NMR Service + Consulting

The word, Protein, evokes fear in the hearts of spectroscopist who develop methods for TD NMR.  The short answer to the question ..."Can we measure protein concentrations by TD NMR?"... depends on the molecular weight of the protein and the matrix that it resides in.

Factors:

• Chemical Analysis of protein concentration by primary method(s)
• Relaxation rates of pure protein (T2, T1) at low field (B < 1.0 Tesla)
• Type of Protein: solubility, pH, ionic charge, temperature latency

The USDA (ARS) studied soybeans (1998) and found a correlation of 0.87 between measured oil by TD NMR with a primary protein method.  The oil % by weight was inversely correlated to the protein % by weight.  This was an indirect comparison with a correlation fact that is too inaccurate for QA/QC work.  But it does show a trend that can be used for generalization.

Some work has been done in protein levels in cheeses.  These proteins are low molecular weight and simple in structure.  Therfore, they give modestly observable proton NMR signals.  In this case, a combination experiment using a FID_ECHO allows the calculation of protein via a subtraction algorithm.  Again, not a direct method but getting closer.

 And, like all secondary methods, a primary method is always needed to confirm inital concenttrations of analytes used as calibration standards.

 References

Soybean research at Purdue Grain Quality Taskforce http://www.ces.purdue.edu/extmedia/GQ/GQ-39.html

Thank you for looking at this website.  It is my passion and goal to see that lesser known methods like mine get their day in the sun.  Secondary analytical methods like low resolution NMR, NIR, FTIR (to name a few) are ready to take their places as the rapid, non-destructive replacements for antiquated primary methods that are time consuming as well generating less reproducible and repeatable results that costs a company lost time and productivity.

I am the new chair position of the Non-Destructive Methods subcommittee on the UAM Committee of AOCS.   One of my goals is to help showcase Analytical Methods and Equipment from companies who specialize in these techniques.   It is my hope that we can influence both ISO and ASTM in rapidly adapting these methods and practices to generate more uniformity in laboratory QA\QC procedures that can lead to low costs and increase productivity.

Just look smaller companies like mine as tugboats and recreational watercrafts, we are small and tip over a lot and we can accomplish quantum leaps (in both directions). A cargo ship (big businesses) cannot easily change directions because of their very design.  Cooperation between the cargo ships and tugboats (big and small business) has and will always be mutually beneficial in increasing efficiency, lower costs and increasing profitability for both parties.