Determination of alpha-solanine and alpha-chaconine in potatoes by high-performance thin-layer chromatography/densitometry

A high-performance thin-layer chromatographic (HPTLC) method was used to de termine the glycoalkaloids alpha -solanine and alpha -chaconine in potatoes . alpha -Solanine and a-chaconine are extracted from dehydrated potatoes wi th boiling methanol-acetic acid (95 + 5, v/v). The analytes are separated o n a Silica Gel 60 F-254 HPTLC plate by a saturated mixture of dichlorometha ne-methanol-water-concentrated ammonium hydroxide (70 + 30 + 4 + 0.4, v/v), which is used for vertical development of the plate up to a distance of 85 mm, For visualization, the plate is dipped 3 times into a modified Carr-Pr ice reagent, 20% (w/v) antimony(III) chloride in acetic acid-dichloromethan e (1 + 3, v/v), and subsequently heated on a hot plate at 105 degreesC for 5 min. The glycoalkaloids all appear as red chromatographic zones on a colo rless background. Densitometric quantification is performed at 507 nm by re flectance scanning. After determination of the appropriate response functio n, the proposed method was validated, Good results with respect to linearit y, accuracy, and precision were obtained in the concentration range studied .