bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Determination of Paracetamol, Chlorzoxazone, and Related Impurities 4-Aminophenol, 4'-Chloroacetanilide, and p-Chlorophenol in Pharmaceutical Preparations by High-Performance Liquid Chromatography
Authors: Ali Mohammed Shahid , Rafiuddin Syed , Ghori Mohsin , Kahtri Aamer Roshanali 
Published: February 2020

Abstract
This paper presents a simple, specific, and precise high-performance liquid chromatographic method for the simultaneous determination of paracetamol (PCM), chlorzoxazone (CXZ), and their related impurities in bulk raw materials and solid dosage forms. The mobile phase consisted of water methanolglacial acetic acid (60 + 40 2, v/v/v). A column containing octadecylsilane chemically bonded to porous silica particles (Spherisorb ODS 1, 25 cm × 4.6 mm, 5 μm) was used as stationary phase. Detection was performed using a variable wavelength ultraviolet-visible detector set at 272 nm for all compounds. Solutions were injected into the chromatograph under isocratic condition at a constant flow rate of 1.2 mL/min. The method was validated according to International Conference on Harmonization requirements and demonstrates good accuracy and precision and a wide linearity range. The method separates PCM, CXZ, and 3 major impurities 4-aminophenol (4AP), 4'-chloracetanilide (4CA), and p-chlorophenol (PCP) with fair resolution in less than 15 min. The developed method is rapid and sensitive (limit of detection for 4AP, 4CA, and PCP established at 31.25, 39.06, and 65.16 ng/mL, respectively) and, therefore, suitable for quality control and stability studies of these compounds in dosage forms.
Fast Cleanup Method for the Analysis of Sudan IIV and Para Red in Various Foods and Paprika Color (Oleoresin) by High-Performance Liquid Chromatography/Diode Array Detection: Focus on Removal of Fat and Oil as Fatty Acid Methyl Esters Prepared by Transesterification of Acylglycerols
Authors: Uematsu Yoko , Ogimoto Mami , Kabashima Junichirou , Suzuki Kumi , Ito Kouichi 
Published: February 2020

Abstract
A fast and effective cleanup method was developed for the analysis of Sudan I, II, III, IV, and Para Red (Sudan dyes) in various foods and paprika color (oleoresin) by high-performance liquid chromatography (LC) with a diode array detector (DAD). Removal of fat or oil in fatty sample was a critical point for reducing the volume of the final sample solution in order to obtain a sufficient level of the analytes. Separation of fat or oil from the dyes with a silica gel solid-phase extraction (SPE) column seemed unfeasible, because elution profiles of oil, fat, and the dyes were similar. Finally, fat and oil were separated from the dyes by elution from the SPE column with n-hexane, not as intact compounds but as fatty acid methyl esters prepared by direct transesterification of acylglycerols in fat and oil, leaving the dyes on the column. The dyes were eluted with n-hexanediethyl ether (9 + 1). Gradient elution with water and tetrahydrofuran was used for separation on a C18 column by LC. Measurement of spectral of μ0.5 g/g of Sudan dyes in foods and 1 μg/g in paprika color (oleoresin) with the DAD was achieved.
Determination of Low-Level Agricultural Residues in Soft Drinks and Sports Drinks by Gas Chromatography with Mass-Selective Detection: Single-Laboratory Validation
Authors: Paske Nathan , Berry Bryan , Schmitz John , Sullivan Darryl 
Published: February 2020

Abstract
In this study, sponsored by PepsiCo Inc., a method was validated for measurement of 19 pesticide residues in soft drinks and sports drinks by gas chromatography/mass spectrometry (GC/MS) with mass selective detection The pesticide residues determined in this validation were -benzenehexachloride (BHC); -BHC; -BHC; delta-BHC; methyl parathion; malathion; chlorpyrifos; aldrin; 2,4-dichlorodiphenyldichloroethylene (DDE); -endosulfan; 4,4-DDE; 2,4-dichlorodiphenyldichloroethane (DDD); dieldrin; ethion; 4,4-DDD; 2,4-dichlorodiphenyltrichloroethylene (DDT); -endosulfan; 4,4-DDT; and endosulfan sulfate when spiked into a 200 mL matrix sample at 0.50 g/L. The samples were diluted with acetonitrile and water, then liquidliquid phase extracted into petroleum ether. The resulting extract was concentrated to near dryness and diluted with hexane:dichloromethane (50:50). The concentrated samples were purified by gel permeation chromatography. The resulting solution was concentrated and separated on a Florisil substrate. The eluent was concentrated to near dryness, reconstituted to produce a 200-fold concentration, and analyzed using a GC/MS instrument operated in the selective ion monitoring mode. The GC/MS instrument was equipped with a large volume injector capable of injecting 25 L. External standards prepared in dichloromethane were used for quantification without the need for matrix-matched calibration because the extraction step minimized the matrix effects. The calibration curves for all agricultural residues had coefficients of determination (r2) of greater than or equal to 0.9900, with the exception of one value that was 0.988. Fortification spikes at 0.50 g/L in 3 matrixes (7UP, Gatorade, and Diet Pepsi) over the course of 2 days (4 days for Gatorade), where n = 8 each day, yielded average percent recoveries (and percent relative standard deviations) as follows (n = 64): 95.6 (24.8) for -BHC; 91.9 (23.6) for -BHC; 89.1 (21.3) for - BHC; 91.7 (19.0) for -BHC; 96.2 (20.1) for methylparathion; 99.8 (26.5) for malathion; 120 (27.3) for chlorpyrifos; 103 (31.4) for aldrin; 111 (25.8) for 2,4-DDE; 116 (21.1) for -endosulfan; 132 (34.6) for 4,4-DDE; 123 (34.4) for 2,4-DDD; 104 (20.8) for dieldrin; 141 (31.4) for ethion; 107 (24.5) for 4,4-DDD; 142 (29.2) for 2,4-DDT; 130 (35.9) for -endosulfan; 146 (25.3) for 4,4-DDT; and 91.5 (21.6) for endosulfansulfate.
Determination of Pesticides in Apples by Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometry and Estimation of Measurement Uncertainty
Authors: Wang Jian , Wotherspoon David 
Published: February 2020

Abstract
A liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method was developed and validated to determine 90 pesticides in apple samples. MS/MS data acquisition was achieved by applying multiple-reaction monitoring of 2 fragment ion transitions to provide a high degree of sensitivity and selectivity for both quantitation and confirmation. Matrix-matched standard calibration curves with the use of isotopically labeled standards (or a chemical analog) as internal standards were used to achieve the best accuracy for the method. Both a conventional method validation procedure and a designed experiment were applied to study the accuracy and precision of the method. A compiled computer program that provided a semiautomated procedure for handling a large number of calculations was used to calculate the overall recovery, intermediate precision, and measurement uncertainty (MU). In general, the overall recoveries from samples spiked at levels of 10, 50, and 80 g/kg, ranged from 60.8 to 121.1%, intermediate precision was &lt;10%, and MUs were &lt;30%. Poor accuracy and/or repeatability was observed for pyridate and etofenprox. The method limits of detection based on a signal-to-noise ratio of &gt;3 were usually &lt;1 g/kg (ppb), except those for aldicarb sulfoxide and pyridaphenthion, which were about 5 g/kg.
On Using an Approximate Noncentral t-Distribution in Determining a One-Side Upper Limit for Future Sample Relative Reproducibility Standard Deviations
Authors: McClure Foster D , Lee Jung K 
Published: February 2020

Abstract
For future sample relative reproducibility standard deviations (RSDR), collaboratively obtained under a completely randomized model (CRM), a new formula for determining a one-tailed 100p% upper limit (p) for such RSDR values was developed based on an approximate noncentral t-distribution with degrees of freedom obtained using Satterthwaite's adjustment. The accuracy of p was assessed by comparing p and its probability levels with similar values associated with a Monte Carlo simulation and with those obtained using another formula (p) that was developed for the same purpose but based on a normal approximation.
Determination of Chondroitin Sulfate Content in Raw Materials and Dietary Supplements by High-Performance Liquid Chromatography with Ultraviolet Detection After Enzymatic Hydrolysis: Single-Laboratory Validation
Authors: Ji David , Roman Mark , Zhou Joseph , Hildreth Jana 
Published: February 2020

Abstract
A method to quantify chondroitin sulfate in raw materials and dietary supplements at a range of about 5 to 100% (w/w) chondroitin sulfate has been developed and validated. The chondroitin sulfate is first selectively hydrolyzed by chondroitinase ACII enzyme to form un-, mono-, di-, and trisulfated unsaturated disaccharides; the resulting disaccharides are then quantified by ion-pairing liquid chromatography with ultraviolet detection. The amounts of the individual disaccharides are summed to yield the total amount of chondroitin sulfate in the material. Single-laboratory validation has been performed to determine the repeatability, accuracy, selectivity, limit of detection, limit of quantification, ruggedness, and linearity of the method. Repeatability precision for total chondroitin sulfate content was between 1.60 and 4.72% relative standard deviation, with HorRat values between 0.79 and 2.25. Chondroitin sulfate recovery from raw material negative control was between 101 and 102%, and recovery from finished product negative control was between 105 and 106%.
Determination of Campesterol, Stigmasterol, and Beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Collaborative Study
Authors: Sorenson Wendy R , Sullivan Darryl ,   Collaborators:, Baugh S , Collison M , Das R , Erickson A , Harmon T , Heathman S , Ji D , Khandelwal B , Kohn A , Morris S , Norden D , Peng T , Post B , Powers E , Reif K , Schulzki G , Shevchuk C , Solyom A 
Published: February 2020

Abstract
An interlaboratory study was conducted to evaluate a method for the determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements at levels &gt;1.00 mg/100 g based on a 23 g sample. Test samples were saponified at high temperature with ethanolic KOH solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with hydrogen flame ionization detection. Twelve blind duplicates, one of which was fortified, were successfully analyzed by 10 collaborators. Recoveries were obtained for the sample that was fortified. The results were 99.8, 111, and 111% for campesterol, stigmasterol, and beta-sitosterol, respectively. For repeatability, the relative standard deviation (RSDr) ranged from 3.93 to 17.3% for campesterol, 3.56 to 22.7% for stigmasterol, and 3.70 to 43.9% for beta-sitosterol. For reproducibility, the RSDR ranged from 7.97 to 22.6%, 0 to 26.7%, and 5.27 to 43.9% for campesterol, stigmasterol, and beta-sitosterol, respectively. Overall, the Study Director approved 5 materials with acceptable HorRat values for campesterol, stigmasterol, and beta-sitosterol ranging from 1.02 to 2.16.
Evaluation of the GeneQuence® DNA Hybridization Method in Conjunction with 24-Hour Enrichment Protocols for Detection of Salmonella spp. in Select Foods: Collaborative Study
Authors: Mozola Mark A , Peng Xuan , Wendorf Michael ,   Collaborators:, Alles S , Artiga L , Buchholz T , Camacho A , Charveron N , Clayborn J , Decker C , Deibel C , Donohue T , Draughon A , Ewings J , Feldworth M , Gane P , Goodwin J , Gunter T , Gutierrez M , Hovland R , Jechorek R , Jones W , Keskinen L , Lamproe B , Larson E , Manwarren H , Merkling A , Osing C , Pangloli P , Remes A , Richter E , Rogers A , Rose B , Ryser E , Secraw S , Slupik M , Wessinger A , Westmoreland R , Yan Z , Zahoor T , Zhang L 
Published: February 2020

Abstract
A multilaboratory study was conducted to compare performance of the GeneQuence® DNA hybridization (DNAH) method incorporating new 24 h enrichment protocols and reference culture procedures for detection of Salmonella spp. in select foods. Six food types (raw ground turkey, raw ground beef, dried whole egg, milk chocolate, walnuts, and dry pet food) were tested by the DNAH method and by the culture methods of either the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) or the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA/BAM). Fifteen laboratories participated in the study. Four of the foods tested (raw ground turkey, dried whole egg, milk chocolate, and dry pet food), showed no statistically significant differences in performance between the DNAH method and the reference procedure as determined by Chi square analysis. Sensitivity rates for the DNAH method ranged from 92 to 100. The DNAH method, with the specific enrichment protocol evaluated, was found to be ineffective for detection of Salmonella spp. in walnuts. For raw ground beef, results from one trial showed a statistically significant difference in performance, with more positives obtained by the reference method. However, evidence suggests that the difference in the number of positives was likely due to lack of homogeneity of the test samples rather than to DNAH method performance.
Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin B1 in Corn Samples: Interlaboratory Study
Authors: Brera Carlo , Debegnach Francesca , Minardi Valentina , Pannunzi Elena , Santis Barbara De , Miraglia Marina ,   Collaborators:, Bergamini C , Biancardi A , Bodda M , Bonassisa L , Burdaspal P , Cantamessa L , Chessa G , Commissati I , Corrao A , Dömsödi J , Esposito G , Focardi C , Garbini D , Gatti M , Gibellino C , Kroeger K , Lombardi F M , Mambelli P , Mastrantoni J , Michelet J Y , Møller T , Pascale M , Petrini C , Pietri A , Piombino M , Piro R , Pittet A , Rizzi N , Stroka J , Thim A M , Ubaldi A , Villani A , Zanon F 
Published: February 2020

Abstract
An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 levels in corn samples, enforced by European Union legislation. A test portion was extracted with methanolwater (80 + 20); the extract was filtered, diluted with phosphate-buffered saline solution, filtered on a microfiber glass filter, and applied to an immunoaffinity column. The column was washed with deionized water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase LC with fluorescence detection after either pre- or postcolumn derivatization. Precolumn derivatization was achieved by generating the trifluoroacetic acid derivative, used by 8 laboratories. The postcolumn derivatization was achieved either with pyridinium hydrobromide perbromide, used by 16 laboratories, or with an electrochemical cell by the addition of bromide to the mobile phase, used by 5 laboratories. The derivatization techniques used were not significantly different when compared by the Student's t-test; the method was statistically evaluated for all the laboratories. Five corn sample materials, both spiked and naturally contaminated, were sent to 29 laboratories (22 Italian and 7 European). Test portions were spiked with aflatoxin B1 at levels of 2.00 and 5.00 ng/g. The mean values for recovery were 82% for the low level and 84% for the high contamination level. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally contaminated samples (blind pairs at 3 levels), the values for relative standard deviation for repeatability (RSDr) ranged from 9.9 to 28.7%. The values for relative standard deviation for reproducibility (RSDR) ranged from 18.6 to 36.8%. The method demonstrated acceptable within- and between-laboratory precision for this matrix, as evidenced by the HorRat values.
Discriminatory Power, Typability, and Accuracy of Single Nucleotide Extension Microarrays
Authors: Berget Ingunn , Heir Even , Petcovic Jelena , Rudi Knut 
Published: February 2020

Abstract
Despite great conceptual promise, the use of microarrays in typing approaches has not yet gained wide acceptance. The establishment of proper criteria for determining discriminatory power as well as typability and the accuracy of microarray data remains to be solved. Purely experimental estimations of these parameters would far exceed what is experimentally practical. We therefore used simulations in combination with experimental results in parameter estimations. Our assay was based on 26 single nucleotide polymorphisms (SNPs) identified in the Campylobacter jejuni Multi Locus Sequence Typing (MLST) database (&lt;ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://pubmlst.org/campylobacter/"&gt;http://pubmlst.org/campylobacter/&lt;/ext-link&gt;). The SNPs were detected using a single nucleotide extension (SNE) typing microarray. Unknown isolates were assigned to the known sequence type(s) by calculating weighted sum of matches minus a weighted sum of mismatches between predicted and candidate genotype. The weights were set according to the Bayesian posterior probability of the SNP classification. These studies showed that any typing or profiling method based on binary data requires an accuracy of &lt;23% error for each datapoint (in our case SNPs) to classify the isolates to the correct allelic profile in 90% of the cases. The classification error for our experimental data was 3.2% (after removing 5 high error SNPs). We therefore conclude that SNE microarrays are promising for future high-throughput typing of bacteria.
Application of a Quantitative Carrier Test to Evaluate Microbicides against Mycobacteria
Authors: Springthorpe V Susan , Sattar Syed A 
Published: February 2020

Abstract
Microbicides for reprocessing heat-sensitive medical devices, such as flexible endoscopes, must be mycobactericidal to reduce the risk of nosocomial infections. Suspension test methods currently used for efficacy evaluation lack the stringency required for assessing inactivation of mycobacteria on surfaces. The quantitative carrier test method reported here is based on mycobacteria-contaminated reference carrier disks of brushed stainless steel. Each disk was contaminated with 10 L of a suspension of Mycobacterium terrae containing a soil load. Each disk with a dried inoculum was placed in a glass or Teflon vial, and then overlaid with 50 L of the test formulation or 50 L saline for the control carriers. Five test and 3 control disks were used in each run. At the end of the contact time, each vial received 9.95 mL neutralizer solution with 0.1% Tween-80 to stop the reaction and perform the initial microbicide dilution. The inoculum was eluted by mixing on a Vortex mixer for 60 s, and the eluates and saline used to subsequently wash the vials and the funnels were membrane-filtered. Filters were placed on plates of Middlebrook 7H11 agar and incubated at 37C for at least 30 days before colonies were counted and log10 reductions were calculated in colony-forming units. Tests with a range of commercially available products, having claims against mycobacteria, or believed to be broad-spectrum microbicides, showed that the method gave reproducible results. Products used included oxidizing agents (sodium hypochlorite and an iodophore), a phenolic, a quaternary ammonium compound, and ortho-phthalaldehyde. This method represents a much more realistic evaluation than the currently used quantitative suspension test method for the evaluation of mycobactericidal formulations for registration and, when performed at different product concentrations, allows an assessment of any safety margin or risks in using the test formulation in the field.
A Method for Determination of Selenium in Organic Tissues Using Microwave Digestion and Liquid Chromatography
Authors: Govasmark Espen , Grimmett Mark G 
Published: February 2020

Abstract
An existing laboratory procedure for selenium analysis using open-vessel wet digestion and liquid chromatographic fluorescence determination was modified for use with microwave digestion. The proposed microwave digestion method eliminated the hazards associated with the use of HCIO4 while maintaining excellent recoveries of selenium. A 2-step HNO3/H2O2 digestion procedure was developed. Digested samples were derivatized with 2,3-diaminonaphthalene, and the resultant piazselenol complex was measured fluorometrically using a liquid chromatograph. Measured values were in agreement with 9 different certified reference materials. The detection limit for this method was 0.54 ng Se/g tissue (3 ), and the calibration curve remained linear (r2 = 0.9968) up to 2 g Se/g.
Determination of Arsenic, Cadmium, Mercury, and Lead by Inductively Coupled Plasma/Mass Spectrometry in Foods after Pressure Digestion: NMKL Interlaboratory Study
Authors: Julshamn Kaare , Maage Amund , Norli Hilde Skaar , Grobecker Karl H , Jorhem Lars , Fecher Peter ,   Collaborators:, Hentschel A , Martin de la Hinojosa I , Viehweger L , Mindak W R , Lindholm K , Holm K , Olsson B , Engman J , Habernegg R , Hammer D , Lewis J , van der Wielen J , Hovind H , Vadset M 
Published: February 2020

Abstract
Thirteen laboratories participated in an interlaboratory method performance (collaborative) study on a method for the determination of arsenic, cadmium, mercury, and lead by inductively coupled plasma/mass spectrometry (ICP/MS) after pressure digestion including the microwave heating technique. Prior to the study, the laboratories were able to practice on samples with defined element levels (pretrial test). The method was tested on a total of 7 foodstuffs: carrot puree, fish muscle, mushroom, graham flour, simulated diet, scampi, and mussel powder. The elemental concentrations in mg/kg dry matter (dm) ranged from 0.0621.4 for As, 0.0328.3 for Cd, 0.040.6 for Hg, and 0.012.4 for Pb. The materials used in the study were presented to the participants as blind duplicates, and the participants were asked to perform single determinations on each sample. The repeatability relative standard deviations (RSDr) for As ranged from 3.8 to 24%, for Cd from 2.6 to 6.9%, for Hg from 4.8 to 8.3%, and for Pb from 2.9 to 27%. The reproducibility relative standard deviations (RSDR) for As ranged from 9.0 to 28%, for Cd from 2.8 to 18%, for Hg from 9.9 to 24%, and for Pb from 8.0 to 50%. The HorRat values were less than 1.5 for all test samples, except for the determination of Pb in wheat flour at a level close to the limit of quantitation (0.01 mg/kg dm). The study showed that the ICP/MS method is satisfactory as a standard method for elemental determinations in foodstuffs.