bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability-Indicating High-Performance Liquid Chromatographic Assay of Atorvastatin with Fluorescence Detection
Authors: Khedr Alaa 
Published: February 2020

Abstract
The purpose of this work was to develop a sensitive, selective, and validated stability-indicating high-performance liquid chromatographic (LC) assay of atorvastatin (ATV) in bulk drug and tablet form. ATV was subjected to different stress conditions, including UV light, oxidation, acid-base hydrolysis, and temperature. ATV and its degradation products were analyzed on an Agilent Zorbax XDB C18 column using isocratic elution with acetonitrile0.02 M sodium acetate, pH 4.2 (45 + 55, v/v) for 25 min. The samples were monitored with fluorescence (FL) detection at 282 nm (excitation)/400 nm (emission). The response ratio of FL to UV detection (at 247 nm) for ATV was 1.66. The method showed good resolution of ATV from its decomposition products. The photodegradation products were separated by silica gel thin-layer chromatography using double development with ethyl acetaten-hexaneglacial acetic acidmethanol (40 + 55 + 0.5 + 4.5, v/v/v/v) followed by (39 + 55 + 0.5 + 5.5, v/v/v/v), and confirmed by LC-FL analysis. The FL response was linear over the investigated range for ATV. The linear range was 101200 ng/injection, and the limit of quantitation was 2.0 ng/injection.
Determination of Zearalenone in Cereal Grains, Animal Feed, and Feed Ingredients Using Immunoaffinity Column Chromatography and Liquid Chromatography: Interlaboratory Study
Authors: Campbell Harold M , Armstrong J Fred ,   Collaborators:, Aoyama K , Biselli S , Cea J , de Rijk T , Dmytrow H , Dömsödi J , Friis-Wandall S , Gonzalez; P , Inerowicz D , Kirby P , Kozak A , Marley E , Marth-Schill J , Nordkvist E , Renaud S , Riter K , Roos A 
Published: February 2020

Abstract
A method using immunoaffinity column chromatography (IAC) and liquid chromatography (LC) for determination of zearalenone in cereal grains, animal feed, and feed ingredients was collaboratively studied. The test portion is extracted by shaking with acetonitrilewater (90 + 10, v/v) and sodium chloride. The extract is diluted and applied to an immunoaffinity column, the column is washed with water or phosphatebuffered saline or methanolwater (30 + 70, v/v), and zearalenone is eluted with methanol. The eluate is evaporated, the residue is dissolved in mobile phase and analyzed by reversed-phase LC with fluorescence detection. The presence of zearalenone can be confirmed using an alternate excitation wavelength or diode array detection. Twenty samples were sent to 13 collaborators (8 in Europe, 2 in the United States, one in Japan, one in Uruguay, and one in Canada). Eighteen samples of naturally contaminated corn, barley, wheat, dried distillers grains, swine feed, and dairy feed were analyzed as blind duplicates, along with blank corn and wheat samples. The analyses were done in 2 sample sets with inclusion of a spiked wheat control sample (0.1 mg/kg) in each set. Spiked samples recoveries were 89116, and for the 18 naturally contaminated samples, RSDr values (within-laboratory repeatability) ranged from 6.67 to 12.1, RSDR values (among-laboratory reproducibility) ranged from 12.5 to 19.7, and HorRat values ranged from 0.61 to 0.90.
Hierarchy of Susceptibility of Viruses to Environmental Surface Disinfectants: A Predictor of Activity Against New and Emerging Viral Pathogens
Authors: Sattar Syed A 
Published: February 2020

Abstract
Proper disinfection is crucial to interrupt the environmental spread of many viruses. In the case of new and emerging viruses still awaiting culture and full characterization, it is proposed that any official recommendations for disinfectant use be based on the well-established hierarchy of susceptibility to such chemicals as related to virus particle size and structure.
Multiresidue Determination of Pesticides in Acid-Clay Soils from Thailand
Authors: Amelung Wulf , Nikolakis Alexander , Laabs Volker 
Published: February 2020

Abstract
Tropical and temperate soils differ with respect to their chemical conditions and mineral composition. Consequently, assessment of the contamination of tropical soils with pesticides requires methods that provide exhaustive extraction from the specific soil matrix and reliable quantification. Our objective was to optimize the simultaneous extraction and determination of 32 representative pesticides (organophosphates, organochlorines, synthetic pyrethroids, triazines, acetamides, carbamates, diphenyl ethers, acylalanines, oxadiazoles, thiadiazoles, and phenoxy compounds) frequently used in Thailand. The compounds were added to a clayey Ultisol-topsoil (45 clay) from the Yom Region in Northern Thailand. Ten different solvent mixtures were tested; the use of a shake extraction with acetoneethyl acetatewater (3 + 1 + 1, v/v/v) was most effective in providing exhaustive and reproducible extraction of pesticides both from freshly fortified soil and from fortified soil after incubation for 1428 days. The pesticides were separated and quantified by using gas chromatography with mass selective detection. Except for methamidophos, which was almost completely lost during sample workup, the recoveries of all pesticides from soil ranged from 68.6 to 104 (mean standard error, 2.8) for freshly spiked samples and from 45.9 to 107 (mean standard error, 2.3) for spiked samples incubated for 14 days. The use of internal standards compensated for the losses of most pesticides during workup and increased the mean recovery of the pesticides from freshly fortified soil to 96. The method was successfully applied to the determination of environmental concentrations of pesticides in a range of Thai agricultural soils.
An Updated Liquid Chromatographic Assay for the Determination of Glyphosate in Technical Material and Formulations
Authors: Gavlick Walter K , Tomkins David F 
Published: February 2020

Abstract
An updated liquid chromatographic (LC) method for the determination of glyphosate in technical material and formulations was tested by 7 laboratories. Samples were dissolved in water and injected into an LC system with a C18 guard column, an anion exchange analytical column, and a phosphate buffer mobile phase with 12 to 15 methanol. Detection was by UV absorption at 195 nm or refractive index. Automated injections were made. Calculations were based on peak area comparisons with external standards. The interlaboratory study analyzed 6 matched pairs of 3 glyphosate technical materials and 3 glyphosate formulations. The matched pair results were analyzed by using the AOAC spreadsheet and Youden's matched pair calculations. Coefficients of variation for the 6 samples ranged from 0.46 to 0.85.
Determination of Low-Level Pesticide Residues in Soft Drinks and Sports Drinks by Liquid Chromatography with Tandem Mass Spectrometry: Collaborative Study
Authors: Miller Kathleen D , Milne Paul ,   Collaborators:, Baker S , Barr D , Haghani A , Loo B , Matteini P , Monson K D , Perez R , Rawn T , Rosi F , Schmitz J , Summer S , Yadlapalli S 
Published: February 2020

Abstract
A collaborative study was conducted on a method for the measurement of 11 low-level pesticide residues in soft drinks and sports drinks by liquid chromatography with tandem mass spectrometry. The pesticide residues determined in this study were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D). Blind fortification solutions containing 3 different levels of pesticide residues were provided to 9 collaborating laboratories to create test samples at concentrations of 0, 0.1, and 0.5 g/L with a 10-fold concentration for phorate in a total of 6 matrixes (2 colas, 1 diet cola, 1 clear lemon-lime soft drink, 1 orange soft drink, and 1 sports drink). Good qualitative performance of the method was demonstrated for all pesticide residues. Reproducibility relative standard deviation (RSDR) ranged from 7 to 151 for alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDR ranged from 9 to 57 for alachlor, atrazine, butachlor isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D in all matrixes. Repeatability relative standard deviation (RSDr), applicable to the diet cola and sports drink, ranged from 0 to 124 for the 11 pesticide residues at the 0.1 g/L level (1.0 g/L for phorate). At 0.5 g/L (5.0 g/L for phorate), RSDr ranged from 4 to 26. Recoveries for the 11 pesticide residues in all matrixes ranged from 84 to 300 at the 0.1 g/L level (1.0 g/L for phorate) and from 66 to 127 at the 0.5 g/L (5.0 g/L for phorate) level. Coefficients of determination (r2) of the matrix-matched calibration curves were 0.95. It is recommended that the method be accepted by AOAC as Official First Action with a limit of quantification of 0.5 g/L for alachlor, atrazine, butachlor, isoproturon, malaoxon, methyl paraoxon, monocrotophos, phorate sulfone, phorate sulfoxide, and 2,4-D and 5.0 g/L for phorate.
Development and Validation of Column High-Performance Liquid Chromatographic and Ultraviolet Spectrophotometric Methods for Citalopram in Tablets
Authors: Menegola Jlia , Steppe Martin , Schapoval Elfrides E S 
Published: February 2020

Abstract
Column high-performance liquid chromatographic (LC) and UV spectrophotometric methods for the quantitative determination of citalopram, a potent and selective serotonin reuptake inhibitor, in tablets were developed. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by the reversed-phase technique on an ACE C18 column with a mobile phase composed of 0.30 triethylamine solutionacetonitrile (55 + 45, v/v) adjusted to pH 6.6 with 10 ortho-phosphoric acid at a flow rate of 1.0 mL/min and 25C. The UV spectrophotometric method was performed at 239 nm. The linearity of the LC method was in the range of 10.0070.00 g/mL, and 2.5017.50 g/mL for the UV spectrophotometric method. The interday and intraday assay precision was &lt;1.5 (relative standard deviation) for the LC and UV spectrophotometric methods. The recoveries were in the range 100.70101.35 for the LC method and 98.4898.65 for the UV spectrophotometric method. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the 2 methods. The proposed methods are highly sensitive, precise, and accurate and can be used for the reliable quantitation of citalopram in tablets.
Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Method 996.09 [Visual Immunoprecipitate (VIP®) for E. coli O157:H7] to the Reference Culture Methods
Authors: Feldsine Philip T , Kerr David E , Shen George S , Lienau Andrew H 
Published: February 2020

Abstract
The Visual Immunoprecipitate (VIP®)for the Detection of E. coli O157:H7 in Foods, AOAC Official Method 996.09, has been modified to use a simplified plastic housing for the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Three foods were analyzed. In total, valid results were obtained from 240 samples and controls. Results showed that the VIP for E. coli O157:H7 is equivalent to the reference culture methods for the detection of E. coli O157:H7.
Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Method 997.03 [Visual Immunoprecipitate (VIP®) for Listeria] to the Reference Culture Methods
Authors: Feldsine Philip T , Kerr David E , Shen George S , Lienau Andrew H 
Published: February 2020

Abstract
The Visual Immunoprecipitate (VIP®) for the Detection of Listeria in Foods and Environmental Surfaces, AOAC Official Method 997.03, has been modified to use a simplified housing for the device. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture methods. Two food matrixes and one environmental surface were analyzed. In total, valid results were obtained from 145 samples and controls. Results showed that the modified VIP for Listeria spp. is equivalent to the reference culture methods for the detection of Listeria.
Rapid Method for the Determination of Coumarin, Vanillin, and Ethyl Vanillin in Vanilla Extract by Reversed-Phase Liquid Chromatography with Ultraviolet Detection
Authors: Ali Laila , Perfetti Gracia , Diachenko Gregory 
Published: February 2020

Abstract
A method is described for determining coumarin, vanillin, and ethyl vanillin in vanilla extract products. A product is diluted one-thousand-fold and then analyzed by reversed-phase liquid chromatography using a C18 column and a mobile phase consisting of 55 acetonitrile45 aqueous acetic acid (1) solution at a flow rate of 1.0 mL/min. Peaks are detected with a UV detector set at 275 nm. Vanilla extracts were spiked with 250, 500, and 1000 g/g each of coumarin, vanillin, and ethyl vanillin. Recoveries averaged 97.4, 97.8, and 99.8 for coumarin, vanillin, and ethyl vanillin, respectively, with coefficient of variation values of 1.8, 1.3, and 1.3, respectively. No significant difference was observed among the 3 spiking levels. A survey of 23 domestic and imported vanilla extract products was conducted using the method. None of the samples contained coumarin. The surveyed samples contained between 0.4 to 13.1 and 0.4 to 2.2 mg/g vanillin and ethyl vanillin, respectively.
Simultaneous Determination of Tetracylines and Quinolones Antibiotics in Egg by Ultra-Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometry
Authors: Jia Xiaofei , Shao Bing , Wu Yongning , Yang Yi , Zhang Jing 
Published: February 2020

Abstract
We report here an ultra-performance liquid chromatography coupled with tandem mass spectrometric (MS/MS) method for the simultaneous quantitation of multiclass veterinary drugs in egg. The analysis of the target compounds, including 7 tetracyclines and 4 types of quinolones, may be accomplished in 15 min of total run time. The egg was extracted with ethylenediaminetetraacetic acidMcIlvaine buffer solution and further purified using a polymer-based Oasis HLB solid-phase extraction cartridge. A C18 column was used to separate the analytes followed by MS/MS using an electrospray ion source. The overall average recoveries of the analytes based on matrix-fortified calibration ranged from 71 to 112 with acceptable relative standard deviations of &lt;20 for 6 trials. For all of the target compounds, the limits of quantitation ranged between 0.02 and 4.29 g/kg. The proposed method is sufficiently sensitive and highly selective.
Determination of Albendazole and Its Metabolites in the Muscle Tissue of Hybrid Striped and Largemouth Bass Using Liquid Chromatography with Fluorescence Detection
Authors: Rummel Nathan , Shaikh Badar 
Published: February 2020

Abstract
A liquid chromatographic method was developed for the determination of albendazole and its metabolites albendazole sulfoxide, albendazole sulfone, and albendazole-2-aminosulfone from largemouth and hybrid striped bass muscle tissue with adhering skin. The muscle tissue samples were made alkaline with potassium carbonate and extracted with ethyl acetate. The extracts were further subjected to cleanup by using a series of liquidliquid extractions. After solvent evaporation, the residue was reconstituted in mobile phase and chromatographed. The chromatography was carried out on a reversed-phase Luna C18 column, using acetonitrilemethanol buffer as the mobile phase. The analytes were detected by fluorescence with excitation and emission wavelengths of 290 and 330 nm, respectively. The average recoveries from the fortified muscle tissue of the 2 fish species for albendazole (25100 ppb), albendazole sulfoxide (8.7552.5 ppb), albendazole sulfone (110 ppb), and albendazole-2-aminosulfone (10100 ppb) were 89, 82, 99, and 74, respectively. The coefficient of variation for each compound was 20 in all cases. The procedure was applied to the determination of albendazole and its 3 metabolites in the muscle tissue of the 2 fish species after orally dosing them with albendazole.
Single-Laboratory Validation of a Method for the Determination of c-Phycocyanin and Allophycocyanin in Spirulina (Arthrospira) Supplements and Raw Materials by Spectrophotometry
Authors: Yoshikawa Noritaka , Belay Amha 
Published: February 2020

Abstract
A single-laboratory validation study was conducted for a 2-wavelength spectrophotometric method for the determination of c-phycocyanin (cPC) and allophycocyanin (aPC) in Spirulina supplements and raw materials. The absorption maxima of cPC and aPC are at 620 and 650 nm, respectively. The concentrations of the analytes were calculated from measurement of absorbance at 2 wavelengths. This method provided linear responses for cPC and aPC in the range of 25250 g/mL. Duplicate determinations of cPC and aPC in 4 different test materials on 5 different days resulted in relative standard deviations of 0.31.0 and 1.01.5 for cPC and aPC, respectively. Recoveries were 99.2102.4 and 100.0104.0 for cPC and aPC, respectively. The results were satisfactory for the determination of cPC and aPC in Spirulina supplements.
Determination of Fumonisins B1 and B2 in Corn by Liquid Chromatography/Mass Spectrometry with Immunoaffinity Column Cleanup: Single-Laboratory Method Validation
Authors: Senyuva Hamide Z , Ozcan Sureyya , Cimen Dilek , Gilbert John 
Published: February 2020

Abstract
A single-laboratory method validation was conducted to establish the effectiveness of an immunoaffinity column cleanup procedure followed by liquid chromatography/mass spectrometry (LC/MS) for the determination of fumonisins B1 and B2 (FB1+ FB2) in corn. The test portion is extracted with acetonitrilemethanolwater (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an immunoaffinity column. FB1 + FB2 are removed with methanol and directly determined by reversed-phase LC with MS detection using selected-ion monitoring of 2 characteristic ions in each case. Test portions of blank corn samples were spiked with a mixture of FB1 + FB2 to give total levels of 200 and 500 ng/g, respectively. Recoveries of both FB1 and FB2 from spiked samples averaged 90.4101. Based on results for spiked raw corn (triplicates at 2 levels), the relative standard deviation for repeatability ranged from 2.8 to 7.1. The accuracy of the method was demonstrated by analysis of Food Analysis Performance Assessment Scheme (FAPAS) test material. The method was also applied to a small survey of processed corn products such as corn chips, cornflakes, and popcorn.
Simultaneous Determination of Nickel and Copper by H-Point Standard Addition MethodFirst-Order Derivative Spectrophotometry in Plant Samples After Separation and Preconcentration on Modified Natural Clinoptilolite as a New Sorbent
Authors: Roohparvar Rasool , Taher Mohammad Ali , Mohadesi Alireza 
Published: February 2020

Abstract
For the simultaneous determination of nickel(II) and copper(II) in plant samples, a rapid and accurate method was developed. In this method, solid-phase extraction (SPE) and first-order derivative spectrophotometry (FDS) are combined, and the result is coupled with the H-point standard addition method (HPSAM). Compared with normal spectrophotometry, derivative spectrophotometry offers the advantages of increased selectivity and sensitivity. As there is no need for carrying out any pretreatment of the sample, the spectrophotometry method is easy, but because of a high detection limit, it is not so practical. In order to decrease the detection limit, it is suggested to combine spectrophotometry with a preconcentration method such as SPE. In the present work, after separation and preconcentration of Ni(II) and Cu(II) on modified clinoptilolite zeolite that is loaded with 2-[1-(2-hydroxy-5-sulforphenyl)-3-phenyl-5-formazano]-benzoic acid monosodium salt (zincon) as a selective chromogenic reagent, FDS-HPSAM, which is a simple and selective spectrophotometric method, has been applied for simultaneous determination of these ions.With optimum conditions, the detection limit in original solutions is 0.7 and 0.5 ng/mL, respectively, for nickel and copper. The linear concentration ranges in the proposed method for nickel and copper ions in original solutions are 1.1 to 3.0 103 and 0.9 to 2.0 103 ng/mL, respectively. The recommended procedure is applied to successful determination of Cu(II) and Ni(II) in standard and real samples.
Determination of Trace Amounts of Nickel, Manganese, Cobalt, and Zinc in Environmental Samples After Separation and Preconcentration by Use of Polyacrylic Acid/Alumina Sorbent
Authors: Sabermahani Fatemeh , Taher Mohammad Ali 
Published: February 2020

Abstract
Manganese, nickel, cobalt, and zinc are elements that appear together in many real samples. In this work, a simple, rapid, and sensitive method has been used for the simultaneous separation and preconcentration of trace amounts of these elements using water-soluble polyacrylic acid on alumina as a sorbent in a glass column system. A solution containing Mn, Ni, Co, and Zn was passed through the column at pH 7, and desorption was carried with 5.0 mL of 0.03 M nitric acid. Linearity was maintained between 0.255.0 103, 0.046.0 103, 0.108.0 103, and 0.0281.0 103 ng/mL for Ni, Mn, Co, and Zn, respectively, in the original solution. Eight replicate determinations of a mixture containing 1.0 g/mL of each of the elements in the final solution gave relative standard deviations of 1.4, 1.5, 2.4, and 1.2 for Ni, Mn, Co, and Zn, respectively. The sorption capacities for Mn (mg/g sorbent) obtained were 16.0 for Mn, 9.0 for Ni, 12.0 for Co, and 10.0 for Zn. By using 5.0 mL elution solution, preconcentration factors of 400, 500, 700, and 460 could be obtained for Ni, Mn, Zn, and Co, respectively.
Determination of Decoquinate in Animal Feeds by Liquid Chromatography: Collaborative Study
Authors: Sanchez Anivis A , Campbell Harold M ,   Collaborators:, Ahmed M S , Albert K , Applegate C , Bekele E , Cruz C , Dalgleish J , Dudiková L , Elson C. Focht K , Genouel C , Joubert M , Kirby P , Le Bouquin R , Lerch R , McManus K , Menefee L , Moura S , Murley V , Petrova J , Rues M-C , Siegel V S , Stephens B , Warrick D , Williams S M 
Published: February 2020

Abstract
The performance characteristics of a liquid chromatographic (LC) method for the analysis of decoquinate (DEC) in supplements, premixes, and complete animal feeds at medicating and trace levels were collaboratively studied. DEC is extracted from ground feed samples with 1 calcium chloridemethanol solution using mechanical agitation for 90 min. After centrifugation for 5 min and dilution (if necessary), an aliquot of the extract is diluted with water. The diluted extracts are filtered and analyzed by reversed-phase LC with fluorescence detection. Suspect positive trace-level samples are confirmed by using an alternate excitation wavelength. Fourteen test samples of medicated feeds, supplement, and medicated premix, along with 8 test samples for trace-level analysis, were sent to 13 collaborators (one in Canada, 4 in Europe, and 8 in the United States). Test samples were analyzed as blind duplicates. Acceptable results were received from 12 laboratories for the medicated test samples and from 13 laboratories for the trace-level samples. Repeatability relative standard deviation estimates ranged from 1.3 to 5.6. Reproducibility relative standard deviations estimates ranged from 2.8 to 6.1, and HorRat values ranged from 0.22 to 0.74.