Acetonitrile

1-Benzyl-2-methylimidazole
(120 mmol, 20.67 g, Sigma-Aldrich 90%) and 1,4-Dibromobutane (50 mmol,
10.80 g, Sigma-Aldrich 99%) were added dropwise to 150 mL of acetonitrile
(Scharlab). After 4 days of refluxing and stirring, the solid product
was obtained by filtration and then washed with dimethyl ether. After
drying at room temperature, 1,1′-(butane-1,4-diyl)bis(3-benzyl-2-methylimidazolium)
(4bBnMI) bromide was obtained (yield: 70%). The purity of the product
was confirmed by ¹H and ¹³C NMR spectra by dissolving
the bromide salts in D₂O. ¹H NMR (300 MHz, D₂O) δ 7.55–7.37 (m, 10H), 7.33 (dt, J = 6.8, 2.2 Hz, 4H), 5.37 (s, 4H), 4.27–4.13 (m, 4H), 2.57
(s, 6H), 1.84 (p, J = 3.3 Hz, 4H). ¹³C
NMR (75 MHz, D2O) δ 144.15, 133.66, 129.33, 128.97, 127.79,
121.78, 121.15, 51.51, 47.43, 25.83, 9.33.
To obtain the OSDA
in hydroxide form, 17.73 g 4bBnMI bromide was added to a mixture of
240 mL of pure water and 120 mL of anion exchange resin (Amberlite
IRN78 OH hydroxide from, Sigma-Aldrich; exchange capacity: 1.1 mmol
per mL wet resin). After stirring overnight, the OSDAOH solution was
collected by filtration. The diluted OSDA hydroxide solution was concentrated
in a rotary evaporator at 72 °C, and the concentration of solution
was determined by titration with 0.1 M HCl solution (exchange ratio
91%).

Standards of berberine (Batch No. 20180707, purity > 95%) were gotten from Shanghai Pure One Bio Tech Co., Ltd. (Shanghai, China). Standards of dopamine (DA) and norepinephrine (NE) (Batch No. N-5785, H 8502-5G, respectively; purity > 95%) were gotten from Sigma (St. Louis, MO). The activated carbon (Batch No. 07093005) was purchased from Wuxi Zhanwang Chemical Reagent Co., Ltd. (Wuxi, China). HPLC grade methanol and acetonitrile were purchased from Scharlab, S. L. (Barcelona, Spain). The water for HPLC was purified by an ultrapure water instrument. Other reagents used in the present study were of analytical grade.

Analytical standards of trans-4-GG crocin (crocetin bis-(gentiobiosyl) ester), trans-3-Gg crocin (crocetin gentiobiosyl glucosyl ester) and picrocrocin were purchased from Phytolab (Vestenbergsgreuth, Germany) while p-nitroaniline was obtained from Sigma Aldrich (St. Louis, MO, USA). Acetonitrile and methanol, used for the chromatographic analyses, were of HPLC-MS grade and acquired from Scharlau (Barcelona, Spain). Formic acid was obtained from Sigma Aldrich. The ultrapure water used was distilled and purified using the Milli-Q, Advantage A10 system from Millipore (Bedfore, MA, USA).

Isoprene (99.5%) and d-limonene (95%) were purchased from Sigma-Aldrich (Shanghai, China). Acetonitrile (99.5%) and acetone (99.98%) were ordered from Scharlau (Barcelona, Spian) and Fisher Scientific Company (London, UK). 1,2-pentadiene (95%) and dl-limonene (99.5%) were from Tokyo Chemical Co. (Tokyo, Japan). All chemicals were used without further purification. 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄], (98%)), with water content below 500 ppmv [29 (link)], was purchased from Sigma-Aldrich and it was further purified through rotary evaporation under vacuum.

Azole pesticides (analytical grade quality), hydrogen peroxide solution (33% wt.), nitric acid (65%), and hydroxylamine (≥ 99%) were obtained by Sigma-Aldrich. Acetonitrile (99.9%) and 1,10-phenantroline (≥ 99%) were provided from Scharlau and Fluka, respectively. All reagents were used without further purification. The magnetite mineral powder employed as catalyst (ref: 500121500) was provided by Marphil S.L. (Spain). Natural magnetite granules (ref: 0029882796573), used to pack the magnetite powder in the FBR, were supplied by Inoxia (UK). Unless otherwise indicated, all trials were conducted using deionized water. The main properties of the azole pesticides tested in this work are summarized in Table 2.Table 2

Main properties of the azole pesticides