Figure 4.
Correlations between the organic solvent-plasma volume ratio (▵ or ▴) and extraction efficiency (○ or •) for various compounds. The nonvolatile compounds quercetin, ginkgolide A, orcinol glucoside, tanshinol, and cinnamic acid were measured by LC-MS/MS. Chromatographic separation was achieved using a Phenomenex Gemini 5 μm C18 column (50×2.0 mm id; Torrance, CA, USA). The water/acetonitrile/formic acid-based mobile phases were delivered at 0.3 mL/min for a binary pulse gradient elution41. The precursor-to-product ion pairs m/z 407→351, 301→151, 331→123, 197→135, and 147→103 in the negative ESI ion mode were used for selected reaction monitoring of ginkgolide A, quercetin, orcinol glucoside, tanshinol, and cinnamic acid, respectively.