Tetraethyl orthosilicate-modified Zn–Mg–Al LDHs/polyvinylidene fluoride as a novel and efficient sorbent for thin film microextraction of gemfibrozil and its determination by HPLC-UV

This study introduces a novel thin-film inorganic–organic hybrid material designed for efficient microextraction. The inorganic–organic hybrid material comprises tetraethyl orthosilicate (TEOS)-modified ternary Zn-Mg-Al layered double hydroxides (Zn-Mg-Al LDHs) embedded within a polyvinylidene fluoride (PVDF) matrix. The innovation lies in the TEOS modification, which is hypothesized to generate a silica network that significantly improves the dispersion of the inorganic LDHs within the PVDF polymer. This structural enhancement fosters better compatibility between the organic and inorganic phases, thereby boosting the overall performance of the composite. The developed TEOS-Zn-Mg-Al-LDHs/PVDF film was thoroughly evaluated for its efficacy in the microextraction of gemfibrozil from urine samples. To achieve maximal extraction efficiency, a robust two-step statistical optimization approach was employed. This involved an initial screening of influential parameters using Plackett-Burman design (PBD), followed by meticulous optimization via response surface methodology (RSM). Quantitative analysis of the extracted gemfibrozil was performed using high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Under optimal conditions, the method demonstrated excellent analytical performance, yielding a limit of detection (LOD) of 0.3 µg L^− 1, a limit of quantification (LOQ) of 1.0 µg L^− 1 and a wide linear dynamic range (LDR) of 1.0–500.0 µg L^− 1. Also, Batch-to-batch reproducibility for three different film was 5.9% to 6.8%. These figures of merit highlight the high sensitivity and precision of the developed method. The successful application of this thin film microextraction (TFME) technique, utilizing the novel composite film for the sensitive and reproducible microextraction of gemfibrozil from biological fluids, underscores its significant potential for practical applications in real sample analysis within clinical and pharmaceutical settings.