The study and application of analyte adduct based ionisation of propofol in the analysis with liquid...

The ionisation of propofol was studied on the basis of analyte adduct formation with the components of the mobile phase. The identification of an appropriate propofol adduct ion generated in an acetate salt based buffer in the negative electrospray ionisation mode made the propofol LC-MS/MS analysis with two multiple reaction monitoring experiments possible without analyte derivatisation. Since a product ion of the deprotonated analyte was also used in the detection, these two fragmentation experiments were performed with different precursor ions. Liquid-liquid extraction with 1-chlorobutane was applied for sample preparation. A Luna 5 μm C18 (2) 100 A, 150 mm × 2 mm analytical column together with a mobile phase composed of water/methanol (3/97, v/v) with 10 mmol·L^-1 ammonium acetate and 0.1% acetic acid were applied. The limit of detection and quantification were 0.02 mg/L and 0.06 mg/L appropriate. Other results of the validation experiments performed like linearity of the calibration range, accuracy and precision, processed sample stability, recovery, matrix effect and selectivity revealed that this propofol quantification strategy developed can be defined as an applicable alternative to other methods presented.