Chemiluminescence detection of trace amounts of cobalt(II) with the 2,6,7-trihydroxy-9-(4′-chlorophenyl)-3-fluorone–hydrogen peroxide–cetyltrimethylammonium bromide system

Abstract

Chemiluminescence was observed when 2,6,7-trihydroxy-9-(4′-chlorophenyl)-3-fluorone was oxidized with hydrogen peroxide in alkaline solution in the presence of trace amounts of Co^II. Trace amounts of Co^II catalysed this chemiluminescence reaction strongly, especially in the presence of the cationic surfactant cetyltrimethylammonium bromide, and the chemiluminescence intensity was proportional to the concentration of Co^II. The optimum conditions for the chemiluminescence reaction were investigated in detail. A chemiluminescence method for the determination of ultratrace amounts of Co^II was developed with a detection limit of 0.07 ng ml^–1. The relative standard deviation was 2.1% for 6 ng ml^–1 Co^II. The method was used for the analysis of water samples without prior separation.