bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simplification of Analytical Methods in Pesticide Residue Analysis by Liquid Chromatography/Electrospray Ionization Mass Spectrometry and Tandem Mass Spectrometry
Authors: Stout Steven J , daCunha Adrian R , Picard Gerald L , Safarpour Maximilian M 
Published: February 2020

Abstract
This report presents a historic, scientific, and economic overview of why mass spectrometry (MS) is rapidly becoming a routine detector for trace analysis of pesticide residues in the regulatory area. Liquid chromatography/electrospray ionization MS and tandem MS dramatically simplify cleanup procedures, reducing not only sample analysis time, but even more important, method development time. Examples include direct determination of imidazolinones in water at 1 ppb, determination of imazethapyr and its metabolites in crop commodities, and determination of imazethapyr in soil.
Simultaneous Determination of Chloramphenicol, Florfenicol, and Thiamphenicol Residues in Milk by Gas Chromatography with Electron Capture Detection
Authors: Pfenning Allen P , Madson Mark R , Roybal José E , Turnipseed Sherri B , Gonzales Steve A , Hurlbut Jeffrey A , Salmon Garrett D 
Published: February 2020

Abstract
A gas chromatographic (GC) method is described for determining residues of chloramphenicol (CAP), florfenicol (FF), and thiamphenicol (TAP) in raw milk, with meta-nitrochloramphenicol (mCAP) as internal standard. Milk is extracted with acetonitrile, centrifuged, evaporated, reconstituted in water, and passed through a C18 solid-phase extraction (SPE) column. The SPE column is eluted with 60℅ methanol, and then the eluate is evaporated and derivatized with Sylon BFT {N,0-bis(trimethylsilyl) trifluoroacetamide [BSTFA]-trimethylchlorosilane [TMCS], 99 + 1}. After derivatization, toluene is added directly to the sample, followed by water, to quench the derivatization process. After centrifugation, the organic layer is carefully removed. Analytes are determined by GC with electron capture detection (ECD). Milk was fortified with fenicols (the collective name for CAP, FF, and TAP) at 5,10, 20, 40 and 80 ng/mL (target level = 10 ng/mL). Overall recoveries were 92,100, and 104℅ for CAP, FF, and TAP, respectively. Overall interassay (betweenday) variabilities were 6.1, 6.7, and 6.0℅ for CAP, FF, and TAP, respectively. Raw milk samples containing incurred residues of FF were also analyzed.
Determination of the Fusarium Mycotoxins Nivalenol, Deoxynivalenol, 3-Acetyldeoxynivalenol, and 15-0-Acetyl-4-deoxynivalenol in Contaminated Whole Wheat Flour by Liquid Chromatography with Diode Array Detection and Gas Chromatography with Electron Capture Detection
Authors: Walker Frank , Meier Barbara 
Published: February 2020

Abstract
A rapid and sensitive method was developed for simultaneous detection of nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-A-DON), and 15-O-acetyl-4-deoxynivalenol (15-A-DON) in wheat flour. Samples were extracted with acetonitrilewater (84 + 16), and the extract was filtered and purified by a column containing a combination of charcoal, celite, and other adsorbents. For screening analysis, the column eluate was only extracted with ethyl acetate. After evaporation of the solvent, the dried residue was redissolved in acetonitrilewater (2 + 8) and then analyzed by reversed-phase liquid chromatography (LC) with diode array detection. Recoveries of NIV, DON, 3-A-DON, and 15-ADON from whole wheat flour spiked at 2 levels were 49-55, 92-97,98-100, and 100-105℅, respectively. To quantitate mycotoxin amounts lower than 1 ppm, purified column extracts were evaporated to dryness, derivatized with heptafluorobutyric anhydride, and analyzed by gas chromatography with electron capture detection (GC-ECD). Average recoveries of NIV, DON, 3-A-DON, and 15-A-DON from whole wheat flour spiked at 2 levels, were 45- 52, 91-103, 81-85, and 84-92℅, respectively. GCECD detection limits for all mycotoxins tested at a signal-to-noise ratio of 4:1 were ˂30 ng/g. Results of GC-ECD analysis for whole wheat flour samples spiked with mycotoxins at 3 and 10 ppm compared well with results (2.8 and 9.9 ppm) for the same samples analyzed by LC.
Determination of Salicin and Related Compounds in Botanical Dietary Supplements by Liquid Chromatography with Fluorescence Detection
Authors: Luo Wenhong , Ang Catharina Y W , Schmitt Thomas C , Betz Joseph M 
Published: February 2020

Abstract
A sensitive and reliable method is described for quantitative determination of salicin (including salicyl alcohol) and salicylic acid in botanical dietary supplements by reversed-phase liquid chromatography (LC) with wavelength-programmed fluorescence detection. One gram sample material was extracted with 20 mL aqueous phosphate buffer (pH 5.0), which was heated in an 80C water bath for 30 min. After centrifugation and cooling of the extract to room temperature, the supernatant was diluted with additional buffer. A1 mL portion of diluted extract was mixed with 1 mL β-glucosidase solution (2 mg/mL) and incubated for 40 min in a 37C water bath. The extract was passed through a 0.45 μm syringe filter and analyzed by LC. Limits of quantitation for salicin and salicylic acid were 20 and 1 μg/g, respectively. Recoveries from samples fortified with salicin at 20,100, and 1000 μg/g and with salicylic acid at 5, 20, and 50 μg/g ranged from 85 to 110℅, with standard deviations less than 7℅.
Analysis of Sulfonylurea Herbicides in Soil Water at Sub-Part-Per-Biffion Levels by Electrospray Negative Ionization Mass Spectrometry Followed by Confirmatory Tandem Mass Spectrometry
Authors: Bossi Rossana , Koppen Benny , Spliid Niels Henrik , Streibig Jens C 
Published: February 2020

Abstract
Liquid chromatography coupled to mass spectrometry (MS) with an electrospray ionization interface was used to analyze 4 sulfonylurea herbicides: chlorsulfuron, metsulfuron-methyl, thifensulfuron-methyl, and tribenuron-methyl. Fortified soil water was acidified to pH 4.5 (the pH was maintained neutral for tribenuron-methyl because it rapidly hydrolyzes at low pH) and extracted on Ci8 cartridges. Extracts were cleaned up on silica cartridges. MS analysis was accomplished by selected ion monitoring of the deprotonated molecular ion in negative-ion mode. The 4 compounds were quantitated with the external standard technique based on the integrated abundance of the molecular ion [M - H]~. Good reproducibility and high sensitivity (detection limits for the 4 compounds were between 0.002 and 0.005 μg/L) were achieved. Tandem MS (MS/MS) in selected reaction monitoring mode on a characteristic product ion (m/z139 for chlorsulfuron, metsulfuron-methyl, and thifensulfuron-methyl; nvzA53 for tribenuronmethyl) was used as confirmatory method. High sensitivity was maintained also with MS/MS, making it possible to identify sulfonylurea herbicides at very low concentrations.
Liquid Chromatographic Determination of Flumequine, Nalidixic Acid, Oxolinic Acid, and Piromidic Acid Residues in Catfish (Ictalurus punctatus)
Authors: Munns Robert K , Turnipseed Sherri B , Pfenning Allen P , Roybal Jose E , Holland David C , Long Austin R 
Published: February 2020

Abstract
A peer-verified, liquid chromatographic (LC) method for simultaneous determination of residues of flumequine (FLU), nalidixic acid (NAL), oxolinic acid (OXO), and piromidic acid (PIR) in catfish muscle is presented. Sample workup involves homogenizing tissue with acetone, defatting with hexane, and extracting quinolones into chloroform. Sample is purified further by partitioning into base and then subsequently back-extracting into chloroform after acidifying the aqueous phase. After solvent is evaporated, the residue is diluted with mobile phase, and analytes are introduced into an LC system where separations are made with a 5 |am, reversed- phase polymer column and an isocratic, buffered acetonitrile- tetrahydrofuran mobile phase. Determinations are made by UV detection at 280 nm for PIR and by fluorescence detection (excitation at 325 excitation and emission at 365 nm) for the other 3 analytes. Each quinolone was used to fortify catfish muscle at 5, 10, 20, 40, and 80 ng/g. The following recoveries and relative standard deviation (RSD) values represent an average of the 5 levels for each analyte: FLU, 79.7℅ (RSD = 5.7℅); OXO, 80.8℅ (RSD = 6.3℅); PIR, 75.0℅ (RSD = 5.9℅); andNAL, 87.1℅ (RSD = 10%). Assay of 5 levels (base incurred catfish, plus 4 dilutions with control catfish) of catfish muscle incurred with the 4 quinolones gave the following averages: FLU: base, 198 ng/g (RSD = 2.3℅); dilutions, 98.0 ng/g (RSD = 4.2℅), 61.6 ng/g (RSD = 4.4℅), 21.6 ng/g (RSD = 2.8℅), 9.24 ng/g (RSD = 8.7℅); OXO, base, 257 ng/g (RSD = 6.9℅); dilutions, 146 ng/g (RSD = 5.5℅), 95.0 ng/g (RSD = 4.1℅), 30.7 ng/g (RSD = 3.8%), 13.7 ng/g (RSD = 4.6%); PIR, base, 22.1 ng/g (RSD = 4.2%); dilutions, 13.7 ng/g (RSD = 6.7℅), 6.49 ng/g (RSD = 15℅), 2.65 ng/g (RSD =15℅); and NAL, base, 75.1 ng/g (RSD = 3.8℅); dilutions, 42.3 ng/g (RSD = 5.1℅), 24.1 ng/g (RSD = 6.3℅), 8.59 ng/g (RSD = 4.8℅). A second multiresidue analysis of the 4 quinolones was performed by an outside analyst. Average recoveries from catfish fortified at 5, 10, 20, and 40 ng/g were FLU, 75.9℅ (RSD = 4.0℅); OXO, 84.0℅ (RSD = 5.5℅); NAL, 85.6℅ (RSD = 8.9℅); and PIR, 66.2℅ (RSD = 8.7℅).
Determination of Fluoride in Bovine Urine
Authors: Osheim David L , Rasmusson Mary C 
Published: February 2020

Abstract
Fluoride concentration in bovine urine is determined by using a selective ion electrode. Urine is buffered and measured against known fluoride (F) standards. The method is applicable to 2 to 40 mg F/L without further dilution. Typical normal urine contains less than 10 mg F/L. Concentrations greater than 10 mg/L support a clinical diagnosis of fluorosis in cattle. Repeatability coefficient of variation (CV) ranged from 1.6 to 3.5℅ for F concentrations of 3.2-13 mg/L. Reproducibility CV ranged from 0.3 to 7.3℅ for F concentrations of 7.0-17.2 mg/L.
Thin-Layer Chromatographic Determination of Monensin in Feeds: Screening Method
Authors: Landgraf Wynne W , Ross P Frank 
Published: February 2020

Abstract
Monensin is extracted from feed with methanol and purified by solvent-partitioning solid-phase extraction. After solvent reduction, monensin is separated by thin-layer chromatography on silica gel and visualized by color development with vanillin. No false-positive results were obtained in validation studies by submitting or peer laboratories when blank samples were analyzed. Three of 20 samples spiked with 5 ppm monensin were reported as containing no monensin. All samples spiked with 10 ppm monensin were reported positive for monensin.
Determination of Fat in Olestra-Containing Savory Snack Products by Capillary Gas Chromatography
Authors: Schul David , Tallmadge Daniel , Burress Derek , Ewald Deborah , Berger Belinda , Henry David 
Published: February 2020

Abstract
A quantitative method to determine fat in olestra-containing savory snack products was validated within the AOAC Peer-Verified Methods Program. The method may be used to demonstrate compliance with the guidelines of the U.S. Nutrition Labeling and Education Act for labeling products as "fat free" or "low fat." The method can measure total and saturated fat in savory snacks when present at levels of 0.2-10 g total fat and 0.1-3 g saturated fat per 30 g serving. The method is standardized to measure C6- C24 fatty acids. Extraction of olestra-containing savory snack samples with chloroform-methanol (modified AOAC Official Method 983.23) yields a lipid extract containing the total fat and olestra. The extracted lipid is hydrolyzed by lipase, yielding fatty acids and unreacted olestra. The fatty acids are precipitated as calcium soaps. Olestra is extracted from insoluble soaps with hexane and then discarded. The isolated soaps are converted back into fatty acids with hydrochloric acid and extracted with hexane. The isolated fatty acids are converted to methyl esters with boron trifluoride-methanol and quantitated by capillary gas chromatography using internal standard. Test samples were prepared by blending olestra-containing and full-fat (triglyceride) snacks to obtain 6 levels of spiking (0-10 g total fat added/30 g serving) in potato chips, potato crisps, cheese puffs, and nacho cheese-flavored corn chips. Results were linear (r2 &gt; 0.997) between 0 and 10 g fat/30 g serving for each product matrix. Mean recovery was 101 6% standard deviation (SD) for total fat and 104 ± 6% SD for saturated fat. Mean recovery by peer laboratory was 88 ± 5% SD for total fat and 95 ± 4% SD for saturated fat in potato chips (0-3 g total fat added/30 g serving). Two sets of 10 replicates of potato chips (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) and potato crisps (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) were analyzed by submitting and peer laboratories. Repeatability relative standard deviations ranged from 3.90 to 7.33% for total fat and from 4.01 to 11.53% for saturated fat. Reproducibility relative standard deviations were 7.33% (total fat, potato chips), 7.15% (total fat, potato crisps), 11.36% (saturated fat, potato chips), and 13.50% (saturated fat, potato crisps)
Determination of Chromium in Wine and Other Alcoholic Beverages Consumed in Spain by Electrothermal Atomic Absorption Spectrometry
Authors: Lendinez Elena , Carmen Lopez M , Cabrera Carmen , Luisa Lorenzo M 
Published: February 2020

Abstract
A reliable and rapid method is described for the determination of chromium in alcoholic beverages by electrothermal atomic absorption spectrometry (ETAAS) after optimization of the temperature-time program for the graphite furnace. Chromium in wines was determined directly without sample pretreatment. Other samples were first mineralized with HN03 and V2O5. The method was validated, and its analytical characteristics were checked. The detection limit was 1 pg (for a sample volume of 10 μL). Accuracy was 99.20 ± 3.80% for wines and 98.90 ± 2.00% for other beverages. Precision ranged from 3.50 to 4.50%. The proposed method was applied to 124 samples of alcoholic beverages frequently consumed in Spain. Mean values obtained (μg/L) were 20.28 for wines, 8.75 for beer, 7.85 for cider, 14.60 for brandy, 7.50 for rum, 10.25 for whisky, 8.80 for gin, 9.25 for vodka, 24.45 for anisette, and 10.08 for liquors. The advantages of the proposed method (rapidity, sensitivity) and versatility) make it useful for routine analyses and for estimations of dietary intake of chromium
Expert System for Catalytic Titrimetry—Part 2: Determination of Monobasic Carboxylic Acids
Authors: Abramovic Biljana F , Abramovic Borislav K , Gaál Ferenc F , Obradovtc Danilo M 
Published: February 2020

Abstract
An expert system (ES) to solve the problem of choosing a catalytic titrimetric procedure for determining monobasic carboxylic acids is described. Carboxylic acids were divided into 3 groups—aliphatic, aromatic, and α-aminocarboxylic acids— based on their behavior in catalytic titrations with different indicator reactions, titrant, and/or solvent and the possibility of their selective determination in the presence of other acids
Improved Parameterization of Fertilizer Particle Size Distribution
Authors: Perfect Edmund , Xu Qiang , Terry David L 
Published: February 2020

Abstract
Particle size distribution is an important physical property of granular fertilizers that influences their bulk behavior (e.g., packing and segregation). Several parameter systems for fertilizer particle size distributions are analyzed in this paper. The most common system used by the fertilizer industry is the SGN-UI system, where SGN is the size guide number (the median particle size) and Ul is the uniformity index (the 10th percentile particle size expressed as a percentage of the 95th percentile particle size). This 2-parameter system, however, has many limitations. For example, it does not give a distribution function. Furthermore, the Ul parameter does not accurately reflect the spread of particle sizes. It is therefore necessary to find a better parameterization system. Three size distribution functions (the log-normal, the Rosin-Rammler and the Gaudin-Schuhmann equations) were tested on a size distribution database composed of 377 samples from 7 fertilizer materials. Each function was fitted to the data by nonlinear regression. The Rosin-Rammler function is the best parameter system on the basis of an analysis of variance of the sum of squares of error from the nonlinear fits. Comparisons between the Rosin-Rammler and the SGN-UI parameters were also made. The Rosin- Rammler system is more accurate than the SGN-UI system, possesses the ability of prediction, and provides a measure of the goodness of fit. Therefore, the Rosin-Rammler system should be used to characterize size distribution of granular fertilizer materials instead of the SGN-UI system.
Detection of Thiazide-Based Diuretics in Equine Urine by Liquid Chromatography/Mass Spectrometry
Authors: Garbis Spiros D , Hanley Luke , Kalita Shelley 
Published: February 2020

Abstract
Thiazide-based diuretics are included in the list of banned drugs in the horse-racing industry. One effect of their misuse is increased urine flow, contributing to dilution of other doping agents. Their determination is essential in ensuring compliance to horse-racing regulation. This study evaluates the feasibility of using liquid chromatography/mass spectrometry (LC/MS) with electrospray and atmospheric pressure chemical ionization interfaces to analyze thiazidic diuretics in equine urine samples. Existing LC and gas chromatography/MS methods are limited in their applicability to thiazide analysis. Sample preparation, analyte extraction, chromatographic separation, ion-source collision induced dissociation, solvent composition, ionization mode, and ion polarity are discussed. The practicality of LC/MS for this analysis is demonstrated with actual equine administration samples collected at specified time intervals. Detection limits were 270 ng/mL for chlorothiazide, 131 ng/mL for hydrochlorothiazide, and 384 ng/mL for trichlormethiazide
Liquid Chromatographic Determination of Histamine in Fish, Sauerkraut, and Wine: Interlaboratory Study
Authors: Beljaars Paul R , Van Dijk Remmelt , Onker Klaas M , Schout Louis J ,   Collaborators:, Brans G , Boomkamp J , Bosman J C , van Dijk R , de Jeu C , Krekelberg C , v d Luitgaarden A , Sens C , v d Weert R , Wijma E 
Published: February 2020

Abstract
An interlaboratory study of the liquid chromatographic (LC) determination of histamine in fish, sauerkraut, and wine was conducted. Diminuted and homogenized samples were suspended in water followed by clarification of extracts with perchloric acid, filtration, and dilution with water. After LC separation on a reversed-phase C18 column with phosphate buffer (pH 3.0)-acetonitrile (875 + 125, v/v) as mobile phase, histamine was measured fluorometrically (excitation, 340 nm; emission, 455 nm) in samples and standards after postcolumn derivatization with ophthaldialdehyde (OPA). Fourteen samples (including 6 blind duplicates and 1 split level) containing histamine at about 10- 400 mg/kg or mg/L were analyzed singly according to the proposed procedure by 11 laboratories. Results from one participant were excluded from statistical analysis. For all samples analyzed, repeatability relative standard deviations varied from 2.1 to 5.6%, and reproducibility relative standard deviations ranged from 2.2 to 7.1%. Average recoveries of histamine for this concentration range varied from 94 to 100%
Determination of Maleic Hydrazide in Pesticide Formulations by Capillary Electrophoresis
Authors: Kubilius Donna T , Bushway Rodney J 
Published: February 2020

Abstract
A capillary electrophoresis method was developed to quantitate the growth regulator maleic hydrazide (MH) in pesticide formulations. Liquid formulations were dissolved in water, injected into a capillary electrophoresis instrument, and monitored at 220 nm. The running buffer was 10 mM dibasic sodium phosphate at pH 9.0. Total analysis time was 10 min. Four liquid formulations with a guarantee of 30.2 or 30.3% potassium salt of MH were analyzed. Within-day coefficients of variation (CVs) ranged from 3.0 to 7.7%, and between-day CVs ranged from 5.5 to 10.0%. Purity of each MH peak was checked by using a photodiode array detector in the spectrum mode. No interferences were observed.
Multiresidue Liquid Chromatographic Method for Determining Residues of Mono- and Dibasic Penicillins in Bovine Muscle Tissues
Authors: Boison Joe O , Keng Lily J -Y 
Published: February 2020

Abstract
A liquid chromatographic method with UV detection at 325 nm was developed for simultaneous determination of amoxicillin, ampicillin, penicillin G, and cloxacillin residues in bovine muscle tissue as their mercaptide derivatives. The penicillins are extracted from bovine tissues with 0.1 M phosphate buffer (pH 8.5), cleaned up on a t-C18 Sep-Pak cartridge, and eluted with 2 ml acetonitrile. After the acetonitrile in the eluate is evaporated to dryness, the residue is dissolved in 200 |µL (40 + 60, v/v) aceton itrile-phosphate buffer (pH 6.5) and derivatized with acetic anhydride and mercuric chloride in the presence of 1,2,4-triazole at 65°C for 30 min. Gradient analysis on a Spherisorb 5 µm ODS(2) (octadecyl silane) analytical column using a binary mobile phase consisting of acetonitrile and 0.10M phosphate buffer (pH 6.5) in the presence of 0.0157M sodium thiosulfate at 1 mL/min permits determination of each intact penicillin in bovine muscle tissue at ≥10 ppb with recoveries ≥72%. This laboratory method provides detection sensitivities equivalent to those of rapid tests used for screening β-lactam drug residues in bovine tissue samples for regulatory enforcement.
Determination of Apramycin in Swine Kidney Tissue by Liquid Chromatography with Fluorescence Detection
Authors: Sweeney Daniel J , Coleman Mark R 
Published: February 2020

Abstract
A liquid chromatographic method for determining apramycin in swine kidney tissue is described. Apramycin is extracted from tissue with basic methanol and purified by ion-pair extraction. By using an automated derivatization and injection procedure, the purified extract is derivatized with ophthaldehyde, separated on a C18 column, and detected with a fluorescence detector. For fortified kidney samples, between-run coefficients of variation ranged from 4.8 to 7.1 % at 1.00 ppm and from 9.6 to 14.3% at 0.50 ppm. Recoveries ranged from 76 to 86%. Standard curves were linear over the range 10-100 ng/mL.
Variability Associated with Testing Shelled Corn for Fumonisin
Authors: Whitaker Thomas B , Trucksess Mary W , Johansson Anders S , Geesbrecht Francis G , Hagler Winston M , Bowman Daryl T 
Published: February 2020

Abstract
Variances associated with sampling, sample preparation, and analytical steps of a test procedure that measures fumonisin in shelled corn were estimated. The variance associated with each step of the test procedure increases with fumonisin concentration. Functional relationships between variance and fumonisin concentration were estimated by regression analysis. For each variance component, functional relationships were independent of fumonisin type (total, B1, B2, and B3 fumonisins). At 2 ppm, coefficients of variation associated with sampling (1.1 kg sample), sample preparation (Romer mill and 25 g subsample), and analysis are 16.6,9.1, and 9.7%, respectively. The coefficient of variation associated with the total fumonisin test procedure was 45% and is about the same order of magnitude as that for measuring aflatoxin in shelled corn with a similar test procedure.