Application of microemulsion electrokinetic chromatography for the detection of preservatives in foods

In this study, a microemulsion electrokinetic chromatographic (MEEKC) method was used to separate seven preservatives which are commonly used as additives in various food products. The RSDs were in the range of 0.64–0.95% for migration time and 0.18–1.21% for reproducibility of sample injection, thus indicating the separation performance was very good even though sample preparations contained high levels of organic solvent (methanol) (up to 20 (v/v)%). Although the separation of soy sauce and wine samples required a C8 solid phase extraction as a pretreatment step in order to reduce matrix interference, this MEEKC method proved to be successful in determining preservatives found in various food products, such as soft drinks, soy sauces and wines.