Abstract: The influences of ion-suppressors on retention behaviors of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in reversed-phase high performance liquid chromatographic (RP-HPLC) separation were investigated. The organic modification effects of acids, i.e., trifluoroacetic acid (TFA) and buffer salts, i.e., TFA-ammonium acetate (AmAc) were studied emphatically. The relationships between retention factors of solutes and volume percentages of ion-suppressors in the mobile phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, separately. The separation of nine food additives was completed by a gradient elution with acetonitrile-TFA (0.01%, v/v)-AmAc (2.5 mmol/L) aqueous solution as the mobile phases. An RP-HPLC method was established for the simultaneous determination of nine food additives in red wine. In the range of 10.0~100.0 mg/L, nine food additives showed good linearity with the correlation coefficients (r2) larger than 0.9991. The limits of detection (LODs) were in the range of 0.33~2.36 mg/L and the limits of quantification (LOQs) were in the range of 1.11~7.80 mg/L. The spiked recoveries were between 87.61% and 108.4% with the relative standard deviations (RSDs) of 2.2%~9.4%. These results are of referential significance for the rapid establishment and accurate optimization of RP-HPLC separation for the simultaneous determination of food additives in other foods.

Key words: ammonium acetate, food additives, ion-suppressor, wine, reversed-phase high performance liquid chromatography (RP-HPLC), trifluoroacetic acid