bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of 30 Acidic Herbicides and Related Compounds as Their Pentafluorobenzylic Derivatives Using Gas Chromatography/Mass Spectrometry
Authors: Heberer Thomas , Butz Susanne , Stan Hans-Juergen 
Published: February 2020

Abstract
Thirty phenoxyalkanoic acids, other acidic herbicides, and related compounds were derivatized with pentafluorobenzyl bromide to form their pentafluorobenzylic derivatives. Mass spectra are presented. Determination and detection of the derivatives was performed by capillary gas chromatography (GC)/mass spectrometry. With selected- ion monitoring, an optimized GC method, and appropriate time-window setting, the determination of all compounds could be achieved in a single GC run. The determination of ≤1 pg of the target compounds was achieved using electron-impact ionization in selected-ion monitoring mode. Most of the analytes were extracted from tap water, and recoveries were 80–100% when solid-phase extraction was applied with a carefully selected reversedphase-C18 adsorbent. The method enabled the detection of these contaminants from drinking water at the low nanogram-per-liter level when applying a concentration factor of 10 000.
Determination of Tin in Canned Fruits and Vegetables by Atomic Absorption Spectrometry and Liquid–Liquid Extraction
Authors: Martín Ana M , Sánchez Mercedes , Espinosa Pedro , Bagur Gracia 
Published: February 2020

Abstract
A method was developed for the determination of tin based on the extraction of its 5,5-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7,50 μg tin) were 0.20 μg/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.
Cleanup with Two Florisil Columns for Gas Chromatographic Determination of Multiple Pyrethroid Insecticides in Products of Animal Origin
Authors: Pang Guo-Fang , Zhao Tie-Sheng , Chao Yan-Zhong , Fan Chun-Lin 
Published: February 2020

Abstract
A gas chromatographic method was developed for the simultaneous determination of 9 pyrethroid insecticides in products of animal origin. The multiresidues of the pyrethroids in different samples were extracted with acetone–petroleum ether (1+1), and extracts were cleaned up on a Florisil partition column and a Florisil adsorption column. Four animal tissue samples were examined at 0.05–0.25 ppm fortification levels. The average recoveries of all insecticides were 76.9–88.0%, and the coefficients of variation were &lt;4.6% for all insecticides except permethrin. The detection limits of the method were ca 5 ppb for all insecticides but permethrin, which had a detection limit of ca 10 ppb.
Effects of Sample Size and Sample Acceptance Level on the Number of Aflatoxin-Contaminated Farmers’ Stock Lots Accepted and Rejected at the Buying Point
Authors: Whitaker Thomas B , Wu Jeremy , Dowell Floyd E , Hagler Winston M , Giesbrecht Francis G 
Published: February 2020

Abstract
Sixteen different aflatoxin sampling plan designs were evaluated using the negative-binomial distribution. Evaluations were used to predict the effects of 4 different sample sizes and 4 different sample acceptance levels on the classification of farmers’ stock lots according to the lot aflatoxin concentration. The 4 sample sizes evaluated were 2.27 kg (5 lb), 4.54 kg (10 lb), 9.08 kg (20 lb), and 18.16 kg (40 lb). The 4 sample acceptance levels evaluated were 5,50,100, and 180 ng/g. A decrease in the sample acceptance level from 180 to 5 ng/g decreased the number of lots accepted at all lot concentrations, increased the number of lots rejected at all lot concentrations, and decreased the average aflatoxin concentrations among all lots accepted. At the highest sample acceptance level, 180 ng/g, increase in sample size from 2.27 to 18.16 kg decreased the percent of lots accepted at concentrations above the sample acceptance level and increased the percent of lots accepted at concentrations below the sample acceptance level. At the lowest sample acceptance level investigated, 5 ng/g, an increase in sample size from 2.27 to 18.16 kg decreased the percent of lots accepted at all concentrations. The effect of using sampling designs with 2 sample acceptance levels to classify lots into 3 categories was investigated. The advantages of using dual sample acceptance levels over a single sample acceptance level was demonstrated for 2.27 and 9.08 kg samples.
Determination of 1,8-Cineole in Eucalyptus Essential Oils by Thin-Layer Chromatography and Densitometry
Authors: Rossini Carmen , Pandolfi Enrique , Dellacassa Eduardo , Moyna Patrick 
Published: February 2020

Abstract
A thin-layer chromatography (TLC) method with scanning is described for evaluation of the 1,8-cineole content of Eucalyptus essential oils. Samples were developed on silica gel G 60 with light petroleum–chloroform (70 + 30) as mobile phase. Color was developed with 4-dimethylaminobenzal-dehyde–sulfuric acid reagent. The absorbance of colored spots was measured at 460 nm. The response was linear between 15 to 75 μg of 1,8-cineole, with a correlation coefficient of 0.9997. The results of each assay were compared with those from gas–liquid chromatography (GLC). The TLC to GLC ratio was constant (0.92).
Liquid Chromatographic Procedure for the Determination of Novobiocin Residues in Bovine Milk: Interlaboratory Study
Authors: Reeves Valerie B 
Published: February 2020

Abstract
Novobiocin is used for the treatment of mastitis in dairy cattle. In 1982, the tolerance was set at 0.1 ppm in milk from dairy animals. A laboratory trial has been completed for a liquid chromatographic procedure that can quantitate novobiocin residues in bovine milk at tolerance level. In this procedure the milk is diluted with buffer, the proteins are precipitated with methanol, and the solution is filtered. Novobiocin is determined after separation of milk components using re-versed-phase chromatography with UV detection at 340 nm. The participating laboratories analyzed 2 concentrations of biologically incurred residues as well as control milk and control milk fortified at 0.05, 0.1, and 0.2 ppm. Recoveries of novobiocin reported by the participating laboratories were 89 to 99% at 0.05 ppm; 93 to 101% at 0.1 ppm; and 89 to 100% at 0.2 ppm. Coefficients of variation (CVs) ranged from 2.0 to 6.2%. The average concentrations for the low levels of incurred novobiocin in milk samples were 0.073, 0.072, and 0.081 ppm, with intralaboratory CVs of 3.3, 7.2, and 2.4%, respectively. The samples with high levels of incurred novobiocin averaged 0.139, 0.121, and 0.144 ppm, with CVs of 6.2, 0.7, and 4.7%, respectively.
An Interlaboratory Trial on the Identification of Irradiated Spices, Herbs, and Spice–Herb Mixtures by Thermolummescence Analysis
Authors: Schreiber Georg A , elle Norbert , Bögl Klaus W 
Published: February 2020

Abstract
Thermoluminescence analysis was used in an interlaboratory study to detect irradiation treatment of spices, herbs, and spice–herb mixtures in the dose range used for the reduction of microbial counts. About 3 and 9 months after irradiation, 14 participating laboratories determined the thermoluminescence of mineral contaminants that had been isolated from coded samples. A total of 18 different products (6 spices, 6 herbs, and 6 spice–herb mixtures) were examined. The method gave correct identifications as irradiated or nonirradiated in 99.1% of 317 samples. Only 3 irradiated samples were not correctly identified. This result was achieved by integration of whole glow curves. By glow curve analysis, a temperature range could be determined in which differentiation between irradiated and nonirradiated samples was even better than on the basis of the total integral values.
Gradient Multipeak Liquid Chromatographic Method for Determination of Ardacin in Bulk Chemical and Premix Formulations
Authors: Abdel-Kader Hafez , Kobylkevich Myriam M , Wigman Larry S , Menon Govind K 
Published: February 2020

Abstract
A liquid chromatographic (LC) method was developed for the determination of ardacin in bulk chemical (78 to 100%, w/w anhydrous) and premix formulations (3.3 to 26.4%, w/w). The method is based on reversed-phase LC resolution of ardacin components and detection by UV absorbance at 220 nm. Ardacin has 10 components, and each component can be quantitated separately. Total ardacin is determined by summing the areas of the 10 component peaks. Calculations are performed using an external standard approach. The method is linear for ardacin at 50 to 150 μ/mL. The method accuracy for a typical bulk chemical is ± 1.5%, w/w (relative standard deviation [RSD], 1.6%), and recovery from a typical pilot scale premix is 99.9% (RSD, 3.4%). The method is useful for monitoring stability during storage.
Generic Performance Tests for the Fertilizer Sample Preparation Laboratory
Authors: Beine Robert L , Tompkins David H , Ranta Kirk R , Puentes Julio 
Published: February 2020

Abstract
Good sample preparation is an essential first step to almost all laboratory analytical procedures. The procedures presented are intended to stimulate interest in generic methods for performance testing of various steps in fertilizer sample preparation, including initial reduction of unground sample, grinding, and mixing. Sample reduction quality is measured by 2 types of procedures, the first using 2 sizes of glass beads for a more theoretical approach, and the second using 2 common fertilizer materials for a more empirical method. Grinding performance is measured by recovery and carryover methods, followed by particle size and uniformity estimates of the ground material. Mixing after grinding is tested by measuring time-to-blend of a segregated mixture.
Aflatoxins in Foods Collected in Osaka, Japan, from 1988 to 1992
Authors: Taguchi Shuzo , Fukushima Shigehiko , Sumimoto Tatsuo , Yoshtoa Seisaku , Nisihmune Takahiro 
Published: February 2020

Abstract
A total of 195 samples of imported foods were analyzed for aflatoxins. Samples of nuts, spices, natural cheese, meats, cereals, and beans were collected in Osaka prefecture, Japan, from 1988 to 1992. Eight samples were contaminated with aflatoxins.Aflatoxins were detectd in 4 of 38 samples of peanut products, 2 of 3 samples of nutmeg, one of 13 samples of white pepper, and one of 2 samples of red pepper. Aflatoxins were not detected in almonds, cashews, macadamia nuts, pistachios, walnuts, black pepper, garlic, ginger, mustard, cheese, beef, corn, rice, buckwheat, Job’s tears, or bean products.
Glucoamylase Activity in Industrial Enzyme Preparations Using Colorimetric Enzymatic Method: Collaborative Study
Authors: Elder Michael T , Montgomery Rachel S 
Published: February 2020

Abstract
Fifteen laboratories participated in a collaborative study to validate a colorimetric assay for the determination of glucoamylase in industrial enzyme preparations. All laboratories received 12 samples as blind duplicates provided by 3 industrial producers. Each sample was analyzed once a day for 3 days. Results from one laboratory were excluded from the statistical analysis. Performance of the method was calculated according to the AOAC guidelines. For all 15 laboratories the repeatability relative standard deviation (RSDr) values ranged from 0.89 to 2.37%, and the reproducibility relative standard deviation (RSDR) values ranged from 7.92 to 9.86. After excluding outliers the RSDr values ranged from 0.74 to 2.24%, and RSDR values ranged from 3.46 to 8.92. The colorimetric enzymatic method for determination of glucoamylase activity in industrial enzyme preparations has been adopted first action by AOAC INTERNATIONAL.
Purge-and-Trap Gas Chromatographic-Mass Spectrometric Determination of Benzene in Denture Adhesives
Authors: Barry Thomas L , Petzinger Glenn , Lehr Gary , Specchio John J 
Published: February 2020

Abstract
A purge-and-trap gas chromatographic-mass spectrometric procedure is presented for determination of trace levels of benzene in denture adhesives and their raw materials. The limit of quantitation is 10 ppb, reproducibility is ± 10%, and recoveries of d6-benzene are 70–85%. Results of a nationwide survey of 109 finished products and their raw materials representing 32 brand name products from 17 manufacturers are reported.
Second-Derivative UV Spectrometric Microdetermination of Dithiocarbamate Residues as Methyl Xanthate
Authors: Schwack Wolfgang , Nyanzi Steven 
Published: February 2020

Abstract
The microdetermination of dithiocarbamate fungicide residues as methyl xanthate using second-derivative UV spectrometry is described. The residue analysis is based on a hot-acid decomposition, scrubbing the evolved CS2 with lead acetate and concentrated H2SO4, and absorbing the CS2 in methanolic KOH. The absorbance of the xanthate system (conventional method) and the height of the negative peak at 302 nm (second-derivative method) are used to quantitate the CS2. The molar absorptivity of the xanthate system within the range of 0.3–2.4 μg CS2/mL where Beer’s law is obeyed, was 1.70 × 104 L mol-1 cm-1. The derivative procedure was more selective and sensitive to CS2 than the classical method. The calibration graph of the derivative procedure was rectilinear from 0.1–1.1 μg/mL of CS2. The coefficient of variation for the determination (n = 10) of a 0.28 (μg/mL standard of CS2 was 2.6%. The detection limit for CS2 was 0.08 μg/mL. The second-derivative procedure was applied to the residue analysis of thiram on tomatoes.
Screening for Okadaic Acid by Immunoassay
Authors: Chin Julia D , Quilliam Michael A , Fremy J Marc , Mohapatra Sushil K , Skorska Hanna M 
Published: February 2020

Abstract
Increasing incidences of phytoplankton blooms with the potential danger of toxin release into the food chain have necessitated the search for new diagnostic methods that can detect toxins quickly and reliably. A competitive enzymelinked immunosorbent assay (ELISA) was developed to quantitate okadaic acid in shellfish and phytoplankton extracts. To determine the specificity of the assay, a number of toxins, such as calyculin A, brevetoxin-1, and dinophysistoxins-1, -2, and -3 were analyzed. Both dinophysistoxins-2 and -1 could be detected by the assay but in concentration ranges 10- and 20-fold higher than that for okadaic acid, respectively. Dinophysistoxin-3, calyculin A, or brevetoxin-1 could not be detected with this assay. To validate the accuracy of the method, 18 mussel and 7 phytoplankton extracts were analyzed in parallel for okadaic acid content by ELISA and liquid chromatography combined with either fluorescence or mass spectrometric detection. Very high correlation between the results was found.
Detection of Ciguatera and Diarrheic Shellfish Toxins in Finfish and Shellfish With Ciguatect Kit
Authors: Park Douglas L 
Published: February 2020

Abstract
The Ciguatect test kit for the detection of ciguatoxin, okadaic acid, and related polyether compounds, based on solid-phase immunobead assay technology, was developed for rapid screening of toxic fish and shellfish in harvesting areas and the marketplace. Earlier formats, based on radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) technology, were used successfully to identify and separate ciguatoxic fish harvested from Hawaiian waters. The new format utilizes a membrane attached to a plastic strip, immunobead solution, and a user-friendly readout. Multiple formats of the test kit, including a rapid extraction method (REM) and ELISA, were demonstrated to be more sensitive than the mouse assay for detection of ciguatera-related compounds. Depending on the format used, the level of detection can be as low as 50 pg okadaic acid per gram of tissue. The test kit has been used to map ciguatoxic and nontoxic fishing areas around the islands of Hawaii through the use of a biomarker and the monitoring of toxic fish obtained from Pacific and Caribbean regions. Ciguatera-related toxins can be detected directly on fish flesh or after extraction by traditional procedures or the newly developed REM. Initial applications of the test kit to monitor diarrheic shellfish poisoning (DSP)-related toxins in mussels before, during, and after Dinophysis sp. blooms and during depuration operations were successful. The Ciguatect methodology can be used to monitor reef fishing areas for ciguatera potential, shellfish beds for DSP toxins, and shellfish depuration operations for elimination of DSP toxins and to screen for toxic fish and shellfish in the marketplace.
Practical Assay of Feed Premixes for Selenite Adsorbed on Reduced Iron
Authors: Hulen Joele , Eisenberg Sylvan 
Published: February 2020

Abstract
This method assays feed premixes for added selenite in 5–10 min. It requires that selenite be added in a form easily isolated from the premix. Sodium selenite adsorbed on a reduced iron carrier serves this purpose since it can be retrieved magnetically from samples. The assay is done either indirectly by weighing the iron and calculating the amount of Se or directly by extracting the selenite from the iron carrier and determining it by titration. The indirect assay may be done any time after production of premix. The direct method requires retrieval of the additive from the premix soon after production. The actual assay may be done later. The indirect method gives high results with some matrixes unless adjusted for background ferromagnetic material. The direct method gives results with an accuracy and precision equal to those of the U.S. Food and Drug Administration’s Center for Veterinary Medicine regulatory enforcement method with all matrixes studied.
Accumulated Pesticide and Industrial Chemical Findings from a Ten-Year Study of Ready-to-Eat Foods
Authors: Office Kan-Do , Team Pesticides 
Published: February 2020

Abstract
This report lists the pesticide and industrial chemicals found in the ready-to-eat foods tested repetitively for 10 years through the U.S. Food and Drug Administrations’s Revised Market Basket Study. The study operated from 1982 to 1991. During that time 37 market baskets, each containing 234 food items that represented about 5000 food types in American diets covering all age groups, including infants and children, were collected. Each food item was individually prepared for eating; that is, it was opened, unwrapped, washed, peeled, sliced, formulated by recipe, or cooked. Each item was then composited and analytically screened for about 300 different chemicals, including chlorphenoxy acids, ethylenethiourea, methyl carbamates, organochlorines, organophosphates, organosulfurs, phenylureas, and pyrethroids. Overall, less than 1% of the potential of 2.5 million findings occurred for the 10-year study period. In total, 138 different chemical residues accounted for 17 050 accumulated findings. Most findings were less than 1 μg/g, which is considered a low-level finding. Each food item averaged about 2 low-level findings per analysis.
Electrochemical Behavior and Polarographic Assay of Nitroxynil
Authors: Alvarez-Lueje Alejandro F , Bastías Marcos , Bollo Soledad , Núñez-Vergara Luis J , Squella Juan A 
Published: February 2020

Abstract
Nitroxynil is an anthelmintic veterinary drug used in prophylaxis and treatment of hepatic distomatosis. A simple method for its identification and determination in pharmaceutical parenteral solutions is described. The method is based on electrochemical reduction of the nitro group at the dropping mercury electrode. The ac and dc polarographic and cyclic voltammetric responses of the drug are reported. Accuracy and precision of the method are good, and sample preparation is easy.
Determination of Carbohydrates in Soluble Coffee by Anion-Exchange Chromatography with Pulsed Amperometric Detection: Interlaboratory Study
Authors: Prodolleet Jacques , Bugner Emmanuel , Feevberg Max 
Published: February 2020

Abstract
A collaborative study was conducted to validate a liquid chromatographic (LC) method to determine the free and total (after acid hydrolysis) carbohydrate profile of soluble coffee. Carbohydrates were separated on a pellicular anion-exchange column using pure water as mobile phase, and were detected by pulsed amperometry. Eleven collaborators were sent 6 test samples of commercial soluble coffee for duplicate analysis. They were also sent a practice sample with known levels of free and total carbohydrates and material for preparation of all standard solutions. The reproducibility relative standard deviations (RSDR) were 9.9–59.5% for mannitol, 35.6–72.6% for fucose, 4.9–21.1% for arabinose, 4.1–13.0% for galactose, 6.1–24.3% for glucose, 10.0–41.6% for sucrose, 20.2–37.7% for xylose, 10.6–40.0% for mannose, 15.5–71.7% for fructose, and 17.8–97.9% for ribose. Precision in the determination of free and total carbohydrates was very similar. The average repeatability RSDr and RSDR values were 4.5 and 14.3%, respectively, for carbohydrate levels above 0.3%. The precision of the technique was considered good, regardless of the usual peak integration problems always encountered in LC, the low levels of free carbohydrates, the hydrolysis step, and the relative lack of experience of most participating laboratories. The method allows good and reproducible separation of all major carbohydrates found in soluble coffee and is, therefore, suitable for routine analysis.