| Instrumentation and/or methodology have been developed to study gas and solution phase matter in environments that require highly sensitive optical detection. These include optical detection of gas-phase ions trapped in a Fourier transform mass spectrometer, fluorescence lifetime measurements inside electrosprayed droplets, and development of a dual beam flash photolysis system.; Gas-phase optical detection provides intrinsic information about molecular species without the presence of solvent. The fluorescent lifetimes of [Ru(bpy) 3]1+ trapped in a novel optical detection cell within a Fourier transform mass spectrometer were obtained using matrix-assisted laser desorption/ionization to generate the ions using 2,5-dihydroxy-benzoic acid (DHB) or sinapinic acid (SA) as matrix. The rate constants for transients derived using DHB were k1 = 4.8 x 107 s -1 and k2 = 1.2 x 107 s -1, while the rate constant using SA were k1 = 1.8 x 107 s-1 and k2 = 5.2 x 106 s-1. Photodissociation experiments revealed that [Ru(bpy)3]1+ generated using DHB does decompose to [Ru(bpy)2]1+, whereas ions generated using SA showed no decomposition when used as the matrix. Comparison of the mass spectra with the fluorescent lifetimes illustrates the promise of incorporating optical detection with trapped ion mass spectrometry techniques.; Electrospray ionization is a proven method for introducing large intact molecules into the gas phase. However, the processes that occur within this associated apparatus are poorly understood. Instrumentation and methodology were developed to probe the evolution of droplets within the electrospray plume. Using laser-induced fluorescence emission lifetimes of [Bis(ruthenium-bis(2,2 '-bipyridine))-2,2':4'.4 ″:2″,2″-quaterpyridine] (RuQPY) with known quenchers of the excited state 2,3,5,6-tetramethyl-p-phenylendiamine and ammonium peroxydisulfate, were observed. Rate constants of RuQPY with and without both quenchers were also determined and correlated with the Stern-Volmer relationship. Stern-Volmer plots reveal the linearity of the quenching reaction and were used to determine the concentrations of quencher at various stages in droplet evolution.; Laser flash photolysis (FP) is a powerful technique for investigating the kinetics of large proteins, such as those involved in respiration. Enhancements to current instrumentation have been made to increase the signal-to-noise ratio, speed of detection, and reduce light-scattering. These enhancements include the development of a dual beam FP system which incorporates low energy laser probes and inexpensive circuitry. |
