[Detection of morphine and codeine in blood samples with gas chromatography/mass spectrometry (NCI and PCI) for differentiating codeine use from use of heroin and morphine].

Morphine and codeine were isolated from blood with C18 Bond Elut columns and derivatised with pentafluoropropionic anhydride (PFPA). The PFPA-derivatives were examined by means of gas chromatography/mass spectrometry using electron impact and chemical ionisation (positive and negative mode). The negative chemical ionisation, as most sensitive, was applied for the quantitation of both examined substances in forensic blood samples.