Online CE - MALDI-TOF MS using a rotating ball interface
We report on the construction and performance of a rotating ball interface for online coupling of capillary electrophoresis (CE) to matrix-assisted laser desorption ionization (BALDI) mass spectrometry with a time-of-flight (TOF) mass analyzer. The interface is based on a rotating stainless steel ball that transports samples from atmospheric pressure to the high vacuum of the mass spectrometer for desorption and ionization. The sample is deposited directly from a 50-μm-i.d. separation capillary onto the 19-mm ball that is rotating at 0.03 to 0.3 rpm. The sample is mixed online with matrix flowing from a separate 50-μm-i.d. capillary. The sample deposit dries before it is rotated past a polymer gasket and into the laser ionization region. Cleaning of the interface is accomplished using solvent-saturated felt, which cleans the ball surface after it rotates out of the ionization chamber. Online CE-MALDI is demonstrated, and the performance is evaluated with the analysis of a mixture of three peptides: [Lsy8] vasopressin, substance P, and neurotensin. The rotating ball interface to MALDI-TOF MS demonstrated mass detection limit in the high femtomole range. The interface has negligible memory effect and shows no significant electrophoretic peak broadening when operated under optimized conditions.
Publication Source (Journal or Book title)
Musyimi, H., Narcisse, D., Zhang, X., Stryjewski, W., Soper, S., & Murray, K. (2004). Online CE - MALDI-TOF MS using a rotating ball interface. Analytical Chemistry, 76 (19), 5968-5973. https://doi.org/10.1021/ac0489723