bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Nucleotides and Nucleosides in Milks and Pediatric Formulas: A Review
Authors: Gill Brendon D , Indyk Harvey E 
Published: February 2020

Abstract
Nucleotides and nucleosides play important roles as structural units in nucleic acids, as coenzymes in biochemical pathways, and as sources of chemical energy. Milk contains a complex mixture of nucleotides, nucleosides, and nucleobases, and because of the reported differences in their relative levels in bovine and human milks, pediatric formulas are increasingly supplemented with nucleotides. Liquid chromatography is the dominant analytical technique used for the quantitation of nucleospecies and is commonly applied using either ion-exchange, reversed-phase, or ion-pair reversed-phase modes. Robust methods that incorporate minimal sample preparation and rapid chromatographic separations have been developed for routine product compliance analysis. This review summarizes the analytical techniques used to date in the analysis of nucleospecies in bovine and human milks and infant formulas.
Determination of Chlorinated Acid Herbicides in Vegetation and Soil by Liquid Chromatography/Electrospray-Tandem Mass Spectrometry
Authors: Schaner Angela , Konecny Jaclyn , Luckey Laura , Hickes Heidi 
Published: February 2020

Abstract
The method presented uses reversed-phase liquid chromatography with negative electrospray ionization and tandem mass spectrometry to analyze 9 chlorinated acid herbicides in soil and vegetation matrixes: clopyralid, dicamba, MCPP, MCPA, 2,4-DP, 2,4-D, triclopyr, 2,4-DB, and picloram. A 20 g portion is extracted with a basic solution and an aliquot acidified and micropartitioned with 3 mL chloroform. Vegetation samples are subjected to an additional cleanup with a mixed-mode anion exchange solid-phase extraction cartridge. Two precursor product ion transitions per analyte are measured and evaluated to provide the maximum degree of confidence in results. Average recoveries for 3 different soil types tested ranged from 72 to 107 for all compounds with the exception of 2,4-DB at 5699. Average recoveries for the 3 different vegetation types studied were lower and ranged from 53 to 80 for all compounds.
Simultaneous Identification and Quantification of Anthraquinones, Polydatin, and Resveratrol in Polygonum multiflorum, Various Polygonum Species, and Dietary Supplements by Liquid Chromatography and Microscopic Study of Polygonum Species
Authors: Avula Bharathi , Joshi Vaishali C , Wang Yan-Hong , Khan Ikhlas A 
Published: February 2020

Abstract
A high-performance liquid chromatographic (HPLC) method with ultraviolet absorption detection was developed to determine the presence of anthraquinones, polydatin, and resveratrol in Polygonum multiflorum Thunb. as well as other medicinal Polygonum species, viz., P. cuspidatum, P. oriental, P. aviculare, and P. vulgare, as well as commercial products that claim to contain P. multiflorum. The best results were obtained with a Phenomenex Gemini C18 column using gradient mobile phase composed of water (0.1 acetic acid) and acetonitrile (0.1 acetic acid). Elution was at a flow rate of 1.0 mL/min. The detection wavelength was 280 nm for anthraquinones and 320 nm for polydatin and resveratrol. The main anthraquinones identified were emodin and physcion. The HPLC pattern of P. multiflorum was also compared with 5 other species of Polygonum. The method was validated for precision, repeatability, and accuracy. The relative standard deviation was between 0.9 and 1.6. The method was sensitive, quick, and accurate for determination of anthraquinones, polydatin, and resveratrol in 6 different species of Polygonum and can be used for quality control of P. multiflorum. The commercial samples and the 6 Polygonum species were compared microscopically, and a detailed description is provided for P. multiflorum.
Stability-Indicating Methods for Determination of Tiapride in Pure Form, Pharmaceutical Preparation, and Human Plasma
Authors: Metwally Fadia H , Abdelkawy Mohammad , Abdelwahab Nada S 
Published: February 2020

Abstract
Four different stability-indicating procedures are described for determination of tiapride in pure form, dosage form, and human plasma. Second derivative (D2), first derivative of ratio spectra (1DD), spectrofluorimetric, and high-performance column liquid chromatographic (LC) methods are proposed for determination of tiapride in presence of its acid-induced degradation products, namely 2-methoxy-5-(methylsulfonyl) benzoic acid and 2-diethylaminoethylamine. These approaches were successfully applied to quantify tiapride using the information included in the absorption, excitation, and emission spectra of the appropriate solutions. In the D2 method, Beer's law was obeyed in the concentration range of 1.59 g/mL with a mean recovery of 99.94 1.38% at 253.4 nm using absolute ethanol as a solvent. In 1DD, which is based on the simultaneous use of the first derivative of ratio spectra and measurement at 245 nm in absolute ethanolic solution, Beer's law was obeyed over a concentration range of 1.59 g/mL with mean recovery 99.64 1.08%. The spectrofluorimetric method is based on the determination of tiapride native fluorescence at 339 nm emission wavelength and 230 nm excitation wavelength using watermethanol (8 + 2, v/v). The calibration curve was linear over the range of 0.23 g/mL with mean recovery of 99.66 1.46%. This method was also applied for determination of tiapride in human plasma. A reversed-phase LC method performed at ambient temperature was validated for determination of tiapride using methanoldeionized watertriethylamine (107 + 93 + 0.16, v/v/v) as the mobile phase. Sulpiride was used as an internal standard at a flow rate of 1 mL/min with ultraviolet detection at 214 nm. A linear relation was obtained over a concentration range of 230 g/mL with mean recovery of 99.66 0.9%. Results were statistically analyzed and compared with those obtained by applying the reference method. They proved both accuracy and precision.
Evaluation of Different Polymerase Chain Reaction Methods for the Identification of Vibrio Parahaemolyticus Strains Isolated by Cultural Methods
Authors: Croci Luciana , Suffredini Elisabetta , Cozzi Loredana , Paniconi Mara , Ciccaglioni Gianni , Colombo Mauro M 
Published: February 2020

Abstract
Control of contamination by Vibrio Parahaemolyticus in fishery products is often hampered by the lack of standardized methods and by the uncertainty associated with biochemical identification of the isolates. In this study, 5 polymerase chain reaction (PCR) methods for the identification of V. parahaemolyticus to the species level were evaluated by using 25 Vibrio reference strains and 163 isolates from fishery products, environmental sources, and clinical samples. Sequence targets of the methods were toxR, gyrB, and tlh genes (tested with 2 protocols), and the fragment pR72H. Isolate identification was confirmed by sequencing of the 16S rRNA gene and by PCR protocols for the identification of other Vibrio species. The PCR assay targeting the toxR gene achieved the highest performance (100 inclusivity and exclusivity). The 2 PCR protocols based on tlh gene detection, although showing the same inclusivity (100), differed in the exclusivity (50 and 91, respectively). Finally, the results provided by the PCR assays targeting the gyrB gene and pR72H fragment were less reliable and, in some cases, difficult to assess. According to the results of this study, the characteristics of accuracy expressed by the toxR identification method make it a suitable candidate as a reference method for the molecular identification of V. parahaemolyticus strains.
Liquid Chromatographic Method for the Quantification of Zearalenone in Baby Food and Animal Feed: Interlaboratory Study
Authors: Arranz Isabel , Mischke Carsten , Stroka Joerg , Sizoo Eric , van Egmond Hans , Neugebauer Michael ,   Collaborators:, Biselli S , Bonzaaijer G , Breyl I , Brodacz W , Bujara I , Burdaspal P , Cea J , Chan D , Danier J , Debreczeni L , De Girolamo A , De Rechter P , De Saeger S , Dittmar F , Esteves M E , Frohmuth G , González P , Griffin J , Hackenberg R , Hanschmann G , Iversen A , Jaus A , Just P , Lauber U , Legarda T , Li Feng-Qin , Meister U , Michelet J Y , Michels K , Mrkvilova M , Nordkvist E , Nuotio K , Özkaya Ş , Patel S , Petrová J , Pittet; A , Raditschnig A , Reutter M , Ritscher M , Schenerr H , Slezarova A , Sona T , van Osenbruggen T , Van Peteghem C , Vojsová Y , Wilson P , Wisniewska-Dmytrow H , Woese K 
Published: February 2020

Abstract
An interlaboratory trial for determination of zearalenone (ZON) in baby food and animal feed was conducted. The study involved 39 participants in 16 European Union member states, as well as Turkey, Uruguay, and China, representing a cross-section of industry, and official food control and research institutes. The method is based on immunoaffinity column cleanup followed by high-performance liquid chromatography using fluorimetry (HPLC-Fl). The test portion of the sample is extracted with methanolwater (75 + 25, v/v). The sample extract is filtered, diluted, and passed over an immunoaffinity column. ZON is eluted with methanol. The separation and determination of ZON is performed by reversed-phase HPLC-Fl with an excitation wavelength of 274 nm and an emission wavelength of 446 nm. Test portions of the samples were spiked at levels of 20 and 30 g/kg ZON in baby food and at levels of 100 and 150 g/kg ZON in animal feed. Mean recoveries from each participant ranged from 78 to 119 with an average value of 92 for baby food and from 51 to 122 with an average value of 74 for animal feed. Based on results for spiked samples (blind duplicates at 2 levels), as well as naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) in baby food ranged from 2.8 to 9.0. For animal feed, this value ranged from 5.7 to 9.5. The relative standard deviation for reproducibility (RSDR) in baby food ranged from 8.2 to 13.3, and for animal feed this value ranged from 15.5 to 21.4. The Horwitz ratio (HorRat) in baby food ranged from 0.3 to 0.4, and for animal feed this value ranged from 0.6 to 0.9. The method showed acceptable within-and between-laboratory precision for each matrix, as required by European legislation.
Simultaneous Determination of Cu(II) and Ag(I) on SP Sephadex C25 as Complexes with 1-Phenyl-1,2-Propanedione-2-Oximethiosemicarbazone by Derivative Spectrophotometry
Authors: Morales Libby , Toral M Inés 
Published: February 2020

Abstract
The proposed method was based on retention and preconcentration of the complexes Cu(II)PPDOT and Ag(I)PPDOT on a solid phase in acid medium. The complexes were quantitatively retained in the cation exchanger SP Sephadex C25, and the analytical measurements were executed directly in the solid phase by derivative spectrophotometry. In this simultaneous determination, the second derivative and the zero crossing method were used. The determination of copper and silver was carried out to 321.0 and 427.0 nm, respectively. In order to obtain quantitative recoveries of the metal ions, various experimental analytical parameters, such as pH, stirring time, volume, and amount of solid phase, were optimized. The effect of interfering ions on the determination was described. The recovery values for Cu(II) and Ag(I) were found to be &gt;98, and the relative standard deviation was 2. The detection limits (3 criterion) for Cu(II) and Ag(I) were found to be 0.9 108 and 13 108 M, respectively. The developed method was utilized for preconcentration and determination of Cu(II) and Ag(I) in industrial effluents and natural water samples. The results were consistent with those provided by inductively coupled plasma/mass spectrometry.
Modifications to the AOAC Use-Dilution Test for Quaternary Ammonium Compound-Based Disinfectants That Significantly Improve Method Reliability
Authors: Arlea Crystal , King Sharon , Bennie Barbara , Kemp Kere , Mertz Erin , Staub Richard 
Published: February 2020

Abstract
The AOAC use-dilution test (UDT) for bactericidal disinfectant efficacy (Method 964.02) has often been criticized for its extreme variability in test results, particularly for quaternary ammonium compound (QAC)-based disinfectants against Pseudomonas aeruginosa. While efforts are under way to develop a new and better test method for hospital disinfectant products that is globally acceptable, U.S. manufacturers and formulators of QAC products must continue in the interim to measure their product performance against the current UDT method. Therefore, continued variability in the UDT places an unnecessary and unfair burden on U.S. QAC product manufacturers to ensure that their products perform against an, at best, unreliable test method. This article reports on evaluations that were conducted to attempt to identify key sources of UDT method variability and to find ways to mitigate their impact on test outcomes for the method. The results of testing across 4 laboratories, involving over 6015 carriers, determined that operator error was a key factor in test variability. This variability was found to be significantly minimized by the inclusion of a simple culture dilution step. The findings from this study suggest possible refinements to the current AOAC UDT method that would serve to improve the overall ruggedness and reliability of the method and to optimize recovery of cells from the carrier surface, thereby further improving the accuracy and reproducibility of counts and test outcomes until such time as a replacement method is implemented.
Alkaloids and Saponins in Dietary Supplements of Blue Cohosh (Caulophyllum thalictroides)
Authors: Satchithanandam Subramaniam , Grundel Erich , Roach John , White Kevin D , Mazzola Eugene , Ganzera Markus , Rader Jeanne I 
Published: February 2020

Abstract
Preparations of blue cohosh (Caulophyllum thalictroides) have been used traditionally by Native Americans for medicinal purposes. Dietary supplements containing dried roots or extracts of blue cohosh rhizomes are available as dietary supplements. The safety and efficacy of these preparations have not been systematically evaluated. Recent studies indicate that ingestion of specific alkaloids in blue cohosh preparations can produce birth defects and neonatal heart failure. Blue cohosh also contains saponins, which may be responsible for uterine-stimulating effects. We determined the amounts of major alkaloids and saponins in preparations of blue cohosh by high-performance liquid chromatography (HPLC). Alkaloids and saponins were monitored with a photodiode array detector and an evaporative light-scattering detector, respectively. Profiles were compared with those of authenticated blue cohosh root extracts. Identities of the alkaloids and saponins were confirmed by HPLC/mass spectrometry and nuclear magnetic resonance spectrometry. Calculations based on the results of analyses of dietary supplements showed that maximum daily intake of alkaloids and saponins will vary with the form (e.g., root, liquid extract) and doses recommended in product labeling. Intakes may vary from &lt;1 to 75 mg/day for alkaloids and from about 9 to 420 mg/day for saponins.
Determination of Hydrazine in Maleic Hydrazide Technical and Pesticide Formulations by Gas Chromatography: Collaborative Study
Authors: Riggs Anthony S , Borth David M , Tutty David G , Yu Wan S ,   Collaborators:, Barclay B , Bertrand N , Burns A , Cassidy P , Cobra J , Krol W , LaForge R , Phillips T , Podhorniak L , Rains D , Rose J , Simons C , Summer S 
Published: February 2020

Abstract
Twelve collaborating laboratories assayed hydrazine in technical maleic hydrazide (MH), 6-hydroxy-2H-pyridazin-3-one, and 2 formulated products, a liquid concentrate and a soluble granule, using gas chromatography (GC) with electron capture detection. The hydrazine content in the samples ranged from 0.03 ppm, in the liquid concentrate, to 0.26 ppm, in MH technical. Hydrazine and MH are dissolved in an aqueous solution. The MH is then precipitated out of solution by acidification. The solution containing hydrazine is treated with excess pentafluorobenzaldehyde (PFB) to form pentafluorobenzaldehyde azine (PFBA). The PFBA is extracted with hexane for analysis by GC using an electron capture detector. Peak area responses of PFBA are measured and quantified by external standardization. Hydrazine concentration is calculated from the PFBA determination. The laboratories weighed each test sample in duplicate with duplicate analysis for each weighing. Data from these laboratories were statistically analyzed. The average relative repeatability was determined to be 5.34 and the average relative reproducibility was 27.99.
Validated Stability-Indicating Methods for the Determination of Nizatidine in the Presence of Its Sulfoxide Derivative
Authors: Youssef Rasha M 
Published: February 2020

Abstract
Four new selective, precise, and accurate methods are described for the determination of nizatidine (NIZ) in the presence of its sulfoxide derivative in both the raw material and pharmaceutical preparations. Method A is based on zero-order (0D), first-derivative (1D), and second-derivative (2D) spectrophotometric measurement of NIZ in aqueous solution at the zero-crossing point of its sulfoxide derivative (at 314, 295334, and 318348 nm, respectively). Method B is a 1DD spectrophotometric method based on the simultaneous use of the first derivative of the ratio spectra and the measurement of peak amplitude at 297 nm. Method C uses a solvent-induced derivative-difference spectrophotometry with D1 measurement from peak to peak at 315345 nm. Method D involves quantitative densitometric evaluation of a mixture of the drug and its sulfoxide derivative after separation by high-performance thin-layer chromatography on silica gel plates with chloroformmethanol (9 + 1, v/v) as the mobile phase; Rf values for NIZ and its sulfoxide derivative were 0.4 and 0.2, respectively. The spot was scanned at 254 nm. The first-derivative spectrophotometric method was used to investigate the kinetics of the hydrogen peroxide degradation process at different temperatures. The apparent pseudo-first-order rate constant, half-life, and activation energy were calculated. The results obtained by the proposed methods were analyzed statistically and compared with those obtained by the official method. These methods are suitable as stability-indicating for the determination of NIZ in the presence of its oxidation-induced degradation product (sulfoxide derivative) either in the bulk powder or in pharmaceutical preparations.
Development and Validation of an HPLC Method to Quantify Camptothecin in Polymeric Nanocapsule Suspensions
Authors: Granada Andra , Murakami Fabio S , Sartori Tatiane , Lemos-Senna Elenara , Silva Marcos A S 
Published: February 2020

Abstract
A simple, rapid, and sensitive reversed-phase column high-performance liquid chromatographic method was developed and validated to quantify camptothecin (CPT) in polymeric nanocapsule suspensions. The chromatographic separation was performed on a Supelcosil LC-18 column (15 cm 4.6 mm id, 5 m) using a mobile phase consisting of methanol10 mM KH2PO4 (60 + 40, v/v; pH 2.8) at a flow rate of 1.0 mL/min and ultraviolet detection at 254 nm. The calibration graph was linear from 0.5 to 3.0 g/mL with a correlation coefficient of 0.9979, and the limit of quantitation was 0.35 g/mL. The assay recovery ranged from 97.3 to 105.0. The intraday and interday relative standard deviation values were &lt;5.0. The validation results confirmed that the developed method is specific, linear, accurate, and precise for its intended use. The current method was successfully applied to the evaluation of CPT entrapment efficiency and drug content in polymeric nanocapsule suspensions during the early stage of formulation development.
Selective and Stability-Indicating Methods for the Simultaneous Determination of Mexiletine Hydrochloride and/or Its Related Substance: 2,6-Dimethylphenol
Authors: Belal Tarek S , Haggag Rim S , Shaalan Rasha A 
Published: February 2020

Abstract
Four simple, rapid, sensitive, and selective analytical procedures were developed for determination of mexiletine hydrochloride (MX) and/or its related substance: 2,6-dimethylphenol (DMP). The latter is a synthetic impurity for which a maximum pharmacopeial limit is defined. The first method depends on derivative-ratio spectrophotometry, for which the first-derivative signals of the ratio spectra at 259 nm ( = 3 nm) are selected for the determination of MX. The second method is based on the spectrofluorometric measurement of MX in alkaline solution in the presence of 15 mM sodium dodecyl sulfate micellar medium at 292 nm (Ex 260 nm). The third method is based on liquid chromatographic (LC) separation of MX and DMP on an RP-C8 column with a mobile phase consisting of 50 mM Na2HPO4acetonitrile (60 + 40, adjusted to pH 2.4), and quantification of the analytes is achieved with UV detection at 212 nm based on peak area. The fourth method uses the coupling reaction of DMP with 2,6-dibromoquinone-4-chlorimide (DBQC) in borate buffer to form an intensely colored product that was spectrophotometrically measured using first-derivative amplitudes at 670 nm ( = 6nm) for the determination of DMP. Different variables affecting each method were carefully investigated and optimized. The reliability and analytical performance of the proposed methods, including linearity, range, precision, accuracy, and detection and quantitation limits, were statistically validated. The first 3 methods were successfully applied for the stability-indicating determination of MX in laboratory-prepared mixtures with DMP, as well as for the determination of MX in capsules. Also, the LC and the DBQC spectrophotometric methods permitted the selective determination of DMP in the presence of a large excess of the parent drug at or near the pharmacopeial limit (0.11).
Bioactive Peptides
Authors: Shahidi Fereidoon , Zhong Ying 
Published: February 2020

Abstract
Peptides with biological activities, released during gastrointestinal digestion or food processing, play an important role in metabolic regulation and modulation, suggesting their potential use as nutraceuticals and functional food ingredients for health promotion and disease risk reduction. Many studies have reported that peptides from various food sources possess bioactivities, including antihypertensive, antioxidant, anticancer, antimicrobial, and opioid activities as well as immunomodulatory and cholesterol-lowering effects. More studies are being performed exploring the sources, bioavailabilities, and possible physiological/functional properties and the mechanisms of action of bioactive peptides. Technological approaches in terms of peptide preparation, purification, and characterization have also been investigated.
Gas Chromatographic Determination of High Molecular Weight Alcohols from Policosanol in Omega-3 Fish Oil by Acylation with Acetyl Chloride
Authors: Antolín Ernesto J Méndez , Canavaciolo Vctor L González , Pérez Roxana Sierra 
Published: February 2020

Abstract
A new validated gas chromatographic (GC) method using acetyl chloride as a derivatizing agent for determining policosanol's high molecular weight alcohols (policosanol's fatty alcohols; PFAs) in fish oil (FO) is described. Before derivatizing the alcohols, FO was subjected to a methylation reaction, and then the PFAs were isolated in a chloroform fraction by silica gel by column liquid chromatography. GC analysis was performed using a BPX-5 wide-bore column and 1-eicosanol as an internal standard. Validation assays applied to the method proved noninterference by a very complex mixture of the FO with PFAs, even for samples subjected to stress conditions. Good linearity [correlation coefficient &gt;0.999, relative standard deviation (RSD) of the slope &lt;1.3, and RSD of the response factors &lt;1.9 with no bias] and accuracy (average recovery from 100.6 to 102.2) over a range of 28142 of the nominal concentration were obtained. Within-day and intermediate precisions at the nominal dose (100) were 1.7 and 2.9, respectively. The method was successfully used to identify and quantitate the PFAs in FO