Solid Phase Microextraction Sampling: A Probe-based Technique for Sample Extraction from Graft Tissues

Long-term storage of an organ graft affects its metabolic profile, which is an indicator of organ function and early-stage organ rejection.

To isolate these metabolites, begin by taking a thin solid-phase microextraction or SPME probe coated with a biocompatible sorbent. Immerse the probe in a hydroalcoholic cleaning solution to hydrate the coated sorbent and loosen up any bound impurities.

Agitate the probe to remove the impurities. Next, place the probe in an activation solution and agitate again. Chemicals in the activation solution modify the probe surface, enhancing its adsorption potential. Rinse the probe with water and sterilize it to remove microbial contaminants.

Now, insert the sterile and activated probe into the organ graft such that the tissue matrix covers the entire sorbent surface. The sorbent material attracts free polar and non-polar metabolites from the graft, enabling adsorption onto its surface. Retract the probe and rinse it with water to remove any residual tissue.

Then, place the probe into a desorption solution, which interacts with the adsorbed metabolites. Agitate the probe to separate and solubilize the captured metabolites into the desorption solution. Finally, remove the probe and process the resultant metabolite mixture for subsequent analysis.