Nylon syringe filters

Ciprofloxacin (CIP) (≥99%), titanium (IV) oxide (≥99.5%), polyvinylpyrrolidone (average mol wt 10,000) (PVP), tert-butanol, tetrahydrofuran (THF) and triethanolamine were obtained from Sigma-Aldrich (Schnelldorf, Germany). Formic acid (98%) for mass spectrometry was from Fluka Analytical. HPLC-grade acetonitrile was purchased from Scharlab (Barcelona, Spain). Ethyleneglycol and melamine (99%) were from Alfa Aesar (Kandel, Germany). Nylon syringe filters (13 mm, 0.22 µm) were from Scharlab (Barcelona, Spain).
The precursor [Au₂Ag₂(C₆F₅)₄(OEt₂)₂]_n was prepared according to the literature [15 (link)].

The HPLC-grade solvents such as methanol (MeOH) and ethanol (EtOH) were obtained from Scharlab (Barcelona, Spain), and acetonitrile (ACN) was obtained from Fisher Chemical (Madrid, Spain). Monosodium phosphate (NaH₂PO₄) and disodium phosphate (Na₂HPO₄) were purchased from Panreac (Barcelona, Spain). Ultrapure deionized water with a resistance of 18.2 MΩ cm was obtained by a Milli-Q system (Billerca, MA, USA). Nylon syringe filters (0.45 μm, 13 mm) were purchased from Scharlab (Barcelona, Spain). For standard solutions preparation, α-solanine (>99%) and α-chaconine (>99%), purchased from Phytolab (Madrid, Spain), were used. Individual stock standard solutions of α-solanine and α-chaconine were prepared at a concentration of 200 μg/mL in MeOH and stored at −20 °C. The calibration standards were prepared at the appropriate concentrations (1, 2.5, 5, 10, 25, 50, and 100 mg/L for both analytes) by serial dilution of the stock solutions in MeOH. The prepared solutions were stored in the dark at a temperature of −20 °C.