Chapter 5: Advances in AAS (HR CS AAS) Check Access

High-resolution continuum source AAS utilizes a xenon short arc lamp operating in a hot spot mode as the continuum source and is free from the problem of stacking HCL for individual elements. Spectral radiance of the CS is at least one order higher than HCL to compensate for geometrical conduction losses to obtain comparable detection limits with LS (line source) AAS. The improved Xe short arc lamp with increased UV emission (developed by GLE, Berlin, Germany) is optimized to run in a hot spot mode with a diameter <0.2 mm and a temperature of 10 000 K, causing appreciably higher radiation intensities in the far UV range. The discharge mode is characterized by the appearance of an extremely small plasma with a diameter of <0.2 mm close to the cathode as opposed to diffused arc shape in the common Xe lamps. High resolution is obtained by using a double monochromator with a prism as a pre-monochromator and an echelle grating monochromator for high resolution to the pm range with a linear CCD array detector.