Purple sweet potato (Ipomoea batatas L.) contains cyanogenic glycosides that can potentially hydrolyze into hydrogen cyanide (HCN) upon tissue mechanical damage. This quantitative descriptive laboratory experimental study aimed to identify the presence and measure the concentration of HCN in sweet potato soaking water prepared with coconut water (Cocos nucifera L.) at a 1:2 ratio for 12 hours after an 8-day storage period. Qualitative identification was performed using saturated picric acid paper (8% Na2CO3) heated at 60°C. Quantitative determination was conducted in triplicates (n=3) via Liebig-Deniges Argentometric Titration utilizing 0.01N AgNO3 standard solution, 5% KI indicator, and 6 M NH4OH alkaline medium. The qualitative test yielded a positive result (+), indicated by the color transition of picrate paper from yellow to reddish-brown due to isopurpuric complex formation. In the quantitative assay, the titration endpoint was marked by a persistent pale-yellow turbidity, requiring an average titrant volume of 1.37 mL (1.30 mL, 1.40 mL, and 1.42 mL). Based on Liebig–Deniges volumetric calculations, the average concentration of dissolved HCN in the soaking water was 7.43 mg/L (ppm). This study demonstrates that the Liebig–Deniges Argentometric method is highly sensitive, specific, and effective for HCN quantification in natural liquid matrices.
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