Residue-Based Thermogravimetric Analysis: A Novel Method to Quantify Carboxylate Group Modifications in...

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Analytical Chemistry

Background:

• Accurate quantification of the degree of modification (DoM) in hyaluronic acid (HA) is essential for developing advanced biomaterials.
• Existing spectroscopic methods face challenges due to diverse functional groups in HA derivatives, hindering precise quantification.

Purpose of the Study:

• To develop a novel, label-free method for quantifying carboxylate modification in HA derivatives.
• To establish a technique applicable across various HA modifications, including those previously unquantifiable.

Main Methods:

• Utilized thermogravimetric analysis (TGA) by comparing the inorganic residue (Na2CO3) from sodium hyaluronate (NaHA) and its modified derivatives.
• Analyzed thermal decomposition profiles to quantify the sodium content, reflecting the degree of carboxylate modification.

Main Results:

• Successfully quantified the DoM for four diverse HA derivatives (aldehyde, furan, thiol, cyanoacetate) using TGA.
• Achieved excellent agreement with 1H NMR/UV-vis data for aldehyde, furan, and thiol derivatives.
• Enabled the first-time quantification of the cyanoacetate HA derivative, previously unquantifiable by other methods.

Conclusions:

• The residue-based TGA method provides a robust, label-free tool for quantifying carboxylate modification in HA.
• This approach is independent of the pendant chemical group and transferable to other carboxylate-bearing polymers.
• The technique effectively characterizes 'silent groups,' offering significant potential for biomaterials characterization and development.