Simple validated LC–MS/MS method for the determination of atropine and scopolamine in plasma for clinical and forensic toxicological purposes

• Atropine and scopolamine were determined by a new and validated LC–MS/MS method.
• LLOQ of 0.10 ng/mL is guaranteed after deproteinisation of only 100 μL plasma.
• Scopolamine was determined in human plasma for the first time after deproteinisation.
• A simplified matrix effect calculation for deproteinisation procedures is proposed.
• This simple and fast LC–MS/MS method can be used for forensic and clinical purposes.

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the determination of atropine and scopolamine in 100 μL human plasma was developed and validated. Sample pretreatment consisted of protein precipitation with acetonitrile followed by a concentration step. Analytes and levobupivacaine (internal standard) were separated on a Zorbax XDB-CN column (75 mm × 4.6 mm i.d., 3.5 μm) with gradient elution (purified water, acetonitrile, formic acid). The triple quadrupole MS was operated in ESI positive mode. Matrix effect was estimated for deproteinised plasma samples. Selected reaction monitoring (SRM) was used for quantification in the range of 0.10–50.00 ng/mL. Interday precision for both tropanes and intraday precision for atropine was <10%, intraday precision for scopolamine was <14% and <18% at lower limit of quantification (LLOQ). Mean interday and intraday accuracies for atropine were within ±7% and for scopolamine within ±11%. The method can be used for determination of therapeutic and toxic levels of both compounds and has been successfully applied to a study of pharmacodynamic and pharmacokinetic properties of tropanes, where plasma samples of volunteers were collected at fixed time intervals after ingestion of a buckwheat meal, spiked with five low doses of tropanes.

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