Reaction #1702040

Reaction equation

ferricyanide

ferricyanide

→

ferricyanide

ferrocyanide

Solvents

phosphate

Conditions

Workup

1. 1
   Temperaturemaintained at 37 C in a jacketed cuvette
2. 2
   OtherThe sample was illuminated with a 785 nm laser
3. 3
   Otherthe resultant ferricyanide Raman scattering from the mediator, evident at 2132 cm−1, was collected at 1800
4. 4
   workup.ADDITIONwas added to the cuvette
5. 5
   Otherto be produced

Procedure

To determine GOx kinetic constants under the sensing conditions, 600 microL of GOx (0.0127 mM) in 0.5 M phosphate buffer (pH 7.4) and 100 microL of the 0.5 M ferricyanide solution (in 0.5 M phosphate buffer, pH 7.4) were well mixed and maintained at 37 C in a jacketed cuvette. The sample was illuminated with a 785 nm laser and the resultant ferricyanide Raman scattering from the mediator, evident at 2132 cm−1, was collected at 1800 and recorded by a CCD camera. While continuously monitoring the ferricyanide Raman scattering peak, 100 microL of glucose solution (20 mM) was added to the cuvette. The oxidation of glucose by glucose oxidase caused hydrogen peroxide to be produced, which then reduced the free ferricyanide, Fe(CN)63−, to ferrocyanide, Fe(CN)64−, resulting in an intensity loss from ferricyanide scattering. Ferricyanide scattering intensity was normalized to one by dividing the specific intensity by the initial intensity. FIG. 10 shows the change in normalized ferricyanide scattering intensity monitored via Raman scattering at 785 nm at 2132 cm−1 over time after addition of 20 mM glucose. The same experiment was also completed for glucose concentrations of 31, 10 and 5 mM. The ferricyanide response was fit with a normalized ferricyanide concentration, C/Co, modeled using Michaelis-Menton kinetics

Source