UM-40 : Determination of trace elements by atomic spectrometry

Abstract

The report describe some basic concepts, instrumentation and techniques of atomic spectrometry. In particular, attention is given to atomic absorption and atomic emission spectrometric techniques.

Although atomic absorption is a very sensitive technique, with detection limits in the ppm range, flame interference at extremely low concentrations has been the major source of problems. Recently, systems have been developed to overcome this problem by the introduction of nonflame atomizers, such as the graphite furnace. With flameless techniques, the detection limits are usually enhanced by a factor of 103. However, this technique does not replace the conventional flame method, but is regarded as a supplement for special studies. Being quicker and more precise, the conventional flame technique is given preference for routine analysis and automation.

The most promising development in the field of emission spectroscopy is the new source of excitation known as a plasma i.e ., an electrically generated luminous gas containing a significant fraction of ionized atoms or molecules in inert gas. The inductively coupled plasma (ICP) derives its sustaining power by induction from high-frequency magnetic fields. It has been reported that the ICP has virtually ideal characteristics for simultaneous multi-element determinations.

The report has been divided into four chapters. Chapter 1 describe some fundamental concepts of atom and the atomic processes involved in various atomic spectrometric techniques. More detailed information about atomic absorption and atomic emission spectroscopy techniques have been presented in chapter 2 and 3 respectively. Important comparison criteria for selecting a particular technique for a particular analytical problem have been discussed in chapter 4. The report ends with some important references on the topic.