Fabrication of nano-porous hydroxyapatite modified electrode and its application for determination of p-chlorophenol

Nano-porous hydroxyapatite (HAp) modified electrode was fabricated by simply electrodepositing HAp onto the glassy carbon electrode (GCE) from the electrolytes solution containing Ca(NO3)2 4H2O and NH4H2PO4, the resulting electrode (nano-HAp/GCE) was characterized with scanning electron microscopy (SEM). The electrochemical behavior of p-chlorophenol (p-CP) at nano-HAp/GCE was studied by cyclic voltammetry. The electrode displayed selective and enhanced electroanalytical response towards p-CP, obviously because p-CP is accumulated at the electrode. For the greater sensitivity, a semi-derivative technique was adopted to obtain the current signal. The results indicated that the nano-HAp/GCE exhibits substantial enhancement in electrochemical sensitivity for p-CP due to its large surface area and particular adsorbability. After accumulation of 4 min for p-CP on nano-HAp/GCE, the peak height was linearly related to the concentration of p-CP in the range of 1.0 x 10(-8) to 1.0 x 10(-7) mol L(-1). The detection limit was 4.0 x 10(-9) mol L-(1) at 3sigma level. Based on this, the modified electrode was successfully applied in water samples with low cost and high sensitivity.