Coupling a microfluidic chip to a MALDI mass spectrometer

The inherent advantages of microfluidic devices combined with the excellent sensitivity and resolution of the matrix-assisted laser desorption/ionization (MALDI) technique were discussed. The experiments were performed on a specially constructed 1 m linear time-of-flight mass spectrometer that allowed interfacing to a microfluidic chip at atmospheric pressure even though the MALDI ion source was under vacuum. The microfluidic chips were mounted on or near the source flange and held at high voltage during operation. It was observed that the chip interfaces were tested based on continuous flow MALDI, both with a frit mounted directly in the chip or with the chip effluent directed to a frit interface mounted on the source flange