Atomic absorption spectrometry—has it gone or where is it going?

Abstract

A brief survey of the current literature would suggest that atomic absorption spectrometry (AAS) is on its way out as an analytical technique. Each year, fewer papers appear describing novel AAS instrumentation, techniques or applications. Instead, most studies on atomic spectrometry are concerned with the inductively coupled plasma, alternative plasma sources or novel means of detection. This apparent trend is considered, the development (or decline) of AAS is compared with that of competing techniques for elemental analysis and unusual directions in AAS and similar methods are reviewed. Although the number of recently published manuscripts that deal with AAS is indeed declining, the number of AAS determinations performed each year remains substantial. Similarly, sales of AAS instruments remain strong. This trend can be attributed in large measure to the simplicity and convenience of use that surrounds AAS procedures. Also, the sensitivity of furnace AAS continues to be important in many applications. Detracting from AAS are its continued and recognised shortcomings as a truly simultaneous multi-element method. The necessary straight-line geometry of an absorption process, coupled with the convenience of the hollow-cathode lamp as a primary source, make it difficult to adapt AAS to multi-element schemes. As a result, complex samples must be run repeatedly for a full elemental profile to be determined. Furthermore, performing qualitative analysis on samples becomes an arduous task by AAS. Atom cells ordinarily used for AAS also remain one of the method's limitations. Most determinations are currently performed with furnace-based units, and great care must be exercised to avoid interferences which can plague such systems. Clearly, for AAS to remain viable in the face of strong competition from alternative techniques will require novel instrumentation or approaches. Among the novel concepts that have been introduced are those involving continuum sources and high-resolution spectral-sorting devices, interesting atomisation devices and entirely new detection approaches. The impact of these developments will be evaluated against the backdrop of similarly exciting advances in competing techniques. The date when AAS will no longer be a viable technique is predicted.