Syringe filter

A Pyrex batch reactor of beaker with volume of 250 mL, was used for performing the reactivity experiments. Illumination is provided by solar simulator UVACUBE 400, Honle, Germany. The photocatalytic activity of prepared photocatalyst is tested by reactions of photo-degradation of 4-nitrophenol. 100 ml of 20 ppm of pollutant (PNP, Cr⁶⁺ ions) was added to photoreactor. The photocatalyst of 50 mg was suspended in 100 ml of aqueous solution of pollutant and then stirred for 30 min to make the photocatalyst homogeneously dispersed into the solution of reaction. Then, the solar simulator was turned on, sample were taken at time interval. The concentration of 4-nitrophenol and Cr⁶⁺ ions are analyzed by a JASCO- V-730, UV–Visible recording spectrophotometer at λ_max = 318 and 350 nm, respectively. Before determination, the withdrawn suspensions are filtered with syringe filter (Whatman, 0.45 µm). The pathway of photocatalytic mechanism is investigated in presence of ethanol, ascorbic acid (AA), and ethylene diamine tetra acetate (EDTA) with concentration (2 mM) for each one as ^•OH radical, O₂^−• radical and holes scavengers, respectively.

Pretreatment-derived supernatants were re-centrifuged at 2465g and 200 μl of the supernatant was filtered using a syringe filter (0.2 µm, Whatman International Ltd, Maidstone, UK), and injected into vials. The concentrations of the fermentation inhibitors 2-furfuraldehyde (2-FA), 5-hydroxymethylfurfural (5-HMF), and the organic acids (formic and acetic acid) were analysed by an HPLC using a Flexar LC instrument (PerkinElmer, Seer Green, Bucks., UK) equipped with refractive index and photo diode array detectors (outputting chromatograms at 210, 280, and 325 nm wavelengths) in series. The analyses were carried out using an Aminex HPX-87H organic acid analysis column (Bio-Rad Laboratories Ltd, Hemel Hempstead, UK) operating at 65 °C with 0.004 mol/l H₂SO₄ (Sigma-Aldrich) as the mobile phase at a flow rate of 0.6 ml/min.

For the QuEChERS extraction, 7 mL Milli-Q water and 15 mL acetonitrile (ACN) were added to the spiked GFFs. The mixture was shaken head-to-head for 30 min. Afterwards, 5 g of anhydrous magnesium sulphate (MgSO4) and 1.5 g of sodium acetate were added. The tube was then vortexed for 1 min and centrifuged at 3500 rpm for 5 min. For LC-QTOF analysis, an aliquot of 125 µL was transferred to a LC vial, and 25 µL of the LC injection standard mix and 350 µL of Milli-Q water were added. The extract was filtered by a syringe filter (0.2 µm, Whatman) prior to analysis. For the GC-MS/MS analysis, an aliquot of 4.5 mL was transferred into a 15 mL Eppendorf tube, and different steps for the clean-up with a dispersive SPE were tested as described in the “Clean-up of sample extracts” section. For the final d-SPE clean-up, MgSO4, primary secondary amine (PSA) and C18 were added. The tube was vortexed for 1 min and centrifuged at 3500 rpm for 15 min. An aliquot of 3.5 mL was transferred into a Barkey vial and evaporated under nitrogen to 150 µL. A solvent switch was performed by the addition of 150 µL of hexane, vortexing the mixture for 1 min, and transferring the upper hexane phase into a GC vial. 20 µL of the GC injection standard was added before analysis.

All chemicals were used without further purification. The picene single crystals were prepared by the drop-drying method^{17 (link)}. The saturated precursor solution was prepared as follows: picene (Alpha Aesar, 99%) powder was dissolved in toluene (Alfa Aesar, 98%) and then sonicated for 30 min. The solution was kept at room temperature for 10 min, and then, the saturated solution was filtrated using a syringe filter with the pore size of 0.02 μm (Whatman, Maidstone, Kent, UK) to remove the undissolved picene. A small amount (approximately 20 μL) of the saturated solution was dropped onto a SiO₂/Si substrate and dried under ambient conditions by allowing the evaporation of toluene. Picene crystals were obtained upon evaporation of the solution. Complete evaporation of the solvent took approximately 15 minutes. The obtained crystals were used for further experiments without any other treatments.

The CEFBPG was dissolved in the mobile phase of semi-preparative liquid chromatography, then filtered through a 0.45 μm syringe filter (Whatman, Brentford, Middlesex, UK). The resulted clear yellow solution is directly injected into the column by a 7125i Rheodyne injector. The fractions containing individual ginsenoside were collected respectively, and then combined and concentrated under vacuum. Ginsenoside F₅ and F₃ were finally obtained as white powder.