Phosalone

The various insecticides, including diazinon, paraoxon-ethyl, phosalone, dimethoate, fenitrothion, chlorfenvinphos, and heptenophos, were purchased from Sigma-Aldrich (Schnelldorf, Germany) (for the purity of the analytes, see Table S1). The target compounds were selected to investigate the impacts of the polarity and solubility in the water/octanol system on the extraction process using the developed SPME fibers. Additionally, the selected compounds varied significantly in terms of their molecular sizes, which may have had an influence on the kinetics of the extraction process. Quantitatively, the aforementioned properties were determined by the pKa values (in the range 2.6–8.39), Log K_ow (octanol/water partition coefficient) (in the range of 0.78–4.38), and molar masses (in the range of 229.30–367.81). Detailed data are provided in Table S1 in the Supplementary Materials. A stock standard solution (100 mg L⁻¹) of each compound was prepared in acetonitrile. Furthermore, working standard solutions were prepared by diluting the prepared stock solutions with methanol (HPLC grade, Sigma-Aldrich, Poznan, Poland). The solutions were stored at 4–5 °C.

CRM for organochlorine pesticides comprised a mixture of 20 compounds viz. α-BHC, β-BHC, γ-BHC, Δ-BHC, heptachlor, Aldrin, heptachlor epoxide, trans-chlordane, cis-chlordane, endosulfan-I, endosulfan-II, endosulfan sulfate, 4,4′-DDE, 4,4′-DDD, 4,4′-DDT, dieldrin, endrin, endrin aldehyde, endrin ketone and methoxychlor; a herbicide mix of 5 compounds viz. atrazine, simazine, alachlor, metolachlor and butachlor and were procured from Sigma Aldrich (USA).
Individual standards for hexachlorobenzene, and several organophosphate pesticides including ethion, disulfoton, malaoxon, fenthion, phosalone, methyl parathion, methyl chlorpyrifos, ethyl parathion, fenitrothion, propazine and methyl paraoxon, were all procured from Sigma Aldrich (USA). Standards for malathion, acephate, phosphamidon, captafol, diazinon and monocrotophos were procured from Accustandard, Inc. (USA). A mixture of pyrethroid compounds including Cyfluthrin, L-cyhalothrin, cypermethrin-I, cypermethrin-II, cypermethrin-III, deltamethrin, pendimethalin, permethrin-I, permethrin-II, fenvalerate, and tefluthrin were also purchased from Accustandard, Inc. (USA).