination of Ampicillin Residues in Fish Tissues by Liquid Chromatography
Authors: Nagata Tomoko , Saeki Masanobu
Published: February 2020

A liquid chromatographic (LC) method is described for determination of ampicillin residues in fish tissues. The drug is extracted from tissues with methanol, and the extract is evaporated to dryness. This residue is cleaned up by Florisil cartridge chromatography. LC analysis is carried out on a Nucleosil C18 column, and ampicillin is quantitated by ultraviolet detection at 222 nm. Recoveries of ampicillin added to tissues at levels of 0.2 and 0.1 ppm were 73.2 and 61.5%, respectively. The detection limit was 3 ng for ampicillin standard, and 0.03 ppm in tissues.
Gas Chromatographic Determination of Fensulfothion in Formulations: Collaborative Study
Authors: Betker William R ,   Collaborators:, Balcer E W , Bennett O O , Coffman W R , DiPilla E J , Hodgins W E , Karr J J , Koenig D K , Korger P D , Meinen V J , Owen M E , Riggs T H , Schulz R , Tengler H , Zank T L
Published: February 2020

A collaborative study was conducted on a gas chromatographic method for determination of fensulfothion. Eleven laboratories analyzed 2 technical and two 6 lb/U.S. gal. spray concentrate samples. In the analysis, samples are dissolved in methylene chloride which contains 4-chlorophenyl sulfoxide as an internal standard, and solutions are injected into a gas chromatograph equipped with an OV-330 column. Withinlaboratory repeatability was 0.79% for technical product and 0.37% for the spray concentrate samples, with coefficients of variation of 0.88 and 0.58%, respectively. Among-laboratories reproducibility was 0.81% for technical product and 0.53% for the spray concentrate, with coefficients of variation of 0.91 and 0.84%, respectively. The method has been adopted official first action.
On-Line Generation of Cyanogen Chloride in Semiautomated Determination of Niacin and Niacinamide in Food Products
Authors: Ge Hoon , Oman Gary N , Ebert Frank J
Published: February 2020

The current AOAC procedure for semiautomated determination of niacin specifies the use of externally generated cyanogen bromide. Because of the safety concerns in handling this material, we investigated the use of an alternative system of generating cyanogen chloride in situ, using chloramine-T and potassium cyanide. Recovery studies conducted on 9 different food products yielded average recoveries of 101 %. A repeatability study resulted in a measured coefficient of variation of 2.9%. The AOAC niacin method was compared with this semiautomated method; 115 paired analyses on 8 different food types over 6 separate analytical replications indicated no significant difference by a paired t-test at the 95% confidence level.
Liquid Chromatographic Determination of Major Organic Acids in Apple Juice and Cranberry Juice Cocktail: Collaborative Study
Authors: Coppola Elia D , Starr Martin S ,   Collaborators:, Chang G H , DeVries J , Durst R , Elkins E , Frost B , Funk B , Hastings H J , Lento H G , Morawski S , Munsey J , Post S , Reese B L , Rovella M A , Schmoeger D R , Schwartz H , Smith W , Thomas L V , Thornburg W H , Virkler W , Wrolstad R E , Wu A , Zurawski J W
Published: February 2020

Twelve laboratories collaboratively studied a liquid chromatographic method for determination of quinic, malic, and citric acids in cranberry juice cocktail and apple juice. Samples are passed through a disposable silica cartridge, filtered, and directly injected into the chromatograph. The mobile phase is 0.2M KH2PO4 (pH 2.4). Two reverse phase columns are used, with UV detection at 214 nm. Six samples of cranberry juice cocktail and 6 samples of apple juice were sent to each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.2 to 7.6% and from 2.9 to 14.7%, respectively, for quinic, malic, and citric acid levels above 0.10%. The precision of the method is satisfactory. The method has been adopted official first action.
Development of Machine Smoking Parameters for Measurement of Cigarette Tar Yield in the United Kingdom
Authors: Johnson Joseph C
Published: February 2020

The smoking and analytical methods used by government and tobacco industry laboratories are the result of many years of collaborative work within the industry and through international bodies such as the International Standards Organization. Recently, some publications have criticized the validity and scientific soundness of these procedures. It is shown that such criticisms are totally unfounded by reviewing the work that led to the adoption of the current technique. Tar tables, published by the UK Health Departments are valid in ranking brands in order of their yields, while not necessarily reflecting the absolute tar delivery to the smoker. These tables are intended to and do provide a relevant guide for smokers about the proportional tar yields of UK cigarettes.
Gas Chromatographic Determination of Histapyrrodine Hydrochloride in Pharmaceutical Preparations
Authors: Sane Ramesh T , Doshi Vipul J , Joshi Sanjay K , Shastri Vijay K , Sapre Dhananjay S , Jukar Swati , Sawant Satish V
Published: February 2020

A simple gas chromatographic method is described for the determination of histapyrrodine HC1 in marketed formulations. Chlorpheniramine maleate is used as the internal standard. The amount of histapyrrodine HC1 found by the proposed method averaged 19.91 mg/tablet, compared with the label claim of 20 mg/tablet. The method was statistically evaluated for accuracy and precision.
Liquid Chromatographic and Spectroscopic Characterization of Pentamidine Isethionate and Impurities in Bulk Drug and Injectables
Authors: Mount Dwight L , Miles James W , Churchill Frederick C
Published: February 2020

A liquid chromatographic (LC) method is described for evaluating purity of pentamidine isethionate (PI), a life-saving drug used in the treatment of Pneumocystis carinii pneumonia, which is a leading cause of death in persons with acquired immunodeficiency syndrome (AIDS). Six potential impurity compounds were synthesized to test the selectivity of the chromatographic system and to permit quantitation of impurities in various lots of PI products. The drug and impurities were separated with gradient elution on a cyano-bonded LC column. The analytic system provided information on the identities and levels of impurities in early experimental lots of PI. These results assisted the manufacturer in altering reaction conditions and purification procedures to ensure that succeeding lots were within the specification limits, i.e., no more than 0.4% of any single impurity or 0.7% of total impurities found in the final product.
Liquid Chromatographic Determination of Multiresidue Fluorescent Derivatives of Lonophore 1 Compounds, Monensin, Salinomycin, Narasin, and Lasalocid, in Beef Liver Tissue
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

A liquid chromatographic (LC) method with fluorometric detection was developed to quantitatively determine residue levels of monensin, salinomycin, narasin, and lasalocid in beef liver tissue. The ionophores are extracted from the tissue, purified by both alumina and Sephadex LH-20 column chromatography, and then derivatized. Lasalocid was directly esterified with 9-anthryIdiazomethane (ADAM), but monensin, salinomycin, and narasin were first acetylated with acetic anhydride and then esterified with ADAM. The ADAM derivatives were purified on a silica gel column and separated by LC using an RP C-8 5 μm column. A fluorescence detector set at 365 nm (excitation) and 418 nm (emission) was used to monitor the column effluent. The detection limits were 0.15 ppm, and the calibration curves were linear between 0.5 and 5.0 ppm for all 4 ionophores. Mean recoveries were 57, 70, 75, and 90% for lasalocid (5 ppm), monensin (2.5 ppm), salinomycin (2.5 ppm), and narasin (2.5 ppm), respectively. The ionophores were also separated and semiquantitated by using bioautography and thin layer chromatography with a vanillin spray.
Determination of Trace Metals in Low Ionic Strength Waters Using Zeeman and Deuterium Background Correction for Graphite Furnace Atomic Absorption Spectrometry
Authors: Fishman Marvin J , Perryman Gary R , Schroder LeRoy J , Matthews Edward W
Published: February 2020

Each U.S. Geological Survey water quality laboratory evaluated one of 2 background correction techniques: Zeeman and deuterium. A L’vov-type platform was used to determine cadmium, chromium, cobalt, copper, lead, manganese, nickel, and zinc in low ionic strength waters, submitted as blind samples. Matrix modifers were used to determine cadmium, chromium, lead, manganese, and zinc. Results were comparable for all metals, except cadmium and nickel, at the μg/L range. Analytical ranges for a 20 μL sample volume are presented. Detection limits can be changed by varying the volume of sample injected, by using multiple injections, or by changing the analytical wavelength.
Gas Chromatographic Determination of Butachlor in Formulations: Collaborative Study
Authors: Tomkins David F ,   Collaborators:, Baird J , Bowermaster J , Brunhouse E , Caparoon W C , Chenery L T , Galoux I M , Gentry G M , Hodgins W E , Jurgens D , Koenig D K , Law M W , Lee B , Liu J , McAfee S E , Spencer D A , Torma L
Published: February 2020

An isothermal gas chromatographic (GC) method for measuring butachlor in formulations was tested by 15 laboratories. Samples were prepared in acetone and determined using a GC column of 10% SP-2250 on 100-120 mesh Supelcoport, and triphenyl phosphate as internal standard. Collaborators made single determinations on each of 2 similar materials (matched pairs) on 2 days for 2 pairs of samples. The study generated 56 matched pairs which were used in Youden’s matched pair calculations. Coefficients of variation (CV,) for liquid formulations were 1.06 and 0.98%. The method was simple to use and did not reveal any interferences in the samples tested. The method has been adopted official first action as an AOAC-CIPAC method.
Simultaneous Liquid Chromatographic Determination of Some Tetracyclines in Serum
Authors: Tyczkowska Krystyna , Aronson Arthur L
Published: February 2020

A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30 000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 μg/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.
Interlaboratory Comparison of Analyses for Heavy Metals in Clam Tissue
Authors: Hendzel Marilyn R , Fallis Bruce W , Demarch Brigitte G E
Published: February 2020

Results are reported for an interlaboratory study conducted to assess the reproducibility of analyses for lead, copper, cadmium, and zinc. The 10 participating laboratories analyzed 2 samples of freeze-dried clam tissue and 1 disguised sample of NBS Oyster Tissue. Interlaboratory variations were observed for all metals, although the methods yielded reproducible data for Cu and Zn with average interlaboratory coefficients of variation of 15 and 11%, respectively. The performance of methods used for Cd and, more so, for Pb was less than satisfactory. Cadmium levels in the 3 samples ranged from about 0.7 to 3.7 ppm with an average interlaboratory coefficient of variation (CV) of 24%. Lead levels in the 3 samples were about 0.5 ppm with an interlaboratory CVof 68%. Some laboratories' results were consistently high or low but data were insufficient to relate these trends to one particular variable. Results from this study were compared with 5 other studies reported in the literature since 1980. Coefficients of variation from all studies were comparable for samples with similar metal concentrations
Liquid Chromatographic Determination of Bendiocarb in Technical Materials and Wettable Powder Formulations: Collaborative Study
Authors: Carter Peter L , Overton Keith C ,   Collaborators:, Baker P G , Bennett O O , Brown M , Carlstrom A A , Claussen K , Dobrat W , Freedlander R S , Hamilton D G N , Hitos P , Hodgins E , Kaiser L , McDermott W H , Minyard J P , Noel R J , Montgomery W A , Pauling K O , Pavel K , Tyler J F , Vinson D W
Published: February 2020

A liquid chromatographic method for determination of bendiocarb in technical materials and wettable powders was tested by 12 collaborators. Bendiocarb is dissolved in acetonitrile containing 0.1% propiophenone as internal standard. This solution is analyzed on a liquid chromatograph utilizing a reverse phase (C18) column. The compound is detected at 254 nm and peak area is used for quantitation. The 3 different materials studied contained 20, 80, and nominally 100% bendiocarb. Each was examined in duplicate to provide the necessary matched pairs. Collaborators approved of the ease and simplicity of the method and, in particular, the way the method can be applied to automatic injection assemblies. The statistical data show acceptable precision of the method: Reproducibility coefficients of variation were 20% material, 2.04%; 80% material, 1.02%; and nominal 100% material (technical product), 0.64%. The method has been adopted official first action.
Evaluation of Asparagine in the AOAC Use-Dilution Method
Authors: Cole Eugene C , Rutala William A
Published: February 2020

An asparagine solution (0.1%) is required in the AOAC use-dilution method to cover stainless steel carriers during sterilization and storage. The rationale for using an asparagine soak is unclear. It has been proposed that asparagine enhances bacterial adherence to carriers or inhibits corrosion of the metal carriers or both. The former theory was assessed in this study by comparing bacterial adherence on seeded carriers stored in 0.1 and 1% asparagine solution to those stored dry or in water. The anticorrosive properties of asparagine on stainless steel carriers were microscopically evaluated after 9 months. The results demonstrate that asparagine neither enhances bacterial adherence to carriers nor is necessary to prevent corrosion.
Validation of Liquid Chromatographic Method for Assay of Calcitriol and Alfacalcidol in Capsule Formulations
Authors: Flann Bruce C , Lodge Bruce A
Published: February 2020

The validation of a liquid chromatographic procedure suitable for the determination of calcitriol and alfacalcidol in their respective formulations labeled to contain at least 0.25 μ.g drug per unit is described. The capsule content is diluted and chromatographed in 15-20 min on silica columns (5 μm) with a mobile phase of hexane-tetrahydrofuranmethylene dichloride-isopropanol (72 + 12 + 12 + 4, v/v) with detection at 254 nm. The calibration curve is linear. Recoveries of “spikes” averaged 101% with a standard deviation of 2%. Precision was better than 1.5%.
Bioautographic Method for Evaluation of Glycopeptide Actaplanin in Milk
Authors: Bories Georges F , Baradat Maryse M , Corpet Denis E
Published: February 2020

A bioautographic method is described that allows the identification and semiquantitation of residues of the glycopeptide antibiotic actaplanin in cow’s milk at 0.01 ppm. The milk sample is precipitated with acetonitrile and the resultant pellet is extracted by a buffer. This extract is defatted, then chromatographed on an Amberlite resin column. Actaplanin is eluted with methanol-HCI. Purified extract is then chromatographed on a cellulose thin layer, developed in a methanol-chloroform- ammonium hydroxide mixture. This thin layer chromatography increased the sensitivity of the determination by concentrating the actaplanin components in a single spot. The antibiotic was then detected by bioautography, using Bacillus subtilis as a test organism. Parameters influencing the diffusion of the antibiotic (namely, the nature and concentration of the agar-agar), and the sensitivity of the test strain (namely, the nutritional value of the medium, and the addition of a synergistic inhibitor) have been optimized.
Determination of Fluorene in Fish, Sediment, and Plants
Authors: Lebo Jon A , Smith Lawrence M
Published: February 2020

Methods and their applications are described for the determination of fluorene in fish, sediment, and plants. Sample extracts are enriched by using 2 or more of the following: gel permeation, silica gel, potassium silicate, sulfuric acid-impregnated silica gel, and activated carbon. Efficiency was improved by applying the adsorbents in combination or as tandem enrichment modules. Analyses by liquid chromatography (LC) with ultraviolet or fluorescence detection (LC/UV or LC/F) yielded limits of detection of 30, 3, and 30 ng/g and average recoveries of 80, 81, and 74% for fish, sediment, and plants, respectively.
Single-Laboratory Validation of EPA Method 8150 for Determination of Chlorinated Herbicides in Hazardous Waste
Authors: Gurka Donald F , Shore Fred L , Pan Shu-Teh , Amick E Neal
Published: February 2020

Method 8150, published in the second edition of Test Methods for Evaluating Solid Waste, Manual SW-846, required optimization, ruggedness testing, linearity determinations, precision tests, bias testing, gas chromatographic/mass spectrometric confirmation, and quality control guidelines for validation of the protocol. This single-laboratory validation, which is applicable to the determination of the herbicides dicamba, silvex, 2,4-D, 2,4-DB, 2,4,5-T, dinoseb, MCPP, MCPA, and dichlorprop in hazardous waste extracts, was completed and is described in this report. Final ruggedness testing of the optimized procedure gave a mean recovery of 89.3% with a standard deviation of 4.3%. Percent relative standard deviations are less than 10 (n = 20, each analyte) over a 102 linear range of concentration for MCPP and MCPA and over a 103 linear range of concentration for the other target herbicide esters. Instrumental detection limits for electron capture detection and mass spectrometric identity confirmation were determined and found to be matrix-dependent.
UV Spectrophotometry Determination of Piperine in Pepper Preparations: Collaborative Study
Authors: Lupina Ted , Cripps Howard
Published: February 2020

Eight collaborating laboratories performed replicate analyses for piperine on 5 samples representing pepper raw spice, oleoresins, and soluble seasonings. Piperine is extracted into ethylene dichloride and measured at maximal absorbance 342-345 nm with a UV light source. Piperine content is calculated using an absorbance factor derived from piperine. Intralaboratory coefficients of variation (CV0) ranged from 0.5 to 3.1%; interlaboratory coefficients of variation (CVX) ranged from 3.0 to 5.8%. The method has been adopted as an official method of the American Spice Trade Association and as an official first action method by AOAC.
Liquid Chromatographic Determination of Cyclopiazonic Acid in Poultry Meat
Authors: Norred William P , Cole Richard J , Dorner Joe W , Lansden John A
Published: February 2020

A liquid chromatographic procedure has been developed for the determination of cyclopiazonic acid (CPA) in poultry meat. CPA is extracted from ground meat with chloroform-methanol (80 + 20), partitioned into 0.1 N sodium hydroxide, acidified, and extracted into dichloromethane. An interfering component of meat is removed by transferring the dichloromethane extract to a minicolumn containing silica gel and washing the column with petroleum ether and chloroform. CPA is eluted with methanol-acetic acid (99 + 1), and subjected to ligand-exchange liquid chromatography. Recovery of CPA from 40 separate samples of meat spiked with CPA at levels from 0.016 to 15.6 ppm was 70.4 + 14.1%. Analysis of meat from a chicken orally dosed with 10 mg CPA/kg body weight revealed that 14.5% of the dose was in muscle 48 h after administration.
Fast and Sensitive Screening Method for Detection of Trichothecenes in Maize by Using Protein Synthesis Inhibition in Cultured Fibroblasts
Authors: Scossa-Romano Donata A , Bickel Regula E , Zweifel Ulrich , Reinhardt Christoph A , Luthy Jurg W , Schlatter Christian L
Published: February 2020

A fast and sensitive bioassay with hamster (BHK-21 C13) fibroblasts for the detection of toxic trichothecenes in maize is described. Cells are exposed to pure toxins or crude maize extracts for 30 min. The mixture is then incubated with [l-14C]-leucine for an additional 60 min and the radioactivity incorporated into the protein of the washed cells is determined. The sensitivity of the assay was in the nuige 1-10 ng/mL (or 50 ppb in maize) for T-2, HT-2, and diacetoxyscirpenol. At least 1000-fold higher concentrations of non-trichothecene mycotoxins and plant toxins were necessary to cause an inhibition of protein synthesis in the cells. Of 24 maize samples tested, 14 gave a positive response in this assay and the presence of trichothecenes could be confirmed chemically in 11 samples. Therefore, the described bioassay is proposed as a useful screening method for cytotoxic trichothecenes in maize.
Determination of Adulterated Natural Bitter Almond Oil by Carbon Isotopes
Authors: Krueger Dana A
Published: February 2020

Bitter almond oil (benzaldehyde), a flavoring compound used in many foods, was isolated from apricot kernels; 2 synthetic benzaldehyde samples were obtained from commercial sources. All samples were analyzed for radiocarbon (l4C) content. The natural sample yielded a value consistent with its natural origin (approximately 116% of Modern Standard Activity), while the synthetic samples were devoid of 14C activity as expected for a petrochemical material. Implications for quality control of bitter almond oil are discussed