Chitosan-Ni/Fe layered double hydroxide composites as an efficient solid phase extraction sorbent for HPLC-PDA monitoring of parabens in personal care products

There is a dire need for development of efficient and sensitive methods to efficiently screen parabens. In this research, we focused on quantification of four parabens (i.e., methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butyl paraben (BP)) using chitosan intercalated nickel/iron layered double hydroxide (CS-Ni/Fe-LDH) composites as solid phase extraction sorbent prior to HPLC-PDA analysis. CS-Ni/Fe LDH composites with a heterogeneous, porous texture, and coral reef-like structure exhibit appealing extraction efficiency for the target parabens due to the enhanced possibility for the formation of hydrogen bonding and hydrophobic interactions. The performance of the composites was assessed and optimized for solid phase extraction of parabens from standard samples and real samples (rose water, cream, toothpaste, hair serum, and sunscreen). The LDH-SPE-HPLC method exhibited a wide linear range (e.g., 100-50,000 ng L^-1), good linearity (R² ≥ 0.999), and good precision (relative standard deviation (RSD) < 3%). This method successfully enriched selected parabens with remarkable recovery above 85.95% and a good RSD (0.01-2.90%). The quantitation of MP, EP, PP, and BP was made at detection range (and limits of detection (LOD)) of 5-15 (9.8), 11-21 (16.2), 6-18 (12.4), and 10-20 (15.6) ng L^-1, respectively. The prepared composites also displayed excellent performance with enhanced reusability/durability (n = 30 cycles) and reproducibility (n = 5).