Simultaneous screening and quantification of 25 opioid drugs in post-mortem blood and urine by liquid chromatography–tandem mass spectrometry

A method for simultaneous screening and quantification was developed for the fentanyls alfentanil, fentanyl, p-fluorofentanyl, cis-3-methylfentanyl, trans-3-methylfentanyl, alpha-methylfentanyl, norfentanyl, remifentanil, sufentanil, and the other opioid drugs 6-acetylmorphine, buprenorphine, codeine, dextropropoxyphene, ethylmorphine, heroin, methadone, morphine, naloxone, naltrexone, norbuprenorphine, normethadone, oxycodone, pentazocine, pethidine, and tramadol in post-mortem blood and urine samples by LC–MS/MS. Samples were extracted with butyl acetate at pH 7. The drugs were separated by LC on a Genesis C18 reversed-phase column, with a gradient consisting of acetonitrile and ammonium acetate at pH 3.2. The mass spectrometric analysis was performed with a quadrupole-linear ion-trap mass spectrometer equipped with a turbo ion spray interface in positive mode using multiple reaction monitoring (MRM). Quantification was performed based on five isotope-labelled internal standards. Validation included assessment of linearity, limit of quantification, inaccuracy, precision, and matrix effects. The limits of quantification were adequate for screening and quantification of opioid drugs at low therapeutic or abuse concentration levels, with inaccuracy less than 23% and precision better than 24% both in blood and urine samples. When this method was applied to autopsy cases, its results were in agreement with those of reference methods.