Real-Time Sample Analysis Using a Sampling Probe and Miniature Mass Spectrometer

Abstract

A miniature mass spectrometry system with a sampling probe has been developed for real-time analysis of chemicals from sample surfaces. The sampling probe is 1.5m in length and is comprised of one channel for introducing the spray and the other channel for transferring the charged species back to the Mini MS. This system provides a solution to the problem of real-time mass spectrometry analysis of a three-dimensional object in the field and is successful with compounds including those in inks, agrochemicals, explosives, and animal tissues. This system can be implemented in the form of a backpack MS with a sampling probe for forensic analysis or in the form of a compact MS with an intra-surgical probe for tissue analysis.

Miniature and Fieldable Mass Spectrometers: Recent Advances

“…Regardless of these difficulties, a sampling probe 1.5 meters in length has been developed to interface DESI with a miniature mass spectrometer. 18 …”

Ambient ionization and miniature mass spectrometry system for chemical and biological analysis

“…A dual-channel configuration was used in the probe designs, with one channel delivering the charged droplets for desorption ionization (as in DESI) and the other one for transferring the ions back to the mass spectrometer. An integrated miniature system with such a probe has also been developed [56]. A flexible and light-weight sampling probe was integrated into a modified Mini 10 (Fig.…”

“…As one of the most studied ambient ionization methods, DESI has been applied in various applications, such as high-throughput analysis [11,12,57], reaction monitoring and mechanistic studies [58–60], and bio-imaging [27,28,32]; however, the high flow rate of the nebulizing gas represents a significant difficulty for practical implementation with a miniature MS system to be operated in a physician's office. However, with the design of the probe utilizing the nebulizing gas as the carrier gas for transferring the ions back from tissue sample, the miniature MS system for potential endoscopic examination was developed [56]. The low-temperature plasma (LTP) probe [21] uses no solvent and low flow rate (0.4 L/min) for the discharge gas, and therefore could be suitable for portable MS systems.…”

“…(f, g) Direct analysis of tissue sections of rat brain (f) and lung (g) by the miniature MS system equipped with a 1.5 m long sampling probe. (Reprinted with permission from [56], American Chemical Society).…”

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

“…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. The Venturi effect relies on fluid dynamics principles, conservation of energy, and acceleration of a fluid through a small constriction to generate a low pressure region that induces flow [25].…”