These plans are based on literature, please modify them to meet your specific needs.
1. Acid-base pH indicator[1]
Dissolve 0.5g of Phenolphthalein Disodium Salt powder in 50mL of 95% ethanol or isopropanol. Dilute with distilled water to 100mL to obtain the phenolphthalein solution (pH=8.3 indicator). In titration, generally add 1-2 drops per 100mL of sample (until a faint pink endpoint appears).
2.Qualitative and quantitative characterization of cyclodextrin materials[2]
(1) Qualitative
1)Prepare the working solution by dissolving Phenolphthalein Disodium Salt in ethanol to a concentration of 35-40μM, and adjust the pH to 12.7.
2) Add 0.1g of the film sample to 10mL of the working solution. Since the sample's absorption of phenolphthalein changes over time, monitor the color change of the solution through visual observation and digital recording.
(2) Quantitative
1)Prepare calibration curve: Different concentrations of cyclodextrin solution are mixed with 2mL of phenolphthalein working solution (373.29μM) and 2mL of sodium carbonate solution (28mM). Dilute it to 25mL and the pH is adjusted to 12.7. The absorbance of the solution is analyzed at 553nm using a spectrophotometer. The concentration values are correlated with the absorbance values to obtain a calibration curve, which is then fitted using mathematical methods.
2)0.1g of the film sample is added to the system each time, the absorbance is measured at 553nm, and the cyclodextrin concentration in the sample is calculated according to the calibration equation.
References:
[1] Simplified procedures for water examination. M12. American Public Health Association; 2012.
[2] Rodríguez-Varillas S, Michel M, Garrido-Molina F, et al. Controlled release of carvacrol and curcumin: bio-based food packaging by synergism action of TEMPO-oxidized cellulose nanocrystals and cyclodextrin. Carbohydrate Polymers. 2024;329:121123. |
