Novel approach to the analysis and use of fullerenes in capillary electrophoresis.

The analysis and use of fullerenes in capillary electrophoresis (CE) was investigated. Sodium dodecyl sulfate (SDS) was used to solubilize fullerenes C60, C70, and a mixture of C60 and C70 in water. The behavior of the solutions of the C60- and C70-SDS complexes was examined by CE with on-line UV-Vis diode array detection. This study included the use of a C60-SDS complex as a new method of micellar electrokinetic chromatography (MEKC) for the separation of polycyclic aromatic hydrocarbons (PAHs) using CE with uniwavelength detection. Since SDS micelles act as a pseudostationary phase in which the PAH compounds partition with their hydrophobic interior, the addition of C60 within the micelles enhanced separation of the PAHs. The preliminary results using C60-MEKC with SDS were compared to those obtained with MEKC with SDS. The capillary electrophoretic separations were performed in 10 mM borate-phosphate buffer with 100 mM SDS at pH 9.5.

UV resonance Raman detection and quantitation of domoic acid in phytoplankton.

Cultures of the phytoplankton diatom, Pseudonitzschia multiseries, have been harvested under controlled growth conditions ranging from late logarithmic to late stationary phase (17-58 days). The amount of domoic acid (DA) present in the growth media and in the homogenized cells has been determined by HPLC. Defined samples of media, homogenized cells, whole cells, and whole cells in media have been laser excited at 251 nm for the purpose of selectively exciting intense UV resonance Raman spectra from DA in the samples. Neither media nor cell component spectra from algae seriously interfere with DA spectra. The spectral cross sections for the dominant 1652-cm-1 mode of DA have been determined for 242-, 251-, and 257-nm excitation. Maximum sensitivities are achieved with 251-nm excitation because cross sections for DA are a maximum, and interference from other algal components becomes very small. DA concentrations that have been determined with 251-nm excitation by resonance Raman methods correlate closely with values determined independently with HPLC, especially at higher DA concentrations. The UV resonance Raman analysis of DA in phytoplankton algae is shown to be very sensitive and quantitative as well as rapid and nonintrusive.