Calibrationless Determination of Potassium Hexacyanoferrate(II) and Hexaammineruthenium(III) Chloride at the Interdigitated Microelectrode Array (IDA)

摘要

The interdigitated microelectrode array (IDA) has been employed to the calibrationless chronoamperometric quantitative analysis.The approach utilizes the phenomenon of the mixed diffusion flux of the electroactive species;linear and nonlinear (semi-cylindrical) towards the IDA surface.Each of the two components of the total flux can be calculated from a single chronoamperogram with the background correction using Aoki's equation.It was observed that the linear flux decreases rapidly for digit width of 5 mum.Thus,after 10-20 s the potential imposition the total flux comprises over 95% of nonlinear diffusion.Knowing the linear and nonlinear components one can iteratively calculate the bulk concentration of the electroactive species from the amperometric experiment with calibration (using standards).The method was validated with [Fe(N)_6]~(4-) and [Ru(NH_3)_6]~(3+) model ions.It provides reliable results within the concentration range:10~(-4)-10~(-3) mol L~(-1).