Improved flow cell design for a more performant Gel Permeation Chromatography – Fourier Transform infrared (GPC-FTIR) analysis

Gel Permeation Chromatography (GPC) and Fourier-Transform Infrared Spectroscopy (FTIR) are two powerful analytical techniques that have been used in polymer chemistry for decades. GPC can separate polymers based on their molecular weights, while FTIR can identify the functional groups present in the macromolecular chain. The main benefit of coupling GPC and FTIR is that they complement each other to provide a deeper insight into the molecular weight distribution and chemical composition of challenging polymers. Although over the last 60 years sporadic papers have been published on coupling the GPC with FTIR using a flow cell, the method has not gained widespread acceptance. This was largely due to the challenges associated with creating an interface to effectively combine both techniques without compromising their performance. Furthermore, the studies were done on in-house built instruments using components from various providers, as none of the major analytical laboratory equipment manufacturers had a specific program in place to support the development of GPC-FTIR technology. Here we present the development of a GPC-FTIR instrument based exclusively on Agilent Technologies components, with an improved design of the flow cell aimed at boosting signal-to-noise ratio and minimizing peak width. The system’s performance was evaluated by analyzing polymethylmethacrylate (PMMA) samples with narrow and broad molecular weight distributions.