Real-Time Sniffing Mass Spectrometry Aided by Venturi Self-Pumping Applicable to Gaseous and Solid Surface Analysis

Abstract

Based on the Venturi self-pumping effect, real-time sniffing with mass spectrometry (R-sniffing MS) is developed as a tool for direct and real-time mass spectrometric analysis of both gaseous and solid samples. It is capable of dual-mode operation in either gaseous or solid phase, with the corresponding techniques termed as Rg-sniffing MS and Rs-sniffing MS, respectively. In its gaseous mode, Rg-sniffing MS is capable of analyzing a gaseous mixture with response time (0.8–2.1 s rise time and 7.3–9.6 s fall time), spatial resolution (<80 μm), three-dimensional diffusion imaging, and aroma distribution imaging of red pepper. In its solid mode, an appropriate solvent droplet desorbs the sample from a solid surface, followed by the aspiration of the mixture using the Venturi self-pumping effect into the mass spectrometer, wherein it is ionized by a standard ion source. Compared with the desorption electrospray ionization (DESI) technique, Rs-sniffing MS demonstrated considerably improved limit of detection (LOD) values for arginine (0.07 μg/cm2 Rs-sniffing vs 1.47 μg/cm2 DESI), thymopentin (0.10 μg/cm2 vs 2.67 μg/cm2), and bacitracin (0.16 μg/cm2 vs 2.28 μg/cm2). Rs-sniffing is applicable for the detection of C60(OCH3)6Cl–, an intermediate in the methoxylation reaction involving C60Cl6 (solid) and methanol (liquid). The convenient and highly sensitive R-sniffing MS has a characteristic separation of desorption from the ionization process, in which the matrix atmosphere of desorption can be interfaced by a pipe channel and self-pumped by the Venturi effect with consequent integration using a standard ion source. The R-sniffing MS operates in a voltage-, heat-, and vibration-free environment, wherein the analyte is ionized by a standard ion source. Consequently, a wide range of samples can be analyzed simultaneously by the R-sniffing MS technique, regardless of their physical state.

Applications of ambient ionization mass spectrometry in 2022: An annual review

“…Finally, some groups have endeavoured to create new sampling strategies that can feasibly be coupled with multiple types of ambient ion sources. R‐sniffing MS utilizes a Venturi pump for constant sampling, enabling either direct gas analysis or aspiration of a solvent droplet applied to a surface for the analysis of solids 173 . In this study, the device was coupled with ESI and APCI, but could feasibly be integrated with other AIMS techniques.…”

“…R‐sniffing MS utilizes a Venturi pump for constant sampling, enabling either direct gas analysis or aspiration of a solvent droplet applied to a surface for the analysis of solids. 173 In this study, the device was coupled with ESI and APCI, but could feasibly be integrated with other AIMS techniques. Modifications of the ASAP probe have also been developed for improved sample delivery.…”

Two-Dimensional SERS Sensor Array for Identifying and Visualizing the Gas Spatial Distributions of Two Distinct Odor Sources

“…By analyzing the spatial distribution of the detected gas influenced by airflow, we can use a robot equipped with recognition algorithms to determine the location of the odor source [10][11][12]. Additionally, through the analysis of the spatial distribution of gas evaporating from the odor source, we can clarify the information contained in the odor source, including composition, localization, and temporal variations [13][14][15][16].…”