Reflectance spectroscopy and electrophoresis in the evaluation of retention and loss of modified starch

This study used reflectance spectroscopy in the UV-visible range to measure the amount of modified starch on paper surface. The method is then combine d with microelectrophoresis for determining the modified starch content of pulp slurry and white water as well by measuring charge density and streami ng current. Quantification of charge content in modified starch solution an d in waste wafer was performed by electrokinetic charge measurement. The io nic charge mass balance obtained by quantifying charge content before wet-e nd addition and in waste water gives a fairly good estimate of the retentio n and loss of modified starch additives. After correcting charge content of fines that interfered with the ionic charge of starch in waste water; the net charge demand of waste water linearly increased with initial starch dos age independent of the ionic functionality of the modified starches.