Is the Calibration Transfer of Multivariate Calibration Models between High- and Low-Field NMR Instruments Possible?...

Area of Science:

• Analytical Chemistry
• Spectroscopy

Background:

• Quantitative mixture analysis using nuclear magnetic resonance (NMR) spectroscopy is established.
• Calibration transfer between NMR instruments, particularly high-field and benchtop devices, remains largely unexplored.

Purpose of the Study:

• To investigate the feasibility of calibration transfer for quantitative analysis between high-field (600 MHz) and benchtop (43 and 60 MHz) NMR instruments.
• To assess the transfer of partial least squares regressions for determining the weight average molecular weight (Mw) of lignin.

Main Methods:

• Employed three calibration transfer methods: piecewise direct standardization, canonical correlation analysis, and extreme learning machine auto-encoder.
• Utilized high-field NMR data and transferred calibrations to benchtop NMR devices for validation.

Main Results:

• Demonstrated successful calibration transfer from high-field to low-field NMR for lignin molecular weight.
• Achieved validation errors close to the original high-field calibration, with errors only 1.2 times higher in the best cases.
• Showcased the feasibility despite significant resolution differences between instruments.

Conclusions:

• Calibration transfer from high-field to benchtop NMR is viable for physical properties like molecular weight.
• This facilitates the use of existing high-field NMR calibrations on more accessible and economical benchtop NMR instruments.
• Opens new avenues for cost-effective quantitative analysis using benchtop NMR devices.