Raftery et al. used a methanol-chloroform mixture to extract plasma and RBC for NMR detection of cellular energy metabolites, such as ATP, ADP and AMP. However, these compounds could not be detected in the plasma using conventional NMR. As both solvents are compatible with nh-PHIP, this was a good starting point for the current work. It would also be interesting to determine whether the enhanced sensitivity of nh-PHIP could rise to the challenge and successfully detect ATP in plasma.