Selection of chromatographic column is essential in UPLC–
MS/MS, and the test efficiency is related to specifications of C18 column,
C18 column with particle size of 1.7 lm has been commonly
used y because this column has large specific surface and small
particle size, which are beneficial to improve the test efficiency.
However, due to the complex matrix composition of real samples,
column blockage and high column pressure occur frequently,
affecting the working-life span of column. Therefore, we have chosen
C18 columns with particle size of 2.2 lm to avoid column
blockage and high pressure.