Application of Experimental Design to Develop a Robust RP-TLC/ Densitometry Method for Quantification of Phthalates in Person al Care Products

Objective: A rapid, simple and economic RP-TLC/Densitometry method for the simultaneous quantification of Phthalates, namely Dimethyl Phthalate (DMP), Diethyl Phthalate (DEP) and Di-n-butyl Phthalate (DBP) in Personal care products was developed and validated. Central Composite design (CCD) with three factors and one response is employed to study the robustness of the developed method. Method: The best chromatographic separation was achieved using Methanol: Toluene: Hexane: GAA (6:2:1:1 v/v/v/v) as the solvent system at 275 nm. The developed method was examined for validation parameters like linearity, specificity, precision, accuracy and robustness. Results: The method was found linear over a wide range of 2.0–200 ng/band with a regression coefficient of 0.999, 0.998 and 0.998 for DMP, DEP and DBP respectively. Limit of detection (LOD) and Limit of Quantification (LOQ) was found to be 0.035 and 0.106 ng/band, 0.072 and 0.218 ng/band 0.076 and 0.232 ng/band for DMP, DEP and DBP respectively. The %RSD for Precision studies for DMP, DEP and DBP were found to be 1.63 – 1.82, 1.13 – 1.52 and 1.58-1.60 respectively. Accuracy, ascertained by employing % Recovery was calculated and found between 97-103% w/w. CCD generated and carried out proves the method devel oped was robust. Conclusion: All the validation parameters were reported to be within the acceptance limit. The proposed and developed RP-TLC/ Densitometry method can be applied for routine analysis of DMP, DEP and DBP in Personal care products and can also be extended to the analysis in pharmaceuticals and food products.