Rapid and Selective Determination of Water in Nonaqueous Solutions by Flow Injection Method Using Quenching Reaction of Chemiluminescence between Cyclohexane and Methylsilicone Solid Polymer

Abstract

The quenching of chemiluminescence between cyclohexane and methylsilicone solid polymer was applied to the determination of water in nonaqueous solutions using a flow injection method. The proposed system comprises one single flow line and is expected to serve as a rapid, simple and highly selective method. The analytical time required was less than 4 s for a single run. Although 10(v/v)% tetrahydrofuran and 10(v/v)% acetonitrile gave interfering signals of a few percent to the quenching response of a 0.7(v/v)% solution of water, thirty five ionic species (such as metal ions) did not interfere with the quenching signal of water, even when their concentration was as large as 1×10^-2 M. The detection limit was 0.1(v/ v)%for 10 μl sample injection, and the relative standard deviation was 2.3% in 10 repeated runs involving 10 μl injections of 1.0(v/v)% solutions of water. The present method was compared with that of Karl Fischer by analyzing actual samples, coolant and hydraulic fluids used for automobiles; the values obtained by the two methods agreed well with each other.