Recent Developments in X-Ray Spectrometry

I. INTRODUCTION

Although X-ray spectrometry has a history covering nearly 70 years,¹ it is only within the last 25 that the technique has added significantly to the armory of weapons available to the analytical chemist. The reasons for the rapid increase in the use of the technique in recent years are not hard to find. A very large proportion of the requirements for inorganic elemental analysis can be met by X-ray spectrometry: All of the elements from uranium down to sodium and, with limitations, on to beryllium, can be detected and determined at concentrations from 100% to below 1 ppm in favorable cases, and with a relative precision, when necessary, of 0.1% for the higher concentrations. The methods are inherently nondestructive in most cases, and samples are almost always available for repetitive checks, or for further analysis by other means. The sample state can be solid, liquid, or gaseous and in the first case can take a very wide variety of forms. Qualitative spectra are easily interpreted and quantitative precision is largely within the analyst's control, although accuracy, as always, is more difficult to ensure.