Characterization of Rhodamine 6G Release in Electrospray Ionization by Means of Spatially Resolved Fluorescence Spectroscopy
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Daniel Riebe
Abstract
In the present work, the density distribution of rhodamine 6G ions (R6G) in the gas phase and the droplets of an electrospray plume was studied by spatial and spectral imaging. The intention is to contribute to the fundamental understanding of the release mechanism of gaseous R6G in the electrospray ionization (ESI) process. Furthermore, the influence of ESI-parameters on the release efficiency of R6G, e.g. solvent flow, R6G and salt concentration were examined via direct fluorescence imaging of R6G. A solvent-shift of the fluorescence maximum, λmax = 555 nm in methanolic solution and λmax = 505 nm in gas phase, allows the discrimination between solvated and gaseous R6G. Two experimental setups were used for our measurements. In the first experiment, the R6G fluorescence and the light scattered from the spray plume were imaged in two spatial dimensions using a tunable wavelength fil ter. The second experiment was designed for obtaining 1-dimensional spatially resolved emission spectra of the spray. Here, the intensity distribution of solvated and gaseous R6G as well as scattered light (λ=355 nm) were measured simultaneously.
The results show the distribution of gaseous R6G in the plane, orthogonal to the ESI capillary, decreasing slightly towards the spray center and showing maxima at the cone margins. The distribution of gaseous R6G confirms the preferred release of gaseous ions from nano-droplets, indicating the ion evaporation model (IEM) to be the dominating release mechanism. Up to now, only a few fluorescence spectra of ionic compounds in the gas phase were published because the measurement of emission spectra of mass-selected ions in an ion trap is experimentally challenging. The fluorescence spectrum of gaseous lucigenin at atmospheric pressure is reported for the first time. This spectrum of lucigenin in the gas phase exhibits a blue shift of about Δλ=10 nm in comparison to the corresponding spectrum in methanol.
© by Oldenbourg Wissenschaftsverlag, Potsdam-Golm, Germany
Artikel in diesem Heft
- Preface
- OH and NH Stretching Vibrational Relaxation of Liquid Ethanolamine
- Transient anisotropy in degenerate systems: A semi-classical approach
- First Cavity Ring-Down Spectroscopy HO2 Measurements in a Large Photoreactor
- Relaxation Dynamics of Electronically Excited C60− in o-Dichlorobenzene and Tetrahydrofuran Solution
- 3CH2 + O2: Kinetics and Product Channel Branching Ratios
- What Do We Know About the Iconic System CH3 + CH3 + M ↔ C2H6 + M?
- Thermochemistry and Kinetics for 2-Butanone-3yl Radical (CH3C(=O)CH•CH3) Reactions with O2
- Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
- Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames
- Characterization of Rhodamine 6G Release in Electrospray Ionization by Means of Spatially Resolved Fluorescence Spectroscopy
- Femtosecond interferometry of molecular dynamics – the role of relative and absolute phase of two individual laser pulses
- Photodecarbonylation of Diphenylcyclopropenone – a Direct Pathway to Electronically Excited Diphenylacetylene?
- Yield of HO2 Radicals in the OH-Initiated Oxidation of SO2
- Pyrolysis of Ethyl Iodide as Hydrogen Atom Source: Kinetics and Mechanism in the Temperature Range 950–1200 K
- Reaction of OH and NO at Low Temperatures in the Presence of Water: the Role of Clusters
Artikel in diesem Heft
- Preface
- OH and NH Stretching Vibrational Relaxation of Liquid Ethanolamine
- Transient anisotropy in degenerate systems: A semi-classical approach
- First Cavity Ring-Down Spectroscopy HO2 Measurements in a Large Photoreactor
- Relaxation Dynamics of Electronically Excited C60− in o-Dichlorobenzene and Tetrahydrofuran Solution
- 3CH2 + O2: Kinetics and Product Channel Branching Ratios
- What Do We Know About the Iconic System CH3 + CH3 + M ↔ C2H6 + M?
- Thermochemistry and Kinetics for 2-Butanone-3yl Radical (CH3C(=O)CH•CH3) Reactions with O2
- Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3
- Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames
- Characterization of Rhodamine 6G Release in Electrospray Ionization by Means of Spatially Resolved Fluorescence Spectroscopy
- Femtosecond interferometry of molecular dynamics – the role of relative and absolute phase of two individual laser pulses
- Photodecarbonylation of Diphenylcyclopropenone – a Direct Pathway to Electronically Excited Diphenylacetylene?
- Yield of HO2 Radicals in the OH-Initiated Oxidation of SO2
- Pyrolysis of Ethyl Iodide as Hydrogen Atom Source: Kinetics and Mechanism in the Temperature Range 950–1200 K
- Reaction of OH and NO at Low Temperatures in the Presence of Water: the Role of Clusters
