DEVELOPMENT OF A SYSTEM FOR THE DETECTION OF INTERFERENCES DURING ROUTINE ANALYSIS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

The development of a strategy for the detection of interferences durin g the routine analysis of unknown samples by graphite furnace atomic a bsorption spectrometry is discussed. Since indications of interference s must be found in the shape and position of the signal, different met hods for the characterisation of the atomic absorption signal are eval uated. For each signal different correlated parameters are monitored, so that the possibility to summarise them in a multivariate test stati stic, called Hotelling's T2, is investigated. The use of control limit s for this parameter, established from the measurement results in matr ix-free solutions, permits the detection of interferences. However, it is much more difficult to say how strongly the quality of the determi nation is affected by the detected interferences. Another problem that remains to be solved is the fact that it is difficult to compare sign als that are measured in different runs.