Elution Time (min) Buffer A % Buffer B % Column Temperature (°C) Flow (ml/min) 0 55 45 42 1.35 0.03 35 65 42 1.35 10 0 100 42 1.35 17 0 100 42 1.35 17.1 55 45 42 1.35 25 Stop

Table 1:Chromatography gradient conditions for o-phthaldialdeydeaminegroup detection.