bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of Sulfaquinoxaline, Sulfadimethoxine, and Their N4-Acetyl Derivatives in Chicken Tissues During Frozen Storage
Authors: Parks Owen W
Published: February 2020

The N4-acetyl derivatives of sulfaquinoxaline and suifadimethoxine were stable in fortified chicken liver and thigh muscle tissues during frozen storage for 1 year at –20 and –70°C. In contrast, the parent compounds depleted approximately 35% in liver tissues at –20°C. The transformation of the depleted sulfa drugs to their N4-glucopyranosyl derivatives was negligible, suggesting that products other than glucosides resulted during the storage period.
Biotic and Abiotic Factors in Fumonisin Bi Production and Stability
Authors: Le Bars Joseph , Le Bars Pierrette , Dupuy Jacques , Boudra Hamid , Cassini Renee
Published: February 2020

The occurrence of a few cases of equine leuko-encephalomalacia in France has indicated a potentially widespread, low-level contamination of corn by fumonisins. To develop strategies for prevention, biotic and abiotic factors in fumonisin B1 (FB1) production and stability were investigated. The potential for FB1 production from 2 groups of Fusarium moniliforme strains was tested in corn cultures. The first group consisted of 48 strains that were previously isolated from corn, asparagus, watermelon, and vanilla. The second group consisted of 25 strains that were freshly isolated from corn. Respective frequencies in the first and second groups of strains and in each toxigenic class were as follows: 23 and 0%, <50 μg/g; 16 and 12%, 50–200 μg/g; 23 and 4%, 200–800 μg/g; 33 and 68%, 800–3200 μg/g; and 5 and 16%, >3200 μg/g. The initial rate of FB1 production decreased in the following order of temperature: 20, 25, 15, 30, 10°C. FB1 was not detected at 5, 35, or 40ΰC. Also, no FB1 was detected in confined atmosphere at 25°C during 10 weeks. Significant amounts (>200 μg/g) of FB1 were produced within 12 days, in laboratory conditions, with moisture contents of corn frequently encountered at harvest (≥27%). Thermal decomposition of FB1 in dried corn culture followed a first-order reaction. Half-life times at 150, 125, and 100°C were 10, 38, and 175 min, respectively. Therefore, contamination of foods and feeds by this stable mycotoxin is, theoretically, a permanent threat.
Labeled Fumonisins: Production and Use of Fumonisin B1 Containing Stable Isotopes
Authors: Plattner Ronald D , Branham Bruce E
Published: February 2020

Fumonisin B1 (FB1) labeled on the branch methyl groups with deuterium was produced in liquid cultures, and methyl-D3-labeled methionine was added. The isolated FB1 had 90% incorporation of 6 deuterium atoms and 9% incorporation of 3 deuterium atoms. The labeled FB1 was used as an internal standard for 2 analytical methods to measure FB1 in extracts of corn, corn products, and cultures. One method was hydrolysis followed by gas chromatography/mass spectrometry (GC/MS) of the derivatized backbone, and the other was analysis by fast atom bombardment MS (FAB/MS). Incorporation of labeled FB1 into samples resulted in a GC/MS method with improved precision and accuracy and allowed for a quantitative FAB/MS method.
Survey of Fumonisin Production by Fusarium Isolated from Cereals in Europe
Authors: Visconti Angelo , Doko M Bruno
Published: February 2020

Strains of Fusarium isolated from corn, sorghum, wheat, barley, and mixed feed from Italy, Spain, Poland, and France were tested for the production of fumonisins B1 and B2 (FB1 and FB2) in corn cultures. All strains of F. moniliforme (1 from France, 10 from Italy, 15 from Poland, and 17 from Spain) and the one tested strain of F. proliferatum produced fumonisins in amounts scattered within a wide range of concentrations (0.7–4100 μg FB1/g). None or insignificant amounts of FB1 were detected in cultures of 11 F. subglutinans strains (<0.5 μg/g for 5 of 11 strains) or in cultures of 3 strains of Fusarium spp. not belonging to Liseola. FB2 was produced by all but one of the strains that produced FB1, and the FB2/FB1 ratio ranged from 0.1 to 0.37 (average, 0.22). The highest production of fumonisin was obtained with isolates from corn (average, 1259 μg FB1/g), followed by isolates from wheat (average, 769 μg FB1/g) and barley (average, 320 μg FB1/g). The production of fumonisins by isolates from sorghum was 2 orders of magnitude lower than corn. These results support data reported for similar surveys in geographical areas other than Europe. In particular, data indicate a situation in Europe that is very similar to North America in respect to fumonisin production by different Fusarium species (F. moniliforme and F. subglutinans) isolated from different substrates (corn and sorghum).
Determination of Sulfamethazine in Bovine and Porcine Tissues by Reversed-Phase Liquid Chromatography
Authors: Boison Joe O K , Keng Lily J-Y
Published: February 2020

A simple, sensitive, and rapid method for the liquid chromatographic determination of sulfamethazine in animal tissues was developed by using sulfaethoxypyridazine as the internal standard. Homogenized tissue is extracted with chloroform, and the sulfa drugs are back-extracted from chloroform into alkaline sodium chloride solution. The pH of the aqueous extract is adjusted to 6, and the sulfas are concentrated on a conditioned C18 cartridge and eluted with 1 mL methanol. Sulfamethazine and sulfaethoxypyridazine are separated from tissue co-extractives by reversed-phase chromatography on a C18 column by using 0.05M sodium dihydrogen phosphate-methanol (7 + 3). Detection is performed at 265 nm. The method has a detection limit of 2 ng/g. Results obtained by this method were compared with those obtained by the official thin-layer chromatography/densitometric method.
Determination of Semduramicin Sodium in Poultry Liver by Liquid Chromatography with Vanillin Postcolumn Derivatization
Authors: Ericson Jon F , Calcagni Albert , Lynch Martin J
Published: February 2020

A liquid chromatographic (LC) method is described for the quantitative determination of semduramicin sodium in broiler liver when administered under projected use conditions. For this procedure, semduramicin sodium is extracted from liver with methanolic ammonium hydroxide, separated and concentrated by solid-phase extraction steps, and determined by LC with postcolumn derivatization with vanillin. The mean recovery of drug was 95% over the 40-320 ng/g range, the coefficient of variation was ±10% or better, and no interference was observed from commercial poly ether ionophores. The minimum level of detection for semduramicin sodium in broiler liver is 25 ng/g.
Determination of p-Toluenesulfonamide in Ice Cream by Combination of Continuous Flow and Liquid Chromatography: Summary of Collaborative Study
Authors: Beuaars Paul R , Van Dijk Remmelt , Brands Arie
Published: February 2020

A collaborative study of the determination of p-tolu-enesulfonamide (p-TSA) in ice cream by a combination of continuous flow and on-line liquid chromatography was conducted. Seven ice cream samples containing 0-6.35 mg p-TSA/kg at 4 levels (1 blank and 3 pairs of split level samples) were analyzed by 11 laboratories. For all samples analyzed, the repeatability relative standard deviation varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviation ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55,1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101 %). No false positive results were reported for the blank sample, and no interference was encountered by the presence of vanillin in samples. The method has been adopted first action by AOAC INTERNATIONAL.
Effect of Various Commercially Available Enzymes in the Liquid Chromatographic Determination with External Standardization of Thiamine and Riboflavin in Foods
Authors: Hägg Margareta
Published: February 2020

The efficacy of various commercially available enzymes in the determination of thiamine and riboflavin in foods was studied by liquid chromatography (LC) using external standards. Different enzymes, as well as the same enzyme produced by different manufacturers, very strongly affected the determination of both vitamins. The recoveries for different foods ranged from 85 to over 100% for thiamine and from 80 to 100% for riboflavin. The present LC method was accurate and precise when tested on a food and a feed reference material, and coefficients of variation were 5.5% for thiamine and 10% for riboflavin in a rye flour reference material tested for 8 months.
Analysis of Heavy Metals in Aceto Balsamico Tradizionale di Modena by Flame Atomic Absorption Spectroscopy
Authors: Corradini Fulvio , Marcheselli Luigi , Marchetti Andrea , Preti Carlo , Biancardi Claudio
Published: February 2020

A detailed investigation of Aceto Balsamico Tradizionale di Modena (ABTM) was carried out. The necessity of knowing the metal content of this original and widely used product is of great importance. Measurements were carried out on a large number of samples of different ages to check the dependence of metal content on product aging.
Rapid Abrasion Test To Indicate Lead on the Surface of Ceramicware
Authors: Dolan Scott P
Published: February 2020

A rapid abrasion test (RAT) was developed for screening ceramicware for Pb. A Pb-sensitive chromogen (rhodizonic acid) reacts to form a persistent colored complex, indicating the presence of Pb. RAT takes 2-5 min to complete; a positive test is easily discernible. RAT, which provides only qualitative information, is useful for screening large numbers of ceramicware items for the presence of Pb at ≥0.05 μ/mL.
Quantitative Procedure for CWorophyllin Copper Complex
Authors: Chernomorsky Simon
Published: February 2020

The reliability of the currently used quantitative assay for commercially available chlorophyllin copper complex is discussed. It was shown that optical measurements at 405 nm can overestimate the purity of the preparation by 16.4–49.5%. This conclusion is from comparative studies using spectrophotometry at 405 nm and elemental analysis (copper content) of chlorophyllin copper complex. Spectrophotometry at 630 nm resulted in closer agreement with data calculated from elemental analysis. These observations have to be taken into consideration by those involved in the manufacture and distribution of chlorophyllin copper complex as well as in the development of the United States Pharmacopeia compendial monograph for this preparation.
Analysis of Streptomycin and Dihydrostreptomycin in Milk by Liquid Chromatography
Authors: Gerhardt Geoff C , Salisbury Craig D C , Macnebl James D
Published: February 2020

A method developed for the determination of the aminoglycoside antibiotics streptomycin and dihydrostreptomycin in tissues was applied to the analysis of fluid milk. Samples are extracted with 3.6% perchloric acid, and then injected onto a trace enrichment column, from which they are eluted onto a reversed-phase analytical column. The analytes are detected by fluorescence following postcolumn derivatization with 1,2-naphthoquinone-4-sulfonic acid. Recovery of analytes was in the range of 50–65% for skim or partially defatted fluid milk, while recoveries for homogenized whole milk were lower. Limits of quantitation were 10 ppb for streptomycin and 20 ppb for dihydrostreptomycin.
Information Technology/Laboratory Information Management Systems: Problems of Regulatory Compliance
Authors: Rawling Alan K
Published: February 2020

Despite the attention paid to the regulatory requirements for computer systems, recent inspections continue to report basic failings in the standards of validation and documentation. This paper describes the need for validation of vendor-supplied software such as Laboratory Information Management Systems and the procedures necessary for control of the production phase in a regulated environment. Whereas these requirements may be considered “good computing practices,” their adherence remains a management challenge at odds with pressures of cost, business need, and time.
Determination of Lead in Table Wines by Graphite Furnace Atomic Absorption Spectrometry
Authors: Mindak William R
Published: February 2020

A quick, easy method was developed for the analysis of table wines for lead quantitated at ≥14 ng Pb/mL wine. The method uses graphite furnace atomic absorption spectrometry with Zeeman background correction and a L’vov pyrolytic graphite platform. Ammonium dihydrogen phosphate is used as a matrix modifier. Wines are diluted by a factor of 10 with 1% HNO3 and analyzed directly. Their absorbances are compared with those of a standard curve prepared with 1 % HNO3. Analytical results obtained by comparison with a standard curve agreed with those obtained by the method of standard additions. Four white, 4 red, and 2 rosé wines were studied. Pb concentrations varied from 15 to 135 ng Pb/mL. Wines fortified with 100 ng Pb/mL had an average recovery of 94%. The average short-term relative standard deviation (RSD) was 2.1%; the average long-term RSD was 7.4%. The estimated detection (3 σ) and quantitation (10 σ) limits were 4 and 14 ng Pb/mL, respectively.
Liquid Chromatographic Determination of Phenolic Acids in Soil
Authors: Kelley William T , Coffey David L , Mueller Thomas C
Published: February 2020

A rapid and sensitive method is described for the determination of phenolic acid concentrations in soil. The method consists of extraction with 0.1 M NaOH for 16 h, centrifugation, filtration, pH adjustment to reduce detector interference, and liquid chromatographic separation on a C18 column and UV detection at 280 nm. Recoveries of 6 phenolic acids (ferulic, p-coumaric, caffeic, syringic, vanillic, and p-hydroxybenzoic) were 58,100,0,66,83, and 123%, respectively. The limits of detection were 0.5 μg/g for p-hydroxybenzoic, vanillic, and syringic acids and 1.0 μg/g for ferulic and p-coumaric acids. Caffeic acid was not detectable with this method.
Liquid Chromatographic Determination of Pyrethroids as Active Ingredients in Pesticide Formulations
Authors: Koppen Benny
Published: February 2020

A normal-phase liquid chromatographic method for determining pyrethroids as active ingredients in pesticide formulations was developed. The method uses isooctane–ethyl acetate as mobile phase and UV detection at 275 nm. The method was evaluated for the following 7 pyrethroid active ingredients: α-cypermethrin, cypermethrin, deltamethrin, esfenvalerate, fenvalerate, fenpropathrin, and permethrin. Evaluation covered 3 formulation types (emulsifiable concentrate, suspension concentrate, and water-dispersible granule) containing a single pyrethroid active ingredient. The method separates diastereomers of cypermethrin, fenvalerate, and permethrin and can be used to determine total content as well as relative distribution of diastereomers.
Performance of Various Tests Used to Screen Antibiotic Residues in Milk Samples from Individual Animals
Authors: Cullor James S , Van Eenennaam Alison , Gardner Ian , Perani Lynn , Dellbvger Jon , Smith Wayne L , Thompson Teresa , Payne Michael A , Jensen Leon , Guterbock Walter M
Published: February 2020

The 10-point Milk and Dairy Beef Quality Assurance Program was developed collaboratively by the National Milk Producers Federation and the American Veterinary Medical Association and is designed to promote and document the responsible use of antibiotics in the dairy industry. One area of emphasis in this program is testing of individual animals for antibiotic residues after a specified post-treatment withdrawal time. We examined the performance of various assay systems on milk samples from individual cows. These assays are used at present on bulk tank milk samples by regulatory agencies, processing plants, producers, and veterinarians to detect the presence of β-lactam antibiotics. A high proportion of false-positive results was obtained for both the pretreatment milk samples from cows with clinical mastitis and the milk samples obtained 21 days after initial therapy (nonantibiotic and antibiotic) for the treatment of mastitis. A high proportion of false-positive outcomes was obtained from the milk of clinically normal cows that had not received any medication for at least 30 days prior to evaluation. The results indicate a serious problem in the use of some assays that were designed to evaluate residues bulk tank milk samples to analyze samples from individual cows. This error in assay specificity results in the unjustifiable discarding of milk that meets regulatory standards and may be misused to accuse the producer or veterinarian of not adhering to regulatory guidelines. Maintaining a safe, high-quality milk supply is a constant goal of the dairy industry, which must be provided the appropriate tools and techniques to meet this challenge.
Liquid Chromatographic Method for Determination of Triglycerides in Vegetable Oils in Terms of Their Partition Numbers: Summary of Collaborative Study
Authors: Firestone David
Published: February 2020

The IUPAC Commission on Oils, Fats and Derivatives undertook development of a method and collaborative study for the determination of triglycerides in vegetable oils by liquid chromatography. Three collaborative studies were conducted from 1985 to 1987. Refinements were made in the method after the first collaborative study, and the second and third collaborative studies demonstrated that the method produces acceptable results. Materials studied were soybean oil, almond oil, sunflower oil, olive oil, rapeseed oil, and blends of palm and sunflower oils, and almond and sunflower oils. Six test samples were analyzed by 18 laboratories from 11 countries in the second study; 4 test samples were analyzed by 16 laboratories from 12 countries in the third study. The method for determination of triglycerides (by partition numbers) in vegetable oils by liquid chromatography was adopted first action by AOAC INTERNATIONAL as an IUPAC–AOCS–AOAC method.
Determination of 1,2-Dibromoethane and l,2-Dibromo-3-chloropropane in Water by Microextraction and Gas Chromatography: Collaborative Study
Authors: Edgell Kenneth W , Longbottom James E
Published: February 2020

A collaborative study of U.S. Environmental Protection Agency (EPA) method 504 for the determi nation of 1,2-dibromoethane (EDB) and 1,2-dibromo-3-chloropropane (DBCP) in aqueous samples by microextraction using gas chromatography with an electron capture detector was conducted by EPA, Environmental Monitoring Systems Laboratory, Cincinnati, OH. Ten volunteer laboratories reported data for 6 concentration levels in each of 2 water matrixes: reagent water and groundwater. The method was tested over the concentration range of 0.050–6.70 μg/L. Generally, the between-laboratory relative standard deviation ranged from 6–22%, and the withinlaboratory relative standard deviation ranged from 4–10%. The microextraction/gas chromatographic method for determination of EDB and DBCP in water has been adopted first action by AOAC INTERNATIONAL.
Ruggedness of the Monensin and Narasin Liquid Chromatographic Assays
Authors: Coleman Mark R , Macy Thomas D , Morgan John W , Rodewald J Matthew
Published: February 2020

Supplementary validation data were generated for the monensin and narasin liquid chromatographic (LC) assays. Several parameters of the LC system and the sample preparation procedures were evaluated. Feed samples are routinely extracted in meth-anol-water (9 + 1, v/v). The ratio of methanol to water was varied to evaluate the ruggedness of the extraction procedure. The LC parameters evaluated included flow rates of the mobile phase and vanillin reagent, reactor temperature, and water content of the mobile phase. The resolution of monensin A, monensin B, and narasin A; retention times; tailing factors; peak areas; and peak widths were monitored as LC parameters were varied. The stabilities of monensin and narasin reference standard solutions over time when stored at room temperature and under refrigeration were also monitored. The results show that deviations in the methanol-water ratio of the extraction solution did not significantly affect final assay results. Modification of LC parameters may substantially affect retention time, peak area, and resolution factors.
Improved Esterification of Mecoprop for Sensitive Detection on Capillary Gas Chromatography with Mass Selective and Electron Capture Detection
Authors: Lee Arthur S , Hong Moo-Ki , Smith Albert E
Published: February 2020

Analytical methods for determination of the derivatives of the herbicide mecoprop, (±)-2-(4-chloro-2-methylphenoxy)propionic acid (MCPP), by capillary column gas chromatography with mass selective detection (GC-MSD) and electron capture detection (GC-ECD) were studied. A successful procedure was introduced for the ester preparation using H2SO4 as the catalyst and the alcohols 2,2,2-trichloroethanol (TCE) or 2,2,2-tri-fluoroethanol (TFE). The identification and elucidation of MCPP by GC-MSD following the esterifica-tion with diazomethane, BF3-methanol, H2SO4-methanol, TCE, TFE, or pentafluorobenzyl bromide (PFB) were carried out. A comparison of the response sensitivities among those MCPP esters was made with GC-ECD. Although the methyla-tion product of MCPP was confirmed with GC-MSD, its low sensitivity to the ECD limited the detection of MCPP. TCE, TFE, and PFB derivatiza-tion methods resulted in a high rate of MCPP esteri-fications and very sensitive ECD molecular responses. On the basis of efficiency, convenience, worker safety, and least sample contamination, TFE esterification was considered as the superior method for MCPP analysis compared with the other methods of derivatization. An accurate method is described for quantifying MCPP in soil leachates by GC-ECD at very low concentrations without the requirement of a complicated cleanup process. As a result, MCPP residues at concentrations of less than 0.1 μg in 100 mL soil leachate were detected.
Screening of Chloramphenicol Residues in Pork Muscle by Planar Chromatography
Authors: Abjean J P
Published: February 2020

A rapid planar chromatographic method is described for the qualitative determination of chloramphenicol residues in muscle. The drug is extracted with ethyl acetate and purified by solid-phase extraction. After elution, the collected phase is evaporated to dryness. The residue is dissolved in methanol, spotted on a silica gel plate, and chromato-graphed. After elution, the chloramphenicol is visualized after reduction with fluorescamine. This method detects chloramphenicol in meat at 10 μg/kg and has a sample throughput of about 25 samples per analyst per day.
Confirmation of Leucogentian Violet in Chicken Fat by Gas Chromatography/Mass Spectrometry
Authors: Wilson Roger T , Wong John , Johnston John , Epstein Robert , Heller David N
Published: February 2020

A gas chromatographic/mass spectrometry (GC/MS) procedure for confirming the identity of leucogentian violet (LGV) in chicken fat was developed for regulatory application. The unused portion of the extract remaining from a determinative procedure was back-extracted into an organic phase, concentrated, and analyzed by GC/MS. Confirmation of the identity of LGV was based on matching the retention times and relative abundances of 6 ions in the extract to corresponding values obtained for the LGV standard. The procedure was validated by replicate analyses of negative control, fortified control, and residue-incurred chicken fat. The presence of LGV was confirmed by the GC/MS procedure in all samples found to contain LGV by prior liquid chromatographic analyses. There were no interferences in the control samples.
Chemical Test for Mammalian Feces in Ground Black Pepper: Collaborative Study
Authors: Gerber Harriet R
Published: February 2020

A collaborative study for determining mammalian feces in ground black pepper was conducted, using a modified version of the AOAC Of ficial Method 986.28 for mammalian feces in grain products. With the proposed method, the presence of alkaline phosphatase, an enzyme found in mammalian feces, was determined by using phenolphthalein diphosphate as the enzyme substrate in a test agar medium containing 1% agar in a borate buffer, pH 9.5. Ground black pepper was stirred in water to extract interfering color. The mixture was filtered and the residue was scattered on plates of liquid test agar. The alkaline phosphatase cleaved phosphate radicals from phenolphthalein diphosphate, generating free phenolphthalein, which appeared as pink to red-purple around the fecal particles in the previously colorless medium. For the 10- and 20-particle spike level, collaborators recovered averages of 12.3 and 24.1 particles, respectively. The experimental background was zero. Collaborators reported that the method was clear and easy to perform.
Effects of Incubation Atmosphere, Novobiocin, and Modified Plating Media on the Efficiency of a DNA Probe for Recovering Shigella flexneri
Authors: Satchell Felicia B , Bruce Verneal R , Andrews Wallace H , June Geralddse , Sherrod Patricia S , Hammack Thomas S , Feng Peter
Published: February 2020

An oligonucleotide probe specific for the invasion plasmid of Shigella spp. was used to study the effect of several culture method variables described in the Bacteriological Analytical Manual for retention of the plasmid in Shigella flexneri. Results of colony hybridization analyses showed that, in many instances, a slightly greater number of Shigella were detected by the DNA probe on MacConkey agar than on trypticase soy agar. Elevating the incubation temperature from 35° to 42°C slightly reduced the number of Shigella detectable by the probe. However, neither aerobic nor anaerobic incubation atmosphere or the inclusion of novobiocin in the media showed any consistent effect on the recovery of S. flexneri by the probe. Moreover, the detection efficiency of the probe was not generally affected by the different MacConkey agar formulations tested.
Reversed-Phase Liquid Chromatographic Determination of Hypoglycin A (HG-A) in Canned Ackee Fruit Samples
Authors: Sarwar Ghulam , Botting Herbert G
Published: February 2020

A reversed-phase liquid chromatographic (LC) method involving precolumn derivatization with phenylisothiocyanate (PITC) was developed for determining levels of hypoglycin A (HG-A) in canned ackee fruit samples. HG-A was extracted by homogenizing the drained fruit in 80% ethanol. By using a Waters Pico-Tag amino acid analysis 15-cm-long column (which is also used for analyzing protein hydrolysates and biological samples) and an LC system, the baseline separation of HG-A from other amino acids was completed in about 6 min. The total time for analysis and equilibration was 16 min. HG-A levels in the edible portion of fruit in 18 cans varied from 18.27 to 87.50 mg HG-A/can. Recoveries of added standard HG-A averaged 101%. To our knowledge, this is the first report of the use of this method to determine HG-A in ackee fruit.
Comparison and Assessment of the Difference in Total Dietary Fiber in Cooked Dried Legumes as Determined by Five Methods
Authors: Mongeau Roger , Brassard René
Published: February 2020

Dried beans (kidney and great northern) and dried peas (chick, green, and yellow) were cooked according to package instructions. Total dietary fiber (TDF) was measured by the Mongeau (AOAC 992.16), Prosky (AOAC 985.29), and Lee (AOAC 991.43) methods (A, B, and C, respectively). Non-starch polysaccharides (NSP) were measured by the Englyst gas-chromatographic method that included dimethyl sulfoxide treatment, and the lignin measured separately was added to NSP (method D). TDF was also measured by the Li method (E). TDF values ranged from 7 to 48 g/100 g dry weight. Methods B and C gave similar TDF values, which were higher than those from other methods. For kidney beans I, TDF values by methods B and C were up to 2.5 times higher because of the inclusion of starch. The fiber residues from methods A and C contained the same amounts of arabinose, xylose, mannose, galactose, and uronic acid, but glucose was 4 times higher in residue C than in residue A. When α-amylase from porcine pancreas was incorporated in methods B or C for 5 samples, the discrepancies among methods A, B, and C were reduced by 60-98%.
Determination of Sulfite in Rainwater by Solid-Phase Spectrophotometry
Authors: Bosque-Sendra Juan M , Molina Francisca , Nechar Mounir
Published: February 2020

A simple and specific method was developed for the determination of sulfite in rainwater based on solid-phase spectrophotometry (SPS). Rainwater was collected on morpholine, sulfite was stabilized by forming an adduct that reacted with pararosanil-ine and formaldehyde, and the reaction product was fixed on Dowex 1-X8 resin. The absorbance of the solid phase was measured directly at 565 and 700 nm. The calibration curve was linear in the concentration range of 1-50 μg/L in solution (relative standard deviation = 1.7%); the International Union of Pure and Applied Chemistry detection limit was 0.8 μg/L. In simulated rainwater, the values of the calibration curve slopes were similar to that of the standard calibration curve slope, and recoveries for 40-497 μg/L sulfite ranged from 97 to 105%. Linearity, analytical sensitivity, and precision were better for the SPS method than the solution method, and the detection and quantitation limit values were lower for the SPS method than the solution method based on the similar reaction. The SPS method was subsequently used to determine sulfite in real rainwater.
Determination of Levels of Lead Contamination in Food and Feed Crops
Authors: Cabrera Carmen , Gallego Carmen , Lopez Maria C , Lorenzo Maria L , Lillo Enrique
Published: February 2020

A rapid, precise procedure is described for the determination of lead in food and feed products with electrothermal atomic absorption spectrophotometry. Samples were mineralized in a microwave acid digestion bomb in the presence of nitric acid and vanadium pentoxide. Lead concentrations were determined directly from digested samples. The detection limit was 0.04 ng/mL. Accuracy and precision were checked against National Institute of Standards and Technology standard reference material. The analytical method was tested with 51 food and feed crops from Mediterranean zones in Spain and found to be suitable for these products. Lead concentrations in samples ranged from not detectable to 2.695 μg/g (fresh weight).
Analysis of Calcium and Lead in Calcium Supplements by Inductively Coupled Plasma-Atomic Emission Spectrometry and Graphite Furnace Atomic Absorption Spectrophotometry
Authors: Shtonen Paul H , Thompson Harold C
Published: February 2020

A method was developed to analyze various calcium supplements for Ca and Pb content. The analysis involves a dry ash of the supplements followed by wet digestion. The Pb is determined by graphite furnace atomic absorption spectro–photometry (GFAAS). Analysis of Ca is by inductively coupled plasma–atomic emission spectrometry (ICP–AES). Ca supplements fortified with Pb at levels ranging from 0.25 to 10.0 μg/g yielded recoveries ranging from 82.7 ± 4.2 to 105.0 ± 1.7%. To test accuracy, the method was applied to National Institute of Standards and Technology standard reference materials (NIST SRMs) 1572 citrus leaves and 1486 bone meal. GFAAS analysis of SRM 1572 averaged 13.1 ± 0.6 μg Pb per g (certificate value, 13.3 ± 2.4 (μg Pb per g), and analysis of SRM 1486 averaged 1.34 ± 0.11 μg Pb per g (certificate value, 1.335 ± 0.014 μg Pb per g). ICP–AES analysis of SRM 1572 averaged 3.12 ± 0.01% Ca (certificate value, 3.15 ± 0.10% Ca by weight), and analysis of SRM 1486 averaged 27.63 ± 0.27% Ca (certificate value, 26.58 ± 0.24% Ca). The method's limit of quantitation (LOQ), on supplement Ca basis and a 1 g sample, averaged 0.75 μg Pb per 1 g Ca for supplements containing 9 to 35% Ca by weight. At a Pb level of 0.663 μg/g Ca, the reproducibility relative standard deviation (RSDr) averaged 7.3% and the repeatability relative standard deviation (RSDr) averaged 8.0%. It is recommended that the method be studied collaboratively.
Identification of Synthetic Colors in Beverage Alcohol Products by Solid-Phase Extraction and Thin-Layer Chromatography
Authors: Dugar Sumer M , Leibowitz Jeffrey N , Dyer Randolph H
Published: February 2020

A solid-phase extraction (SPE) sample cleanup and enrichment procedure coupled with thin-layer chromatography (TLC) is described for the enrichment of synthetic colors in all types of beverage alcohol products. SPE followed by TLC provides the identification of synthetic colors at sub-part-per-million levels. TWo complementary solvent systems afford detection of all the permitted (and some prohibited) synthetic colors in beverage alcohol products. This method is simple, offers consistency, and has no artifacts in TLC.
Determination of Ardacin in Premix, Supplement, and Animal Feed by a Rapid and Sensitive Two-Peak Liquid Chromatographic Method with Correlation to a Gradient Multipeak Liquid Chromatographic Method
Authors: Abdel-Kader Hafez , Fagan Sylvia V , Menon Govtnd K , Wigman Larry S , Chapin Frederic
Published: February 2020

A rapid and sensitive 2-peak liquid chromatographic (LC) method is described for extracting and quantitating ardacin in premix, supplement, and animal feed formulations. Ardacin is extracted from the formulations and analyzed after dilution or cleanup by reversed-phase LC with UV detection at 220 nm. The method correlates well with a more information-rich gradient multipeak LC method. Recoveries for premix formulations ranged from 96.8% (relative standard deviation [RSD], 0.8%) to 103.7% (RSD, 1.3%) for laboratory samples spiked at levels ranging from 1.6 to 39.6% ardacin. Recoveries for protein supplement mash formulations ranged from 98.7% of claim (RSD, 4.1%) to 106.0% of claim (RSD, 7.7%) at ardacin levels ranging from 37.5 to 600 mg/lb. Recoveries for cattle feed ranged from 90.0% of claim (RSD, 11.9%) to 105.6% of claim (RSD, 2.7%) at ardacin levels ranging from 4 to 30 g/ton.
Validation Study of Assay for Neomycin in Feed
Authors: Stahl Gerald L , Gilbertson Terry J , Kratzer D Dal , Blondia James J , Stoline Michael R
Published: February 2020

The neomycin microbiological cylinder plate assay using an ionic extraction method was validated for 2 swine feeds with neomycin base concentrations of 140.0 and 280.0 g/ton, 2 cattle feeds with neomycin base concentrations of 140.0 and 280.0 g/ton, and 2 premixes with neomycin base concentrations of 1.4 and 7.0 g/lb. The accuracy, precision, and reproducibility were evaluated by assaying the 6 feed samples in duplicate on 6 different days by an Upjohn laboratory (Laboratory 1) and 2 outside laboratories (Laboratories 2 and 3) for a total of 72 data points per laboratory. Three plates were used for each sample assayed. The recovery over all complete (type C) feed samples and (type B) premixes tested, ranged from 82 to 109% for Laboratory 1,85 to 114% for Laboratory 2, and 78 to 134% for Laboratory 3. Mean percent recoveries for all samples tested were 98.0,98.9, and 103.7% for Laboratories 1,2, and 3, respectively. Day-to-day performance yielded 95% confidence limits of ±11.9, ±16.9, and ±25% for Laboratories 1,2, and 3, respectively. Of 215 assay values, 206 (96%) fell within 20% of the actual targeted recovery (100%). Plate-to-plate variation of each of the 3 laboratories also was assessed. Statistical estimates for the use of 1,5, and an infinite number of plates showed that when 2 plates were used by Laboratories 1,2, and 3, than 99,99, and 95%, respectively, of the assay results fell within the acceptable assay compliance limits (70–125% recovery) for complete feeds and premixes. Slight improvement was found only for Laboratory 3, when more than 2 plates were used.
Identification and Quantitation of Corticosteroids and Their Esters in Pharmaceutical Preparations of Creams and Ointments by Thin-Layer Chromatography and Densitometry
Authors: Datta Kajal , Das Saroj K
Published: February 2020

A rapid, simple, and specific thin-layer chromatographic (TLC) method is described for estimation of various corticosteroids and their esters when present in combination with other drugs in pharmaceutical preparation of creams and ointments. The cream or ointment is dissolved in chloroform; water and insoluble material, if any, are removed by centrifugation, and the steroid is separated from other ingredients by TLC on silica gel G with n-hexane as the first developing solvent (to wash out cream or ointment base) and chloroform–ethyl acetate (1 + 1 , v/v, for free steroids or 2 + 1 , v/v, for steroid esters) as the second developing solvent. The separated steroid or ester is visualized under shortwave UV (254 nm) and estimated by spectrodensitometry at 240 nm. Recoveries of the steroids are between 98.0 and 101.7%. Results were compared with those obtained by official methods, where applicable, and excellent agreement was found.
Simultaneous Determination of Ibuprofen and Acetaminophen in Pharmaceutical Preparations by Proton Magnetic Resonance Spectroscopy
Authors: Husain Sajid , Kifayatullah M , Sekhar R
Published: February 2020

A simple, rapid, and specific method for simultaneous determination of ibuprofen and acetaminophen in pharmaceutical preparations by 1H Fourier transform nuclear magnetic resonance spectroscopy was developed using methyl and aromatic proton signal areas against ferf-butyl alcohol as internal standard. Average recoveries of ibuprofen and acetaminophen were 99.2 and 98.6%, with standard deviations of ± 0.76 and ± 0.81, respectively. The results were compared with those obtained using the procedure recommended by the British Pharmacopoeia and were in close agreement.
Determination of Leucogentian Violet in Chicken Fat by Liquid Chromatography with Electrochemical and Ultraviolet Detection: Interlaboratory Study
Authors: Schermerhorn Patricia G , Munns Robert K
Published: February 2020

A laboratory trial was completed for a liquid chromatographic method that can quantitate leucogentian violet (LGV) in chicken fat at 10 ppb. With this method, LGV is isolated from the fat matrix by a series of liquid–liquid extractions. This trial evaluated 2 detection systems: electrochemical (EC) and ultraviolet (UV). The participating laboratories determined incurred residues at 2 levels as well as fat samples fortified at 5,10, and 20 ppb. Using UV detection, the 3 laboratories reported the following range of recoveries: 71.0–89.6% at 5 ppb, 74.7–83.9% at 10 ppb, and 77.2–79.0% at 20 ppb. When these same samples were chromatographed with EC detection, the 2 reporting laboratories obtained the following average recoveries: 79.0 and 92.5% at 5 ppb, 75.9 and 85.4% at 10 ppb, and 77.3 and 79.8% at 20 ppb. The average concentrations found for the first level of incurred sample were 6.3,6.3, and 5.4 ppb with coefficients of variation (CVs) of 2.4,7.6, and 33.7%, respectively, when UV detection was used. Samples chromatographed with EC detection averaged 6.3 and 6.4 ppb with CVs of 4.0 and 8.2%, respectively. The second level of incurred sample gave average concentrations of 27.6,29.0, and 10.9 ppb with CVs of 11.0,5.0, and 42.8%, respectively, when the UV detection system was used. With the EC detector, the concentrations averaged 27.2 and 30.7 ppb with CVs of 15.7 and 3.5%, respectively.
Extraction and Liquid Chromatographic Analysis of Sulfadimethoxine and 4-N-Acetylsulfadimethoxine Residues in Channel Catfish (Ictalurus punctatus) Muscle and Plasma
Authors: Walker Calvin C , Barker Steven A
Published: February 2020

A simple and rapid method was developed for the simultaneous extraction and liquid chromatographic (LC) determination of sulfadimethoxine (SDM) and 4-N-acetylsulfadimethoxine (N-acetyl SDM) in channel catfish muscle and plasma. Tissues fortified at 0, 50,100,200,400, and 1000 ppb were examined. Matrix solid phase dispersion (MSPD) was used for muscle extraction. Plasma was extracted with a modified MSPD procedure in which 100 μL plasma and 400 mg C18 were blended by Vortex mixing in a disposable chromatographic column. Recovery of SDM based on radioactivity was 79% for muscle and 67% for plasma. Standard curves based on extracted fortified samples were used for quantitation of /V-acetyl SDM. LC run times of 12 min were obtained using a microbore analytical column and an isocratic mobile phase of aqueous 0.017M phosphoric acid–acetonitrile at ratios of 71:29 for muscle and 73:27 for plasma extracts. Method detection limits were 26 ng SDM and 26 ng N-acetyl SDM/g muscle, and 33 ng SDM and 11 ng N-acetyl SDM/mL plasma. Intra-assay variation was <10% for both compounds at all concentrations examined. Inter-assay variation for SDM was 13% for muscle and 14% for plasma, and for N-acetyl SDM was 11% for muscle and 10% for plasma.
Determination of Total Phosphorus in Foods by Colorimetric Measurement of Phosphorus as Molybdenum Blue after Dry-Ashing: NMKL1 Interlaboratory Study
Authors: Pulliainen T Katrdna , Wallin Harriet C
Published: February 2020

A spectrophotometric method in which the sample is dry-ashed in the presence of zinc oxide, and total phosphorus content is measured colorimetrically as molybdenum blue was evaluated by 12 participating laboratories from the Nordic countries. The study included potato flour, sausage, cold ham, infant formula powder, cheese, and skimmed milk powder. The materials were presented to the participants as 12 randomly coded samples of 2 blind duplicates of each material. The phosphorus content of the materials varied between 0.076 and 0.96 g/100 g. The relative standard deviation for repeatability of the method varied from 1.1% for 0.96 g phosphorus/100 g to 5.4% for 0.29 g phosphorus/100 g. The relative standard deviation for reproducibility varied from 3.6% for 0.96 g phosphorus/100 g to 7.7% for 0.23 g phosphorus/100 g.
Full Scan Confirmation of Tetrahydrophthalimide in Whole Milk Using Gas Chromatography/Ion Trap Mass Spectrometry
Authors: Chichila Tina M P , Erney D Ronald
Published: February 2020

The determination of tetrahydrophthalimide (THPI) in whole milk extracts by gas chromatography/ion trap mass spectrometry (GC/ITMS) in the full-scan, electron impact (El) mode is presented. THPI is first isolated from whole milk by a procedure including protein precipitation, liquid–liquid partitioning, and 2 solid-phase extraction (SPE) cleanup steps. GC/ITMS in the El mode is used for the determinative step. The average recovery of THPI at fortification levels ranging from 5 to 54 ppb was 85.6% (n = 16, coefficient of variation = 9.13%). Full-scan mass spectral confirmation of THPI in milk extracts was obtained at the 5 ppb fortification level. The limit of detection was estimated to be 0.5 ppb. Chemical ionization also was used for THPI determination in whole milk extracts. The simultaneous isolation and determination of captan and captofol in whole milk are also discussed.
Simple Cleanup Procedure for Analysis of Buprofezin Residues and Its Metabolite in Crops by Gas Chromatography
Authors: Nishizawa Hideo , Shigemura Masao , Suzuki Takashi , Uchida Matazaemon
Published: February 2020

An analytical method for determining residues of buprofezin (2-tert-butylimino-3-isopropyl-5-phenylperhydro- 1,3,5-thiadiazin-4-one) and its p-hydroxy metabolite (p-hydroxybuprofezin, one of its major metabolites in plants) in crops such as rice, citrus, and tomato was investigated. On the basis of the basicity of these compounds, a liquid–liquid partition, rather than column chromatography, was used for cleanup. Samples were extracted with acetone or methanol, and the concentrated extracts were partitioned between n-hexane and 1N HCI. After the aqueous layer was neutralized with 10N NaOH, the compounds were extracted with n-hexane, and the extract was analyzed with a gas-liquid chromatograph (GLC) equipped with an alkali flame ionization detector (AFID). p-Hydroxy- buprofezin was detected after acetylation with acetic anhydride–pyridine because its peak was broad and showed tailing on GLC. The limits of detection for buprofezin and p-hydroxybuprofezin were 0.005 ppm in hulled rice, citrus flesh, and tomato and 0.01 ppm in rice straw and citrus peel. Recoveries of both compounds fortified at 0.1 or 0.2 ppm were 75–97%.
Reversed-Phase Liquid Chromatographic Determination of Cromolyn Sodium in Drug Substance and Select Dosage Forms
Authors: Ng Linda L
Published: February 2020

This study, presented as a technical communication, describes a reversed-phase liquid chromatographic method for select commercial formulations, namely, inhalation solution, nasal solution, capsule and inhalation aerosol. Miscellaneous validation parameters are also discussed.
Improved Precision in the Automated Analysis of P2O5 in Fertilizer
Authors: Kane Peter F , Newlon Natalie F
Published: February 2020

Traacs autoanalyzers were first configured to analyze fertilizer P2O5 in 1988. In order to maximize precision, changes in the original instrument hardware and manifold design were developed. Platens were machined to higher tolerances and now allow better pump performance. Run protocols were modified to minimize sampler variation. Sampler wash reagent was changed to match sample matrix. The manifold was modified to eliminate wetting agent pump tubes. Heating and cooling effects were minimized with the use of insulated manifold tubing. Standard deviations of replicate analysis of the same solution were reduced to ⅓ of those obtained before modifications were made.
Liquid Chromatographic Determination of β-Lactam Antibiotics in Milk: A Multiresidue Approach
Authors: Moats William A , Harik-Khan Raida
Published: February 2020

In the United States, testing of all milk for residues of β-lactam antibiotics is now mandatory. Although a number of screening tests for determination of β-lactam antibiotic residues have been proposed, few reference methods of the required sensitivity (<10 ppb) are available. Methods for determination of several β-lactam antibiotics using an automated liquid chromatography (LC) cleanup have been described recently. This paper describes the integration of these methods into a single extraction and cleanup procedure. Milk was deproteinized with 0.2M Et4NCI and acetonitrile. The resulting filtrate was evaporated to about 1 mL, made to 4 mL, and filtered through a disposable filter cartridge. For cleanup, 2 mL filtrate was loaded onto a bonded C18 LC column in 0.01 M KH2PO4 (A) and eluted with an acetonitrile (B) gradient using a program of 100 A:0 B (0–3 min) to 60 A:40 B (30 min). The β-lactams were concentrated into narrow bands and separated from each other. A fraction corresponding to each compound of interest was collected and rechromatographed for analysis. The procedure has been applied successfully to determination of ampicillin, amoxicillin, cephapirin, penicillin G, penicillin V, ceftiofur, and cloxacillin. In principle it can be applied to the determination of any β-lactam antibiotic or metabolite thereof by collecting the appropriate fractions.
Modified Immunodiffusion Method for Detection of Salmonella in Raw Flesh and Highly Contaminated Foods: Collaborative Study
Authors: Warburton Donald W , Feldsine Philip T , Falbo-Nelson Maria T , Ackerl J , Adamik D , Aldenrath S , Allain P , Arling V , Beaton L , Bowen B , Brocklehurst F , Catherwood K , Cavadini J , Coignaud C , Cooper A , Coulter R , Davis T , Douey D , Downey W , Drummond J , Durzi S , Dzogan S , Foster R , Fox C , Gibson E , Gour L , Gover G , Gray M , Heidebrecht P , Kerwood J , Krohn G , Kupskay B , LaFreniere D , Massicotte R , McDonagh S , Molleken B , Oggle J , Perlette M , Pugh P , Purvis U , Saint W , Trottier Y , Vinet J , West D , Wheeler B , Zebchuk A
Published: February 2020

A total of 19 government and private industry laboratories in Canada and the United States participated in the collaborative study. Naturally contaminated ground poultry and animal meals, as well as inoculated raw shrimp, were examined for presence of Salmonella by both the modified immunodiffusion method and the Bacteriological Analytical Manual culture method, resulting in an agreement rate of 93.1%. The 2 methods are statistically equivalent for all food types at each inoculation level and for all lots of naturally contaminated foods evaluated in this study. The modification of the AOAC Official Method 989.13, immunodiffusion (1–2 TEST) method for detection of motile Salmonella in all foods, has been adopted revised first action by AOAC INTERNATIONAL.