Magnetic resonance signals are inherently small and difficult to detect. To detect such small signals with good resolution, high field gradients or magnetic fields are necessary which requires expensive and bulky instruments. But even then required sample volumes and/or measurement times remain substantial. Recently, a state-of-the-art approach was developed that tackles all of these drawbacks. The method utilizes a diamond defect which can transform the small magnetic resonance signal of molecules in the surrounding into an optical signal. These optical signals can be detected with a sensitive microscope. Based on this principle, I want to develop a spectrometer that can detect magnetic resonances from nanoliters of sample within microseconds, which would vastly expand the current possibilities. To achieve this goal I would like to use an approach, which has been patented by my team. Part 1 of this Vidi-project aims to further optimize the spectrometer. Next, I will explore its applications and use the new spectrometer to approach two questions that cannot be resolved with the classical methods. Thus, in part 2a I focus on radical scavenging: How and when do drugs or nutrients scavenge radicals and how can I influence that process?. In part 2b I will follow chemical reactions during the synthesis of drugs, including their intermediate products. This should provide a platform for high-speed screening of drug candidates in the drug discovery field and potentially aid drug synthesis and process control.