A selective adsorption-based separation of low-mass molecules from biological samples towards high-throughput mass spectrometry analysis in a single drop of human whole blood.

In this work, a newly designed multifunctional adsorbent material, octadecyl-modified ordered mesoporous carbon (C18 -CMK-8), was synthesized and employed for simultaneous analysis of multiple small molecules by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The C18 -CMK-8 was facilely prepared by one-step chemical binding of octadecyltrimethoxysilane to an ordered mesoporous carbon CMK-8. The nanosized pore structure of C18 -CMK-8 can selectively enrich low-mass molecules while excluding interferences from large molecules in whole blood; meanwhile, the C18 chain can greatly enhance the affinity for a wide range of small molecules. Then, the C18 -CMK-8-based solid-phase extraction (SPE) combined with MALDI-TOF MS measurement was applied in rapid and high-throughput screening of six doping agents (triamterene, trenbolone, testosterone, methyltestosterone, clenbuterol, and strychnine)) in single-drop human whole blood samples. The method showed high analytical sensitivity (detection limit 0.05-0.1 ng mL-1 ), good recoveries (67.2-114.3%), minimal sample requirement (∼20 μL), and robust anti-interference ability. With distinct advantages such as high throughput, rapidness, minimal sample requirement, and high sensitivity, this study not only offers a versatile enrichment material for complex sample preparation, but also demonstrates a promising tool for minimal whole blood analysis.