A novel multi-aptamer electrospun nanofibrous membrane for simultaneous selective extraction of monoamine neurotransmitters and determination in biological samples by LC-MS.

Abstract

Dopamine (DA) and serotonin (5-HT) are key monoamine neurotransmitters, the sensitive determination of which in biological matrices is challenging owing to low concentrations and strong matrix interference. In this study, a multi-aptamer-functionalized electrospun membrane (MA-Au@PVP/PVDF) was developed by simultaneously immobilizing the DA aptamer (Apt-DA) and the 5-HT aptamer (Apt-5-HT) on the membrane surface via Au-S bonds. The membrane combines high specific surface area, good stability, and aptamer-based specificity, enabling simultaneous and selective extraction of DA and 5-HT from complex samples. The enriched analytes were subsequently quantified using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS). The maximum adsorption capacities of the MA-Au@PVP/PVDF membrane were 190.8 ng/cm² for 5-HT and 165.1 ng/cm² for DA, with the adsorption process fitting well to the Langmuir isotherm model (R² ≥ 0.99). Under optimized extraction conditions, the established method was thoroughly validated in both serum and urine matrices, exhibiting wide linear ranges (2.5-1000 ng/mL, R² ≥ 0.9905), low limits of quantification (LLOQ 2.5-10 ng/mL), satisfactory intra- and inter-day precision (RSD < 10.54%), and negligible matrix effects (86.37%-108.92%). The recoveries in serum and urine were 88.91%-103.22%, demonstrating its good broad applicability in different matrices. The proposed method was successfully applied to the determination of DA and 5-HT in human urine samples, providing a reliable and efficient pretreatment strategy for trace neurotransmitter analysis.