HA solutions before injection were filtered with the use of 0.45 μm nylon syringe filter and injected into the FIA system. The volume of injection was 10 μL. The standard HA solutions used for optimization were injected into the system for each experimental condition so that parameters of the proposed system be optimized. After the optimization, HAs isolated from L2, and L3, were dissolved in 1.10−8 mol L−1 KOH solution and were injected into the system. The HA content was estimated on the basis of the absorbance at 410 nm.