Dear all..

I used to prepare snack sample for food colours determination by HPLC, after homogenizing the sample, I wash the sample by diethyl ether to remove oil, then I add methanol : ammonia solution ( 90: 10 ) and filtered it using filter paper and dry the filtrate and diluted to 25 ml water, but the solution is not clean and still of contamination, my question how I clean the sample without loosing the sample? any one has another sample preparation method for food colours in snacks?

Thanks