Indication Ion Square Wave Voltammetric Determination of Thiamine and Ascorbic Acid

Abstract

Cd²⁺ ion was used as an electrochemical indicator to detect V_B1 or Vc using square ware voltammetry (SWV) at a mercury film‐coated glassy carbon (GC) electrode. At pH=10 NH₃‐NH₄Cl buffer, a new cathodic peak was found at −0.360 V (vs.SCE) by addition of thiamine, and the peak current of SWV was linear with the concentration of thiamine in the range of 1×10⁻⁶ to 4×10⁻³ M. On the other hand, the SWV peak current of Cd²⁺ at −0.856 V linearly decreased with addition of ascorbic acid in the range of 6×10⁻⁶∼10⁻³ M. The effects of interference, such as citric acid, DL‐malic acid, and calcium panlothenate, on thiamine or ascorbic acid determination were investigated. This method was successfully applied to the determination of thiamine or in pharmaceutical preparation.

Keywords:

• Indication ion
• square wave voltammetry
• Cd²⁺
• thiamine
• ascorbic acid

Acknowledgments

The financial support of the NSFC (50574006) is gratefully acknowledged.