  The atmospheric composition of planets is determined by the chemistry of the
disks in which they form. Studying the gas-phase molecular composition of disks
thus allows us to infer what the atmospheric composition of forming planets
might be. Recent observations of the IRS 48 disk have shown that (asymmetric)
dust traps can directly impact the observable chemistry, through radial and
vertical transport, and the sublimation of ices. The asymmetric HD 142527 disk
provides another good opportunity to investigate the role of dust traps in
setting the disk's chemical composition. In this work, we use archival ALMA
observations of the HD 142527 disk to obtain an as large as possible molecular
inventory, which allows us to investigate the possible influence of the
asymmetric dust trap on the disk's chemistry. We present the first ALMA
detections of [C I], 13C18O, DCO+, H2CO and additional transition of HCO+ and
CS in this disk. In addition, we have acquired upper limits for non-detected
species such as SO and CH3OH. For the majority of the observed molecules, a
decrement in the emission at the location of the dust trap is found. For the
main CO isotopologues continuum over-subtraction likely causes the observed
asymmetry, while for CS and HCN we propose that the observed asymmetries are
likely due to shadows cast by the misaligned inner disk. As the emission of the
observed molecules is not co-spatial with the dust trap and no SO or CH3OH are
found, thermal sublimation of icy mantles does not appear to play a major role
in changing the gas-phase composition of the outer disk in HD 142527 disk.
Using our observations of 13C18O and DCO+ and a RADMC-3D model, we determine
the CO snowline to be located beyond the dust traps, favouring cold gas-phase
formation of H2CO, rather than the hydrogenation of CO-ice and subsequent
sublimation.
