bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Malachite Green and Its Metabolite, Leucomalachite Green, in Catfish (Ictalurus punctatus) Tissue by Liquid Chromatography with Visible Detection
Authors: Roybal José E , Pfenning Allen P , Munns Robert K , Holland David C , Hurlbut Jeffrey A , Long Austin R 
Published: February 2020

Abstract
To determine residues of malachite green (MG) and its metabolite, leucomalachite green (LMG), in catfish tissue, analytes are extracted with acetonitrilebuffer and the extract is partitioned into methylene chloride. Final cleanup and isolation are performed on neutral alumina solid-phase extraction (SPE) and propylsulfonic acid cation-exchange SPE columns before analysis by liquid chromatography with visible detection. PbO2 postcolumn oxidation is performed by isocratic elution with a buffered mobile phase from a cyano column. Recoveries and relative standard deviations (RSDs) from fortified catfish tissues were 72.9% (RSD, 1.92%; 23 ppb), 75.5% (RSD, 6.85%; 11 ppb), and 69.6% (RSD, 6.93%; 5.7 ppb) for MG and 87.4% (RSD, 2.92%; 21 ppb), 88.1% (RSD, 5.94%; 10 ppb), and 82.6% (RSD, 11.5%; 5.3 ppb) for LMG. The method was applied to MG-incurred catfish at depuration times of 0,2,4,8, and 24 h. Average levels of residual MG and LMG in the 24 h depuration catfish tissue were 73.4 and 289 ppb, respectively.
Detection of Sodium Channel Toxins: Directed Cytotoxicity Assays of Purified Ciguatoxins, Brevetoxins, Saxitoxins, and Seafood Extracts
Authors: Manger Ron L , Leja Linda S , Lee Sue Y , Hungerford Jem M , Hokama Yoshttsugi , Dickey Robert W , Granade H Ray , Lewis Richard , Yasumoto Takeshi , Wekell Marleen M 
Published: February 2020

Abstract
Neuroblastoma cells in culture were used to detect sodium channel-specific marine toxins based on an end-point determination of mitochondrial dehydrogenase activity. The assay responds in a dose-dependent manner to ciguatoxins, brevetoxins, and saxitoxins, and delineates the toxic activity as either sodium channel enhancing or sodium channel blocking. The assay responds rapidly to sodium channel activating toxins, allowing dose dependent detection in 4 to 6 h. Brevetoxins can be detected at 250 pg, and purified ciguatoxins are detected in the low picogram and subpicogram levels. The results obtained from cell bioassay of ciguatoxic finfish extracts correlates with those obtained from mouse bioassays. Sodium channel blocking toxins can also be detected with an approximate sensitivity of 20 pg in 24 to 48 h. This cell-based technique is simple, sensitive, demonstrates potential as an alternative to animal testing for sodium channel activating and blocking toxins, and can be automated.
Radioimmunoassay for PbTx-2-Type Brevetoxins: Epitope Specificity of Two Anti-PbTx Sera
Authors: Poli Mark A , Rein Kathleen S , Baden Daniel G 
Published: February 2020

Abstract
Antiserum against PbTx-2-type brevetoxins was produced by immunizing rabbits with a PbTx-2–bovine serum albumin (BSA) conjugate. This serum had a higher affinity, but lower titer, than our current goat serum. Using 4 natural brevetoxins and 6 synthetic derivatives as competitors in our brevetoxin radioimmunoassay, we determined the epitope specificity of both sera. Modification of the backbone structure at C-42 on the K-ring had little or no effect on the antigen-binding capability of either serum. Reduction of the double bond between C-2 and C-3 on the A-ring by reduction of the lactone decreased binding 500 to 750-fold. Epoxidation of the double bond between C-27 and C-28 on the H-ring did not affect binding, which suggested that the goat serum is specific for the A-ring region of the brevetoxin backbone. In contrast, modifying the A-ring had no effect on rabbit serum binding. However, epoxidation of the H-ring decreased binding 5 to 20-fold, which suggested that the rabbit antiserum is specific for the H-ring region of the molecule. These results suggest that assays utilizing only one antibody may not adequately detect toxin metabolites if molecules are altered in the critical region of antibody recognition.
Determinations of Marine Toxins in Foods
Authors: Yasumoto Takeshi , Fukui Masakazu , Sasaki Katsunori , Sugiyama Kiminori 
Published: February 2020

Abstract
Prospects of new analytical methods for determining marine toxins in foods are described. The methods discussed include fluorometric liquid chromatography, cytotoxicity assays, channel binding assays, and enzyme-immunoassays. Emphasis was laid on assay methods for ciguatoxins and diarrhetric shellfish toxins.
Microbiological Plate Assay for Determination of Tilmicosin in Bovine Serum
Authors: Coleman Mark R , Peloso James S , Moran John W 
Published: February 2020

Abstract
A microbiological agar plate assay is described for determination of tilmicosin in bovine blood serum. The serum or serum dilution is added directly to wells cut in the agar plates. Tilmicosin activity is determined by measuring the zone of bacterial growth inhibition in agar medium inoculated with Micrococcus luteus, ATCC 9341. The assay was validated by evaluating the following parameters: accuracy, precision, linearity, parallelism, ruggedness, storage stability, and relative activity of isomers. Accuracy was evaluated with freshly collected bovine serum and with commercially available sera. Recoveries ranged from 93.4 to 97.5% across a fortification range of 0.08 to 1.28 μg/mL. Precision was estimated over a 6-day period with serum obtained from a tilmicosin-treated animal. Relative standard deviations were 0.63 to 3.13% within day and 5.23% across 6 days. Standard curves were linear with little variation in slope. No parallelism was observed between tilmicosin in serum and tilmicosin in buffered saline. The limit of detection was estimated to be 0.05 μg/mL, and the validated limit of quantitation was 0.08 μg/mL. Ruggedness was evaluated with different lots of antibiotic medium, different lots of sera, and different analysts. These variables did not affect method performance. Analyses of tilmicosin in frozen sera demonstrated that tilmicosin is stable for up to 16 days when stored at −20°C. A comparison of the relative microbiological activities of the purified cis and trans isomers of tilmicosin to that of the reference standard indicated no differences in microbiological activities, and showed a parallel response among the 3. The validation data demonstrate that this method is a rugged, reliable, and simple assay for tilmicosin in serum.
Liquid Chromatographic Determination of Fluorescent Derivatives of Six Sulfonamides in Bovine Serum and Milk
Authors: Tsai Chin-En , Kondo Fusao 
Published: February 2020

Abstract
A rapid and sensitive liquid chromatographic (LC) method with fluorometric detection was developed to detect sulfadiazine, sulfathiazole, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, and sulfadimethoxine residues in bovine serum and milk. p-Aminobenzoic acid (PABA) was added as an internal standard. The sulfonamides were extracted from samples and derivatized with fluorescamine, and 50 μL was injected into a NovaPak C18 LC column and eluted with acetonitrile– 10 mM potassium phosphate (30 + 70, v/v). The sulfonamides were detected fluorometrically (excitation, 390 nm; emission, 475 nm), and their retention times ranged from 6.2 to 16.5 min without interference from coextractives. The detection limit for standard sulfonamide solution was 0.1 ng/mL; the calibration curves were linear between 1 and 100 ng/mL in the presence of PABA as internal standard. Recovery rates of sulfonamides from spiked samples (1 and 10 ppb) were 95.4–107.2 and 81.4–89.6% for serum and 80.7–91.1 and 62.6–84.1% for milk, respectively.
Determination of Soluble and Insoluble Dietary Fiber in Psyllium-Containing Cereal Products
Authors: Lee Sungsoo C , Rodriguez Flo , Storey Maureen , Farmakalidis Efi , Prosky Leon 
Published: February 2020

Abstract
A method for soluble and insoluble dietary fiber determinations was developed for psyllium-containing food products, which are highly viscous in aqueous solutions. The assay is based on a modification of the AOAC soluble and insoluble dietary fiber method (991.43), which was recommended for nutrition labeling in the final U.S. food labeling regulations. We found that method 991.43 and other existing dietary fiber methods could not be applied to psyllium food products, which exhibit high viscosity in aqueous solutions, because highly viscous solutions could not be filtered easily. In this study, we modified AOAC method 991.43 to accommodate the filtration process of viscous sample solutions. Sonication followed by highspeed centrifugation was used before filtration. The principles of the method are similar to those for AOAC method 991.43, including the use of the same 3 enzymes (heat-stable α-amylase, protease, and amyloglucosidase) as well as similar enzyme incubation conditions. The modification using sonication and high-speed centrifugation did not alter the method performance for analytically normal products such as wheat bran, oat bran, and soy fiber. Yet, the modification allowed the separation of soluble dietary fiber fractions from insoluble fractions for psyllium products with satisfactory precision. This method for psyllium dietary fiber determinations may be applied to other food products that exhibit high viscosity in aqueous solutions.
Multiresidue Method for the Chromatographic Determination of Triazine Herbicides and Their Metabolites in Raw Agricultural Products
Authors: Pardue John R 
Published: February 2020

Abstract
A method is described for the determination of 19 triazine herbicides and 4 metabolites in 6 agricultural products that represent diverse matrixes. In addition, a modification of this method to determine the more water-soluble metabolite, de-sethyldesisopropylatrazine, is described. In both these procedures, residues are extracted with methanol, and the product coextractives are removed using solvent partition and cation-exchange solid-phase extraction chromatography. A nitrogen phosphorus detector and DB-17 megabore column are used for the temperature-programmed chromatographic determination of samples fortified at 0.02–1.0 ppm levels. Average recoveries ranged from 81.1 to 106.2% for the parent herbicides and from 59.6 to 87.5% for the metabolites on all crops. An average recovery of 101.1% was obtained for de-sethyldesisopropylatrazine.
Microwave Digestion–Inductively Coupled Plasma Atomic Emission Spectrometric Determination of Boron in Raw Noodles
Authors: Ziaziaris John , Kacprzak Jurgen L 
Published: February 2020

Abstract
Samples of raw noodles in a mixture of nitric acid and hydrogen peroxide were microwave digested in sealed tetrafluoromethaxil (PTFE TFM) vessels. The digests were diluted to volume with distilled water and quantitated by inductively coupled plasma atomic emission spectroscopy (ICP–AES). The recoveries of boron for spikes of 2.5, 250, and 500 μg were 88,101, and 102%, respectively. The quantitation limit was estimated to be 1.5 mg B/kg. The method is rapid and ideally suited to large numbers of samples.
Improved Determination of Chlorite and Chlorate in Rinse Water from Carrots and Green Beans by Liquid Chromatography and Amperometric and Conductivity Detection
Authors: Beitler Mark K , Chin Henry B 
Published: February 2020

Abstract
A method is presented for determining chlorite and chlorate in the presence of interfering organic compounds in rinse water from vegetables. Rinse water from cut raw carrots and green beans was fortified separately with chlorite and chlorate, filtered (0.45 μm), and analyzed by liquid chromatography with amperometric and conductivity detection. Detection limits for chlorite and chlorate in carrot rinse water were 17 and 50 ppb, respectively. Average recoveries from rinse water were 95% for chlorite in a 0.084–1.00 ppm range and 90% for chlorate in a 0.078–1.00 ppm range.
Evaluation of Sampling Plans Used in the United States, United Kingdom, and The Netherlands To Test Raw Shelled Peanuts for Aflatoxin
Authors: Whttaker Thomas B , Springer Janet , Defize Peter R , Dekoe Willem J , Coker Ray 
Published: February 2020

Abstract
The United States is a large producer and exporter of peanuts. The United Kingdom and The Netherlands are major importers of U.S. peanuts. Each country has a different guideline or legal limit for peanut products containing aflatoxin. Peanuts are tested for aflatoxin in each country by using specifically designed aflatoxin sampling plans to determine if the aflatoxin concentration in a lot of raw shelled peanuts is less than the guideline or legal limit. For raw shelled peanuts, the U.S. plan has the highest sample acceptance limit of 15 ng total aflatoxin/g, the UK plan has a sample acceptance limit of 10 ng total aflatoxin/g, and the Dutch Code of Practice (called the Dutch plan) has the lowest sample acceptance limit at 3 ng aflatoxin B1/g. The U.S. plan uses a maximum of 3 sampling units, each weighing 21.8 kg; the UK plan uses a single sampling unit of 10 kg; and the Dutch plan uses 4 sampling units, each weighing 7.5 kg. The sampling variance is lowest for the U.S. plan and highest for the Dutch plan. The sample preparation variance is lowest for both the Dutch and UK plans and highest for the U.S. plan, primarily because of the mill type used to comminute the kernels in the sample. For a given distribution among lot concentrations, the U.S. plan accepts the greatest number of lots and the Dutch plan rejects the greatest number of lots. The average aflatoxin concentration among accepted lots is highest for the U.S. plan and lowest for the Dutch plan. The U.S. plan accepts the greatest number of good lots, whereas the Dutch plan rejects the greatest number of bad lots. The Dutch plan rejects the greatest number of good lots, whereas the U.S. plan rejects the lowest number of good lots. The Dutch plan accepts the lowest number of bad lots, whereas the UK plan accepts the greatest number of bad lots.
Immunoassay of Pesticides: An Update
Authors: Kaufman Bennett M , Clower Marion 
Published: February 2020

Abstract
Measurement of levels of pesticide residues in foods and crops most often requires extensive cleanup and instrumental techniques such as gas chromatography. Immunoassay measurement techniques, on the other hand, may be used directly on the test portion or require only minimal cleanup. Further refinements of the common antibody–enzyme-based solid-phase assays, such as use of coated magnetic particles, antibody-coated crystals, and continuous-flow devices, have extended the measurement range and applicability of these assays. Likewise, new immunoassays for pesticides have been developed, and existing assays have been refined, optimized, and more completely characterized and validated. In addition to their ability to accurately and reliably measure amounts of residues present in food and crops, immunoassays can be readily used as rapid screening methods for contaminants in field samples. We have previously reviewed much of the work in the area of pesticide immunoassay; this report updates previous information and discusses some new immunoassay techniques.
Statistical Analysis of Spectrometric Procedures for Determination of Fe(III) and V(V) with Desferrioxamine B
Authors: Luterotti Svjetlana , Grdinic Vladimir 
Published: February 2020

Abstract
For statistical evaluation of VIS-spectrometric procedures for determination of Fe(III) and V(V), with desferrioxamine B as a chromogenic agent, the slightly modified Gottschalk concept is used and found to be appropriate. Favorable metrological characteristics of both analytical procedures make them likely candidates for standard quantitative protocols.
Determination of Flunixin in Milk by Liquid Chromatography with Confirmation by Gas Chromatography/Mass Spectrometry and Selected Ion Monitoring
Authors: Rupp Heidi S , Holland David C , Munns Robert K , Turnipseed Sherri B , Long Austin R 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was developed for the determination of flunixin (FNX) in raw bovine milk. The milk was acidified and mixed with silica gel, and the mixture was packed into a chromatographic column. The column was defatted with water-saturated dichloromethane–hexane (30 + 70, v/v), and the analyte was eluted with EtOAc. The EtOAc extract was washed with water at pH 3.5, the water was discarded, and the EtOAc layer was then extracted with 0.1 M NaOH. The aqueous layer was drained, passed through a primed C18 solid-phase extraction (SPE) column, and eluted with EtOAc. The EtOAc layer was dried under N2, taken up in a solution of MeOH–(5 mM tetrabutylammonium [TBA]–H2PO4 + 2 mM NaOH) (50 + 50), sonicated, and filtered. FNX was determined by LC using a C18 column (ODS Hypersil), a mobile phase mixture of 58% A (MeOH) and 42% B (5 mM TBA–H2PO4 + 2 mM NaOH), and a diode-array ultraviolet detector at 285 nm. FNX was determined in raw milk at 5 spiking levels (5,10,20,40, and 80 ng drug/mL milk). Absolute recoveries ranged from 69.6 to 74.4%, and relative standard deviations ranged from 1.1 to 6.9%. The limit of quantitation was 1.7 ng drug/mL milk. A lactating cow was dosed intravenously (2.2 mg/kg) with flunixin meglumine (Banamine) to generate incurred milk residues. FNX residues ranged from 7.34 ng/mL at 16 h postdose to 1.74 ng/mL at 24 h postdose. Both levels were obtained with additional β-glucuronidase treatment (almost no incurred drug was detected at these low levels without the enzyme treatment). The presence of FNX in incurred milk was confirmed by gas chromatography/mass spectrometry with selected ion monitoring.
Multiresidue Determination of Pesticides in Fruit and Vegetables by Gas Chromatography–Mass-Selective Detection and Liquid Chromatography with Fluorescence Detection
Authors: Fillion Julbe , Hemdle Ralph , Lacrolx Mario , Selwyn Jennifer 
Published: February 2020

Abstract
A method is described for determining 199 pesticides in fruit and vegetables. Residues are extracted from samples with acetonitrile, and coextractives are removed with a miniaturized charcoal–Celite column cleanup. Analysis is performed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Two injections per sample are required to cover all compounds. Positive analytes are confirmed by retention time and ion ratios. Carbamates are analyzed by liquid chromatography with postcolumn reaction and fluorescence detection. Recovery data were obtained by fortifying 3 matrixes (pears, carrots, and bananas) at 0.1–0.5 ppm. In addition, the method demonstrated acceptable performance for analysis of other crops such as apple, strawberry, orange, pineapple, asparagus, beet, cucumber, tomato, pepper, squash, green peas, potato, and sweet potato. Limits of detection ranged from 0.02 to 0.2 ppm depending on the compound.
Market Basket and Duplicate Portion Estimation of Dietary Intakes of Cadmium, Mercury, Arsenic, Copper, Manganese, and Zinc by Japanese Adults
Authors: Tsuda Taizo , Inoue Tomohiro , Kojima Mihoko , Aoki Shigeru 
Published: February 2020

Abstract
Daily intakes of selected metals from meals in Shiga Prefecture (Japan) were investigated by the duplicate portion method and market basket method. In 1991 and 1992, daily intakes of metals by women, determined by the duplicate portion method, were, respectively, 37 and 27 μg for Cd, 4.3 and 3.5 μg for Hg, 260 and 210 μg for As, 1200 and 1200 (ig for Cu, 4700 and 3600 (ig for Mn, and 8000 and 7200 μg for Zn. Those determined by the market basket method were, respectively, 32 and 35 μg for Cd, 4.3 and 9.9 μg for Hg, 160 and 280 μg for As, 1100 and 980 μg for Cu, 3600 and 4700 μg for Mn, and 8700 and 8500 fig for Zn. No wide differences between the 2 methods were found, except for Hg data in 1992. Daily intakes of Cd and Hg in Shiga Prefecture were lower than the provisional tolerable daily intakes of 57-72 μg for Cd and 43 μg for Hg, proposed by the Food and Agricultural Organization and the World Health Organization.
Determination of Reserpine and Chlorothiazide in Commercial Tablets by Liquid Chromatography with Fluorescence and UV Absorbance Detectors in Series
Authors: Cieri Ugo R 
Published: February 2020

Abstract
A procedure is presented for determination of reserpine and chlorothiazide in commercial tablets by liquid chromatography (LC). Powdered sample, equivalent to the weight of one tablet, is dissolved in 10.0 mL dimethyl sulfoxide, the mixture is diluted to 100.0 mL with methanol, and the solution is filtered; 10 mL of the filtrate is then diluted to 100.0 mL with methanol. The standard solution is prepared in the same solvent mixture and contains the 2 ingredients in approximately the same quantities as in the diluted sample solution. For LC, a 7.5 cm long normal-phase column is used; mobile phase consists of methanol containing a small volume of an aqueous solution of 1-pentanesulfonic acid, sodium salt. Two detectors are arranged in series: a fluorescence detector set at 280 nm excitation and 360 nm emission quantitates reserpine and a UV absorbance detector set at 300 nm determines chlorothiazide. Several synthetic mixtures containing the 2 ingredients in amounts ranging from 80 to 120% of quantities declared in commercial tablets were analyzed by the proposed method. Two samples of commercial tablets were also analyzed; for each sample, 5 determinations were made on a ground composite of 20 tablets; 10 individual tablets were also analyzed. The composites were also analyzed by the current U.S. Pharmacopeia method for this product.
Determination of Thiabendazole Residues in White and Sweet Potatoes by Liquid Chromatography with Fluorescence Detection
Authors: Arenas Rene V , Rahman Hafizur , Johnson Nelson A 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was developed for determination of thiabendazole (TBZ) residues in or on whole, unwashed white potatoes (Solarium tuberosum) and sweet potatoes (Ipomoea batatas). TBZ is extracted from the potato homogenate with ethyl acetate and the extract purified and concentrated on a cation-exchange, solidphase extraction column. The extract is analyzed for TBZ residues by column LC with a cation-exchange column and fluorescence detection. Recoveries of TBZ from whole white potatoes fortified with TBZ at 0.05–20 ppm and from whole sweet potatoes fortified with TBZ at 0.005–0.1 ppm averaged 100 and 94%, respectively. The method is also applicable for quantitation of TBZ residues in white potato waste (dried peel) used as an animal feed additive. The present method for monitoring TBZ residues in white and sweet potatoes and white potato waste (dried peel) is simple, rapid, and sensitive.
Analysis of 2,2,2-THfluoroethyl Derivatives of Carboxylic Acid Herbicides by Gas Chromatography with Mass-Selective and Electron Capture Detection
Authors: Lee Arthur S , Hong Moo-Ki , Smith Albert E 
Published: February 2020

Abstract
A method for derivatizing carboxylic acid herbicides with 2,2,2-trifluoroethanol (TFE) in preparation for gas chromatographic (GC) analysis was developed. Esterification efficiency was determined by GC with electron capture detection (ECD), and esters were identified by GC with mass-selective detection (MSD). On the basis of reaction temperature for optimum esterification efficiency, 13 common carboxylic acid herbicides were separated into 2 groups before reaction with TFE. TFE derivatization was optimized for simultaneous analyses by altering reaction temperature, reaction time, and concentration of sulfuric acid in reaction solutions. The method is simple, safe, and economical, and it gives good resolution without a laborious cleanup. Recovery of 13 analytes from water, taken from a pesticide residue well, was greater than 80% for all except 2 analytes. The well-water was fortified with analytes at the lower microgram-per-liter concentrations required for detection of pesticide residues in potable water systems. The method can simultaneously determine multiple herbicide residues in water samples with a high degree of accuracy and precision.