bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Chromatographic Methods for Determination of Trazodone and Related Compounds in Drug Raw Materials
Authors: Beaulieu Normand , Sears Roger W , Lovering Edward G
Published: February 2020

Liquid chromatographic methods for the determination of trazodone and 10 related compounds are described. An octylsilane column was used with a mobile phase of tetrahydrofuran–methanol–acetonitrile–0.5% trifluoroacetic acid (6 + 2 + 6 + 27) and detection at 248 nm. Minimum quantifiable amounts of the related compounds were less than 0.05% based on coefficients of variation of less than 10%. Total impurities in 5 raw drug materials were less than 1 %.
Determination of Sulfadimethoxine and Ormetoprim Residues in Channel Catfish Fillets After Treatment with Romet and Evaluation of a Commercially Available Rapid Diagnostic Test for Drug Residues in Fish Fillets
Authors: Milner Nicholas P , Johnson Michael R , Perry Kim J
Published: February 2020

Sulfadimethoxine (SDM) and ormetoprim (OMP) residues were determined in catfish fillets after treatment with Romet. A liquid chromatographic (LC) method capable of simultaneously detecting SDM and OMP at 0.05–40 ppm was used. The recoveries were 92% for SDM and 108% for OMP. The intra- assay variabilities were determined for SDM and OMP at fortification levels of 0.05–40 ppm, and a coefficient of variation (CV) of less than 10% was achieved at all levels. The interassay variations were determined at fortification levels of 0.1 ppm (CVs: SDM, 6.4%; OMP, 4.9%) and 1.0 ppm (CVs: SDM, 2.8%; OMP, 3.5%). SDM and OMP residues in catfish fillets were rapidly depleted after treatment with Romet. By day 2 posttreatment, SDM and OMP were essentially nondetectable. The use of an enzyme-linked immunoassay (ELISA)-based rapid diagnostic test to determine SDM and OMP in catfish fillets was evaluated. An assay procedure to adapt the test for residues in tissue samples was developed. SDM and OMP were extracted from ground catfish fillet with methanol–water (80 + 20, v/v); the extract was diluted with buffer and filtered, and the filtrate was then tested with an EZ Screen test card. The effectiveness of the rapid test assay to detect SDM residues at levels above the U.S. Food and Drug Administration tolerance (0.1 ppm) was verified with fillets from Romet-treated catfish. All samples with residues at >0.1 ppm were identified correctly by the test. The results indicate that the diagnostic test could be used as a rapid method for monitoring Romet residues in catfish.
Depletion of Residues from Milk and Blood of Cows Dosed Orally and Intravenously with Sulfamethazine
Authors: Paulson Gaylord D , Feil Vernon J , Zaylskie Richard G , Giddings John M , Slanger William D
Published: February 2020

Cows were dosed orally (n=4) or intravenously (n = 4) with sulfamethazine [sulmet; 4-amino-N(4,6-dimethyl-2-pyrimidinyl)benzenesutfonamide] for 5 consecutive days (220 mg/kg of body weight on day 1 and 110 mg/kg on days 2–5). The concentrations of sulmet, N4-acetylsulfamethazine (Ac-sulmet), and the N4-lactose conjugate of sulfamethazine (lac-sulmet) were measured in milk and blood collected at 24 h intervals after the last doses of sulmet were given. The method of analysis included (1) spiking of samples with known amounts of 13C6-labeled reference compounds, (2) resolution of the 3 compounds by reversed- phase chromatography, (3) hydrolysis of lac-sulmet, (4) treatment with diazomethane to yield N1-methyl derivatives, and (5) gas chromatography/mass spectrometry. The ratios of intensities of selected mass spectral ions containing 12C6 and the corresponding ions containing 13C6 were used for residue quantitation. Sulmet, which was always the most abundant residue in the blood, decreased to less than 100 ppb 4 days after the last doses were given and to less than 10 ppb 7 days after the last doses. The concentrations of sulmet in milk were approximately one fifth the concentrations of sulmet in blood. The concentrations of lac-sulmet and Ac-sulmet in milk were lower than the concentrations of sulmet in milk.
Determination of Clenbuterol in Cattle, Sheep, and Swine Tissues by Electron Ionization Gas Chromatography/Mass Spectrometry
Authors: Wilson Roger T , Groneck Joseph M , Holland Kathleen P , Carolyn Henry A
Published: February 2020

A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid–liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 CI). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 ± 6.6% for liver tissues across all 3 species and 67.1 ± 3.8% for muscle tissue across all 3 species.
Selection of a Simple and Sensitive Method for Detecting Zearalenone in Corn
Authors: Quiroga Nora M , Sola Inés , Varsavsky Edith
Published: February 2020

A simple, rapid, and sensitive method for determining zearalenone in corn was selected. The toxin was extracted from 50 g test portions with 180 mL acetonitrile and 20 mL 4% KCl solution. A portion of the extract was defatted with isooctane. The acetonitrile extract was cleaned up with 20% lead acetate solution. The zearalenone was partitioned into toluene. The toluene solution was dried, and the residue was redissolved in benzene. The toxin was determined by thin-layer chromatography with silica gel plates and chloroform–acetone (9 +1) as the developing solvent. The overall average recovery of zearalenone from corn was 97%. The limit of detection was 50 μg/kg; this limit may be lowered by using fast violet B salt as spray reagent. The method was compared with 2 previous methods that determine zearalenone in biologically contaminated corn.
Analysis of Wortmannin (H-1) by Liquid Chromatography and Gas Chromatography
Authors: Xu Yichun , Mirocha Chester J
Published: February 2020

An analytical method for detection of wortmannin in corn kernels was developed based on liquid chromatography (LC) and gas chromatography (GC). The sample was extracted with ethyl acetate, subjected to cleanup procedures on Sep–Pak silica gel column, and eluted with dichloromethane–chloroform (1+1). Analysis was made either by LC or GC. The limit of detection was 2.5 by LC and 25 ng/g by GC. The recovery from corn by LC at 2.5, 5.0, 10, 25, 50, 100, 250, 500, and 1000 ng/g was 89 (11.5 sd), 72 (2.6), 69 (7.4), 90 (7.5), 78 (9.3), 72 (6.1), 84 (17.5), 82 (11.5), and 76 (12.9), respectively. Recovery measured by GC at 25, 50, 100, 250, 500, and 1000 ng/g was 78 (12.5), 72 (14.0), 78 (3.8), 69 (2.6), 74 (16.9) and 81 (8.3)%, respectively. The average recovery was 79% by LC and 75% by GC.
Analysis by Liquid Chromatography of Fusarochromanone (TDP-1) Added to Corn and Wheat
Authors: Xu Yichun , Mirocha C J , Xie W
Published: February 2020

An analytical method was developed for the detection of fusarochromanone (TDP-1) in com and wheat by liquid chromatography. Extraction was done with methanol-water-ammonium hydroxide (90 + 10 + 2), and cleanup was by elution through a silica Sep-Pak cartridge. The limit of sensitivity of TDP-1, detected on the basis of its fluorescence properties, is 200 pg, whereas the detection limit of the method for corn and wheat is 5 ng/g. The average recoveries of TDP-1 added at 5,25,100,500, and 1000 ppb were 86% for corn and 83% for wheat. Confirmation was done by thin-layer chromatography.
Determination of Methyl 2-Benzimidazolecarbamate in Bulk Fruit Juice Concentrates by Competitive-Inhibition Enzyme Immunoassay
Authors: Bushway Rodney J , Young Barbara E S , Paradis Lance R , Perkins Lewis B , Martin Susan K , Brown Myrna P
Published: February 2020

A polyclonal enzyme immunoassay (EIA) was used to quantitate methyl 2-benzimidazolecarbamate (MBC or carbendazim), a degradation product of benomyl, in bulk fruit juice concentrates. These concentrates are used by industrial producers to prepare juice or juice concentrates sold in supermarkets. Total sample analysis time was less than 18 min without cleanup or 35 min with cleanup. As many as 8 samples can be analyzed simultaneously, with a limit of quantitation of 10 ppb. The assay’s dynamic range ran from 0.5 to 20 ppb MBC but was best from 0.5 to 10 ppb. Intra-assay coefficients of variation (CVs) varied from 4.0 to 13% for standards and from 4.1 to 26% for samples. Inter-assay CVs varied from 4.5 to 47% for standards and 5.6 to 22% for samples. Average recovery of several juice concentrates spiked at 10 to 290 ppb was 97%. A total of 140 juice concentrates comprising 20 different kinds of juice were analyzed by 2 EIA methods and one liquid chromatographic (LC) procedure. MBC-positive samples gave the following correlation coefficients: 0.954 for EIA without cleanup vs LC, 0.956 for EIA with cleanup vs LC, and 0.978 for EIA with cleanup vs EIA without cleanup. MBC concentrations in MBC-positive juice samples ranged from 5 to 2960 ppb.
Determination of Inorganic Anions in Water by Ion Chromatography: Collaborative Study
Authors: Edgell Kenneth W , Longbottom James E , Pfaff John D
Published: February 2020

The U.S. Environmental Protection Agency (U.S. EPA) and the American Society for Testing and Materials (ASTM) conducted a joint collaborative study validating an ion chromatographic method for determination of inorganic anions (U.S. EPA method 300.0A and the equivalent proposed revision to ASTM method D4327). This study was conducted to determine the mean recovery and precision of analyses for bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate in reagent water, drinking water, and wastewater. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The test waters were spiked with the anions at 6 concentration levels, prepared as 3 Youden pairs. The 22 volunteer laboratories were instructed to dilute 10 mL sample concentrate to 100 mL test water. A measured volume of sample (20-200 μL) was injected into an ion chromatograph equipped with a guard column, anion exchange column, and a chemical micromembrane suppression device. The anions were then separated using 1.7 mM sodium bicarbonate and 1.8 mM sodium carbonate, and measured by a conductivity detector. Submitted data were evaluated using U.S. EPA's IMVS computer program, which follows ASTM D2777-86 statistical guidance. U.S. EPA method 300.0A and ASTM method D4327 were judged acceptable for measurement of the above anions (except sulfate) at concentrations ranging from 0.3 to 25 mg/L and sulfate concentrations from 2.9 to 95 mg/L. Mean recoveries for the 7 anions from all matrixes, as estimated from the linear regression equations, ranged from 95 to 104%. At concentrations above 2-6 mg/L for bromide, fluoride, nitrate, nitrite, and orthophosphate, and above 24 mg/L for sulfate, the overall and single-analyst relative standard deviations were less than 10 and 6%, respectively. As concentrations decreased, precision became more variable. The relative standard deviations of results for chloride were slightly higher than the other anions, especially in matrixes with high chloride background. Analysis of Variance (ANOVA) tests at the 95% confidence interval indicated a statistically significant matrix effect for chloride, nitrite, and nitrate analyses in drinking water compared to analyses in reagent water. Because these matrix effects were caused by the spiking process and not the drinking water itself, the ANOVA determination was not considered to be of practical significance.
Capillary Gas Chromatographic Determination of Thiabendazole in Citrus and Apple Juices
Authors: Oishi Mitsuo , Onishi Kazuo , Kano Itsu , Nakazawa Hiroyuki , Tanabe Shinzo
Published: February 2020

A rapid and simple procedure for the determination of thiabendazole (TBZ) residue in citrus and apple juices is described. A juice sample is made basic with 2M NaOH and applied to a disposable Extrelut prepacked column. TBZ is eluted with hexane–ethyl acetate (3 + 1) from the column. The eluate is evaporated to dryness under reduced pressure and then dissolved in an internal standard solution. TBZ is monitored without derivatization by capillary gas chromatography with nitrogen-phosphorus detection. The recoveries of TBZ added to fruit juices at 0.05-1.0 μg/g were 90-96%. The limit of detection of the method for TBZ was 0.01 μg/g. The proposed method is rapid, simple, and sensitive and is applicable to the determination of TBZ in commercial fruit juices.
Liquid Chromatographic Determination of Nifursol in Concentrates, Premixes, and Finished Turkey Feeds
Authors: De Vries Ellen Jan , Bas Richard C , Kuil Henny
Published: February 2020

A specific liquid chromatographic method was developed for determination of nifursol in premixes and turkey feeds. Nifursol is extracted from test sample into tetrahydrofuran. Butylhydroxytoluene is added to prevent degradation of nifursol. The extract is diluted with tetrahydrofuran–water (50 + 50, v/v); an aliquot is injected onto a Zorbax ODS column. The mobile phase is water-acetonitrile (525 + 475, v/v) adjusted to an apparent pH of 3.5 with formic acid and ammonia. The wavelength of detection is 380 nm. The system can separate nifursol from dimetridazole and ronidazole. The method is specific; has linearity of more than one order of magnitude; and has a limit of quantitation in the 1–2 ppm range. Recovery averaged 98% or more, and the reproducibility had a coefficient of variation of better than 2.5% in pelleted feed.
Liquid Chromatographic Determination of Diclazuril in Premix and Supplemented Feed: Interlaboratory Study
Authors: Fontaine Andre , Haustraete Karel
Published: February 2020

Diclazuril, Janssen Research Compound R 64433 (Clinacox), is analyzed by liquid chromatography (LC). Compound R 062646, with a structure analogous to that of diclazuril, is used as internal standard. The drug is extracted from feed with acidified methanol. Diclazuril is then isolated by solid-phase extraction (SPE) with a cartridge containing a C18 phase. The eluate is evaporated, and the residue is redissolved in dimethylformamide. An aliquot is injected onto a reversed-phase ODS LC column, and the drug quantitated at 280 nm with a UV detector. Peak areas are obtained at the retention times corresponding to the internal standard and diclazuril. The quantity of active ingredient is determined by comparing the ratio of the peak height of diclazuril to that of internal standard in the sample with the same ratio in a single calibration solution. SPE is not necessary for the analysis of premixes. Eleven laboratories participated in the collaborative study. Laboratories were provided with 2 samples of premixes and 3 samples of feed for poultry. Feed sample K1 was sent to only 6 laboratories. The reproducibility relative standard deviations (RSDRS) were 7.38 and 7.53% for the 2 premixes and 9.67,13.65, and 18.61% for the 3 samples of supplemented feed.
Determination of Chlorobiphenyls in Cleaned-Up Seal Blubber and Marine Sediment Extracts: Interlaboratory Study
Authors: Boer Jacob De , Der Meer Jaap Van , Reutergårdh Lars , Calder John A
Published: February 2020

An interlaboratory study on the determination of individual chlorobiphenyl congeners (CBs) in cleaned-up seal blubber and marine sediment extracts was organized by the International Council for Exploration of the Sea, the Intergovernmental Oceanographic Commission, and the Oslo and Paris Commissions, as the second part of a stepwise-designed interlaboratory study on the determination of CBs in marine media. Fifty-eight laboratories from 16 countries participated in this exercise, which involved the determination of 10 CBs in a standard solution, a cleaned-up seal blubber extract, and a cleaned-up marine sediment extract. Suggestions were given for instrument optimization. Standard errors of 1.16–1.17 for the standard solution, 1.20–1.33 for the seal blubber extract, and 1.31–1.56 for the sediment extract were obtained for CBs 52,101,118,138,153, and 180 by all laboratories with the exception of the laboratories giving consistently outlying results. The results for CBs 28,31,105, and 156 showed larger standard deviations. The 2 major difficulties for participants in this exercise were correct preparation of a calibration solution and chromatographic separation. The results of the sediment analysis showed a complete lack of agreement. It is recommended that, prior to the organization of the third part of this study, participants should install gas chromatographic columns with minimum lengths of 50 m and maximum internal diameters of 0.25 mm and should prepare calibration solutions from solids of known purity.
Radionuclides in Domestic and Imported Foods in the United States, 1987–1992
Authors: Cunningham William C , Anderson David L , Baratta Edmond J
Published: February 2020

Findings from the U.S. Food and Drug Administration’s Radionuclides in Foods program are summarized for foods collected between October 1,1986, and September 30,1992. Concentrations of radionuclide activity in the Total Diet Study and reactor-survey foods were in Range I or low in Range II of the surveillance and control recommendations of the Federal Radiation Council; no control actions were suggested. Dietary intake of 90Sr continued the general decline observed since 1961. Approximately 2600 test portions of imported foods were analyzed for contamination associated with the Chernobyl nuclear accident. Concentrations of radionuclide activity were below limits of detection for the vast majority of the imported food test portions but were above the levels of concern for 23 portions. Since 1986, the fraction of imported food test portions having measurable amounts of contamination has steadily declined, as have the average concentrations of radionuclide activity; however, contamination is still occasionally found. Continued monitoring of both domestic and imported foods is planned.
Liquid Chromatographic Determination of Cromolyn Sodium and Related Compounds in Raw Materials
Authors: Duhaime Randy M , Rollins Lorna K , Gorecki Dennis J K , Lovering Edward G
Published: February 2020

Liquid chromatographic methods for the assay of cromolyn sodium and 3 related compounds were developed. The methods, which differ only in the composition of the mobile phase, use an octadecylsilane bonded-phase column and an acetonitrile–water–cetyltrimethylammonium bromide mobile phase. Minimum quantitatable amounts of the related compounds were less than 0.05%; assay method precision was better than 1 %. Impurity levels in raw material samples from 4 manufacturers were less than 0.1 %.
Liquid Chromatographic Determination of Amiodarone Hydrochloride and Related Compounds in Raw Materials and Tablets
Authors: Lacrok Pauline M , Curran Norman M , Sy Wing-Wah , Goreck Dennis K J , Thibault Pierre , Blay Pearl K S
Published: February 2020

A liquid chromatographic method for the determination of amiodarone hydrochloride and 10 related compounds in drug raw material and for assay of drug in tablets was developed. The method specifies a 3 jxm Hypersil nitrile column (150 × 4.6 mm), a mobile phase of 1 + 1 acetonitrile–ammonium acetate buffer (0.1 M adjusted to pH 6.0 with 0.1 M acetic acid), a flow rate of 1 mL/min, and detection at 240 nm. The lower limit of quantitation of the related compounds is 0.02% or less. Drug contents in 2 raw material samples were 100.1 and 99.9% and ranged from 98.2 to 99.4% in 3 tablet formulations. Impurity levels in 2 samples of raw material from different manufacturers were ca 0.4%. The presence of 3 of the known related compounds in these samples was confirmed by liquid chromatographymass spectrometry. The method applied to raw materials was evaluated by a second laboratory and found to be satisfactory.
Detection of Salmonella in Dry Foods Using Refrigerated Pre-Enrichment and Enrichment Broth Cultures: Summary of Collaborative Study
Authors: D’Aoust Jean-Yves , Sewell Anne M , Greco Paula
Published: February 2020

A collaborative study was conducted to compare the productivity of refrigerated pre-enrichment and enrichment broth cultures with the U.S. Food and Drug Administration culture methods for detection of Salmonella. The refrigerated pre-enrichment and selective enrichment broth culture methods for detection of Salmonella in dry foods have been adopted first action by AOAC INTERNATIONAL.
Extraction of Aflatoxins from Naturally Contaminated Peanuts with Different Solvents and Solvent/Peanut Ratios
Authors: Cole Richard J , Dorner Joe W
Published: February 2020

A study was conducted to compare the extraction efficiencies of aflatoxins (B1, B2, G1, and G2) from low, medium, and high concentrations (approximately 10,100, and 1000 ppb, respectively) of naturally contaminated peanut samples by using different solvents and solvent-to-peanut sample ratios. Solvents used were 80:20 methanol/water at 2:1,3:1, and 5:1 solvent to sample ratios; 60:40 methanol/water at 5:1 solvent to sample ratio; and 90:10 acetonitrile/water at 2:1 and 4:1 solvent to sample ratios. The solvents 80:20 methanol/water at a 3:1 ratio of solvent to sample and 90:10 acetonitrile/water at a 2:1 ratio were consistently more efficient than all other solvents, regardless of the aflatoxin concentration. The solvent 90:10 acetonitrile/water at a 4:1 solvent-to-sample ratio was consistently the least efficient regardless of aflatoxin concentration based on analytical results with liquid chromatography (LC). The results are relevant in selecting an appropriate extraction solvent for use at peanut grading points.
Comparison of Mercury and Copper Based Catalysts in the Kjeldahl Determination of Nitrogen in Meat and Meat Products: Collaborative Study
Authors: Price Cindy G , Webb Neil B , Smith Wertice J , Marks Harry M , Yoffe Aron M
Published: February 2020

A copper catalyst for use in AOAC Method 928.08, Nitrogen in Meat, Kjeldahl Method, was subjected to a collaborative study in which it was compared to the standard mercury catalyst. Nine laboratories (including one author’s laboratory) performed blind duplicate determinations of the protein content of 4 samples from each of 6 products (ground beef, canned ham, smoked ham, pork sausage, cooked sausage, and dry cured ham). On the average, protein concentrations obtained with the copper catalyst were lower than those obtained with the mercury catalyst by approximately 1% of the protein content of the meat. For example, with a sample containing 15% protein, the results obtained with mercury would be expected to be 0.15% higher than those obtained with copper. This difference is within the reproducibility standard deviations of the methods. The repeatability standard deviation with copper was on the average approximately 17% larger than that obtained with mercury, but the reproducibility standard deviations for the 2 procedures were not, statistically, significantly different. The Kjeldahl method for nitrogen determination in meat and meat products using copper catalyst has been adopted first action by AOAC INTERNATIONAL.
Gas Chromatographic Detection of Tris(2-chloroethyl) and Tris(2-butoxyethyl)phosphate in Groundwater by Large-Sample-Volume Injection
Authors: Suzuki Toshesari , Yaguchi Kumiko , Ohnishi Kazuo , Yamagishi Tatsunori
Published: February 2020

A capillary gas chromatograph equipped with a flame photometric detector (GC–FPD) for splitless injection of large sample volume was developed. The GC–FPD effectively diverted dichloromethane from the analytical column through a solvent diversion column and quantitatively retained tri(2-chloroethyl) phosphate (TCEP) and tris(2-butoxyethyl)- phosphate (TBXP) on a cold-trap column in front of the analytical column. The optimum conditions for 100 uL injections of TCEP and TBXP in dichloromethane at concentrations from 1 to 100 ng/mL were investigated. With the GC–FPD, relative standard deviations of the peak area and the retention time of the triesters injected at 10 ng/mL were less than 7.0 and 0.05%, respectively. These results were similar to those from normal splitless injection of 1 μL at 1 μg/mL in dichloromethane. A screening method for TCEP and TBXP in groundwater combined with liquid–liquid extraction with dichloromethane permitted detection at low nanogram-per-liter levels. Recoveries of TCEP and TBXP in 500 mL of groundwater were greater than 77.2 and 81.4%, respectively, each at fortified level of 10ng/L.
Determination of Metsulfuron Methyl and Its Two Metabolites in Crops by Liquid Chromatography with Ultraviolet Detection
Authors: Zhou Mjn , Li Gui-Yun , Whalen Stephanie A
Published: February 2020

Metsulfuron methyl, its hydroxy metabolite (A1), and its glucose conjugate metabolite (A) were determined in several crops by liquid chromatography (LC) using a simple extraction and cleanup scheme. After the parent and 2 major metabolites were extracted from crops with methanol, metabolite A was enzymatically hydrolyzed to metabolite A1 with β-glucosidase. The treated extracts were cleaned up chromatographically, and then metsulfuron methyl and metabolite A1 were quantitatively determined by reversed-phase LC with UV detection at 254 nm. Recovery of metsulfuron methyl and its 2 metabolites was 90 ± 6% over a range of 0.005 to 0.4 ppm from fortified samples of brown grain, wheat, barley, sugarcane stalk, and oat straw. Method detection limits (MDLs) were 0.005 ppm for metsulfuron methyl, 0.006 ppm for metabolite A, and 0.003 ppm for metabolite A1 in such crops as brown grain, wheat, barley, and sugarcane, and 0.01 ppm for metsulfuron methyl, 0.015 ppm for metabolite A, and 0.01 ppm for metabolite A1 in oat straw. The MDLs were estimated on the basis of a signal-to-noise ratio of 5 within a confidence interval of 95%. The method has potential application for the analyses of these analytes in other crops and feeds and may be applicable to other sulfonylurea herbicides.
Use of Trimmed Duplicates Derived from Laboratory Data To Estimate Standard Deviation
Authors: Johnson Richard L , Latimer George W , Spiegelman Cliff
Published: February 2020

Improved standard deviation estimates from possibly biased duplicate measurements can be derived from appropriately trimmed plots of standard deviation estimates using pairs of replicates vs the quantiles of a half-normal distribution. Simulated studies show that these estimates exhibit generally lower mean-squared errors and biases than do more standard robust estimators of location—¾ times the interquartile range and 3/2 times the mean absolute deviation from the median.
Estimation of Parameters Relating Crude Fiber in Feeds to Acid–Detergent Fiber
Authors: Jones Neil E
Published: February 2020

By regression analysis of data from 80 check samples from the Association of American Feed Control Officials and applying the least-squares cubic method to the problem of statistical errors in both variables, it was determined that the best linear relation between the percent crude fiber value of a feed and the corresponding percent acid–detergent fiber value is crude fiber (%) = 0.77 × acid–detergent fiber (%) − 0.49.
Voltammetric Determination of Acid Values of Fats and Oils
Authors: Kusu Fumtyo , Fuse Tetsuo , Takamura Kiyoko
Published: February 2020

A new method for determining acid values of fats and oils was developed based on measurement of reduction prepeak current of 2-methyl-1,4-naphthoquinone (VK3) from 8 × 10−6 to 6 × 10−3 M, due to free fatty acid (e.g., linoleic acid). Acid value of 11 samples was determined. The relative standard deviation of acid value for 5 replicates of each sample was less than 2.5%. The method is superior to conventional titration methods in sensitivity and overcomes inaccuracy due to vagueness in color change of acidbase indicators in organic solvents.
International Survey on Dietary Fiber: Definition, Analysis, and Reference Materials
Authors: Lee Sungsoo C , Prosky Leon
Published: February 2020

An international survey was conducted to get the views of 147 professionals in the field on the definition of dietary fiber. The survey also solicited opinions on analytical methods for nutrition labeling, quality control, and nutrition research. The survey finds that dietary fiber is generally defined as polysaccharides and lignin that are not hydrolyzed by human alimentary enzymes. Support is strong for expansion of the definition to include oligosaccharides that are resistant to hydrolysis by human alimentary enzymes. Among techniques for nutrition labeling and quality control, enzymatic-gravimetric methods get the highest support. For nutrition research, more detailed methods such as gas-liquid chromatography and liquid chromatography were considered more appropriate. Respondents support labeling of total, soluble, and insoluble dietary fiber or total dietary fiber alone as sufficient for nutrition labeling of food packages. However, for nutrition research, detailed analytical methods, improvements in accuracy (i.e., closer simulation of in vitro techniques to conditions of human gastrointestinal tract), and improvements in precision and simplicity are suggested. Less than 20% of the participants use reference materials for dietary fiber analysis.
Liquid Chromatographic Methods for Fluoxetine Hydrochloride, Its meta Isomer, and Related Compounds in Raw Materials
Authors: Lacrok Pauline M , Yat Patrick N , Lovering Edward G
Published: February 2020

Liquid chromatographic (LC) methods were developed for assay of fluoxetine hydrochloride, its meta isomer, and 12 related compounds in drug raw materials. The method for assay and determination of the meta isomer requires an Exsil ODS-B column; a mobile phase consisting of tetrahydrofuran, acetonitrile, and buffer; a flow rate of 1 mL/min; and detection at 214 nm. The method for related compounds specifies a Spherisorb nitrile column; a mobile phase consisting of tetrahydrofuran, acetonitrile, and buffer; a flow rate of 1 mL/min; and detection at 214 nm. The limits of quantitation in the presence of the drug are 0.1% for the meta isomer and 0.05% or less for the related compounds. Assay precision was less than 1.0% on triplicate weighings. Drug contents of 4 raw material samples were between 98.8 and 100.1%. Impurity levels in the 4 samples ranged from 0.14 to 0.45%. In addition, one sample contained ca 0.13% of the meta isomer. A second analyst, using columns from different suppliers, obtained similar results.
Stability-Indicating Proton Nuclear Magnetic Resonance Spectroscopic Method for Determination of S-Adenosyl-L-Methionine in Tablets
Authors: Revelle Larry K , d’Avignon D André , Reepmeyer John C , Zerfing Richard C
Published: February 2020

We present a simple, accurate, stability-indicating nuclear magnetic resonance (NMR) method for determining active (S,S) and inactive (R,S) epimers of S-adenosyl-L-methionine (SAM) in tablets. The SCH3 resonances of SAM epimers were well resolved at 300 MHz. Individual assays of 5 SAM tablets gave SAM values of 101.3 ± 1.7% of declared amounts. Tablet solutions were assayed at a level of 8.0 mg/mL, but the method was linear for SAM concentrations ranging from 64 to 1 mg/mL (correlation coefficient, 0.9996). Reproducibility was indicated by a relative standard deviation of 0.33% for 6 replicate assays for total SAM at a concentration of 8 mg/mL. In contrast to the propietary liquid chromatographic (LC) method, which requires SAM as an external standard, the NMR method uses sodium trimethylsilylpropionate-d4 (TSP) both as an internal standard and as a chemical shift reference. The method was used to test the stability of SAM analytes under various pH levels and temperatures. We found 8% inactivation of SAM due to epimerization over a 24 h period at room temperature and pH 5. SAM solutions showed no detectable inactivation after 14 days when stored below 0°C.
Production of Monoclonal Antibodies Specific to Clostridium botulinum Type B Neurotoxin
Authors: Noah Charles W , Poteet Sherilyn S , Ramos Nora C , Perez John C , Huang Shyi Y
Published: February 2020

Four monoclonal antibodies were produced for use in a rapid method to detect Clostridium botulinum type B neurotoxin. Cells of mouse myeloma cell line SP2/0 were fused with splenocytes of immunized BALB/c mice. An immunoblot assay of semipurified commercial neurotoxins of C. botulinum types A, B, C, D, E, and F was used to show specificity. All the monoclonal antibodies reacted with type B neurotoxin but did not cross-react with the other types. The monoclonal antibodies, separately and combined, did not neutralize the toxin in mice, and all showed specificity to the whole neurotoxin molecule and the heavy-chain component by immunoblot. No evidence of specific binding to the hemagglutinin molecule was noted. When tested against concentrated cultured supernatants of C. botulinum types A, B, E, and F, the 4 monoclonal antibodies reacted only against type B strains. They will be incorporated into a rapid assay with other specific monoclonal antibodies to detect C. botulinum neurotoxins from pure cultures or suspect foods.
Gas Chromatographic Method for Quantitation and Confirmation of Trichothecenes in Wheat
Authors: Furlong Eliana B , Valente Soares Lucia M
Published: February 2020

A capillary gas chromatographic method with flame ionization detection was evaluated for quantitation and confirmation of 7 trichothecenes known to occur in grain crops. The method was applied to spiked and naturally contaminated wheat samples. Samples were extracted with methanol-aqueous KCI. After clarification with ammonium sulfate and partition to chloroform, a charcoal–alumina–Celite column cleanup was used. Heptafluorobutyryl derivatives of trichothecenes were quantitated with a methyl eicosanoate internal standard. Confirmation of identity was achieved by comparing the chromatographic behavior of suspected samples with those of standards after acetylation and hydrolysis for group A trichothecenes, and acetylation and reduction for group B trichothecenes. Limits of detection ranged from 0.1 to 0.5 μg/g. Average recoveries for diacetoxyscirpenol (DAS) and nivalenol (NIV) determined at 7 levels of contamination were 88 and 93%, respectively. Average recoveries for deoxynivalenol, NIV, DAS, T2 tetraol, and T2 triol at a single level of contamination were 85,87,83,87, and 91 %, respectively. Relative standard deviations for determinations of naturally contaminated samples ranged from 2.8 to 12.9%. For spiked wheat samples, the relative standard deviations ranged from 4.6 to 11.9%.
Synchronous Spectrofluorimetric Determination of Total Amounts of the Six Polycyclic Aromatic Hydrocarbons Officially Designated as Indicators of Drinking Water Quality
Authors: De Alda-Villaizan Maria J López , García-Falcon Soma , Lage-Yusty Maria A , Simal-Lozano Jesús
Published: February 2020

We report a quick, simple method for determination of the joint concentration of the 6 polycyclic aromatic hydrocarbons (PAHs) designated by current legislation as quality indicators for drinking water and for surface waters destined for use as drinking water. Water samples are extracted with hexane, and total indicator PAH concentration is determined by synchronous spectrofluorimetry (optimal instrumental parameters are reported). The detection limit (5.0 ng/L), quantitation limit (8.4 ng/L), precision (coefficient of variation, 3.8%), and accuracy (recovery, 77%) were well within the legal bounds for reference methods.
Identification of Lead and Other Elements in Ceramic Glazes and Housewares by 109Cd-Induced X-Ray Fluorescence Emission Spectrometry
Authors: Anderson David L , Cunningham William C , Lemdstrom Tyler R , Olmez Ilhan
Published: February 2020

Radioisotope x-ray fluorescence spectrometry was investigated as a potential screening method for Pb and other elements in housewares. Thirty-six commercial houseware items and 87 ceramic test tiles (85 fired with hobby glazes and 2 blank bisques) were examined qualitatively for the presence of Pb by using 109Cd-induced L x-ray fluorescence emission spectrometry. For the housewares, the technique provided fast, nondestructive analysis of areas with about 10 cm diameters (general regions) to about 4 mm diameters (isolated design regions). Pb was found in 25 of 28 ceramicware items, in all 8 other housewares, and in all the testtile glazes above the limit of detection of 1 count per second (cps) for Pb Lβ x-rays. For housewares, Pb identification did not always correspond to Pb leachability. For 68 test-tile glazes labeled as containing Pb (39 of which were also labeled ‘dinnerware safe’ or ‘safe for food containers’), count rates ranged from 290 to 730 cps, whereas for the other 17 glazes labeled (with one exception) ‘nontoxic,’ much lower count rates (5–61 cps) were obtained. Other elements found in the housewares or test glazes were As, Au, Ca, Co, Cr, Cu, Fe, Mn, Nb, Ni, Rb, Sr, Y, Zn, and Zr.
Supercritical Fluid Extraction and Gas Chromatography/Ion Trap Mass Spectrometry of Pentachloromtrobenzene Pesticides in Vegetables
Authors: Lehotay Steven J , Ibrahim Medina A
Published: February 2020

An analytical approach using supercritical fluid extraction (SFE) followed by gas chromatography/ion trap mass spectrometry (GC/ITMS) was developed for the analysis of the fungicide pentachloromtrobenzene and several analogues in vegetables. The method was tested in the analysis of carrots, potatoes, green beans, celery, and radishes fortified with pentachloronitrobenzene, tetrachloronitrobenzene, pentachloroanisole, pentachlorothioanisole, pentachlorobenzene, hexachlorobenzene, and pentachloroaniline. An incurred carrot sample analyzed by the method was shown to contain hexachlorobenzene at 7 ± 3 ng/g, which agreed with the concentration (8 ± 4 ng/g) determined using a traditional solvent-based method. The SFE method consisted of the following steps: (1) homogenizing a 50 g vegetable sample and weighing a 3 g subsample; (2) mixing 2 g sorbent (Hydromatrix) with the subsample to absorb moisture and packing a 10 mL extraction vessel; (3) extracting with 40 mL C02 at 200 atm, 40°C, and a flow rate of 3 mL/min; and (4) collecting the extract on a 1 g alumina basic trap at 25°C and flushing with 8 mL isooctane. Collection of the extract on alumina efficiently removed chlorophyll and other matrix interferences. GC/ITMS in the electron-impact mode confirmed and quantitated the analytes at concentrations as low as 1 ng/g.
Validation of an Analytical Instrumental Method by Standard Addition Methodology
Authors: Rodríguez Luis Cuadros , Campaña Ana M García , Barrero Fermin Alés , Linares Carlos Jiménez , Ceba Manuel Román
Published: February 2020

A statistical procedure to validate an analytical methodology by standard addition methodology is described. The data set obtained in 3 calibration experiments with standard solutions, standard additions, and portions of sample is used. The accuracy of the analytical results is checked by comparison of analyte contents in the different calibrations and from the recovery. Mathematical expressions to estimate the statistical parameters are proposed. The statistical protocol has been applied to fluorimetric determination of molybdenum with alizarin S in vegetable tissues.
Adaptation of a Dry Ashing Procedure for Determination of Selenium by Fluorimetry in High-Fat Foods
Authors: Bellanger Jacques R
Published: February 2020

The wet ashing–dry ashing procedure for destruction of organic matter in high-fat foods for subsequent fluorimetric determination of selenium was investigated. Samples were decomposed by predigestion with nitric acid and dry-ashed with magnesium nitrate and hydrochloric acid. Selenium was recovered quantitatively through the total procedure. Detection limit was about 4 ppb. Accuracy was tested by analysis of several reference materials and by comparison with the wet-digestion method. The present method can be used conveniently for selenium determination in high-fat foods.
Rapid Extraction and Cleanup for Liquid Chromatographic Determination of Domoic Acid in Unsalted Seafood
Authors: Quilliam Michael A , Xie Mie , Hardstaff William R
Published: February 2020

Domoic acid is the toxin responsible for incidents of amnesic shellfish poisoning. A rapid extraction and cleanup for the liquid chromatographic determination of domoic acid in unsalted seafood is reported. The method uses a single-step extraction with 50% aqueous methanol and a selective cleanup and preconcentration with strong-anion exchange, solid-phase extraction. Determination is performed by liquid chromatography with ultraviolet absorbance detection. The detection limit was 20–30 ng/g. Recoveries of 93% were achieved from 0.2 to 20 μg/g in mussel tissues. The method gave a precision of less than 3% for concentrations greater than 2 μg/g and less than 6% at 0.2 μg/g. A linear dynamic range of 104 can be achieved. The method was successfully applied to a variety of seafood products, including mussels, razor clams, crabs, and anchovies.
Analysis of Diarrhetic Shellfish Poisoning Toxins in Shellfish Tissue by Liquid Chromatography with Fluorometric and Mass Spectrometric Detection
Authors: Quilliam Michael A
Published: February 2020

Diarrhetic shellfish poisoning (DSP) is a severe gastrointestinal illness caused by consumption of shellfish contaminated with toxigenic dinoflagellates. The main toxins responsible for DSP are okadaic acid (OA), DTX-1, DTX-2, and DTX-3, the latter being a complex mixture of 7-O-acyl derivatives of the first 3. In this study, existing methods based on liquid chromatography (LC) combined with mass spectrometry (LC–MS) and LC with fluorometric detection (LC–FLD) of anthryldiazomethane (ADAM) derivatives were improved upon to achieve a high degree of accuracy and precision for the determination of DSP toxins in a new mussel tissue reference material (MUS-2). All experimental parameters were examined comprehensively, and a new internal standard and a new solid-phase extraction cleanup method were introduced. Quantitative extraction of DSP toxins from shellfish tissue was achieved by exhaustive extraction with aqueous 80% methanol. Cleanup was accomplished by partitioning the crude aqueous methanol extract with hexane to remove lipids and then with chloroform to isolate the toxins. A further cleanup based on an aminopropylsilica column was useful for LC-MS and looks promising for the ADAM/LC-FLD method. The internal standard, 7-O-acetylokadaic acid, synthesized by partial acetylation of OA, improved accuracy and precision by correcting for incomplete recoveries in extraction, cleanup, and derivatization steps and for volumetric errors and instrumental drift. An improved silica cleanup after ADAM derivatization also was developed by controlling the activities of both sorbent and solvents. The methods were tested with various mussel tissue samples. The resulting improved methods will be useful to analysts involved in routine monitoring of DSP tox ins.
U.S. Food and Drug Administration Monitoring of Lead in Domestic and Imported Ceramic Dinnerware
Authors: Baczynskyj William M , Yess Norma J
Published: February 2020

The U.S. Food and Drug Administration (FDA) conducted a survey of domestic and imported ceramic dinnerware from January to February 1992 to determine the status of lead leaching from this ware. Ceramicware was screened at the collection point by using the Quick Color Test (QCT); if the QCT was positive, the ware was analyzed in the laboratory by using atomic absorption spectroscopy (AAS). For imports, 5222 lots were examined using the QCT. Of these lots, 46 exceeded FDA’s 1991 guidelines as determined by using AAS. For domestic ware, 676 lots were examined using the QCT, and 17 lots exceeded the 1991 guidelines. The violation rates, 0.9% for imports and 2.5% for domestic ware, were about twice as high as they would have been under the 1980 guidelines.
Survey of Deoxynivalenol in U.S. 1993 Wheat and Barley Crops by Enzyme-Linked Immunosorbent Assay
Authors: Trucksess Mary W , Thomas Frederick , Young Kathryn , Stack Michael E , Fulgueras Wendy J , Page Samuel W
Published: February 2020

Wheat and barley from the 1993 crop year were analyzed for deoxynivalenol (DON). A total of 630 samples were collected by the Federal Grain Inspection Service in 25 states and analyzed using a commercially available, direct competitive, enzyme-linked immunosorbent assay. The limit of determination was about 0.5 μg/g. DON contamination in the 483 wheat samples averaged 2.0 μg/g and ranged from <0.5 to 18 μg/g. DON contamination in the 147 barley samples averaged 4.2 μg/g and ranged from <0.5 to 26 μg/g. About 40% of the wheat samples and 57% of the barley samples contained DON levels that were greater than the U.S. Food and Drug Administration 1982 advisory level of 2 μg/g for DON in wheat designated for milling (human consumption).
Determination of Sulfadimethoxine and Sulfamethazine Residues in Animal Tissues by Liquid Chromatography and Thermospray Mass Spectrometry
Authors: Boison Joe O , Keng Lily J-Y
Published: February 2020

A simple, sensitive, and rapid method for simultaneous determination of sulfamethazine and sulfadimethoxine residues in animal tissues by liquid chromatography (LC) with on-line confirmation by thermospray mass spectrometry is reported. Tissue extracts, after cleanup on C18 cartridges, were injected into a reversed-phase C18 column, and the sulfa drugs were determined by ultraviolet (UV) detection at 265 nm. On-line confirmation of sulfamethazine and sulfadimethoxine in the extracts by mass spectrometry was obtained by feeding the sulfa drugs eluting from the chromatographic column after UV detection directly into the ion source of a mass spectrometer with a thermospray ionization LC interface. Analytical results obtained with the LC method, which has detection limits of 2 and 10 ng/g of tissue, for sulfamethazine and sulfadimethoxine, respectively, compared favorably with those obtained with the official thin-layer chromatographic–densitometric method.
Identification of an Impurity in Commercial Sources of the Tomato Glycoalkaloid Tomatine
Authors: Bushway Rodney J , Perkins Lewis B
Published: February 2020

Three commercial sources of tomatine showed 2 peaks of approximately equal size when determined by liquid chromatography (LC). Analysis by liquid chromatography/mass spectroscopy (LC/MS) showed one LC peak having an [M + H] ion at 1035, which corresponds to tomatine. The other peak had an [M + H] ion at 1033, which indicates a tomatine-like molecule that has tomatidenol for the aglycone instead of tomatidine or solasodine. Ultraviolet data support a delta C-5–C-6 double bond in the aglycone. LC of tomatine hydrolysate indicated the presence of tomatidine and tomatidenol and the absence of solasodine. Thus, the impurity was dehydrotomatine. Purity calculations based on mass spectral data showed that the tomatine standards were 80% pure.
Liquid Chromatographic Determination of Vitamin K1 in Infant Formulas and Milk
Authors: Indyk Harvey E , Littlejohn Vernon C , Lawrence Richard J , Woollard David C
Published: February 2020

Vitamin K1 in infant formulas and milk products is determined by reversed-phase liquid chromatography (LC) with UV detection. The sample is hydrolyzed enzymatically, and the vitamin is extracted with hexane. Fractionation by normal-phase semipreparative LC is followed by analytical LC, with quantitation by the internal standard technique. Recovery of the analyte was 97.4 ± 2.8%. Linearity was established between 0.05 and 4.0 fig/mL. The limit of quantitation is 0.5 μg/100 g for milk powder, which allows the method to quantitate endogenous levels of vitamin K1.