A short review is presented on the development of continuum-source atomic absorption spectrometry (CSAAS) . The current status of the technique is assessed and the application of microcomputer controlled single channel CSAAS to the analysis of standard reference materials is described .
The field of atomic absorption spectrometry (AAS) has grown enormously in the last 25-30 years . The pioneering work of Walsh [1] and Alkemade and Milatz [2] has profoundly affected the way in which trace element determinations are carried out in laboratories throughout the world . Although there have been significant developments in AAS instrumentation in the intervening years, the principle of the measurement has remained essentially the same since its inception . The use of a narrow-line spectral light source for AAS measurement was hailed, rightly, as a major breakthrough in the development of analytical atomic spectrometry . The classic exposition of the technique by Walsh [1] has been reiterated in countless papers and textbooks . It is now almost axiomatic that a narrow-line light source, such as a hollow-cathode lamp, is required in order to make sensitive atomic absorption measurements . Yet the future development of the technique may well depend on questioning this rationale, since it imposes severe restrictions on the design of instrumentation for AAS .
HISTORICAL PERSPECTIVES
In offering at alternative basis for atomic absorption measurement, it is pertinent to consider the historical development of the subject . Lockyer [3] described an experimental system for studying absorption spectra as long ago as 1875 . A pictorial representation of the apparatus used, taken from a text published around that time [4] is shown in Fig . 1 . The experimental **Present address : I.C.I. p.l.c., Petrochemicals and Plastics Division,