[Mass spectrometric determination of pethidine in biological samples (author's transl)].

A mass spectrometric method for the determination of pethidine in nanogram range is described. This method excels by its high sensitivity and specificity, which ensures the reliable quantitative determination of the pharmacon also in complex media. Pethidine is extracted with ether from the respective sample together with its (D5) derivative (which is added as an internal standard) and directly (or after gas-chromatographic separation from other components) determined by mass spectrometry. The pethidine concentration is calculated from the ratio of the sums of the molecular ion intensities M+-pethidine/M+-(D5)-pethidine, which are obtained from the chromatographic column by repetitive scanning during the elution of pethidine and its (D5) derivative, respectively.