Detection of Naphthoacetic Acid Using an Electrochemical Sensor Sensitivity-enhanced with Multi-walled Carbon Nanotubes

KeyWord:naphthoacetic acid£¨NAA£©  modified electrode  electrochemical analysis  multi-walled carbon nanotubes£¨MWCNTs£©

Abstract:

      In this study£¬ multi-walled carbon nanotubes£¨MWCNTs£©and sodium dodecylbenzene sulfonate£¨SDBS£©were ultrasonically oscillated in water for 1. 5 h£¬and the obtained SDBS£­MW? CNTs composites were modified onto the surface of glassy carbon electrode£¨GCE£©to construct a SD? BS£­MWCNTs/GCE electrochemical sensor. The electrochemical behaviors of naphthoacetic acid £¨NAA£©on the electrode surface were investigated by cyclic voltammetry and linear scanning voltam? metry. The experimental conditions£¬ including concentration of SDBS£¬ modification dosage of SD? BS£­MWCNTs and pH value of buffer were optimized. Under the optimal conditions of 0. 5 mg/mL SDBS£¬ 5 ¦ÌL SDBS£­MWCNTs and pH 6. 0£¬ the sensor was used to detect different concentrations of NAA standard solution by differential pulse voltammetry£¨DPV£©. Result indicated that there was a good linear relationship between the peak oxidation current and NAA in the concentration range of 0. 4£­45 ¦Ìmol/L£¬ and the detection limit was 0. 07 ¦Ìmol/L. The sensor was applied to the actual de? tection of NAA in astragalus with recoveries of 97. 8%£­102% and RSDs less than 5%. The prepara? tion of the sensor was simple£¬ and the method had high sensitivity£¬ good stability£¬ reproducibility£¬ and anti-interference ability.