Analytical Possibilities of Detecting Trace Quantities of Beryllium by ERIAD Mass-Spectrometry

Abstract

The possibility of mass-spectrometric determination of the beryllium concentration in the air in work rooms is examined. Experiments have shown that the ERIAD ion source (electro-sprayng with controlled atomization in the source) gives the required rapid-analysis of the beryllium content, including at a level 10 times lower than the maximum admissible concentration. Evaluations show that such analysis takes no more than 30 min, including sample preparation; one mass-spectrometer can service 10‐12 sampling points. The aim of the present work is to determine the possibility of using mass-spectrometry with the ERIAD ion source (electrospraying controlled fragmentation and atomization of ions in the source) for fast determination of small concentrations of beryllium in air. Beryllium is an important material used in metallurgy as an alloying additive and in modern microelectronics and the nuclear industry. Its yearly production is several tens of tons, and the demand for it is constantly growing. Beryllium is a toxic element. Strict standards allowing a maximum concentration not exceeding 10 ‐6 g/m 3 in air in a work zone, where it usually exists as an oxide or salts adsorbed on dust particles, have been adopted in our country. There are significant difficulties in sensor monitoring of these requirements: the methods adopted entail multistage sample preparation, including concentrating the samples and chemical release [1]. This method does not permit fast analysis of the beryllium content in air, which in the case of possible accidents or arbitrary emissions can have serious consequences. The conventional optical methods of analysis with excitation of the atoms in inductively coupled plasma or spark excitation are ineffective for detecting trace quantities of beryllium because of the small number of optical lines and their considerable overlapping with the lines of other elements. In practice, a concentration below 50 ppm cannot be determined adequately by these methods without preliminary concentration. Mass-spectrometry has a considerable advantage over other methods of analysis used for detection and quantitative determination of the beryllium concentration because there are no lines of other chemical elements in the region of the mass spectrum where its atomic line lies (9 amu). However, difficulties arise when the beryllium atoms are ionized. For example, surface ionization is ineffective because the ionization potential of beryllium atoms is high (>9 eV); mass-spectrometry with inductively coupled plasma creates a significant spread of the ions at the exit from the source. It is reduced by using a cool