bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereo- and Enantioselective Determination of Pesticides in Soil by Using Achiral and Chiral Liquid Chromatography in Combination with Matrix Solid-Phase Dispersion
Authors: Li Zhao-Yang , Zhang Zhi-Chao , Zhou Qi-Lin , Wang Qing-Min , Gao Ru-Yu , Wang Qin-Sun 
Published: February 2020

Abstract
The separation of enantiomers and diastereomers of 8 commonly used pesticides was investigated by liquid chromatography (LC) using a Chiralcel OD column (cellulose tris-3,5-dimethylphenyl-carbamate as the chiral stationary phase) and a Pirkle-type Chirex 3020 column (urea derivative from the reaction of (R)-1-(α-naphthyl)ethylamine with (S)-tert-leucine, chemically bonded to 3-aminopropylsilanized silica as the chiral stationary phase). The pesticides studied included one organophosphorus insecticide (phenthoate), 3 triazole fungicides (uniconazole, diniconazole, and propiconazole), and 4 pyrethroids (fenpropathrin, β-cypermethrin, β-cyfluthrin, and α-fenvalerate). The enantiomers were separated within 20 min with a resolution of ≥1.5 using a mixture of n-hexane and 2-propanol as the mobile phase for all the pesticides studied except propiconazole, for which only the 2 diastereomers were baseline separated. This method allows determination of the enantiomers or stereoisomers of the above pesticides in soil. The strategy was as follows: (1) First, the total concentration(s) of the enantiomer pair(s) of a chiral pesticide in soil was (were) determined by a newly developed matrix solid-phase dispersion (MSPD) procedure, followed by silica-based LC quantification. The recoveries ranged from 76.5 to 93.6% with relative standard deviations of 6.0%. (2) Second, the enantiomeric ratio(s) (ER(s)) of the chiral pesticide was (were) determined by LC with a chiral stationary phase after fractionation of the MSPD extract by silica-based LC. The determined ERs or stereoisomeric ratio(s) (SR(s); for propiconazole, only the SR of the 2 diastereomers was determined) in soil samples spiked with the above 8 racemic pesticides agreed with those of the corresponding standard solutions. (3) Third, based on the total concentrations and the corresponding ERs, the concentration of each enantiomer in soil was calculated. The proposed method is rapid, precise, and sensitive, and is appropriate for the investigation of the stereo- and enantioselective degradation of pesticides in environmental media.
Determination of Polycyclic Aromatic Hydrocarbons in Honey by Matrix Solid-Phase Dispersion and Gas Chromatography/Mass Spectrometry
Authors: Albero Beatriz , Sánchez-Brunete Consuelo , Tadeo José L 
Published: February 2020

Abstract
A multiresidue method was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in unifloral and multifloral honeys. The analytical procedure is based on the matrix solid-phase dispersion of honey on a mixture of Florisil and anhydrous sodium sulfate in small glass columns and extraction with hexane–ethyl acetate (90 + 10, v/v) with assisted sonication. The PAH residues are determined by gas chromatography with mass spectrometric detection using selected-ion monitoring. Average recoveries for all the PAHs studied were in the range of almost 80 to 101%, with relative standard deviations of 6 to 15%. The limits of detection ranged from 0.04 to 2.9 μg/kg. The simultaneous extraction and cleanup of samples makes this method simple and rapid, with low consumption of organic solvents.
Determination of Sulfathiazole in Type C Medicated Swine Feed by Reversed-Phase Liquid Chromatography with Post-Column Derivatization
Authors: Albert Kendrick , Riter Ken L , Smallidge Robert L 
Published: February 2020

Abstract
A convenient method was developed for determination of sulfathiazole (STZ) in Type C medicated swine feed by reversed-phase liquid chromatography (LC) with post-column derivatization. Addition of extractant solution (0.2N HCl and 1.5% diethylamine in 25% methanol) and an internal standard (IS), sulfamethylthiazole (SMZ), to 5 g sample was followed by mechanical shaking for 1 h. The extract was clarified by chilling, centrifugation, and filtering before injection onto a C18 reversed-phase column. The mobile phase components were 2% acetic acid and 1:1 acetonitrile–methanol (83 + 17%, v/v). Run time was about 20 min. Determination and, largely, the method's selectivity were based on detection at 450 nm of the derivative formed by the post-column reaction of dimethylaminobenzaldehyde with the primary amine of the analyte and IS. The IS, SMZ, differs from STZ by a single substituent methyl group, is stable, and is readily resolved from STZ. Although SMZ is not commercially available, it can be synthesized with relative ease from purchased reagents and will be supplied by the authors to interested laboratories. In single-laboratory validation, linearity was demonstrated over the range of 0.055–550 μg/mL, well beyond the target concentration of 5.5 μg/mL. The estimated limit of detection was 0.04 μg/mL; the calculated limit of quantitation was 0.13 μg/mL (feed concentration of 2.4 g/T or 2.7 mg/kg). Wet-spiking trials with a variety of swine feed matrixes showed recovery to be 100–102% for the intended concentration range, 50–200 g/T, with coefficient of variation (CV) &lt;2%. The method ruggedness was verified with an overall CV of 2.9%.
Validation of Screening Method for Residues of Diethylstilbestrol, Dienestrol, Hexestrol, and Zeranol in Bovine Urine Using Immunoaffinity Chromatography and Gas Chromatography/Mass Spectrometry
Authors: Dickson Leslie C , MacNeil James D , Reid JoAnn , Fesser Adrian C E 
Published: February 2020

Abstract
A method was developed, using commercially available immunoaffinity chromatography cleanup cartridges, followed by detection by gas chromatography/mass spectrometry, to screen for residues of the hormone growth promotants diethylstilbestrol, dienestrol, hexestrol, and zeranol in bovine urine. The single-laboratory, in-house validation included assessment of recoveries, repeatability, linearity of response, detection capability, and specificity (cross-reactivity) with a suite of antibiotics and other hormonal growth promotants. The method was validated for screening at a target concentration of 2.0 μg/L in urine. The detection capabilities for the analytes were diethylstilbestrol, 0.24; dienestrol, 0.15; hexestrol, 0.84; and zeranol, 0.28 μg/L.
Determination of Ephedrine Alkaloids in Human Urine and Plasma by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study
Authors: Trujillo William A , Sorenson Wendy R ,   Collaborators:, Gray D , Laurensen J , Luo G , McClanahan R , Perez R , Roper C , Kotello S , Shevchuk C , Suen E , Sullivan D 
Published: February 2020

Abstract
A collaborative study was conducted to evaluate the accuracy and precision of a method for ephedrine-type alkaloids (i.e., norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, methylephedrine, and methylpseudoephedrine) in human urine and plasma. The amount of ephedrine-type alkaloids present was determined using liquid chromatography (LC) with tandem mass selective detection. The test samples were diluted to reflect a concentration of 5.00–100 ng/mL for each alkaloid. An internal standard was added and the alkaloids were separated using a 5 μm phenyl LC column with an ammonium acetate, glacial acetic acid, acetonitrile, and water mobile phase. Eight blind duplicates of human urine and eight blind duplicates of human plasma were analyzed by 10 collaborators. In addition to negative controls, test portions of urine and plasma were fortified at 3 different levels with each of the 6 ephedrine-type alkaloids at approximately 1, 2, and 5 μg/mL for urine and 100, 200, and 500 ng/mL for plasma. On the basis of the accuracy and precision results for this collaborative study, it is recommended that this method be adopted Official First Action for the determination of 6 different ephedrine-type alkaloids in human urine and plasma.
Determination of Chlorpheniramine Maleate and Tincture Ipecac in Dosage Form by Liquid Chromatography with Ultraviolet Detection
Authors: Eldawy Mohamed A , Mabrouk Mokhtar M , El-Barbary Fawzy A 
Published: February 2020

Abstract
A procedure was developed and validated for measuring chlorpheniramine maleate and tincture ipecac (as emetine hydrochloride) by reversed-phase liquid chromatography with methanol–10mM sodium heptanesulfonate (20 + 30) as the mobile phase; the pH was adjusted to 4 with acetic acid, and the flow rate was at 1.5 mL/min, with ultraviolet detection at 254 nm. Propyl paraben was used as the internal standard. The standard curves were linear (r = 0.998 and 0.9998) for both chlorpheniramine maleate and emetine hydrochlo-ride over the ranges of 5–100 and 0.1–40 μg/mL, respectively. The mean recoveries ± standard deviation were 101.37 ± 2.77% for chlorpheniramine maleate and 98.8 ± 1.47% for emetine hydrochlo-ride. The proposed method was applied to the determination of chlorpheniramine maleate alone in tablet and syrup dosage forms. The method also was applied to the determination of the emetine content of ipecac liquid extract and tincture ipecac; the results were compared with those of the method of the British Pharmacopoeia. The proposed method was applied successfully to the simultaneous determination of chlorpheniramine maleate and tincture ipecac, as emetine hydrochlo-ride, in syrup dosage form. Both drugs and the internal standard were separated from all interfering components in &lt;5 min. The proposed method is simple, specific, and economical, when compared with other published methods that determine each component alone.
Determination of Clopidol Residues in Chicken Tissues by Liquid Chromatography: Collaborative Study
Authors: Pang Guo-Fang , Cao Yan-Zhong , Fan Chun-Lin , Zhang Jin-Jie , Li Xue-Min , MacNeil James D ,   Collaborators:, Bo H B , Chen J H , Chu X G , Fang X M , Guggisberg D , Gupta R C , Hudecova T , Jia X , Kennedy G , Lin A Q , Lin F , Lin H D , Ling Y C , Ma Z D , Nan Z , One Y , Qin Y , Quiroga M A , Sharman M , Song W B , Soraci A L , Tang F B , Tekel J , Tian M , Uscinas R , Wang F C , Xu H , Zhou L , Zhou W , Zhou X P , Zhu G N 
Published: February 2020

Abstract
Eighteen laboratories participated in a collaborative study on the determination of clopidol residues in chicken muscle tissues by liquid chromatography. Of these, results from 16 laboratories which rigorously followed the method were subjected to statistical analysis. The method performance was assessed by all participants using 14 samples of chicken muscle fortified at concentrations ranging from 0.1 to 5.0 mg/kg. In addition, 9 participants each reported results for 6 clopidol-incurred samples in chicken muscle. Test portions were extracted with acetonitrile, and the extracts were purified with alumina and anion exchange resin solid-phase extraction cartridges in sequence. Clopidol was separated by reversed-phase liquid chromatography and quantified at 270 nm. Average recoveries ranged from 81.8 to 85.4%, reproducibility relative standard deviation (RSDR) ranged from 11.9 to 22.6%, and repeatability relative standard deviation (RSDr) ranged from 9.9 to 15.1%. For clopidol-incurred samples at concentrations of 0.100–0.687 mg/kg, the mean determination value range was 0.099–0.659 mg/kg; RSDR was 12.6–19.8%, RSDr was 3.1–8.5%; and HORRAT values were 0.7–1.1. The accuracy and precision of the method are in conformity with the requirements specified by AOAC INTERNATIONAL. The method was adopted Official First Action in April 2003.
Alternative Liquid Chromatographic Method for Determination of the Methoxyl and 2-Hydroxypropoxyl Content in Cellulose Ether Derivatives
Authors: Rashan Joe , Chen Raymond , Zelesky Todd , Sekulic Sonja 
Published: February 2020

Abstract
An alternative liquid chromatographic (LC) method was developed and validated for the simultaneous determination of methoxyl and 2-hydroxypropoxyl substituents in hypromellose and hypromellose acetate succinate. The method uses the hydriodic acid cleavage reaction, catalyzed by adipic acid, of the substituted methoxyl and 2-hydroxypropoxyl groups, which are quantitatively converted to iodomethane and 2-iodopropane. The iodomethane and 2-iodopropane are extracted into xylene, the extract is diluted with methanol, and the analytes are separated and assayed by gradient elution using a reversed-phase C18 column. The method is selective and sensitive and has good linearity with values of 0.999 for R2 and 0.25% for the y-intercept bias from 1.39 to 5.55 mg/mL for iodomethane, and 0.999 for R2 and 0.52% for the y-intercept bias from 0.184 to 0.735 mg/mL for 2-iodopropane. The relative standard precisions for this LC method were found to be ± 2.3% for determining methoxyl at the 23.1% (w/w) level, and ± 3.5% for determining 2-hydroxypropoxyl at the 6.7% (w/w) level. Compared with the current gas chromatographic (GC) compendial (JPE) method, the LC assay method has equal or better precision. It was found that both the standard and sample solutions have limited stability (8 h) after preparation. This limited stability has not been reported previously in the literature and may have an impact on the reported accuracy/precision of the literature data for the GC method. The LC method was proven to be robust with respect to variation in derivatization time and temperature, flow rate, and column temperature. It is well suited for the quality control needed in today's fast-paced pharmaceutical laboratories.
Receptor Binding Assay for Paralytic Shellfish Poisoning Toxins: Optimization and Interlaboratory Comparison
Authors: Ruberu Shiyamalie R , Liu Yun-Gang , Wong Carolyn T , Perera S Kusum , Langlois Gregg W , Doucette Gregory J , Powell Christine L 
Published: February 2020

Abstract
A receptor binding assay (RBA) for detection of paralytic shellfish poisoning (PSP) toxins was formatted for use in a high throughput detection system using microplate scintillation counting. The RBA technology was transferred from the National Ocean Service, which uses a Wallac TriLux 1450 MicroBeta microplate scintillation counter, to the California Department of Health Services, which uses a Packard TopCount scintillation counter. Due to differences in the detector arrangement between these 2 counters, markedly different counting efficiencies were exhibited, requiring optimization of the RBA protocol for the TopCount instrument. Precision, accuracy, and sensitivity [limit of detection = 0.2 μg saxitoxin (STX) equiv/100 g shellfish tissue] of the modified protocol were equivalent to those of the original protocol. The RBA robustness and adaptability were demonstrated by an interlaboratory study, in which STX concentrations in shellfish generated by the TopCount were consistent with MicroBeta-derived values. Comparison of STX reference standards obtained from the U.S. Food and Drug Administration and the National Research Council, Canada, showed no observable differences. This study confirms the RBA's value as a rapid, high throughput screen prior to testing by the conventional mouse bioassay (MBA) and its suitability for providing an early warning of increasing PSP toxicity when toxin levels are below the MBA limit of detection.
Determination of Fat, Protein, Casein, Total Solids, and Somatic Cell Count in Goat's Milk by Near-Infrared Reflectance Spectroscopy
Authors: Albanell Elena , Caja Gerardo , Such Xavier , Rovai Maristela , Salama Ahmed A K , Casals Ramón 
Published: February 2020

Abstract
Analysis using near-infrared reflectance spectroscopy (NIRS) was investigated as a means of predicting quality parameters of goat's milk. Calibration equations were developed with samples from individual goats of Malagueña and Murciano-Granadina dairy breeds at different stages of lactation to obtain a wide range of variation in milk composition. Prediction equations for milk fat, protein, casein, total solids, and somatic cell count (SCC) were developed with 2 sample presentations, liquid drawer (homogenized milk) and aluminium cup (unhomogenized milk), to measure absorbance values, and accuracy of measurements was compared. The multiple correlation coefficient (R) values for homogenized milk were 0.98, 0.96, 0.91, 0.94, and 0.79 and for unhomogenized milk were 0.98, 0.95, 0.92, 0.95, and 0.74 for fat, protein, casein, total solid, and SCC, respectively. To validate the calibrations, an independent set of samples was used. The best simple correlation coefficient (r) values were 0.97, 0.95, 0.91, 0.93, and 0.72 for homogenized milk and 0.97, 0.95, 0.92, 0.95, and 0.79 for unhomogenized milk. The study showed that NIRS is a useful technique for the prediction of fat, protein, casein, total solids, and SCC in unhomogenized goat's milk.
Salmonella in Foods: New Enrichment Procedure for TECRA Salmonella Visual Immunoassay Using a Single RV(R10) Only, TT Only, or Dual RV(R10) and TT Selective Enrichment Broths (AOAC Official Method 998.09): Collaborative Study
Authors: Hughes Denise , Dailianis Angela E , Hill Louise , Curiale Michael S , Gangar Vidhya ,   Collaborators:, Arnold D , Barrat C , Baxter T , Bell J , Brooks R , Bryant D , Burke K , Burnie A , Cliffard D , Danisavich T , Daniels K , Deiss K , D’Onorio A , Faucher K , Finkenbiner D , Gasanov U , Gebler J , Gerry A , Graham D , Graham T , Harris P , Hetrick S , Jurgens J , Keating K J , Klokman R , Le C , Matrozza M , McCarthy R , McCawley C , Munyard S , Pye V , Rajkowski K , Ristov K , Rosinko J , Schneider K , Schubert M J , Sloan E , Souter  , Wilson M , Zuroski K 
Published: February 2020

Abstract
A collaborative study was conducted to compare a new enrichment procedure for the TECRA® Salmonella Visual Immunoassay (TSVIA) with the reference method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual (7th Ed.). Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 3 food types (milk chocolate, dried egg, and raw turkey) were analyzed in the United States. Thirty-eight collaborators participated in the study. The TECRA method was evaluated using both Rappaport-Vassiliadis R10 (RV(R10)) and tetrathionate (TT) broths for selective enrichment. M broth cultures arising from each of the 2 selective enrichment broths were tested in the TSVIA using 2 individual wells, one for each selective broth, and a single well to test the pooled selective enrichment broths. The results for the pooled enrichment broths were reported elsewhere. This study presents the results for the use of single enrichment broths, i.e., RV(R10) only or TT only, with the TSVIA. No significant differences (p &gt; 0.05) were observed for the pairwise comparison of the proportion of positive samples for either RV(R10) or TT used as a single enrichment broth for the TSVIA with that for the reference method.
Amnesic Shellfish Poisoning Toxins in Shellfish: Estimation of Uncertainty of Measurement for a Liquid Chromatography/Tandem Mass Spectrometry Method
Authors: Holland Patrick T , McNabb Paul , Selwood Andrew I , Neil Tracey 
Published: February 2020

Abstract
A liquid chromatography/mass spectrometry (LC/MS) method for amnesic shellfish poisoning toxins in shellfish was developed and validated. Tissue homogenate (4 g) was extracted with 16 mL methanol–water (1 + 1, v/v). Dilution into acetonitrile–water (1 + 9, v/v) was followed by C18 solid-phase extraction cleanup. Domoic acid (DA) and epi-domoic acid were determined by LC/MS/MS with electrospray ionization and multiple reaction monitoring. External calibration was performed with dilutions of a certified reference standard. Advantages of this method include speed, lower detection limits, and a very high degree of specificity. The LC/MS response was highly linear, and there were no significant interferences to the determination of DA. Formal method validation was performed on 4 shellfish species. Fortification studies gave recoveries (mean ± SD; n = 24) of 93 ± 14% at 1 mg/kg, and 93.3 ± 7.6% at 20 mg/kg over all the species. Analysis of a mussel certified reference material showed the bias as &lt;5%. The limits of detection and quantitation were 0.15 and 0.5 mg/kg, respectively. Routine application of the method over 4 months gave a recovery for the QC sample (1 mg/kg fortified blank mussel homogenate) run with each batch of 88.9 ± 5.5% (mean ± SD; n = 37). The total uncertainty of measurement results were estimated as 0.12 (12%) at 0.25–5 mg/kg and 0.079 (7.9%) at 5–50 mg/kg. The major contribution to the uncertainty was the repeatability of the LC/MS determination, probably arising from subtle matrix effects.
Thermoluminescence Detection of Irradiated Fruits and Vegetables: International Interlaboratory Trial
Authors: Sanderson David C W , Carmichael Lorna A , Fisk Saffron ,   Collaborators:, Christensen P , Delincée H , Hammerton K , Nootenboom H , Pfordt J , Pinnioja S , Schreiber G A , Toyoda M 
Published: February 2020

Abstract
An international interlaboratory trial was conducted to validate thermoluminescence methods for detecting irradiated fruits and vegetables. Five products were used in this study. This paper presents the results from prestudy material, homogeneity testing, details of sample preparation, and participants' results. Prestudy results provided a basis for cross comparison of instruments in different laboratories. A wide range of sensitivities, reproducibilities, and signal-to-background ratios were observed. Homogeneity testing showed that the method can distinguish between nonirradiated and irradiated products, including those bleached with 100 J/cm2 artificial daylight, provided that sensitivity rejection criteria are rigorously applied. Blind results were returned by 9 participants in the form of first and second glow integrals and glow ratios for all samples and a qualitative classification for each product. Of the 387 results reported, 327 valid results were obtained from participants. Where valid data were obtained, correct qualitative identifications were made by participants in all cases. Participants' results and homogeneity testing both confirm the validity of the thermoluminescence method for detecting irradiated fruits and vegetables.
Thermoluminescence Detection of Irradiated Shellfish: International Interlaboratory Trial
Authors: Sanderson David C W , Carmichael Lorna A , Fisk Saffron ,   Collaborators:, Christensen P , Delincée H , Nootenboom H , Pfordt J , Pinnioja S , Schreiber G A , Wagner U 
Published: February 2020

Abstract
An international interlaboratory trial was conducted using thermoluminescence for the detection of irradiated shellfish, aimed at validating the method for routine use. Nephrops norvegicus, mussels, brown shrimps, black tiger prawns, and king scallops were presented as nonirradiated and irradiated to 0.5 and 2.5 kGy. The protocol called for the use of 3 preparation methods: extraction of silicates from whole shellfish by acid hydrolysis and physical separation, and of carbonates from powdered shells. Homogeneity was tested on each product and each treatment. Results verified that all methods were able to distinguish between nonirradiated and irradiated samples regardless of dose. Silicate methods produced better discrimination than powdered shell, and acid hydrolysis showed some evidence of better separation between the 2 doses than the physical method. Participants received each product in each treatment category for blind analysis. Six participants returned results for acid hydrolysis, 7 for physical separation, and 5 for the powdered shell method. Their results confirmed the homogeneity testing. Qualitative results gave 100% correct classification for both silicate methods and 85.3% for powdered shell. Silicate methods are therefore preferable unless only shell is available. Overall, the results confirmed the case for validation.