Thirty L of lysate samples were injected andisocratic elution was performed with the equilibration buffer for1.4 min and then with 10 mM Tris, pH 8.0 buffer for 0.9 min. At2.3 min, the column was re-equilibrated with 1.5 M ammoniumsulfate. Plasmid concentration was determined from a calibrationcurve (5–100 g/mL).