TY - JOUR A1 - Lott, S. A1 - Henrion, A. A1 - Malz, Frank A1 - Kessler, A. A1 - Güttler, B. A1 - Aderjan, R. T1 - Reference measurement procedure for Delta9-tetrahydrocannabinol in serum N2 - An isotope dilution gas chromatography/mass spectrometry (ID-GC/MS) reference measurement procedure for Δ9-tetrahydrocannabinol (THC) in serum was developed and validated. The method complies with the concept of a ratio primary reference measurement procedure. The uncertainty was determined for two concentrations of THC in serum (1 ng/mL and 2.4 ng/mL). The calculation procedure is based on the Guide to the Expression of Uncertainty in Measurement (GUM). The relative expanded uncertainty was found to be less than 2% for both concentration levels, corresponding to a 95% confidence interval. For the reference method, it was shown that the measurement of THC within the concentration range covered by the current threshold values is very accurate. The method has the potential to provide traceability for the methods used in practical forensics. KW - THC KW - Uncertainty of measurement KW - GUM KW - Threshold value KW - Reference material KW - Primary method KW - Quantitative NMR PY - 2008 DO - https://doi.org/10.1007/s00216-008-2065-1 SN - 1618-2642 SN - 1618-2650 VL - 391 IS - 3 SP - 1003 EP - 1010 PB - Springer CY - Berlin AN - OPUS4-17628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -