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Linear Calibration Ranges (linear + calibration_range)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Barrel Plating Rhodium Electrode: Application to Flow Injection Analysis of Hydrazine

ELECTROANALYSIS, Issue 14 2005
Jun-Wei Sue
Abstract We introduce here the application of barrel plating technology for mass production of disposable-type electrodes. Easy for mass production, barrel plating rhodium electrode (Rh-BPE) is for the first time demonstrated for analytical application. Hydrazine was chosen as a model analyte to elucidate the electrocatalytic and analytical ability of the Rh-BPE system in pH,7 phosphate buffer solution. Flow injection analysis (FIA) of hydrazine showed a linear calibration range of 25,1000,ppb with a slope and a regression coefficient of 5,nA/ppb and 0.9946, respectively. Twenty-two replicate injections of 25,ppb hydrazine showed a relative standard deviation of 3.17% indicating a detection limit (S/N=3) of 2.5,ppb. The system can be continuously operated for 1 day without any alteration in the FIA signals and is tolerable to the interference of oxalic acid, gelatine, Triton X-100, and albumin for even up to 100 times excess in concentration with respect to 400,ppb hydrazine. Since the fabrication cost of the electrode is cheap, it is thus disposable in nature. Furthermore, barrel plating technique can be extendable to other transition metals for application in many fields of research interest. [source]

Selective detection of superoxide anion radicals generated from macrophages by using a novel fluorescent probe

FEBS JOURNAL, Issue 7 2007
Jing Jing Gao
Quantitation of superoxide radical (O,2,·) production at the site of radical generation remains challenging. A simple method to detect nanomolar to micromolar levels of superoxide radical in aqueous solution has been developed and optimized. This method is based on the efficient trapping of O2,· using a novel fluorescent probe (2-chloro-1,3-dibenzothiazolinecyclohexene), coupled with a spectra character-signaling increase event. A high-specificity and high-sensitivity fluorescent probe was synthesized in-house and used to image O2,· in living cells. Better selectivity for O2,· over competing cellular reactive oxygen species and some biological compounds illustrates the advantages of our method. Under optimal conditions, the linear calibration range for superoxide anion radicals was 5.03 × 10,9,3.33 × 10,6 m. The detection limit was 1.68 × 10,9 m. Fluorescence images of probe-stained macrophages stimulated with 4,-phorbol 12-myristate 13-acetate were obtained successfully using a confocal laser scanning microscope. [source]

Direct Simultaneous Determination of ,- and ,-Naphthol Isomers at GC-Electrode Modified with CNTs Network Joined by Pt Nanoparticles Through Derivative Voltammetry

ELECTROANALYSIS, Issue 5 2006
Xiao-Gang Wang
Abstract The semi-derivative technique was adopted to improve the resolution and surfactant was added to sample solution to enhance the sensitivity, , - and , -naphthol isomers could be determined directly and simultaneously at glassy carbon electrode modified with carbon nanotubes network joined by Pt nanoparticles. In 0.1,mol,L,1 HAc-NaAc buffer solution (pH,5.8), the linear calibration ranges were 1.0×10,6 to 8.0×10,4 mol,L,1 for both , - and , -naphthols, with detection limits of 5.0×10,7 for , - and 6.0×10,7,mol,L,1 for , -naphthol. The amount of naphthol isomers in artificial wastewater has been tested with above method, and the recovery was from 98% to 103%. [source]

Assay of vitamin B in urine by capillary electrochromatography with methacrylate-based monolithic column

ELECTROPHORESIS, Issue 19 2010
Xiaoyi Wei
Abstract A novel and simple method for the separation of major vitamin B analytes, such as thiamine, riboflavin, nicotinamide, vitamin B4, pyridoxine, has been developed by CEC using the monolithic column. It has been found that the baseline separation of the five analytes could be achieved with 5.0,mM phosphate buffer at pH 4.0. Compared with the open-tubular capillary and the bared capillary columns, the poly(butylmethacrylate-co-ethylene glycol dimethacrylate) monolithic capillary could exhibit the best resolution in the analysis. Then the method was validated and the linear calibration ranges were obtained with correlation coefficients more than 0.997. The precision and the recovery were also investigated and showed a good result. Furthermore, the proposed method was successfully applied to assay the concentration of vitamin B analytes and the metabolic situation in human urine samples. [source]

Separation and determination of five major opium alkaloids with mixed mode of hydrophilic/cation-exchange monolith by pressurized capillary electrochromatography

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2007
Xucong Lin
Abstract A method for the separation and determination of five major opium alkaloids (narcotine, papaverine, thebaine, codeine, and morphine) in pericarpium papaveris by pressurized CEC (pCEC) with monolithic column has been developed. Under the optimum condition, linear calibration ranges of narcotine, papaverine, thebaine, codeine, and morphine were obtained as 2,85, 2,85, 5,75, 10,65, and 10,65 ,g/mL, respectively. LODs of these analytes were 1.5,6.0 ,g/mL. The RSD (n = 7) of the migration time and peak area were 1.94,5.24 and 4.05,8.21%, respectively. The proposed method was successfully applied to the analysis of pericarpium papaveris samples. Average recoveries of 79.0,95.9% at different fortified levels of alkaloids were achieved with RSD less than 4.6%. Meanwhile, the mechanism of the separation of the alkaloids on the monolithic column was also discussed. The result showed that the separation of alkaloids was mainly based on the mixed mode of hydrophilic interaction (HI) and cation exchange. [source]