The analysis of EDTA was carried
out using an HPLC system; L-6000 Pump and L-4200 UV-VIS
Detector (210 nm, UVwavelength, Hitachi Co.) with RSpak DE413
column (4.6 mm in diameter and 150 mm length, Shodex
Co.) and a RSpak DE-G guard column (4.6 mm in diameter,
Shodex Co.). 10 mMphosphoric acid was used as the eluent and