Kinetic-catalytic determination of trace amounts of Mn(II) based on a reduced phenolphthalein-periodate reaction

A simple, sensitive and highly selective kinetic method for the determinati on of low levels of Mn(ll) has been described. The method is based upon a r educed phenolphthalein-periodate reaction catalysed by Mn(II). The reaction rate was monitored spectrophotometrically by measuring the increase in abs orbance after a fixed time. The calibration graph was Linear in the range o f 2-200 ng ml(-1) of Mn(II) and the detection limit was 0.9 ng mL(-1). The relative standard deviation of seven replicate determinations of 40 ng ml(- 1) Mn(ll) teas 1.3%.