Author/Authors :
de Oliveira Costa، نويسنده , , Cicero and Miranda، نويسنده , , Paulo R.B. and Hazra، نويسنده , , Banasri and Das Sarma، نويسنده , , Madhushree and de Cلssia Silva Luz، نويسنده , , Rita and Kubota، نويسنده , , Lauro Tatsuo and Goulart، نويسنده , , Marيlia Oliveira Fonseca، نويسنده ,
Abstract :
A sensor based on glassy carbon (GC) electrode modified with cobalt tetrasulfonated phthalocyanine (CoTSPc) and a poly-l-lysine (PLL) film is proposed for diospyrin determination in nanomolar concentrations with differential pulse voltammetry (DPV) technique. The modified electrode showed excellent catalytic activity presenting much higher peak currents than those measured on a bare GC electrode. Linear response range, sensitivity and limit of detection (LOD) were of 1–120 nmol l−1, 220.46 nA l nmol−1 cm−2 and 0.3 nmol l−1, respectively. The repeatability of the proposed sensor, evaluated in term of relative standard deviation (R.S.D.), was measured as 4.4% for 10 experiments in 50 μmol l−1 diospyrin samples. The developed sensor was applied for the determination of diospyrin in the crude extracts of the stem–bark of Diospyros montana Roxb. and the average recovery for these samples was 101.9 (±3.1)%.
