EVALUATION OF THE ANALYTICAL POTENTIAL OF LASER‐INDUCED BREAKDOWN SPECTROMETRY (LIBS) FOR THE ANALYSIS OF HISTORICAL GLASSES*

The novel and—for archaeometrical applications—still rarely used Laser‐Induced Breakdown Spectrometry (LIBS) was tested on various standard glasses for its spectrometric performance. LIBS is an almost non‐destructive method based on the time‐resolved detection of optical emission following direct laser ablation. A frequency‐quadrupoled Nd:YAG laser at 266 nm was found to cause a hardly visible crater of c. 200 µm in diameter. The application of an innovative high‐resolution Echelle spectrograph allows the fast and simultaneous determination of up to 90 elements in the spectral range from 200 to 780 nm, with a resolution of 10–30 pm under ambient conditions. In principle, LIBS has a high analytical potential for archaeometry; in particular, for the determination of light elements (Li, Be, B and others). Because the measurement parameters (laser energy, delay time and number of pulses) do not independently influence the emission signal, their optimization proved to be complex and is rather a compromise for the range of elements. The effects of sample distance, surface roughness and the accumulation of depth profiles were studied. Problems arose for the determination of sodium and potassium in higher contents due to self‐absorption effects. Quantification tests using a silicon line as internal standard yielded a precision range between 3% and 20% relative, but in general no satisfying accuracy for a number of elements. However, these problems might be overcome in the near future by improved spectrometer set‐ups and matrix correction approaches.