Despite its advantages, DNP NMR faces several challenges:
1. Sample Preparation: The introduction of paramagnetic agents can sometimes alter the properties of the sample, making it challenging to obtain accurate results.
2. Instrumentation: DNP NMR requires specialized equipment, including high-power microwave sources and cryogenic systems, which can be costly and complex to operate.
3. Signal Enhancement Limitations: The degree of signal enhancement depends on factors such as the type of paramagnetic agent used, the microwave frequency, and the temperature. Optimizing these parameters for specific samples can be difficult.
