Infrared laser ablation sample transfer for on-line liquid chromatography electrospray ionization mass spectrometry.

We have demonstrated an on-line laser ablation sampling system and coupling of the system to liquid chromatography (LC) using an infrared (IR) laser to ablate and transfer materials into a flowing solvent stream. With this approach, samples are deposited on a microscope slide mounted on a translation stage and ablated in transmission geometry using a pulsed mid-IR laser. The ablated material is captured in an exposed flowing solvent stream that carries the ablated material to the electrospray source. Post-ablation separation is accomplished using a capillary column downstream of the capture zone. The performance of the system was assessed using peptide and protein mixtures ablated from the target and analyzed with and without LC separation.