bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Protein in Milk Powder Using 2-Sulfophenylazo-Rhodanine as a Probe by the Enhanced Resonance Rayleigh Light-Scattering Technique
Authors: Wei Qin , Li Yan , Dong Wenying , Du Bin 
Published: February 2020

Abstract
In this paper, the interaction between 2-sulfophenylazo-rhodanine and protein was investigated by Rayleigh light-scattering technique. Based on this, a novel method for the determination of protein was developed. The effects of different conditions, such as acidity and media, were investigated thoroughly, and the optimum conditions were confirmed. Bis(2-ethylhexyl)sulfosuccinate (AOT) microemulsion, which is introduced into the protein determination, markedly increased the sensitivity of the system by changing the microenvironment. In pH 2.80 Britton-Robinson buffer solution in the presence of AOT microemulsion, the detection limits of bovine serum albumin, human serum albumin, ovalbumin, and -globulin are 5.4, 4.5, 9.8, and 10.1 ng/mL, respectively. The method developed in this paper has been applied to the determination of protein in milk powder with satisfactory results.
Quantitation of Indian Krait (Bungarus caeruleus) Venom in Human Specimens of Forensic Origin by Indirect Competitive Inhibition Enzyme-Linked Immunosorbent Assay
Authors: Brunda Ganneru , Rao Beedu Sashidhar , Sarin Rajendra Kumar 
Published: February 2020

Abstract
An indirect competitive inhibition enzyme-linked immunosorbent assay was reported to detect krait venom in human specimens of forensic origin. Polyclonal anti-krait venom antibodies were characterized by indirect antibody capture assay. The calibration plot was constructed based on linear regression analysis (y = 72.85 12.29x, r2 = 0.98) with concentration ranges from 0.013 to 1000 ng/well of krait venom with a limit of detection of 0.2 ng/mL in the assay system. The IC50 (inhibitory concentration at 50% displacement) value of krait venom was observed to be 70 ng. Spiking studies indicated recoveries of 95100% and 94100% when various concentrations of krait venom were spiked to rat tissues (skin, liver, and kidneys) and pooled human serum, respectively. Polyclonal anti-krait venom antibodies showed no cross-reactivity with cobra and viper venom when tested in the assay system. The coefficient of variation of various concentrations of working range in intra-assay (n = 6) was &lt;5%, whereas in interassay (n = 6) it was observed to be 7%. Further, the method was used to quantitate krait venom in human autopsy and biopsy specimens of forensic origin. Concentration of krait venom was found to be in the range of 4172 ng/100 mg skin or skin scrapings and 64378 ng/mL blood or serum. The methodology may find application in forensic laboratories to assess the cause of death in the cases of krait-bite victims.
A Selective High-Performance Liquid Chromatography Method for the Determination of Reboxetine in Bulk Drug and Tablets
Authors: Önal ArmaĞan , SaĞiri Olcay , Çetin S Müge , Toker Sidika 
Published: February 2020

Abstract
Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 4.6 mm id) with an isocratic mobile phase consisting of methanolphosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 μmL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 150 g/mL (r 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 μg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.781.01 and 1.081.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.
Determination of Semicarbazide in Fresh Egg and Whole Egg Powder by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study
Authors: Calle Maria Beatriz De La , Szilagyi Szilard , Berendsen B ,   Collaborators:, Barbosa J , Berendsen B , Bockhorn I , Brandtner M , Delahaut P , Fuerst P , Griffin C , Hager D , Janosi A , Kennedy G , Laska H , Mandix M , Plonevez S , Posyniak A , Verdon E 
Published: February 2020

Abstract
An interlaboratory validation study was conducted according to harmonized protocols to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in fresh whole egg and in an industrially processed whole egg powder. The sample was extracted with hydrochloric acid and derivatized with 2-nitrobenzaldehyde, with 1,2-[15N213C]SEM as the internal standard. The extract was neutralized and purified on a solid-phase extraction cartridge. SEM was determined by reversed-phase LC with detection by MS/MS. Five fresh egg samples, of which 3 were obtained from hens fed nitrofurazone (NFZ), one was spiked with SEM at 50 μg/kg and one was a blank sample, and 5 industrial whole egg powder samples, of which 3 were spiked with fresh whole egg from hens fed NFZ, one was spiked with SEM at 350 μg/kg, and one was a blank sample, were sent to 15 laboratories in 10 different European countries. Results were obtained from 12 participants. Average recoveries of SEM from the fresh egg and the egg powder samples were 105.3 and 121.3%, respectively. The relative standard deviation for repeatability (RSDr) ranged from 2.9 to 9.3%, and the relative standard deviation for reproducibility (RSDR) ranged from 22.5 to 38.1%. The method showed acceptable within- and between-laboratory precision for both matrixes, as evidenced by the HorRat values, at the target levels for the determination of SEM.
Liquid Chromatography/Fluorescence Method for Emamectin B1a and Desmethylamino-Emamectin B1a Residues in Lobster Tissue
Authors: Tauber Ronald , Gillan Niall , Crouch Louis , Greenhalgh Roy 
Published: February 2020

Abstract
A liquid chromatography (LC)/fluorescence procedure was validated for emamectin (EM B1a) and desmethylamino-emamectin (DMAEM B1a) residues in lobster tissue. They were extracted by shaking and sonicating with 1% ammonium acetatemethanol in the presence of sand. The extract was concentrated, partitioned with ethylacetate, and cleaned up on a propylsulfonic cation exchange cartridge. The analytes were eluted from the cartridge with 5% ammonium hydroxidemethylacetate, the eluate was concentrated, and the solvent was changed to dry 20% ethylacetateacetonitrile before derivatization with trifluoroacetic anhydrideN-methylimidizole. The products were analyzed by LCfluorescence, and no interference [&gt;limit of detection (LOD)] was detected in the control samples. Lobster tissues fortified with EM B1a and DMAEM B1a at 0.5, 5, 10, 25, and 50 ng/g gave overall mean recoveries of 96.7 12.4%, relative standard deviation (RSD) 12.8% for EM B1 and 83.6 12.1%, RSD 14.5% for DMAEM B1a. Regression analysis of the calibration data gave slopes of 0.90 (EM B1a) and 0.71 (DMAEM B1a) with an r2 0.99 for both compounds. The calculated LOD and limit of quantification (LOQ) for EM B1a were 1.10 and 3.32 ng/g, respectively, and for DMAEM B1a were 0.762 and 2.31 ng/g, respectively. Residues of EM B1a and DMAEM B1a in fortified lobster tissues stored at 20C showed that residues were stable for 1012 months. No loss of EM B1a and DMAEM B1a residues was observed after 3 freeze/thaw cycles of fortified tissue in a 5-day period.
Simultaneous Estimation of Pantoprazole and Domperidone in Pure Powder and a Pharmaceutical Formulation by High-Perfomance Liquid Chromatography and High-Performance Thin-Layer Chromatography Methods
Authors: Patel Bhavesh H , Suhagia Bhanubhai N , Patel Madhabhai M , Patel Jignesh R 
Published: February 2020

Abstract
This paper describes validated high-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous estimation of pantoprazole (PANT) and domperidone (DOM) in pure powder and capsule formulations. The HPLC separation was achieved on a Phenomenex C18 column (250 mm id, 4.6 mm, 5 μm) using 0.01 M, 6.5 pH ammonium acetate buffer-methanol-acetonitrile (30 + 40 + 30, v/v/v, pH 7.20) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetatemethanol (60 + 40, v/v) as the mobile phase. Quantification was achieved with ultraviolet (UV) detection at 287 nm over the concentration range 400-4000 and 300-3000 ng/mL with mean recovery of 99.35 ± 0.80 and 99.08 ± 0.57% for PANT and DOM, respectively (HPLC method). Quantification was achieved with UV detection at 287 nm over the concentration range 80-240 and 60-180 ng/spot with mean recovery of 98.40 ± 0.67 and 98.75 ± 0.71% for PANT and DOM, respectively (HPTLC method). These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of PANT and DOM in pure powder and capsule formulations.
A Simplified Modification of the AOAC Official Method for Determination of Total Dietary Fiber Using Newly Developed Enzymes
Authors: Tada Shusaku , Innami Satoshi 
Published: February 2020

Abstract
Since 1985, AOAC Method 985.29 has been globally adopted as a standard method for determination of total dietary fiber in foods. Nevertheless, an aspect of AOAC Method 985.29 that needs to be improved is the laborious process to treat 3 enzymes separately at their individual proper pH, which is quite time-consuming. Several examinations have been carried out to resolve this problem. The characteristics of newly developed thermostable -amylase, neutral protease, and amyloglucosidase were evaluated based on the pH-activity profile and the property of starch hydrolysis in comparison with those of the conventional enzyme reagents. These 3 developed enzymes were found to work under the same pH condition and to accomplish sufficient digestion for the typical 3 starches: soluble starch, corn starch, and wheat starch. The experimental results revealed that the dietary fiber determination in foods could be performed without pH adjustment in the enzymatic digestion process. The modified method will be greatly helpful in determining the total dietary fiber contents in food materials with less laborious work and with an accuracy equivalent to that of AOAC Method 985.29.
Stable Competitive Enzyme-Linked Immunosorbent Assay Kit for Rapid Measurement of 11 Active Beta-Lactams in Milk, Tissue, Urine, and Serum
Authors: FitzGerald Stephen P , O’Loan Nuala , McConnell Robert I , Benchikh El Ouard , Kane Nicola E 
Published: February 2020

Abstract
Beta-lactams are used as veterinary drugs for the treatment of food-producing animals. For consumer protection, legislation is in place to set limits for their residues. An enzyme-linked immunosorbent assay (ELISA) was developed which allowed, in a single reaction, the class-specific measurement of 11 beta-lactams, with limits of detection below European maximum residue limits. Determinations were feasible in milk, tissue, urine, and serum with simple and rapid sample preparation. In this format, the specific capture antibodies were precoated on the microtiter plate and horseradish peroxidase-labeled conjugate was used to compete with free beta-lactams. The stability of the precoated microtiter plate and conjugate was at least 1 year when stored at 2 to 8°C; upon reconstitution, the conjugate was stable for 6 days at 2 to 8°C. The stability of lyophilized ampicillin standards was at least 6 months when stored at 2 to 8°C and at least 1 year when stored at 20°C. A low cross-reactivity, 3.6%, was observed with ampicillin with open beta-lactam ring relative to 100% for intact ampicillin. Generic recognition was shown by relative cross-reactivity values ranging from 22 (penicillin V) to 144% (nafcillin). Cross-reactivity for cephalosporins was &lt;0.1%. Intra- and interassay precisions expressed as coefficient of variation were typically 2-8%. The inhibitory concentration with 50% binding for ampicillin was typically 2 ppb. Recovery for different spiked levels was &gt;70% with all the matrixes.
Gas Chromatographic/Mass Spectrometric Analysis of the Essential Oil of Houttuynia cordata Thunb by Using On-Column Methylation with Tetramethylammonium Acetate
Authors: Ch Muhammad Ishtiaq , Wen Yang F , Cheng YiYu 
Published: February 2020

Abstract
This paper describes a simple and novel on-column derivatization procedure used with gas chromatography/mass spectrometry (GC/MS) for the analysis of essential oil of Houttuynia cordata Thunb (HCT), a traditional Chinese medicine. In the procedure, the essential oil was obtained by hydrodistillation, and the fatty acid components were derivatized with tetramethylammonium acetate (TMAA) at 250°C and identified by GC/MS. Methylation improved the determination of both the fatty acids and the other components in the essential oil of HCT. To obtain optimum methylation conditions, several important factors were investigated with pentadecane as the internal standard and a GC inlet temperature of 250°C. Tetramethylammonium hydroxide (TMAH) and TMAA were compared as the derivatization agent, and a 2:1 ratio of TMAA to capric acid was evaluated. Fatty acid methyl esters produced good chromatographic peak shapes and did not interfere with the determination of dodecanal and caryophyllene. TMAA is a neutral methylation reagent, and it yielded no side reactions during derivatization. It was found that the fatty acid content of the essential oil was about 81%; among the methylated fatty acids found were capric acid, methyl (43.66%), methyl laurate (16.15%), methyl hexadecanoate (9.27%), undecanoic acid, methyl (5.62%), methyl oleate (1.98%), and methyl linoleate (1.40%). Other major constituents were (-)-β-pinene (1.02%), β-myrcene (1.62%), 1-terpinen-4-ol (1.59%), decanal (1.49%), and 2-undecanone (1.47%). The results obtained demonstrated good efficiency for the procedure. Pure chromatograms allowed quantitation, which was obtained by total volume integration. The on-column derivatization procedure was simple to perform, and it improved the sensitivity, the peak resolution, and the selectivity of the GC/MS determination.
Development and Validation of a Spectrophotometric Method for the Determination of Macrolide Antibiotics by Using 2,4-Dinitrophenylhydrazine
Authors: Abdelmageed Osama H 
Published: February 2020

Abstract
A simple, novel, sensitive, and specific spectrophotometric method was developed and validated for the determination of azithromycin (AZ), clarithromycin (CLA), and roxithromycin (ROX) in bulk powders and their dosage forms. The proposed method was based on the interaction of any of the cited drugs with 2,4-dinitrophenylhydrazine in the presence of an acid catalyst, followed by treatment with a methanolic solution of potassium hydroxide; an intensely colored chromogen was formed that was measured in dimethylformamide, as the diluting solvent, at 542−545, 523−526, and 539−542 nm for AZ, CLA, and ROX, respectively. All variables affecting the development of the measured chromogens were studied and optimized. Beer's law was obeyed in the concentration ranges of 540, 535, and 535 μg/mL for AZ, CLA, and ROX, respectively, with good correlation coefficients (0.99910−9999). The limits of detection for this method ranged from 0.77 to 1.47 μg/mL, and the relative standard deviations were 1.24−1.8%. The proposed method was applied successfully to the determination of the 3 drugs in pure bulk form, tablets, and suspensions without interference from commonly encountered additives. The results compared favorably with those of a previously reported method. The mechanism of the reaction was also studied.
Spectrophotometric Determination of Pipazethate Hydrochloride in Pure Form and in Pharmaceutical Formulations
Authors: El-Shiekh Ragaa , Amin Alaa S , Zahran Faten , Gouda Ayman A 
Published: February 2020

Abstract
Three simple, sensitive, and reproducible spectrophotometric methods (AC) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 g/mL for Methods AC, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were 0.83% with recoveries of 98.9101.15%.
Spectrofluorometric Determination of Ketorolac Tromethamine Via Its Oxidation with Cerium(IV) in Pharmaceutical Preparations and Biological Fluids
Authors: Eid Manal , El-Brashy Amina , Aly Fatma , Talaat Wael 
Published: February 2020

Abstract
A simple and sensitive fluorometric method for determination of ketorolac tromethamine was studied. The method depends on oxidation of the drug with cerium(IV) and subsequent monitoring of the fluorescence of the induced cerium(III) at em 365 nm after excitation at 255 nm. Different variables affecting the reaction conditions, such as the concentrations of cerium(IV), sulfuric acid concentration, reaction time, and temperature, were carefully studied and optimized. Under the optimum conditions, a linear relationship was found between the relative fluorescence intensity and the concentration of the investigated drug in the range of 0.10.8 g/mL. No interferences could be observed from the excipients commonly present in dosage forms. The proposed method was successfully applied to the analysis of the investigated drug in its pure form, pharmaceutical preparations, and biological fluids with good accuracy and precision. The recoveries for pharmaceutical formulations ranged from 99.8101.0 0.6% for tablets, 98.5101.0 1.0% for ampoules, and 99.0100.5 0.7% for eye drops. The results obtained by the proposed method were satisfactory compared with those obtained by the official method. The recoveries for biological fluids were 99.1100.4 0.7 and 99.0100.0 0.5% for plasma and urine, respectively.
Development and Validation of Chemometrics-Assisted Spectrophotometry and Liquid Chromatography Methods for the Simultaneous Determination of the Active Ingredients in Two Multicomponent Mixtures Containing Chlorpheniramine Maleate and Phenylpropanolamine Hydrochloride
Authors: Hadad Ghada M , El-Gindy Alaa , Mahmoud Waleed M M 
Published: February 2020

Abstract
Multivariate spectrophotometric calibration and liquid chromatography (LC) methods were used for the simultaneous determination of the active ingredients in 2 multicomponent mixtures containing chlorpheniramine maleate and phenylpropanolamine hydrochloride with ibuprofen and caffeine (mixture 1) or with propyphenazone (mixture 2). For the multivariate spectrophotometric calibration methods, principal component regression (PCR) and partial least squares (PLS-1), a calibration set of the mixtures consisting of the components of each mixture was prepared in distilled water. A leave-1-out cross-validation procedure was used to find the optimum numbers of latent variables. Analytical parameters such as sensitivity, selectivity, analytical sensitivity, limit of quantitation, and limit of detection were determined for both PLS-1 and PCR. The LC method depends on the use of a cyanopropyl column with the mobile phase acetonitrile-12 mM ammonium acetate, pH 5.0 (25 + 75, v/v), for mixture 1 or acetonitrile10 mM potassium dihydrogen phosphate, pH 4.7 (45 + 55, v/v), for mixture 2; the UV detector was set at 212 nm. In spite of the presence of a high degree of spectral overlap of these components, they were rapidly and simultaneously determined with high accuracy and precision, with no interference from the matrix excipients. The proposed methods were successfully applied to the analysis of pharmaceutical formulations and laboratory-prepared mixtures containing the 2 multicomponent combinations.
High-Performance Liquid Chromatographic Determination of Proquazone and Its m-Hydroxy Metabolite in Spiked Human Plasma and Urine
Authors: Hassan Ekram M , Gazy Azza A , Abdel-Hay Mohamed H , Belal Tarek S 
Published: February 2020

Abstract
A simple and rapid high-performance liquid chromatographic method for the determination of proquazone (PQZ) and its major metabolite, m-hydroxyproquazone, in spiked human plasma and urine was developed. Plasma samples were purified using acetonitrile as a protein precipitant, while urine samples were diluted only with the mobile phase and filtered prior to injection. Samples containing the parent compounds and glafenine (internal standard) were eluted from a reversed-phase C8 column using acetonitrile-0.025 M sodium acetate (60 + 40) adjusted to pH 5 as the mobile phase and detected at 234 nm. Peak area ratios of the analytes versus internal standard were used for calibration. The mean recoveries from plasma and urine samples spiked with PQZ and its m-hydroxy metabolite ranged from 97.87 to 103.88%. The relative standard deviation for the within- and between-day analyses were &lt;4%. The proposed method was applied for the assay of PQZ in laboratory-made tablets.
Convenient Analysis of Vitamin D in Cheese and Other Food Matrixes by Liquid Chromatography/Mass Spectrometry
Authors: Dimartino Gianluca 
Published: February 2020

Abstract
A convenient method is presented for determination of vitamin D in natural cheese, processed cheese, milk, cereals, noncarbonated soft drinks, and juice by liquid chromatography/mass spectrometry (LC/MS). Samples were saponified, extracted, evaporated, redissolved in acetonitrile, and injected into an LC-atmospheric pressure chemical ionization-MS system with no preparative chromatographic steps. Vitamin D was determined by selected ion monitoring. MS response was linear for vitamin D3 and its internal standard vitamin D2, and overall average recoveries ranged from 98 to 105. A blending experiment in which shredded vitamin D3-fortified cheddar was mixed with control nonfortified cheddar showed linearity. The limit of detection for vitamin D was 1.3 ng and the limit of quantitation was 3 ng. The method gave good accuracy and precision, with a standard deviation of 9.5 and relative standard deviation of 6.7. Results for vitamin D3 obtained with this method for different food matrixes, at different levels, were in agreement with those obtained with the reference LC/UV method currently used by many laboratories and derived from AOAC Official Method 982.29.