Thin‐layer chromatography and mass spectrometry coupled using proximal probe thermal desorption with electrospray or atmospheric pressure chemical ionization

Abstract

An atmospheric pressure proximal probe thermal desorption sampling method coupled with secondary ionization by electrospray or atmospheric pressure chemical ionization was demonstrated for the mass spectrometric analysis of a diverse set of compounds (dyestuffs, pharmaceuticals, explosives and pesticides) separated on various high-performance thin-layer chromatography plates. Line scans along or through development lanes on the plates were carried out by moving the plate relative to a stationary heated probe positioned close to or just touching the stationary phase surface. Vapors of the compounds thermally desorbed from the surface were drawn into the ionization region of a combined electrospray ionization/atmospheric pressure chemical ionization source where they merged with reagent ions and/or charged droplets from a corona discharge or an electrospray emitter and were ionized. The ionized components were then drawn through the atmospheric pressure sampling orifice into the vacuum region of a triple quadrupole mass spectrometer and detected using full scan, single ion monitoring, or selected reaction monitoring mode. Studies of variable parameters and performance metrics including the proximal probe temperature, gas flow rate into the ionization region, surface scan speed, read-out resolution, detection limits, and surface type are discussed.

Planar Chromatography Mass Spectrometry

“…55 TD from the TLC plate is more efficient for volatile or small apolar compounds than for strongly adsorbed polar ones. 56 Analytes were thermally desorbed directly from the TLC/HPTLC plate. But the layer material is a determinant.…”

Liquid Microjunction Surface Sampling Probe Fluid Dynamics: Characterization and Application of an Analyte Plug Formation Operational Mode

“…Like many other atmospheric pressure surface sampling and ionization approaches coupled with mass spectrometric detection [6][7][8], these probes are conventionally scanned across or brought into contact with surfaces for temporally or spatially-resolved near real-time signal monitoring [9,10]. As a consequence, analyte detection is limited to what is readily extractable from a surface within the timescale of the solvent interaction with the spot of interest.…”

Easily fabricated ion source for characterizing mixtures of organic compounds by direct analysis in real time mass spectrometry

“…Applications for ambient mass spectrometry include, but are not limited to, food science, 6-9 pharmaceutical characterization, [10][11][12][13][14][15] forensics, [16][17][18][19][20][21][22][23][24] detection of volatile and semi-volatile organic compounds, [25][26][27][28][29] biological samples, 30-34 and the analysis of complex organics such as aerosols [35][36][37][38][39] and hydrocarbons. [40][41][42] To be effective, an ambient ionization method must both desorb the target analyte into the gas phase and ionize it, or directly desorb ions from the sample.…”