Quantification of low-polar small molecules using room temperature ionic liquids matrix-assisted desorption corona beam ionization

Abstract

A room temperature ionic liquids (RTILs) matrix-assisted desorption corona beam ionization (DCBI) technique was proposed. The quantification of the DCBI method for low-polar small molecules was improved greatly in terms of accuracy and precision. The thermal desorption processes of analytes in different liquid matrices under DCBI interrogation was investigated with thermal imaging and mass spectrometry simultaneously. When in a volatile liquid matrix, the analyte was not only desorbed thermally from the solid residue phase, but also desorbed along with evaporation of the matrix. The varying matrix evaporation speed and unstable sample introduction path clearly influence the quantitative result. With non-volatile RTILs utilized as the matrix in the sample introduction, a micro slow release system (MSRS) is formed to relieve the fluctuation of analyte evaporation. With the RTILs matrix-assisted DCBI-MS technique, dramatic improvement of the quantification precision (RSD from about 20% to less than 3%) for model analytes was achieved. Seventeen small pharmaceutical and four pesticide molecules were detected successfully. With a shared mechanism, other thermal desorption and/or APCI-related ambient ionization techniques may also benefit from the RTILs matrix.

Plasma‐based ambient mass spectrometry techniques: The current status and future prospective

“…In comparison with spray‐based sources, because plasma‐based sources ionize samples in a softer way, their mass spectra are dominated by [M+H] + in the positive mode and [M−H] − in the negative mode with few multi‐charged, fragmented, or alkali‐metal adducted ions. At the same time, on this basis, previous studies (Andrade et al, ; Wang et al, ) suggest that the plasma‐based sources do apply to molecules of weak or moderate polarity, whereas the effective mass range from several hundred Dalton to ca, 1 kDa. However, a study that combined DESI and DART, termed desorption electrospray/metastable‐induced ionization (DEMI) (Nyadong, Galhena, & Fernández, ), has largely broadened the mass range of analytes.…”

Ionic Liquid Matrices for Mass Spectrometry: Design, Synthesis, and Applications

“…ILMs were tested for quantification of ODNs, peptides, and small proteins. 54 Data showed great improvement in quantitative precision for 21 small low-polar molecules. The main advantage ILMs for quantification of peptides is that MALDI-MS can be used without the use of internal standards.…”

Ionic Liquids Matrices for Laser Assisted Desorption/Ionization Mass Spectrometry

“…Ionic liquids called N,N-diisopropyl ethyl ammonium 3-oxocoumarate and N,N-diisopropyl ethyl ammonium dihydroxymonooxo acetophenoate, were used for the analysis of aliphatic biodegradable polymers [84]. The ability to identify and differentiate the polymers and additives in lubricant residues of condoms were investigated (Figure 8) [85]. The data is very useful for condoms analysis in sexual assault cases [85].…”

“…The ability to identify and differentiate the polymers and additives in lubricant residues of condoms were investigated (Figure 8) [85]. The data is very useful for condoms analysis in sexual assault cases [85].…”

“…3D PCA score plot of seven different condom lubricant types, four of which are easily distinguished.Figure reprintedwith permission from Ref [85]…”