Molecular mass estimation by PFG NMR spectroscopy.

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Spectroscopy

Background:

• Pulsed Field Gradient Nuclear Magnetic Resonance (PFG NMR) is a powerful technique for studying molecular diffusion.
• Accurate determination of molecular mass is crucial in various chemical and biological applications.
• Existing methods for molecular mass determination can be complex and time-consuming.

Purpose of the Study:

• To develop a simplified PFG NMR diffusion analysis method for estimating the molecular mass of small molecules.
• To improve experimental robustness and simplify data analysis using internal referencing.
• To establish relative diffusivity-molecular mass correlations for practical applications.

Main Methods:

• A simplified PFG NMR diffusion analysis was employed.
• Internal referencing using tetramethylsilane (TMS) in CDCl3 and HDO in D2O was utilized.
• Empirical correlations between relative diffusivity and molecular mass were developed for dilute solutions (2-1280 g/mol).

Main Results:

• The developed method accurately estimates molecular mass in dilute aqueous and organic solutions.
• A median error of 10% relative error (rel%) in predicted molecular mass was achieved.
• The method's utility was demonstrated by analyzing components in olive oil.

Conclusions:

• The simplified PFG NMR diffusion method provides a robust and efficient approach for molecular mass estimation.
• Internal referencing enhances the reliability and ease of data analysis.
• This technique is applicable to analyzing complex mixtures like olive oil.