2.3. Procedure
According to procedure, after optimization studies a standard
HQ solution was prepared by taking first 0.3 ml of 0.0001M KMnO4 solution in a 10ml volumetric flask. To this was then added appropriate volume of HQ from a 100gml−1 solutionof HQ, shaken thoroughly and made to the mark with doubly distilled water. Same procedure was repeated for preparing blank but without HQ.The in strument was set at zero in air with appropriate range and the absorbance of HQ solution was read at 245.5nm against the blank put in the reference compartment. The diluted samples of waste photographic developer solution were similarly treated and the unknown concentration of HQ determined from calibration plot.