Solid Phase Spectrophotometric Determination of Zinc in Pharmaceutical Products

Kazem Kargosha², Jila Azad³, Habibeh Haddad¹, S. Waqif Husain⁴

¹Science and Reasearch Branch, Islamic Azad University, Tehran, (lran) ²Chemistry and Chemical Engineering Research Center of lran, Tehran P.O.Box- 14335-186 (Iran) ³Chemistry Department, Alzahra University,Vanak,Tehran, (lran) ⁴Chemistry Department, University of Teacher Training, Tehran, (Iran)

A simple and sensitive solid phase spectrophotometric method for the determination of zinc is proposed based on the reaction between zinc and xylenol orange (XO). The reaction product is fixed on the anionic exchanger resin sephadex QAE A-25 at pH = 5. The optical absorbance of the anionic gel like resin, packed in a 1.00 mm cell is directly measured at 570 nm. The linear range of calibration curve is found to be 65-715 μg L-1, with a detection limit of 11 μg L-1. The relative standard deviation for ten independent determination is 2.9%. The effect of foreign ions are studied. The proposed method is applied to zinc determination in dermal ointments and a very good agreement is observed between the experimental and reported results.

Solid phase; Spectrophotometry; Zinc; Sephadex; Pharmaceutical products