MULTICHANNEL CHROMATOGRAPHY AND ONLINE SPECTRA FROM A FLAME PHOTOMETRIC DETECTOR

A rotating variable interference filter has been incorporated into a flame photometric detector to acquire and simultaneously display low-resolution spectra that are diagnostic for eluting peaks. In its present form this approach yields ten chromatograms (for ten different wavelength segments) that are stored in the computer for subsequent data manipulation such as baseline correction and curve smoothing; three-dimensional display; peak and noise diagnostics; and magnification, subtraction, or elemental correlation of chromatograms. A third, spectral dimension is thus added to the conventional two, chromatographic dimensions of retention time and analyte intensity. The three-dimensional performance is at present accompanied by an order-of-magnitude loss in detection limit and linear range. Typical one-segment (i.e. 5% dwell time) elemental detectabilities, at S/N-p-p = 2, are 7 . 10(-13) g P/s (via HPO*), 3 . 10(-11) g S/s (S-2*), 7 . 10(-12) g Ge/s (GeH*) and 4 . 10(-12) g Ru/s.