Gas-phase diagnostics and LIF-imaging of 3-hydroxypicolinic acid maldi-matrix plumes

The first gated laser induced fluorescence (LIF)-imaging and absorption spectroscopy have been performed on laser desorbed plumes from organic crystals which are commonly used as MALDI (matrix assisted laser desorption ionization) matrices. These plasma diagnostic techniques, and also ion probe measurements, were employed to investigate the desorbed products, densities, fractional ionization and velocity distributions of the plume of 3-hydroxypicolinic acid (3-HPA) under ArF(193 nm)- and KrF(248 nm)-laser irradiation. In both cases, gated LIF imaging using 308 nm excitation revealed two plume components: a fast (maximum ∼0.1 cm/μs) low-intensity component which appear to be 3-HPA fragments, and a slower component of 3-HPA expanding at 0.05 cm/μs.