A method will be developed for the analysis of the galvannealed coating layer on sheet steel by laser induced breakdown spectrometry (LIBS), on-line during production and without interruption of the production. The light pulses generated during laser induced depth profiling will be analysed by a high-speed high sensitivity multi-channel optical spectrometer. Ablation craters will be closed immediately after the measurement by laser based post-treatment, synchronised with the LIBS-measurement.