DIOS with Solid Liquid Extraction

The ease of incorporating funchonal groups to modify the pSi surface for mass spectrometric application has allowed for the development of a convenient and simple method for enriching the concentration of analytes. This technique, termed DIOS solid-liquid extraction (SLE), uses the property of differential adsorption selectively to capture analytes from a solution containing contaminants that impede MS analysis. Hydrophobically modified DIOS surfaces could be readily used selectively to remove interferences prior to analysis. DIOS S LE simply involves the deposition of a droplet containing analytes onto the chemically modified DIOS surface then, after approximately 3 s, the sample is aspirated with the same pipette. This short-term deposition allows for any molecule with a propensity to be adsorbed onto the surface to attach itself, while any potential hydrophilic contaminants such as salts and buffers will remain in solution, leaving the surface free from such contaminants. The van der Waals interaction between the analyte and surface leads to a selective extraction of the small molecules, while the hydrophilic contaminants such as salts are removed with the droplet. The DIOS analysis of peptides and small molecules from complex matrices is greatly enhanced by differential adsorption [47]. 

05 mM EGTA, 0.015% Brij 35,0.05% 1-mercaptoethanol in the original mixture). Thus, SLE may serve as a useful tool for monitoring drugs in biological fluids in the presence of large amounts of proteins and soluble nonvolatile contaminants. 

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