A nanostructured o-hydroxyazobenzene porous organic polymer as an effective sorbent for the extraction and preconcentration of selected hormones and insecticides in river water

Abstract

A nanostructured o-hydroxyazobenzene porous organic polymer (Hazo-POP) was synthesized by the diazo coupling reaction and characterised using various analytical techniques. The nanostructured Hazo-POP material was applied for the extraction and enrichment of neonicotinoid insecticides and steroid hormones in river water samples. The surface characterization techniques confirmed that the synthesized Hazo-POP had a specific surface area of 251 m2 g−1 and it was mesoporous. The influential factors affecting the UA-D-µ-SPE of the neonicotinoid insecticides and steroid hormones were studied using the design of experiments. The quantification of the target analytes in samples was performed using high performance liquid chromatography coupled with a diode array detector (HPLC-DAD). Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used for the confirmation and validation of the results obtained using HPLC-DAD. At optimal experimental conditions, the UA-D-µ-SPE/HPLC-DAD method displayed low limits of detection (LODs) ranging from 0.4 to 1.3 ng/L for steroid hormones and 0.7–1.2 ng/L for neonicotinoid insecticides. Whereas the limits of quantification (LOQs) were 1.3–4.3 ng/L and 2.3–4.0 ng/L for steroid hormones and neonicotinoid insecticides. For UA-D-µ-SPE/UHPLC-MS/MS procedure, LOQs for steroid hormones ranged from 0.03 to 0.50 ng/L and 0.05–0.50 ng/L for neonicotinoid insecticides. The LOQs were 0.10–0.53 ng/L and 0.13–1.70 ng/L for the steroid hormones and insecticides. The accuracy of the method was assessed using a spike recovery test and recoveries of 93.7%–99.5% (n = 4) with precision (relative standard deviation), below 5% for spiked samples at different levels. The applicability of the UA-D-µ-SPE method was evaluated for the analysis of neonicotinoid insecticides and steroid hormones in real water samples before HPLC-DAD and UHPLC-MS/MS determination. The analytical results obtained using HPLC-DAD water samples were < LOQ-56.3 ng/L and < LOQ-56.3 ng/L for steroid hormones and neonicotinoid insecticides. In comparison with the HPLC-DAD results, the concentration of steroid hormones and neonicotinoid insecticides ranged from 0.19 to 55.9 ng/L and 0.38–55.2 ng/L when using UHPLC-MS/MS.