I am using EDC/NHS to cross-link collagen protein. Historically we have added EDC to water first, then NHS. I would like some insight into the reaction rate of the hydrolysis of EDC with water to determine if NHS should be added first. If the hydrolysis of EDC is a slow reaction, it may not effect the cross-linking efficiency of EDC to add EDC first. If it is a near-instant reaction I am worried that my EDC is effectively deactivated as a cross-linker. Thank you for your help.