Determination of sulphur dioxide in white granulated sugar by formaldehyde solution absorption - pararosaniline hydrochloride spectrophotometry - Master's thesis - Dissertation

[Keywords]: formaldehyde, para-rosaniline, white sugar, sulfur dioxide; analysis instruments: V-1100, V-1200 This article introduces a modern analytical method for determining the content of sulfur dioxide in white sugar using spectrophotometry. The technique involves the absorption of sulfur dioxide by formaldehyde solution, replacing traditional mercury-based reagents that are harmful to the environment. After sample preparation, formaldehyde is added to the solution, where it reacts with sulfur dioxide to form a stable compound known as hydroxymethanesulfonic acid. Subsequently, sodium hydroxide is introduced, which facilitates the reaction between the formed compound and para-rosaniline hydrochloride. This reaction produces a distinct purple-red complex, which is measured at a wavelength of 579 nm. The results show a strong linear correlation (r = 0.9998) between the concentration of sulfur dioxide (ranging from 0 to 60 mg/kg) and the absorbance value. The detection limit of this method is 0.81 mg/kg, and the relative standard deviation for the samples ranges between 2.8% and 4.1%, indicating high precision. Additionally, the recovery rate of sulfur dioxide in the samples was found to be between 93.8% and 98.6%, demonstrating good accuracy. When compared with the results obtained using the national standard method, no significant differences were observed, confirming the reliability and effectiveness of this approach. This method not only improves environmental safety but also offers an efficient and accurate alternative for sulfur dioxide analysis in white sugar. [Keywords]: formaldehyde, para-rosaniline, white sugar, sulfur dioxide; analysis instruments: V-1100, V-1200