Validation of a liquid chromatography detection method (HPLC-DAD) for the determination of aloin in Aloe vera food products

Aloin is an anthraquinone found in a wide variety of food products made from aloe, which can cause laxative effects and prolonged ingestion increases the risk of gastrointestinal cancer. In this study, parameters for aloin analysis and extraction methodology were validated using High Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD). Aloin concentration was determined in 14 commercial products consumed in Costa Rica. The quality values evaluated were linearity (R = from 0.9995 to 0.999995), reproducibility (recovery percentage = from 96.7% to 99.9%), intra-day precision (coefficient of variation = from 0.24% to 1.47%), inter-day precision (coefficient of variation = from 1.65% to 2.68%), limit of detection (from 0.063 mg/L to 0.228 mg/L), limit of quantification (from 0.126 mg/L to 0.452 mg/L) and selectivity (<= 0.063 mg/L). The majority of the evaluated food products showed a concentration below the maximum value allowed (10 mg/L), with values between 0.2 +/- 0.1 mg/L and 4.8 +/- 0.1 mg/L of aloin, with an average standard deviation of 0.41 mg/L. Liquid samples presented higher values than the rest of the matrices. Two of the samples (RU/BT1/39A and RU/BT1/45B) were reported with concentrations higher than the maximum aloin value allowed (14.2 +/- 0.1 mg/L and 19.0 +/- 0.1 mg/L). The consumption of these products could have a long-term harmful effect on health, since they exceed the limit mentioned above.