The Cachazo-He-Yuan (CHY) representation for tree-level scattering amplitudes based on the so called scattering equations is proved to hold for six quarks QCD primitive amplitudes. Since the CHY representation allows to separate information into a factor which depends upon the helicities of the particles and into a factor depending on the ordering of the external particles, we prove that the external orderings of a minimal amplitude basis for three quarks pairs remain linearly independent, when viewed as the external orderings of the pure gluonic amplitudes.