Indirect laser-induced fluorescence detection for capillary electrophoresis using a violet diode laser

The violet (415 nm) diode laser is used for indirect laser-induced fluoresc ence detection in capillary electrophoretic separations of inorganic anions and chemical warfare agent degradation products. Inorganic anions were det ected using 8-hydroxypyrene-1,3,8-trisulfonic acid as the indirect probe an d achieved submicromolar (40-80 ppb) detection limits in a 2-min separation . The chemical warfare agent degradation products methylphosphonic acid, et hyl methylphosphonate, isopropyl methylphosphonate, and pinacolyl methylpho sphonate were detected using the porphyrin tetrakis(4-sulfophenyl)porphine as the indirect probe and achieved detection limits of 0.1 muM (9 ppb), whi ch are 1 order of magnitude better than that achieved using indirect W dete ction. Baseline stability achieved with the violet diode laser was excellen t, with dynamic reserve (DR) values of >1000, which are 15 times better tha n that achieved using an unstabilized HeCd laser.