Atomic magneto-optical rotation spectroscopy (AMORS) using a rotating polariser and a segmented graphite rod atomiser

Abstract

An instrumental system for the measurement of optical rotation in a magnetised atomic vapour is described. The apparatus incorporated a hollow-cathode lamp as a source of resonance radiation, a Wollaston prism polariser rotating at 25 Hz, a segmented graphite rod atomiser mounted in a longitudinal magnetic field produced by an electromagnet, a fixed Glan polarising prism, grating monochromator with associated electronic system and computer data processing. Cadmium, copper, lead and silver were determined in simple aqueous solutions. Detection limits comparable with those found for Zeeman atomic absorption spectrometry using the same apparatus were obtained. The linearity of the calibration graph was limited to a maximum of 10° optical rotation in the atomic vapour by the relatively low rotational speed of the polariser. The analytical sensitivity of the system could be adjusted by changing the magnetic field strength.