Amperometric detection of hydrogen peroxide in bleaching and washing processes - Analytical Electrochemistry in Textiles - page 132

temperature on the current signal in the pseudo-limiting-current plateau
was first verified. In prospect of developing a sensor, based on the exam-
ined electrode reaction, the influence of the temperature was examined on
the measured pH.

5.2.2 Relation between current signal and temperature

Initially it was verified, by recording log I vs. pH relations with different
temperatures, whether the reaction order of the hydroxide ions was chang-
ing as a function of the temperature. This appeared not to be the case, from
which it could be concluded that factor x is independent of temperature.
The influence of temperature on the current signal can consequently be
found by measuring this current signal with constant hydrogen peroxide
concentration and pH at different temperatures. This means that the terms
(3/2-1/2 x ) log c HO 2 - and (3/2x- 1 / 2 ) log c OH - in Chapter 4, Equation 4.56 remain
almost constant. Experimentally, a linear relation was found between the
logarithm of the current signal and the temperature, except for relatively
high hydrogen peroxide concentrations in combination with a high pH and
temperature (Fig. 5.1). Equation 4.56 can consequently be transformed into:

4.2

6

4.0

5

3.8

4

3.6

3

3.4

2

3.2

3.0

2.8

1

2.6

2.4

2.2

290 295 300 305 310 315 320 325

Temperature (K)

5.1 Relation between the current signal of the oxidation of hydrogen
peroxide with a glassy-carbon electrode and the temperature, with
E = 0.45 V vs. SCE. The hydrogen peroxide concentration and pH
are (1) 0.1 mol l - 1 and 11.0, (2) 0.3 mol l - 1 and 11.05, (3) 0.1 mol l - 1
and 12.88, (4) 0.6 mol l - 1 and 10.97, (5) 0.3 mol l - 1 and 12.74, (6)
0.6 mol l - 1 and 12.98, respectively.