Design for Electrospray Ionization-Ion Mobility Spectrometry

Abstract

In this study, a new design for electrospray ionization ion mobility spectrometry (ESI-IMS) was developed. This design has two important differences in comparison to the present ESI-IMS systems. First, a few centimeters of the cell comprising the electrospray needle was located outside of the oven used for heating the IMS cell. This modification prevents prespray solvent evaporation problems such as needle clogging and disturbance of the electrospray process. Second, in addition to the drift gas, a counterflow of a heated gas (desolvation gas) was used between the counter electrode and the ion gate to speed up the desolvation process (Hill, H. H., Jr. Anal. Chem. 1998, 70, 4929-4938). This modification increased the solvent evaporation and resulted in decreasing the drift time, increasing the peak intensity and increasing the resolving power (RP) or enhancing the resolution for separation of two adjacent ion peaks. In this work, the ion mobility spectra of different compounds including ethion, malathion, metalaxyl, fenamifos, methylamine, triethylamine, tributhylamine, codeine, and morphine were obtained to confirm enhancing of the resolving power of the ion peaks by using the desolvation gas. Furthermore, the method has also been applied to obtain the figures of merit for ethion as a test compound. The linear dynamic range for ethion was in the range 50-1000 microg/L with a limit of quantification of the 50 microg/L.

Porous graphite sheet spray ionization ion mobility spectrometry

“…The IMS used in this research was designed and constructed in the analytical chemistry laboratory at Isfahan University of Technology . All the pieces of equipment used in this work are the same except the ionization source, which it was replaced with the newly designed source based on the porous graphite sheet.…”

“…The IMS used in this research was designed and constructed in the analytical chemistry laboratory at Isfahan University of Technology. 24,27,28 All the pieces of equipment used in this work are the same except the ionization source, which it was replaced with the newly designed source based on the porous graphite sheet. Briefly, the applied instrument included an IMS drift tube, a pulse generator, two high-voltage power supplies, and an analog-to-digital (A/D) converter coupled to a computer.…”

“…Our research groups have, so far, worked on developing various ionization sources including corona discharge, electrospray, low‐temperature plasma, and paper spray . In this particular work, a new source of ions based on porous graphite sheet spray ionization has been introduced for ion mobility spectrometry.…”

Extraction of methocarbamol from human plasma with a polypyrrole/multiwalled carbon nanotubes composite decorated with magnetic nanoparticles as an adsorbent followed by electrospray ionization ion mobility spectrometry detection†

“…The ESI‐IMS was designed and constructed at Isfahan University of Technology . To describe it briefly, it consisted of the IMS cell, the electrospray needle, two high‐voltage power supplies, a pulse generator, an analogue to digital converter, and a computer.…”

Immobilized aptamer paper spray ionization source for ion mobility spectrometry

“…The electrospray ionization ion mobility spectrometer (ESI-IMS) used for this research was constructed at Isfahan University of Technology [21]. In brief, the IMS cell was divided to two sections: a desolvation region and a drift region, separated by a shutter grid.…”