2.1.3. Determination of Reaction Time

Studies showed that reaction time had a vital role to regulate the SeNPs reaction system [21]. If the reaction time is too short, the reaction between Na2SeO3 and Vc is not sufficient. However, if the reaction time is too long, the SeNPs in the system will gather, leading to increasing the particle size. Therefore, we next further investigated the influence of reaction time on the particle size of system. Fixing the CS concentration of 0.1 mg/mL, the molar mass ratio of Na2SeO3 to Vc of 1:8 and the reaction temperature of 55 ◦C, the reaction time varied from 1 h to 4 h. The result was shown in Figure 1C. When the reaction

time extended from 1 h to 2 h, no significant difference was observed in the particle size of the obtained SeCS. When the reaction time increased to 3 h, the particle size of the obtained SeCS reached to 131.2 ± 9.97 nm. When the reaction time exceeded 3 h, the particle size of the obtained SeCS remarkably increased. Therefore, we selected the reaction time of 3 h as the optimal reaction time to prepare SeCS.
