Application of combined acetate salt based multiple analyte adduct formation in signal separated quantification performed for the purposes of forensic toxicology with liquid chromatography–tandem mass spectrometry — Discussion on the basis of salicylic acid applied as a model drug

Abstract

In this work the examination of analyte adduct formation by the application of both sodium acetate and lithium acetate was performed with salicylic acid used as a model drug. Additionally, on the basis of combined acetate salt based multiple analyte adduct ions it was aimed to investigate the generation of different analyte precursor ions and their application in signal separated quantification with liquid chromatography–tandem mass spectrometry. Adduct identification experiments were performed by infusion experiments and resulted in an optimised detection of analyte adduct ions with lithium acetate, sodium acetate and combined lithium acetate/sodium acetate. Sample preparation based on a fast protein precipitation with a methanol solution containing lithium acetate and sodium acetate. A Luna 5 μm C18 (2) 100 A, 150 mm × 2 mm analytical column and a mobile phase composed of an H₂O/methanol = 3%/97% (v/v) solution with 10 mmol l^-1 ammonium acetate and 0.1% acetic acid were used for chromatographic purposes. The linearity was investigated in the range of 5–500 μg/ml. The limit of detection (LOD of 1.2 μg/ml) and quantification (LOQ 4.0 μg/ml) together with other results of validation experiments revealed that this strategy can be applied for salicylic acid quantification.