of the BAs were prepared in acetonitrile.
The standard BAs for HPLC analysis at individual concentrations of solutions into final concentration of 0.001, 0.005, 0.01, 0.05, 0.1, 0.5 and 1.0 mM for each BA were prepared by diluting the corresponding stock solutions with acetonitrile.
The d0-MASC and d3-MASC solution (1.0 103 M) was respectively prepared by dissolving 3.1 mg farinose solids in 10 mL acetonitrile.
All solutions were stored at 4 C in a refrigerator until for HPLC–MS/MS analysis.