HPLC Determination of the Main Organic Acids in Teeth Bleaching Gels Prepared with the Natural Fruit Juices

An efficient high performance liquid chromatographic (HPLC) method was developed and validated for fast and simultaneous determination of oxalic, citric, tartaric, malic and succinic acids in the teeth bleaching gels prepared with natural fruit juices and to establish the organic acids profile of natural fruit juices. Organic acids were separated through a Carbosep Coregel 87H3 column at 35°C using ultraviolet (UV) absorbance detector at 214 nm. The mobile phase was the sulphuric acid 0.005 M solution at a flow rate of 1 mL min-1. Validation of the method was performed to verify the linearity, limits of detection and quantification, intraand inter-day precision and accuracy. The method showed excellent linearity (R2>0.9993) for target compounds. Limits of detection (LOD) were between 0.15 and 2.47 μg mL-1 and quantification (LOQ) were between 0.49 and 8.15 μg mL-1. The accuracy at three concentration levels ranged between 96 and 102 %. The all relative standard deviations (RSD) values of the precision and accuracy were lower than 4%. Finally, the proposed methodology was successfully applied to the analysis of organic acids in sixteen teeth bleaching gels samples and to find the organic acids profile of eleven natural fruit juices used for preparing teeth bleaching gels.