Determination of the stability constant of Cobalt (ІІ) – Piroxicam complex by spectrophotometery

Abstract

In this work, a new spectrophotometric method for the determination of trace amount of Cobalt (ІІ) ion<br />was investigated and the stability constant of the related complex was evaluated 2.174 × 104. In the Cobalt<br />(ІІ)-piroxicam complex, the maximum absorbance wavelength is 570 nm and the linearity of calibration<br />curve was investigated (5-10 ppm). The relative standard deviation for seven replicate experiments is<br />0.5292 percent. The accuracy is 0.15 percent and limit of detection is 1.19 ppm. The analytical sensitivity<br />allows us to detect the concentration difference of 0.06 ppm with reliable level of confidence. The ligand to<br />metal ratio was determined (1:1) by the continuous variation method. The above spectrophotometric<br />method was optimized in terms of pH, temperature, time, ligand concentration and ionic strength. This<br />method is tolerant against several external matters, which means high selectivity.