On-line capillary zone electrophoresis-ion spray tandem mass spectrometry for the determination of dynorphins.

Capillary zone electrophoresis-mass spectrometry and capillary zone electrophoresis-tandem mass spectrometry with ionization at atmospheric pressure are demonstrated as being feasible for the separation and determination of small peptides such as dynorphins (1-6, 1-7, 1-8, 1-9) and leucine enkephalin at low picomole levels by full-scan mass spectrometry and tandem mass spectrometry and at the low femtomole range under selected ion monitoring conditions. Ion evaporation resulting from the ion spray liquid chromatography-mass spectrometry interface exhibits primarily molecular weight information as singly and multiply charged ions and is shown to be a sensitive and mild ionization method for peptides. The full-scan daughter ion mass spectrum of leucine enkephalin is shown to contain fragment ions consistent with the sequence of the peptide. Parent ion scanning in the tandem mass spectrometry mode is a promising technique for the screening of related peptides.