Quality control in qualitative analysis

In recent years, quality control (QC) has acquired great importance in chemical laboratories, so the international standard ISO/IEC 17025 points out that any laboratory shall establish, implement and maintain a quality system appropriate to the scope of its activity. However, the standard scarcely addresses qualitative analysis in spite of its increasing importance in chemical and biochemical laboratories. In part of the report EUR 20605 EN (2002), QC of qualitative analysis was considered for the first time. This overview presents one view of the state of the art of QC in qualitative analysis. The use of control charts in qualitative analysis is the most important activity of internal QC to monitor and control routine analysis. The paper describes the control charts to be used in qualitative analysis because the control charts typically used in quantitative analysis cannot be used directly. The correct application of proficiency testing (PT) schemes to qualitative analysis, the most important activity of external QC, is also described in this overview.