During the 21^st century, two-dimensional correlation spectroscopy (2D-COS) has emerged as a popular analysis method for data obtained using Raman and infrared (IR) spectroscopy (1). 2D-COS is an analytical technique used to enhance the interpretation of spectral data by revealing relationships between spectral features that are not easily discernible in traditional one-dimensional (1D) spectroscopy (2). By applying mathematical transformations, such as correlation analysis, 2D-COS generates two-dimensional plots that display dynamic changes in a sample's spectral response (2). These plots provide synchronous and asynchronous correlation maps that help identify co-varying signals, sequence of spectral changes, and subtle differences in molecular interactions or chemical environments (2).

Professors Isao Noda and Young Mee Jung are exploring how 2D-COS can be applied in the industry. Professor Noda is an Affiliated Professor in the Department of Materials Science and Engineering at the University of Delaware, in Newark, Delaware. Professor Jung is a Professor in the Department of Chemistry at Kangwon National University, in Chuncheon, Korea.

Recently, Spectroscopy magazine sat down with Noda and Jung to talk about their recent paper that explored the principles of 2D-COS, and how the use of 2D-COS has spurred numerous advancements in material science.

 

 

Could you explain the fundamental principles of two-dimensional correlation spectroscopy (2D-COS) and how it differs from traditional spectroscopic techniques?

Traditional spectroscopy often encounters limitations when analyzing complex systems. By plotting signal intensity against a single variable (for example, the wavelength), it can lead to spectral overlap and hinder the resolution of intricate mixtures. 2D-COS addresses this by transforming 1D spectral data into a 2D correlation map. This approach essentially examines how spectral changes at one frequency are interconnected with changes at other frequencies while the system undergoes perturbation (for example, temperature, pressure). Key advantages of 2D-COS include:
 

     • Enhanced spectral resolution: Overlapping spectral bands can be effectively separated.
     • Determination of sequential spectral changes: The order in which spectral events occur can be established.
     • Amplification of subtle spectral features: Features often obscured in one-dimensional spectra become more prominent.