Instant Notes: Analytical Chemistry

Section A – The nature and scope of analytical chemistry

A6 QUALITY IN ANALYTICAL

LABORATORIES

Quality control Analytical data must be of demonstrably high quality to ensure confidence in the
results. Quality control(QC) comprises a system of planned activities in an
analytical laboratory whereby analytical methods are monitored at every stage to
verify compliance with validated procedures and to take steps to eliminate the
causes of unsatisfactory performance. Results are considered to be of sufficiently
high quality if

● they meet the specific requirements of the requested analytical work within

the context of a defined problem;

● there is confidence in their validity;

● the work is cost effective.

To implement a QC system, a complete understanding of the chemistry and

operations of the analytical method and the likely sources and magnitudes of

errors at each stage is essential. The use of reference materials (Topic A5) during

method validation (Topic A3) ensures that results are traceableto certified

sources. QC processes should include:

● checks on the accuracyand precisionof the data using statistical tests (Section

B);

● detailed records of calibration, raw data, results and instrument performance;

● observations on the nature and behavior of the sample and unsatisfactory

aspects of the methodology;

● control chartsto determine system control for instrumentation and repeat

analyses (Topic B5);

Key Notes

Quality control (QC) is the process of ensuring that the operational

techniques and activities used in an analytical laboratory provide results

suitable for the intended purpose.

Quality assurance (QA) is the combination of planned and systematic

actions necessary to provide adequate confidence that the process of

quality control satisfies specified requirements.

This is a system whereby the quality control and quality assurance

procedures adopted by a laboratory are evaluated by inspection and

accredited by an independent body.

Related topics Analytical techniques and Quality control and chemometrics

methods (A3) (B5)

Quality control

Quality assurance

Accreditation

system