Sol-Gel Thin Films Immobilized with Bromocresol Purple pH-Sensitive Indicator in Presence of Surfactants

Figure 12

Absorption spectra of immobilized BCP/CTB at different pH values (1–13.5): (a) pH 1–8, 𝜆_max = 430 nm and (b) pH 9–13.5, 𝜆_max = 595 nm.