Magnetic partially carbonized cellulose nanocrystal-based magnetic solid phase extraction for the analysis of triazine and triazole pesticides in water

Magnetic partially carbonized cellulose nanocrystals (MPC-CNC) were obtained by sulfuric acid treatment of microcrystalline cellulose (MCC) and then loaded with magnetic Fe3O4 nanoparticles. The material is shown to be a viable material for magnetic solid phase extraction of triazine and triazole pesticides from water. The pesticides (specifically: simazine, ametryn, prometryn, terbutryn, atrazine, triadimenol, epoxiconazole, myclobutanil, triadimefon and tebuconazole) were quantified by ultra HPLC in tandem with a triple quadrupole mass spectrometry (UHPLC-MS/MS). The effects of NaCl concentration, amount of adsorbent, vortex time, sample volume and pH value on extraction efficiency were optimized by Plackett-Burman design and Box-Behnken design methods. Under the optimal conditions, the method shows the following figures of merit: (a) Linear responses in the range from 0.02–10 μg L−1; (b) detection limits between 2.2 to 6.1 ng L−1 (for S/N = 3); (c) recoveries from spiked samples of 73.7–117.1% with relative standard deviations (RSDs) of 2.0–15.7%; and (d) an enrichment factor of 75. The method was successfully applied to the determination of the pesticides in five environmental water samples.