Aminopropyl hybrid silica monolithic capillary containing mesoporous SBA-15 particles for in-tube SPME-HILIC-MS/MS to determine levodopa, carbidopa, benserazide, dopamine, and 3-O-methyldopa in plasma samples

Abstract

This manuscript describes an automated method that combines the selectivity of in-tube solid-phase microextraction (in-tube SPME) with the sensitivity of liquid hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS) to determine levodopa, carbidopa, benserazide, dopamine, and 3-O-methyldopa in plasma samples. An aminopropyl hybrid silica monolithic capillary containing mesoporous Santa Barbara Amorphous (SBA-15) particles for in-tube SPME was prepared by sol-gel reactions (one step). The organic–inorganic hybrid silica monolithic capillary was reused over fifty times without significant extraction efficiency loss, which attested to its robustness. The FTIR spectra displayed readily identifiable peaks that were characteristic of aminopropyl groups. SEM and TEM micrographs showed that the monolithic phase consisted of a homogeneous, continuous, and mesoporous skeleton composed of interconnected ordered particles. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (1.2–170 ng mL−1) to the upper limit of quantification (2000 ng mL−1), and the coefficients of correlation (r) were higher than 0.99. The method was validated with intra-day and inter-day precision and accuracy. In-tube SPME-HILIC-MS/MS was successfully developed to determine levodopa, carbidopa, benserazide, dopamine, and 3-O-methyldopa in plasma samples obtained from patients with Parkinson’s Disease for therapeutic drug monitoring purposes.