Extraction of para-hydroxybenzoic acid and parabens with organic solvents

Extraction of para -hydroxybenzoic acid and nine parabens (methylparaben, ethylparaben, propylparaben, iso -propylparaben, butylparaben, iso -butylparaben, pentylparaben, benzylparaben, phenylparaben) from their water solutions by organic solvents ( n -hexane, chloroform, isoamyl alcohol) was studied. Analytes were quantified by high-performance liquid chromatography with diode-array detection. The distribution constants were calculated. The influence of the nature of extractants and the structure of the studied substances on the obtained values of the constants was analyzed. It was found that the values of the decimal logarithms of the distribution constants for para -hydroxybenzoic acid and parabens increase in the series n-hexane < chloroform < isoamyl alcohol, which corresponds to an increase in the extractive capacity of organic solvents.