Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application

Abstract

Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI-MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability.

The influence of temperature and humidity on swelling and surfactant migration in acrylic emulsion paint films

“…A Prosolia DESI 2D ionization source was used at the ion entrance of the mass spectrometer, and modified in-house with an air flow-assisted (AFA) modification to improve sensitivity (He et al, 2011). Optimized +ESI source parameters were as follows: curtain gas = 10, collision activated dissociation (CAD) gas = high, and IonSpray voltage = +5500 V. The parameters for source temperature, nebulizer gas, and heater gas were all set to zero because they were not applicable to DESI.…”

Enhanced aerodynamic reach of vapor and aerosol sampling for real-time mass spectrometric detection using Venturi-assisted entrainment and ionization

“…However, the majority of these techniques are limited to small and relatively flat substrates that can easily be positioned near the mass spectrometer inlet. To address these limitations, research focused on the non-proximate transport of neutrals and ions has enabled remote sampling and sensitive detection of a range of compounds, eliminating the need for traditional swipe sampling/collection or well-defined substrates that can be manipulated for desorption-based AIMS [12, 16-24]. The transport of neutrals and ions has been accomplished through a number of configurations using various vacuum pumps [18] and Venturi or ejector components [16, 17, 20-23], with glass, metal, and polymer capillaries or tubes.…”

Development of Remote Sampling ESI Mass Spectrometry for the Rapid and Automatic Analysis of Multiple Samples

“…A number of methods, including AFAI (Air Flow Assisted Ionization) have been developed to address this issue. 15) ese techniques use pneumatic assistance to transport the ion generated by DESI or ESI and is performed, at a distance of about 0.5~>1 m from the ion inlet of the mass spectrometer. 15,16) Recently, we also performed in-vivo MS on living mouse that was located approximately 2 m away from the MS using probe electrospray ionization (PESI).…”

“…15) ese techniques use pneumatic assistance to transport the ion generated by DESI or ESI and is performed, at a distance of about 0.5~>1 m from the ion inlet of the mass spectrometer. 15,16) Recently, we also performed in-vivo MS on living mouse that was located approximately 2 m away from the MS using probe electrospray ionization (PESI). 17) e ion was collected remotely using a 1/8 inch metallic tube and a small auxiliary pump was used to provide additional negative pressure.…”