Toward nanomolar detection by NMR through SABRE hyperpolarization

Area of Science:

• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Quantum Chemistry
• Physical Chemistry

Background:

• SABRE (Spin-transfer by Auxiliary-initiated Reversible Exchange) is a hyperpolarization technique.
• It enhances NMR signals by transferring spin order from para-hydrogen (p-H2) to substrate molecules via a metal complex.
• Current limitations include reduced signal enhancement at low substrate concentrations (μM).

Purpose of the Study:

• To overcome the concentration limitations of SABRE.
• To enable NMR detection of low-concentration analytes using SABRE.
• To improve the efficiency of SABRE at μM substrate levels.

Main Methods:

• Investigated the effect of adding coordinating ligands to SABRE solutions.
• Utilized reversible substrate-metal complex formation for spin transfer.
• Employed para-hydrogen (p-H2) as the source of hyperpolarization.

Main Results:

• Demonstrated that addition of a suitable coordinating ligand restores SABRE efficiency at low substrate concentrations.
• Achieved NMR detection of substrates at concentrations below 1 μM.
• Enabled sensitive NMR analysis in a single scan.

Conclusions:

• The addition of coordinating ligands is an effective strategy to enhance SABRE performance at low substrate concentrations.
• This method significantly expands the applicability of SABRE for analyzing dilute solutions.
• The technique offers a pathway for highly sensitive NMR detection in various scientific fields.