  In this paper, we model the chemical evolution of a 0.25 M$_{\odot}$
protoplanetary disc surrounding a 1 M$_{\odot}$ star that undergoes
fragmentation due to self-gravity. We use Smoothed Particle Hydrodynamics
including a radiative transfer scheme, along with time-dependent chemical
evolution code to follow the composition of the disc and resulting fragments
over approximately 4000 yrs. Initially, four quasi-stable fragments are formed,
of which two are eventually disrupted by tidal torques in the disc. From the
results of our chemical modelling, we identify species that are abundant in the
fragments (e.g. H$_{\rm 2}$O, H$_{\rm 2}$S, HNO, N$_{\rm 2}$, NH$_{\rm 3}$,
OCS, SO), species that are abundant in the spiral shocks within the disc (e.g.
CO, CH$_{\rm 4}$, CN, CS, H$_{\rm 2}$CO), and species which are abundant in the
circumfragmentary material (e.g. HCO$^{\rm +}$). Our models suggest that in
some fragments it is plausible for grains to sediment to the core before
releasing their volatiles into the planetary envelope, leading to changes in,
e.g., the C/O ratio of the gas and ice components. We would therefore predict
that the atmospheric composition of planets generated by gravitational
instability should not necessarily follow the bulk chemical composition of the
local disc material.
