Table 3.

Experimental matrix for the Box–Behnken design.

Experiment	Random order	Buffer pH	Buffer volume (μl)	Stirring time (min)
1	13	10.0	300	10
2	5	9.5	300	5
3	14	10.0	300	10
4	9	10.0	100	5
5	10	10.0	500	5
6	6	10.5	300	5
7	7	9.5	300	15
8	8	10.5	300	15
9	11	10.0	100	15
10	4	10.5	500	10
11	12	10.0	500	15
12	3	9.5	500	10
13	2	10.5	100	10
14	1	9.5	100	10
15	15	10.0	300	10