Sodium dodecyl sulfate-modified carbon paste electrodes for selective determination of dopamine in the presence of ascorbic acid.
A carbon paste electrode (CPE) modified by a monolayer film of sodium dodecyl sulfate (SDS) was used for detection of dopamine (DA). Cyclic voltammetry demonstrated improved response of the DA sensor. This suggests the effectivity of surface modification of CPE by SDS. Impedance spectroscopy was used for the characterization of CPE surface properties. The effect of SDS concentration on the electrode quality also reveals that SDS formed a monolayer on CPE surface with a high density of negative-charged end directed outside the electrode. As a result, the carbon paste electrode modified with SDS (SDS/CPE) exerted discrimination against ascorbic acid in physiological circumstance. Thus, it can selectively determine dopamine even in the presence of 220-fold AA combined with differential pulse stripping voltammetry. In pH 7.40 phosphate buffer solution, the oxidation peak current on differential pulse voltammograms increases linearly with the concentration of DA in the range of 5.0 x 10(-7) to 8.0 x 10(-4) mol . L(-1) with a detection limit of 5.0 x 10(-8) mol . L(-1). Satisfying results are achieved when detecting the DA in injection and simulated biology sample.
Zheng
Jianbin
J
Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University, Xi'an 710069, China. zhengjb@nwu.edu.cn <zhengjb@nwu.edu.cn>
Zhou
Xiaoli
X
D001205:Ascorbic Acid / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry*; D045424:Complex Mixtures / Q000032:analysis / Q000737:chemistry; D004298:Dopamine / Q000032:analysis*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009824:Ointments / Q000737:chemistry; D011048:Polarography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*
D045424:Complex Mixtures; D009824:Ointments; D012967:Sodium Dodecyl Sulfate; D002244:Carbon; D001205:Ascorbic Acid; D004298:Dopamine