The Development Of Detection Methods For Aluminum Lake In Food

Aluminum lakes are usually made by aluminum salts precipitation in the synthetic dyes,excess intake may cause an anaphulactic reaction,asthma,DNA damage,hyperactivity,so the use of aluminum lakes are strictly restricted by laws and regulations.This experiment studied a method to simultaneous detection of nine synthetic colours(NewRed,INS102,INS123,INS132,INS124,INS110,INS129,INS133,INS127)and their aluminum lakes by HPLC-PAD,and the method was successfully used for determination of candies,chocolate candies,capsules of drug which contain synthetic dyes and aluminum lakes.Through optimization of pretreatment method,sulfuric acid aqueous solution was used to dissolve aluminum lakes,saturated solution of sodium carbonate was used to adjust the pH of solution to 7.After centrifugal filtration,the dyes portion of aluminum lakes were released.Methyl alcohol and ammonium acetate solution(0.02 M)were used as mobile phase for the determination of nine synthetic colours with gradient elution,the maximum absorption wavelength of each dye was chosen as the detection wavelength.The detection limit of this method was 0.016-0.092 mg/L,and had a good linear relation over ranges of 1-50 mg/L.By comparing the standard curve of tartrazine and its aluminum lake that concluded form HPLC,we conclued that the dye portion existed in aluminum lake was 37%.Candies and capsules of drug were chosen as the matrix of standard addition recovery,different ranges of tartrazine aluminum lake was added in to calculate adding standard recovery,and the content of aluminum lakes was calculate by dyes portion,the samples standard addition recoveries were 92.84%?28.47%,RSD were 0.92%?6.83%.To assess the reproducibility of the method of qualitative and quantitative,the intraday precision and inter-day precision of retention time and peak area were 0.04%-4.27%.In the detection samples,the content of dyes and aluminum lakes in candies were basically accorded with national standard,only one chocolate candy had excess tartrazine and aluminum lake.The content of dyes and aluminum lakes in capsules of drug was not limited.Through the optimization of GB/T 5009.182-2003,the aluminum content was 11.37%±0.64%in tartrazine aluminum lake.By the content of dye portion of aluminum we can speculate the aluminum portion,and make safety assessment.By compared the fourier transform infrared spectra of tartrazine and its aluminum lake,big difference was shown in the fingerprint region.We speculated that the combination mode of sodium and aluminum ions with azo part of dyes were different,sodium ions in ionic bonds and aluminum ions in coordination bonds.