Sensitization Effect of NTA on the Catalytic Photometric Determination of Traces of Manganese(Ⅱ) Based on its Catalytic Action on the Oxidation of Bromophenol Blue by Potassium Periodate

Photometric determination of trace amounts of manganese by its catalytic action on the color-fading oxidation of bromophenol blue with KIO4 was found sensitized by nitrilotriacetic acid (NTA). It was found that linear relationship between the decrease in intensity of absorbance measured at 590 nm (ΔA) and the concentration of Mn(Ⅱ) was held in the range from 0.4 to 10 μg·L-1 with a detection limit of 8.5×10-8g·L-1. RSD (n=6) and recovery found in the analysis of a tea sample were 1.1% and in a range of 94%-108%,and in the analysis of a well-water sample were 3.2% and in a range of 93%-109%.