A micro-electrochemical sensor based on a nanostructured carbon paste electrode as an original tool for selective detection of ultra-traces of 17 α - ethinylestradiol in environmental water samples and in biologic fluids

A new electrochemical micro -sensor has been designed for the sensitive detection of ultra -traces of 17 alpha - ethinylestradiol (EE 2 ). A carbon paste cavity micro -electrode modified by carbon black nanoparticles (GC-nCB)- mu CPE was used with an electrochemical preconcentration (EP) step of EE 2 on (GC-nCB)- mu CPE at 0.0 V during 300 s in a 0.01 mol.L -1 phosphate buffer solution (pH = 7.4) before voltammetric determination. The results demonstrate that two line calibrations were obtained in the concentration ranges of 0.005 to 0.2 mu mol.L -1 and 0.2 to 1 mu mol.L - 1 . The detection and quantification limits are estimated at 1.4 nmol.L -1 and 4.9 nmol.L -1 , respectively. Moreover, a high sensitivity of 4.16 mu A.mol - 1 .L and good selectivity for the quantification of EE 2 in the presence of different interfering organic and inorganic compounds were observed. Based on the results (satisfactory recovery (less than 3.5 %) and relationship standard deviation (less than 2.5 %)), the designed micro -sensor can be successfully applied to the analysis of EE 2 in environmental water samples and in biologic fluids. The modified microsensor presented an efficient and inexpensive tool for the quantification of EE 2 .