Density-dependent MOND on SPARC data: a null result

We test whether the MOND acceleration scale depends on local baryonic density, a_eff = a0·exp(−ρ/ρ*), on the official SPARC data (175 galaxies). Using the signed gas convention, galaxy-level cross-validation against equal-complexity controls, and an independently measured photometric density, we find no robust, separable density signal: the density term does not separate from an equal-complexity pure g_bar control, and with an intrinsic-scatter error model it is never worse and only occasionally, inconsistently better by a few per cent. The global χ² gain is explained by interpolation-shape flexibility. The record contains the preprint and a fully reproducible code package that downloads and SHA-256-verifies the official SPARC tables.