Dispersive Liquid-Liquid Microextraction of Preservatives for Their Chromatographic Determination in Beverages

A method of dispersive liquid-liquid microextraction, based on the dispersion of an extractant by the gas phase formed as a result of a phase transition, i.e., the evaporation of a highly volatile nonpolar organic solvent (dispersant) upon heating the extraction,-is developed. The analytical capabilities of the method are shown in the determination of preservatives (sorbic and benzoic acids) in soft drinks for baby food by high-performance liquid chromatography with photometric detection. The extractant and the dispersant for the microextraction of preservatives are chosen a terpenoid and a highly volatile organochlorine solvent, respectively, which excluded the use of polar organic solvents for dispersing phases, with which the distribution coefficients are reduced. The limits of detection (3 & sigma;) for sorbic and benzoic acids are 0.3 mg/L. The developed method does not require centrifugation for phase separation.

Automated summary

A method of dispersive liquid-liquid microextraction based on the evaporation of a highly volatile nonpolar organic solvent is developed. The method exhibits analytical capabilities in determining preservatives in soft drinks for baby food using high-performance liquid chromatography. The use of a terpenoid and a highly volatile organochlorine solvent as the extractant and dispersant allows for the exclusion of polar organic solvents, reducing the distribution coefficients. The method does not require centrifugation for phase separation.