The apparent electrocatalytic detection of aspirin and salicylic acid is compared using NiO nanoparticles and microparticles supported on graphitic electrodes using abrasive and non-abrasive (drop-dry) immobilisation. However control experiments revealed that, the observed voltammetry is not due to the immobilised NiO materials, but is instead due to the underlying graphitic substrates. Abrasive immobilisation of NiO microparticles on a graphite electrode abrades the underlying electrode surface, introducing more electroactive edge-plane defects. Even when drop-dry immobilisation is used (i.e. non-abrasive), appropriate control experiments are still required as other experimental methods employed may change the nature of the underlying substrate.