Zirconium (IV)-based metal organic framework (UIO-67) as efficient sorbent in dispersive solid phase extraction of plant growth regulator from fruits coupled with HPLC fluorescence detection

A stable zirconium (Ⅳ)-based metal organic frameworks (UIO-67) material possessing good chemical, thermal and water stability was synthesized and applied as a sorbent for the dispersive solid phase extraction (DSPE) of 8 plant growth regulators (PGRs) in fruit samples. Fluorescence labeling combined with high performance liquid chromatography fluorescence detection (HPLC-FLD), was used to quantify the target analytes. Characterization of the UIO-67 material was performed by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The experimental parameters, such as amount of UIO-67, type and volume of eluting solvent, adsorption and desorption time, were optimized. Under the optimized conditions, good linearity was observed in the range of 10–1000 pmol/mL with R 2 >0.9989. The limits of detection and limits of quantification were in the range of 0.21–0.57   ng/mL and 0.81–1.91   ng/mL, respectively. The intra-day and inter-day precisions (based on the relative standard deviation, n =3) of the PGR derivatives were under 3.1% and 5.3% respectively and the accuracies of the method for the PGRs were in the range from 89.3% to 102.3%. The developed method was successfully applied to analyze PGRs residues in fruit samples. The proposed method is proved to be simple, environment-friendly and inexpensive and it is feasible to directly use UIO-67 as sorbent to extract targets by varying conditions.