ULTRAVIOLET-VISIBLE DETECTION FOR CAPILLARY GAS-CHROMATOGRAPHY AND COMBINED ULTRAVIOLET MASS-SPECTROMETRY USING A REMOTE FLOW CELL

A scanning UV-Vis detector, linked by fiber optics to a heated remote flow cell, was interfaced to a gas chromatograph and gas chromatograph-mass spectrometer equipped with conventional split/splitless injectors and a 30 m x 0.32 mm, 0.25 mu m capillary column. Gas-phase UV spectra with a 3 nm effective bandpass are shown for benzene, biphenyl, anthracene, phenanthrene, benzo-alpha-pyrene, methylanisoles and polychlorinated biphenyls. Chromatograms at a single wavelength are presented for Aroclors 1254 and 1221. A dual mass-UV chromatogram is shown for unleaded gasoline. Calibration curves generated for aromatic hydrocarbons suggest linearity of detector response over a range of about 10(4). A total absorbance chromatogram is shown for four components of st test mixture. Detection limits for a moderate UV absorber, biphenyl, were 1.0 ng in summed scanning mode and 750 pg in single-wavelength mode, using a criterion of three standard deviations of the baseline noise. The single-wavelength detection limit for naphthalene, a stronger UV absorber, was 90 pg.