The electrochemical determination of isatin at nanocrystalline boron-doped diamond electrodes: Stress monitoring of animals

Ultra-thin nanocrystalline boron-doped diamond electrodes (B:NCD) were used for the electrochemical determination of isatin in dog urine samples using cyclic voltammetry and square wave voltammetry in a phosphate buffer saline, pH = 7.2. No additional modification or pretreatment of the electrode surface was required in this approach, being of high importance for the facile detection procedure. The increase of the peak current was linearly related to the raised concentration of isatin in phosphate buffer. The limit of isatin detection was equal to 0.2 mu M and 3 mu M for B:NCD and reference glassy carbon electrodes respectively. The relatively high current sensitivities of 1.32 mu Acm(-2) mu M-1 were achieved thanks to the nanocrystalline diamond surface. We have demonstrated that isatin could be determined at B:NCD electrode in the complex urine matrix within the limit of detection having 1 mu M along with sensitivity of 0.46 mu Acm(-2) mu M-1 without pre-treatment procedure of the analyze.