Combination of Raman Spectroscopy and Mass Spectrometry for Online Chemical Analysis

Abstract

Mass spectrometry (MS) and Raman spectroscopy are complementary analytical techniques used to provide information related to chemical structures and functional groups of target analytes. Each instrument provides specific chemical information. If these two analytical tools are coupled online, comprehensive structural information can be simultaneously collected from the analytes of interest without losing any important chemical information. Nevertheless, exploring a suitable interface for coupling of these analytical tools, which are governed with different operation principles, remains challenging. In this study, we used a small piece of tissue paper as an interface for hyphenating a Raman spectroscope and a mass spectrometer online. The paper played multiroles as sample loading substrate and an emitter to generate electrospray. Furthermore, it can facilitate surface-enhanced Raman spectroscopic analysis to improve analyte signals in Raman spectra. A sample droplet was placed on the tissue paper located close to the laser of the Raman spectroscope and the inlet of mass spectrometer. Raman spectra were first collected by the Raman spectroscope through laser irradiation followed by generation of electrospray on the edge of the paper for MS analysis. Positional isomers were used as model samples to demonstrate the effectiveness of the hyphenated analytical tool in distinguishing isomers. The feasibility of using this Raman-MS hyphenated technique for monitoring chemical reactions online in real time was also investigated.

Probing metabolic alterations in breast cancer in response to molecular inhibitors with Raman spectroscopy and validated with mass spectrometry

“…Note that MS by itself is not conducive to early and rapid drug screening since it is both time-and laborintensive, and expensive. But RS trends validated with MS presents a complementary platform 19,33 for rapid, highthroughput, and single-cell level drug screening (with RS) combined with ensemble analysis of large volume of cells (with MS) to simultaneously conrm the changes in multiple metabolites post-treatment (Scheme 1). By correlating the metabolic changes observed with RS and MS, we demonstrate that our approach can distinguish responders from nonresponders as a function of drug dosage, drug type targeting different signaling pathways, and cell type examining different BC lines.…”

Recent advances in hybrid measurement methods based on atomic force microscopy and surface sensitive measurement techniques

“…Raman spectroscopy is the complementary technique to IR spectroscopy as most vibrations are either Raman or IR active, and it is also orthogonal to AFM as Raman is able to gather chemical information of a desired sample. 216,217 The former refers to the different selection rule compared to IR. Raman occurs mainly for symmetric vibrations when the polarizability changes upon excitation.…”

Raman Plus X: Biomedical Applications of Multimodal Raman Spectroscopy

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