Quality Assurance in Analytical Chemistry

Analytical methods have to meet certain quality requirements, so that the results are credible and can be used with confidence for regulatory, economic and research decisions. Analytical quality assurance (QA) contains preventive action and comprises planning steps, quality control (QC), quality assessment, documentation and quality improvement. All factors leading to the analytical result have to be controlled, clearly described and documented. Furthermore, the analytical result should be linked to the sample and related to reference materials (RMs) or measurement standards by an unbroken chain of traceability. Two elements are needed in order to achieve this goal: internal QA measures comprise elements performed by the laboratory, such as method validation and documentation and the use of RMs, external QA relates to performance evaluation by persons outside the laboratory, such as proficiency tests and accreditation.