Description
Synthetic, water-soluble food colours can be semiquantitatively determined with this method, which can be applied to all types of foods. After possible pretreatment the sample is dissolved in hot water and shaken with polyamide, which adsorbs the colours. The plyamide is transferred to a column and washed. The colours are eluted and separated on thin layer plates. The colour zones are scraped off the plate and dissolved. The quantitation is performed using standard solutions which have been subjected to the same procedure as the sample. If the sample contains only a single colour the thin layer plate separation is not always necessary.