Construction of a ringent multi-shelled hollow MIL-88B as the solid-phase microextraction fiber coating for the extraction of organochlorine pesticides

In this work, a ringent multi-shelled hollow MIL-88B (RMH-MIL-88B) was prepared from the original MIL-88B via etching by citric acid, and was used as the fiber (SPME) coating material for the direct-immersion solid-phase microextraction of eleven organochlorine pesticides (OCPs) from fish samples prior to gas chromatography-electron capture detection. The unique multi-shelled structure with void space between shells enables the RMH-MIL-88B to provide more adsorption sites and to have larger adsorption capacities for the OCPs than the original MIL-88B. Under the optimized experimental conditions, a wide linear range (from 3.3 to 600.0 ng g−1) with the coefficients of determination (r2) varying from 0.9960 to 0.9997 was obtained. The limits of detection (S/N of 3) for the analytes were in the range of 1.0–3.0 ng g−1. In the determination of the analytes, the single fiber repeatability (n = 5) by single RMH-MIL-88B-coated fiber ranged from 4.1 % to 7.6 %, while the fiber-to-fiber reproducibility by five parallel RMH-MIL-88B-coated fibers were in the range of 8.0 %–12 %. The established method was successfully applied for the sensitive determination of the eleven OCPs in four fish samples (grass carp, crucian carp, tilapia, and mandarin fish). The relative recoveries of the analytes for spiked fish samples at three concentration levels (15.0, 80.0 and 300.0 ng g−1) were in the range of 82.11 %–115.7 % with the relative standard deviations of 4.4 %–12 %.