Quality Assurance and Method Validation - Forensic Applications of Gas Chromatography - page 57

testing method. In forensic science, we must be certain that the results we
obtain from an instrument are true and that the analytical method is robust
and will not change dramatically from day to day. If you were to stand up in
court and state that the 1 kg of off-white powder submitted to your laboratory
for analysis has been found to contain 65% cocaine free base, you need to be
able to prove that this is the answer you will achieve every time you analyse
the same sample. Method validation is an essential step in forensic analysis
for all analytical testing. Each method must be fit for purpose and must meet
the requirements laid down in the laboratory and by regulatory specifications.
Questions
1. List the four Qs and explain their purpose in instrument qualification.
2. When trying to establish linearity, experimental data were obtained
from the GC instrument; the R 2 value was found to be 0.988. Is this
value acceptable or not?
3. What is the purpose of ISO/IEC 17025?
Reference
1. Society of Cost Estimating and Analysis. Definition of quality assurance (http://
www.sceaonline.org/prof_dev/glossarylisting.cfm?term=q).
Further Reading
Eurachem/CITAC Guide CG-4. 2000. Quantifying uncertainty in analytical mea-
surement, ICH Guideline Q2(R1). Validation of analytical procedures: Text and
methodology.
ISO/IEC. 2005. General requirements for the competence of testing and calibration
laboratories, 17025.
Prichard, E., and V. Barwick. 2007. Quality assurance in analytical chemistry.
Chichester, UK: John Wiley & Sons Ltd.
Ratliff, T. A. 2003. The laboratory quality assurance system: A manual of quality proce-
dures and forms, 3rd ed. Hoboken, NJ: John Wiley & Sons Inc.