Milli q plus

Methanol (HPLC-grade), chloroform (HPLC-grade), and acetonitrile (HPLC-grade) were obtained from Carlo Erba Reagenti (Milan, Italy). Double-distilled water was obtained using a Millipore Milli-Q Plus water treatment system (Millipore Bedford Corp., Bedford, MA, USA). Deuterated water (D₂O) 99.97 atom% of deuterium, methanol-D4 99.80 atom% of deuterium, and chloroform-D 99.80 atom% of deuterium + 0.03% tetramethylsilane (TMS) was purchased from Euriso-Top (Saclay, France). 3-(trimethylsilyl)-propionic-2,2,3,3-d₄ acid sodium salt (TSP) was purchased from Merck (Milan, Italy).

Acetonitrile and methanol (HPLC grade) were obtained from Merck (Darmstadt, Germany). Sodium chloride (NaCl, analytical grade), anhydrous magnesium sulfate (MgSO₄, analytical grade) and ammonium acetate (HPLC grade) were supplied by ANPEL (Shanghai, China). Purified water was prepared using a Milli-Q Plus apparatus (Millipore, Billerica, MA, USA).
The analytical standards (stock solutions) of AOH (100.0 µg mL⁻¹), AME (100.3 µg mL⁻¹) and TeA (101.1 µg mL⁻¹) dissolved in Acetonitrile were purchased from Romer labs (Union, MO, USA).
Yellow peaches with uniform fruit size, ripeness and the absence of physical defects or apparent infections were collected from local retail markets and brought to the laboratory in pre-sterilized polyethylene bags.

Methanol and acetonitrile, both HPLC grade, were obtained from Merck (Darmstadt, Germany). Formic acid and ammonium acetate were obtained from Sigma-Aldrich (St. Louis, MO, USA). Water was purified using a Milli-Q Plus apparatus (18.2 Ω, Millipore, Billerica, MA, USA) prior to use. The standards of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), aflatoxin M1 (AFM1), aflatoxin M2 (AFM2), OTA, ochratoxin α (OTα), fumonisin B1 (FB1), T-2 toxin (T-2), HT-2 toxin (HT-2), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), fusarenon X (FUS-X), ZEN, α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), and β-zearalanol (β-ZAL) were purchased from Romer Labs (Union, MO, USA). The mycotoxin conjugates deoxynivalenol-3-glucuronide (DON-3-GlcA) and zearalenone-14-glucuronide (ZEN-14-GlcA) were prepared in our laboratory as described in a previous study [12 (link)]. The quantification of DON-15-GlcA was based on the standard concentration curve of DON-3-GlcA as described in a previous study [21 (link)].

The blank liposome (with no encapsulated drug) was prepared by hydrating the Pro-lipo duo^® with purified water from a water purification system (Milli-Q Plus, Millipore, Bedford, MA, USA). The Pro-lipo duo^® consisted of 50% unsaturated soybean phosphatidylcholine suspended in hydrophilic medium consisting of glycerol and ethanol. The purified water was used to ensure that the concentration of contaminants in the suspension was negligible. The amount of purified water added was two parts to one part of the pro-liposome. The mixture was then stirred at a moderate speed using a hot plate stirrer (502-P, PMC Industries, Inc., San Diego, CA, USA) for 30 min at room temperature. Prior to use, the suspension of resultant blank liposome was further diluted with five parts of purified water (relative to the pro-liposome) and stirred for another 5 min to produce a homogenous suspension. The lipid concentration in the final dispersion was 6.25% w/v.

The _L- and _D-DOPA (≥98%, CP) were purchased from Sigma-Aldrich (Beijing, China). Hydrochloric acid (HCl), sodium hydroxide (NaOH), sodium chloride (NaCl), phosphate, and potassium chloride (96%, AR) were obtained from Tianjin Kemiou Chemical Reagent Co., Ltd. (Tianjin, China). Phosphate buffered saline (PBS, pH 7.4; 10 mM phosphate, 138 mM sodium chloride, and 2.7 mM potassium chloride) was used as a flowing buffer. The water used in all experiments was prepared by a three-stage Millipore Milli-Q Plus 185 purification system (Millipore Corp., Bedford, MA) and had a resistivity of 18 MΩ cm. The pH values of all solutions were measured with an MP220 pH meter (Mettler Toledo, Switzerland). All solutions were filtered using a 0.22 µm syringe filter before use. Phosphate buffered saline (PBS, pH 7.4; 10 mM phosphate, 138 mM sodium chloride and 2.7 mM potassium chloride) was prepared in our laboratory. The buffers’ pH values were measured using an MP220 pH meter (Mettler Toledo, Switzerland). Ultrapure deionized water was produced by a Milli-Q water purification system (Millipore Corporation, Billerica, MA, USA).

Each sample was dialyzed into desired buffers at 4–10 °C overnight using Zeba desalting columns (Thermo Fischer), after which the concentration was determined using appropriate extinction coefficients in NanoDrop™ 8000 Spectrophotometer (Thermo Fischer). Two solvents were used: 10 mM sodium acetate, 50 mM NaCl, pH 5.0; and Dulbecco’s PBS (pH 7.4) containing 8 mM sodium phosphate dibasic, 1.5 mM potassium phosphate monobasic, 2.7 mM KCl, and 138 mM NaCl. The acetate buffer was prepared by diluting chemicals purchased from Sigma into distilled deionized water from a Milli-Q Plus filtration system (Millipore, Burlington, MA, USA) and titrating to the desired pH 5.0 with 10 N NaOH solution. For all measurements, the sample solutions were used within a week of preparation and stored at 4 °C between measurements.

As the simulated gastric fluid (SGF, pH = 1.2), an aqueous solution of 0.1 M HCl without enzymes was used [21 (link)]. The deionized water used for all experiments was obtained from a Milli-Q Plus water purification system (Millipore, Bedford, MA, USA). Zeolite samples were exposed to SGF solution under mild shaking conditions at 37 ± 0.5 °C in 1:2, 1:1, 2.5:1, 5:1, and 10:1 zeolite-to-SGF ratios (w:v) for 1, 3, 5, and 7 days. After immersion, the liquid phase was separated by centrifugation at 4000 rpm for 5 min and filtered through a 45 µm cellulose acetate membrane. The concentrations of Si, Al, Fe, Ca, Mg, K, Na, and P released in SGF were measured using a 5300 Optima DV (Perkin Elmer, Waltham, MA, USA) inductively coupled plasma optical emission spectrometer (ICP-OES) after microwave digestion using the method described previously [9 ]. For the ICP-OES, external calibration using calibration solutions in the range of 0–20 mg L⁻¹ were prepared from 1000 mg L⁻¹ multielement (Na, K, Ca, Mg, Fe and Al) and monoelement (P and Si) standard solutions (Merck, Darmstadt, Germany) diluted in 0.5% (v:v) HNO₃ [39 (link)]. The experiments were carried out in triplicate and the average values were reported. The pH changes of SGF before and after exposure of zeolites were monitored using a Seven Excellence multiparameter (Mettler Toledo, Schwerzenbach, Switzerland) [9 ].