Figure 5. O.D. values at 9 hours as function of relative concentration for the constituent elements, Zr, Cu, Al and Ag, respectively.

Since a smaller O.D. value corresponds to higher antibacterial activity, the plots suggests that the better performing compositions are in the range of 30–50% Zr, 33–36% Cu, 10–25% Al, and 5–10% Ag, respectively.