Capillary electrophoresis-mass spectrometry using robust poly(ether ether ketone) capillary for tolerance to high content of organic solvents.

•PEEK capillary was used in CE-MS for tolerance to organic solvents.•PEEK capillary showed excellent stability in commonly used organic solvents.•PEEK capillary showed good separation performance in NACE and organic-aqueous CE.•This method was successfully used to quantitative analysis of peimine and peiminine.