Factors affecting sample extraction in the liquid chromatographic determination of organic acids in papaya and pineapple

A solvent extraction method was developed for the extraction of organic acids (oxalic, citric, tartaric, L-malic, quinic, succinic and fumaric acids) in papaya and pineapple. Central composite design “2n + star” was used in order to optimise the following extraction parameters: number of extractions, composition of the extractant mixture, extraction time and extraction temperature. Optimal conditions for extraction were determined by experimental design using response surface methodology. The results suggest that the extractant composition is statistically the most significant factor and that the optimum values for the variables are: three (number de extractions), water as extractant, 60 min (extraction time) and 65 °C (extraction temperature). The separation and determination of the organic acids was carried out by liquid chromatography with UV–Vis detection.