Furthermore, to understands the influence of the interaction of GQDs and lipase, on both the activity of lipase and the emission intensity of GQDs, various incubation conditions were tested to achieve optimized conditions over central composite design algorithm by Design-Expert®, using response surface methodology.  The results show that the GQDs fabricated by thermal decomposition of citric acid at 160°C, with a heating duration of 55 min, obtain almost three times higher QY than the highest values reported previously. 
THERM