Simultaneous Monitoring of Protein and (NH_4)_2SO_4 Concentrations in Aprotinin Hanging-Drop Crystallization Using Raman Spectroscopy

摘要

In the present study the use of fiber optic Raman spectroscopy for the in situ monitoring of aprotinin supersaturation in a hanging-drop crystallization is described. The crystallizing agent, (NH_4)_2SO_4, is Raman active, which allows monitoring of the salt concentration in the drop during the whole hanging-drop crystallization process in addition to monitoring of the appraotinin concentration. Through the continuous measuring of protein and salt concentrations, supersaturation in the drop solution was measured in real time. Moreover, through the monitoring of protein and salt concentrations, the cocrystallization of aprotinin and (NH_4)_2SO_4 was observed.