I use EDC/NHC to activate PEG-COOH so that aminated GQDs can be modified

But the result is often not decorated

And I can't find where the problem is

The following are my experimental steps

PEG was dissolved in deionized water then 0.1M MES PH6 was added

Dissolve EDC/NHS in MES and add the solution to react overnight

PEG/EDC/NHS molar ratios are both 1:1:1 or 1:2:2

There will even be a small amount of white line-like objects in the reacted solution.