Figure 5

(a) Plot of measured optical rotation angle vs sucrose concentration, obtained using a 5-cm optical cell. The measurements were carried out using the same settings as for Fig. 4, except for a slightly reduced averaging time of 3.84 s (equal to 100 outputs of the microcontroller). The markers denote experimental data, while the solid line shows a least-squares optimised linear fit to \({\theta }_{{\rm{rot}}}=l{\theta }_{{\rm{s}}}[S]\), with R² = 99.96% and θ_s = 53.0 ± 0.2 deg·mL·g⁻¹·dm⁻¹ (20 °C, 650 nm). (b) Plot of measured optical rotation angle versus time, obtained using a 0.2 g/ml sucrose solution in 1.34 M HCl and a 1-cm path-length cuvette (blue line). The measurements were carried out using the same settings as for Fig. 4. Hydrolysis of dextro-rotatory sucrose to a laevo-rotatory mixture of glucose and fructose induces an exponential decrease in the optical rotation angle from 0.8975° at t = 0 min to −0.2445° at t = 22.4 min. The dashed orange line shows a least squares curve fit to a mono-exponential decay, with a decay constant of (1.745 ± 0.002) × 10⁻³ s⁻¹.