Chemiluminescence　was　observed　when　dibromoalizarin　violet　was　oxidized　with　hydrogen　peroxide　in　alkaline　solution.　Trace　amounts　of　Co　(II)　catalysed　this　CL　reaction　strongly,　especially　in　the　presence　of　the　cationic　surfactant　cetyltrimethylammonium　bromide,　and　the　CL　intensity　was　proportional　to　the　concentration　of　Co(II).　A　flow　injection　system　with　CL　detection　was　established　to　investigate　this　CL　system.　The　optimum　conditions　for　this　CL　reaction　were　investigated　in　detail,　and　the　optimized　flow　injection　parameters　were　determined　by　the　modified　simplex　method.　A　CL　analytical　method　for　determination　of　ultratrace　amounts　of　Co　(II)　was　developed　with　a　detection　limit　of　4　pg/mL.　It　was　used　for　analysis　of　natural　water　samples,　and　the　results　compare　very　well　with　those　from　GFAAS.　A　possible　mechanism　for　this　CL　reaction　is　proposed　on　the　basis　of　studying　CL　spectra,　absorption　spectra,　fluorescent　spectra　and　HMO　treatment　for　the　reagent　molecule.　The　effects　of　various　types　of　surfactants　on　CL　reaction　are　also　discussed.　©　1994　Springer-Verlag.