  Microfluidic systems hold great potential for the study of live microscopic
cultures of cells, tissue samples, and small organisms. Integration of
hyperpolarisation would enable quantitative studies of metabolism in such
volume limited systems by high-resolution NMR spectroscopy. We demonstrate, for
the first time, the integrated generation and detection of a hyperpolarised
metabolite on a microfluidic chip. The metabolite 1-$^{13}$C-fumarate is
produced in a nuclear hyperpolarised form by (i) introducing para-enriched
hydrogen into the solution by diffusion through a polymer membrane, (ii)
reaction with a substrate in the presence of a ruthenium-based catalyst, and
(iii) conversion of the singlet-polarised reaction product into a magnetised
form by the application of a radiofrequency pulse sequence, all on the same
microfluidic chip. The microfluidic device delivers a continuous flow of
hyperpolarised material at the 2.5 $\mu\text{L}/\text{min}$ scale, with a
polarisation level of 4%. We demonstrate two methods for mitigating
singlet-triplet mixing effects which otherwise reduce the achieved polarisation
level.
