Ion internal energy, salt tolerance and a new technical improvement of desorption nanoelectrospray

Abstract

Figure 4. A comparison of two sets of five nanoDESI spectra of rhodamine B acquired with (right) and without (left) the PTFE gasket. Note the level of noise (represented, e.g. by the ion of butylphthalate at m/z 279 ion) and its reproducibility. JMS letters

Comparison of Internal Energy Distributions of Ions Created by Electrospray Ionization and Laser Ablation-Liquid Vortex Capture/Electrospray Ionization

“…The ratio of molecular ion to fragment ion signal intensities describes the distribution of internal energies the ions created. Benzylpyridinium (BP) salts have been used to characterize 'soft' ionization techniques like ESI [14,16], matrix-assisted laser desorption ionization (MALDI) [17][18][19], and many others [20][21][22][23]. In LDI and MALDI, IE distributions typically show a dependence on laser fluence when using 800nm visible and 337nm UV lasers, respectively [17][18][19]24].…”

Signal enhancement in desorption nanoelectrospray ionization by custom‐made inlet with pressure regulation

“…For nanoDESI, the signal-to-noise ratio did not deteriorate substantially for samples containing up to 2.5 mol L −1 NaCl. 5 Applicability of nanoDESI was further demonstrated, for example, by chiral analysis of pharmaceuticals in whole blood 6 or analysis of anthocyanins in a drop of red wine. 7 Considering imaging applications, the low flow rate of spraying liquid decreases sample washing off which can be advantageous for lateral resolution and can enable repeat scans of the same surface area.…”

“…Promising very good resolution of dye squares (60 μm × 60 μm) has been achieved 8 . Although technical development has improved the robustness of nanoDESI 5 and a modification of inlet has allowed its implementation on a Q‐TOF mass spectrometer, 8 sensitivity of measurement can still be an issue. Because a very small surface area is sampled, only a tiny amount of analyte is available for desorption and ionization.…”

Ion suppression effect in desorption electrospray ionization and electrospray ionization mass spectrometry

“…The ion suppression effect, which cannot be neglected in quantification analysis of complex components, is an important assessment indicator for quantification ability of ionization sources. Many newly developed ionization sources are claimed to have better ion suppression effects than the traditional ones . Desorption electrospray ionization (DESI), first developed in 2004 as a typical ambient source, has been used to analyze varied compounds in different kinds of matrix, such as urine and serum, which implied that DESI has an acceptable quantitative performance in complicated matrices, especially in bio‐matrices.…”

“…Many newly developed ionization sources are claimed to have better ion suppression effects than the traditional ones. [14][15][16] Desorption electrospray ionization (DESI), 17 first developed in 2004 as a typical ambient source, has been used to analyze varied compounds in different kinds of matrix, such as urine 18,19 and serum, 20,21 which implied that DESI has an acceptable quantitative performance in complicated matrices, especially in bio-matrices. Due to the in situ extraction process, 17 DESI exhibits lower ion suppression effects when the amount of interference is much more than the analyte,.…”