Galvanic replacement synthesis of Cu@Zeolitic imidazolate framework-8 reinforced hollow fiber for hollow fiber solid-phase microextraction of diazinon and malathion followed by HPLC-UV determination

This paper represents the synthesis of zinc-based metal-organic framework-8 by the solvothermal method followed by doping of copper (Cu) metal by the purely chemical galvanic replacement method in the synthesized ZIF-8 substrate. Subsequently, the Cu doped ZIF-8 was used as an adsorbent in the hollow fiber solid-phase microextraction (HF-SPME) method for the extraction and determination of organophosphorus pesticides (OPPs), especially diazinon and malathion, from real samples contentiously from tomato, cucumber, apple, and well water. Optimization was done through the Plackett-Burman design and Box-Behnken design. Limits of detection (LODs) of 0.29 µgL⁻¹ and 0.54 µgL⁻¹, while limits of quantification (LOQs) of 0.96 µgL⁻¹ and 1.79 µgL⁻¹ were recorded for diazinon and malathion, respectively. The linear dynamic ranges (LDRs) for both analytes were established as 1–200 µg L⁻¹ and 2–500 µg L⁻¹ with determination coefficients (R²) of 0.9953 for diazinon and 0.9968 for malathion, indicating excellent linearity. The enrichment factors (EFs) were determined to be 152 for diazinon and 146 for malathion. RSDs% were obtained in the range of 4.21 % - 5.78 % for intra-day and 3.53 % - 6.24 % for inter-day precision. The results obtained from the experiments indicate that the developed method has a significant ability to extract and analyze selected analytes in a wide range of real-world samples, which proves the effectiveness and reliability of the method.