TY - JOUR
T1 - Photo-Potentiometry
T2 - Sensing of Sugars Using a pH-Probe Coated with a Film of Intrinsically Microporous Polyamine Containing Graphitic Carbon Nitride Photocatalyst
AU - Martisn, Fernanda
AU - Melchert, Wanessa
AU - Carta, Mariolino
AU - Mckeown, Neil B.
AU - Marken, Frank
N1 - Publishing OA
PY - 2025/6/18
Y1 - 2025/6/18
N2 - At proof-of-concept level, the photochemical transformation of glucose (or more generally of carbohydrates) can be detected analytically as a localised pH change. Using a conventional potentiometric pH-probe, a microporous coating is developed to explore carbohydrate sensing in the 200 to 800 µM concentration range based on localised pH changes induced by light. The photo-responsive film is based on fibrous cellulose (to aid permeability), photocatalytic graphitic carbon nitride (g-C3N4), and an intrinsically microporous polyamine host (PIM-EA-TB, as reaction environment and binder). The film-modified pH-probe is pre-conditioned in a pH 4 buffer (containing phthalate buffer). When immersed in an aqueous solution, switching on a blue LED (λ = 385 nm, approx. 60 mW cm-2) causes a pH transient towards alkaline, which is correlated with the carbohydrate concentration (all three glucose, fructose, or sucrose give very similar signals). The LOD is typically 70 µmol dm-3, with a linear range up to 800 µmol dm-3. Non-linearity beyond 800 µmol dm-3 is tentatively attributed to limited oxygen availability. The photo-electroanalytical mechanism is discussed in terms of competing proton generation and consumption in the photoactive film linked to oxygen depletion (causing alkaline drift) at the pH-probe surface.
AB - At proof-of-concept level, the photochemical transformation of glucose (or more generally of carbohydrates) can be detected analytically as a localised pH change. Using a conventional potentiometric pH-probe, a microporous coating is developed to explore carbohydrate sensing in the 200 to 800 µM concentration range based on localised pH changes induced by light. The photo-responsive film is based on fibrous cellulose (to aid permeability), photocatalytic graphitic carbon nitride (g-C3N4), and an intrinsically microporous polyamine host (PIM-EA-TB, as reaction environment and binder). The film-modified pH-probe is pre-conditioned in a pH 4 buffer (containing phthalate buffer). When immersed in an aqueous solution, switching on a blue LED (λ = 385 nm, approx. 60 mW cm-2) causes a pH transient towards alkaline, which is correlated with the carbohydrate concentration (all three glucose, fructose, or sucrose give very similar signals). The LOD is typically 70 µmol dm-3, with a linear range up to 800 µmol dm-3. Non-linearity beyond 800 µmol dm-3 is tentatively attributed to limited oxygen availability. The photo-electroanalytical mechanism is discussed in terms of competing proton generation and consumption in the photoactive film linked to oxygen depletion (causing alkaline drift) at the pH-probe surface.
U2 - 10.1016/j.talanta.2025.128461
DO - 10.1016/j.talanta.2025.128461
M3 - Article
SN - 0039-9140
VL - 296
JO - Talanta
JF - Talanta
M1 - 128461
ER -