3.2 Samples preparation
Serum and CSF samples were processed with acetonitrile at the volume
ratio of 1:3. Compared with diluting residual with mobile phase, the
single step protein precipitation with acetonitrile had no significant
solvent effect. Therefore, acetonitrile was demonstrated to be protein
precipitation solvent to extract TGC from serum and CSF samples, which
made the extraction procedure convenient and efficient.