The ACTIVA ICP-AES
spectrometer employs a Czerny-Turner configuration for wavelength
dispersion with a two-dimensional CCD detector for
vertically resolved emission measurement. The instrument therefore
has the capability to simultaneously measure the entire
vertical emission profile of the plasma over a defined spectral
range (the x-axis of the CCD detector corresponds to wavelength
and the y-axis to vertical location in the plasma). In the present
study, an extended region in the ICP was used for photon
collection; the observation height ranged from 6 to 15 mm above
the load coil. The spectral resolution of the spectrometer was 8
pm. Unless otherwise specified, integrated spectral intensity was
used throughout the study; that is, the intensity of all CCD pixels
over the entire spectral peak was integrated. Off-peak background
correction was used, and background intensity was measured at
CCD pixels adjacent to the spectral peaks. For continuous sample
introduction, the integration time was set at 3 s with 10 replicates
for each measurement. For flow injection measurements, a 0.2 s
integration time was used.