By GC,MS and NMR techniques

Dear Kevin Bethke, the classical titration in water is very common.

10.1186/2045-9912-2-1

However, in organic solvents some problems are associated, which is the case for most solutes.

https://doi.org/10.1002/bscb.19750840601

https://doi.org/10.1021/ed080p822

NMR with special setup may be used according to the following paper (I couldn't attach it): "Quantitation and Monitoring of dissolved H2 via flow NMR at ... JY Buser · 2014". My Regards