pH value

Concentration (μg/mL) (mean ± SD, n = 2)

3

458.2 ± 6.50

5

270.5 ± 88.65

5.5

302.0 ± 1.62

6

275.0 ± 3.30

6.5

272.0 ± 12.42

7

382.0 ± 55.48

8

342.7 ± 39.16