PHOTOCATALYTIC OXIDATION FOR TOTAL ORGANIC-CARBON ANALYSIS

A new method and apparatus for the determination of organic carbon in water are described. Photocatalytic oxidation of organic matter by near-UV illuminated titanium dioxide is used to convert organic carbon to carbon dioxide. Atmospheric oxygen is the oxidant. The light source is a 20-W black-light fluorescent tube. The carbon dioxide equilibrates between the reaction loop and a conductivity detection loop and the recirculated air forms the interface between the two loops. The method is suitable for analysis of water containing 0.1-30 μg ml-1 organic carbon and sample volumes of 1-40 ml. Higher concentrations can be determined after appropriate dilution. Times for 99% oxidation of organic solutes to carbon dioxide are of the order of 10 min or less. The main advantages of the apparatus are low cost and ease of operation. © 1990.