Indirect determination of total acid-soluble aluminum in natural waters by oscillopolarography using pyrocatechol violet

Indirect determination of total acid-soluble aluminum in natural waters by oscillopolarography in the presence of pyrocatechol violet ( PCV) is presented. In 0.5 mol/L NH4Ac buffer solution (pH 6.4) containing 1 x 10(-3) mol/L PCV, PCV yields two incisions on the dE/dt-E oscillogram at the potentials of -0.80 and -1.20 V. The incision depth (E-p = -1.20 V) declines when adding Al in the solution. The decreases of incision depth shows a linear relationship with increasing Al concentrations (4 x 10(-7) similar to 4 x 10(-6) mol/L). It is the basis of indirect quantitative analysis. The relative standard deviation is 8.3% for 1 x 10(-6) mol/L Al (n = 10) and the detection limit is 2 x 10(-7) mol/L. The proposed method has been applied to determine total acid-soluble Al in natural waters and compared with the results obtained by inductively coupled plasma-atomic emission spectrometric method.