Identification of Synthetic Food Colours in Selected Confectioneries and Beverages in Jaffna District, Sri Lanka

Table 2

TLC and spectrophotometric analysis of some nonpermitted and all permitted synthetic red and yellow food colour standards.

Colour standard	Colour	Permitted (P)/nonpermitted (NP)	Λmax/nm	Solvent system	Rf value
Carmoisine	Red	P	516	n-Propanol : ammonia = 4 : 1	0.50
Ponceau 4R	Red	P	508		0.39
Erythrosine	Pink	P	526		0.77
Allura red	Red	P	506		0.46
Rhodamine B	Pink	NP	553		0.86
Fast red	Red	NP	510		0.55
Sunset yellow FCF	Orange	P	482	Butanol : water : glacial acetic acid = 10 : 6 : 5	0.73
Tartrazine	Yellow	P	426		0.42
Bromocresol purple	Yellow	NP	586		0.91
Metanil yellow	Yellow	NP	441		0.85