A rapid spectrofluorimetric method for the determination of malondialdehyde in human plasma after its derivatization with thiobarbituric acid and vortex assisted liquid-liquid microextraction

A rapid, simple and sensitive methodology has been developed for the determination of trace levels of malondialdehyde (MDA) in human plasma. The method is based on the derivatization of MDA using thiobarbituric acid (TBA) to form a highly fluorescent compound, MDA-TBA at acidic pH. The TBA-derivatized MDA formed was preconcentrated using vortex assisted liquid-liquid microextraction into 90 mu L of n-heptanol as extractant solvent and measured spectro-fluorimetrically. Parameters such as nature of the extraction solvent, extraction time, sample volume, temperature, derivatization reaction time and pH of the sample solution were studied and optimized. The developed protocol was found to yield a linear calibration curve in the concentration range between 1.0-100.0 mu g L-1 with a limit of detection of 0.32 mu g L-1. The enrichment factor for the analyte was calculated to be 65. The repeatability of the method was satisfactory (RSD <= 1.6%). Total extraction time was less than 10 min. The developed method was successfully applied to the determination of MDA in a human plasma sample.