An exploration of 2D-LC-SERS : a novel offline detection modality for multidimensional chromatography

Abstract

Multidimensional liquid chromatography (2D-LC) provides better resolving and separation power than conventional high-performance liquid chromatography (HPLC), and over the past decade has increasingly been applied in many different fields.¹ This thesis seeks to explore the extent to which surface-enhanced Raman spectroscopy (SERS) can be used as an offline detection modality for 2D-LC. This thesis hypothesizes that careful selection and modification of a three dimensional (3D) SERS substrate will be useful for characterization of fractions collected using 2D-LC. In particular, a mixture of four polyphenolic molecules was chosen for this proof-of-concept study. An optimised 2D-LC method was developed as part of this thesis. Various materials were evaluated as potential 3D-SERS substrates, with the most promising option being cellulose-based filter paper. Various modification strategies were explored to enhance the interaction between the polyphenolic molecules and the filter paper substrate. In the end, SERS-based detection of 2D-LC fractions proved challenging, even after optimization.