Qualitative and quantitative nondestructive determination of cyanide in water and distilled spirits by Raman integrating sphere

Abstract

Cyanide often forms as a byproduct during the fermentation process of distilled spirits, and excessive amounts can cause damage to health. Cyanide poisoning is also common in alcoholic beverages and water. Therefore, the cyanide content measurement in water and distilled spirits is essential. Here, a Raman integrating sphere technique for the in situ detection of cyanide has been established, and a lower limit of detection of 1.56 mg L⁻¹ in water and ethanol was achieved, owing to the efficient collection of Raman signals and the efficient use of laser power. The Raman peak of cyanide is located at 2080 cm⁻¹. The detection range was from 1.56 to 25 mg L⁻¹ cyanide in water, ethanol, and liquor with high linearity (R² = 0.9986, 0.9986, and 0.9908) and precision (%RSD = 5.53%, 6.92%, and 14.12%). This instrument provides an alternative method for detecting cyanide, which can not only be used for accurate qualitative and quantitative detection of cyanide but also for food safety detection and physical evidence analysis of cyanide in beverage poisoning. Key to our method is that it offers advantages such as no need for sample pretreatment, simplicity and speed of operation, non-destructive analysis, minimal sample consumption (only 3 milliliters are required for a single measurement), and the ability to preserve the analyzed sample as evidence.