HPLC Determination of Sudan Dyes in Egg Products

HPLC was applied to the determination of residual amounts of sudan dyes,including sudan Ⅰ,Ⅱ,Ⅲ,Ⅳ and para red in egg products.Sudan dyes in the sample were extracted with acetone,and the extracts were separated and purified by solidphase extraction on the MAX column and eluted with methanol,NaOH solution and ethyl acetate.Finally the column was eluted with an eluant composed of ethyl acetate,methyl alcohol,and formic acid.The eluate was dried and the residue was taken up with acetonitrile in which the sudan dyes were determined by HPLC.Detection limit of the method was found to be 0.1 mg·L-1.Recovery tests were made by adding 0.25 mg·kg-1 and 1.0 mg·kg-1 of standards of the dyes to a sample of salted egg,and the results obtained were in the range of 76%-92%.Test for precision was made and the values of RSD′s (n=5) found were less than 4.5%.