Ethyleneglycol, anhydrous ethanol, sodium acetate anhydrous, iron(iii ) chloride hexahydrate, tetraethyl orthosilicate (TEOS), concentrated ammonium aqueous solution (25 wt%), sodium citrate, silver nitrate, sodium nitrite, hydrochloric acid, sodium carbonate, acetonitrile, potassium chloride and sodium chloride were purchased from the Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Salbutamol (SAL), sulfanilic acid, 2,2′-benzidinedisulfonic acid, clenbuterol hydrochloride, l -lysine monohydrate, aminoacetic acid, glycerol and phosphate-buffered saline (PBS, pH 7.4) contained NaCl (100 mM) and 10 mM Na2HPO4/KH2PO4, were bought from Aladdin Reagent Co. Ltd. (Shanghai, China). Deionized water (Millipore) with a resistivity of 18 MΩ cm was used in all experiments.
2.39 mg SAL was dissolved in 10 mL methanol (1.0 × 10−3 M) and kept in the dark at 4 °C as stock solution. Then its standard solution was obtained by diluting the stock solution to the desired concentration with distilled water.
2.39 mg SAL was dissolved in 10 mL methanol (1.0 × 10−3 M) and kept in the dark at 4 °C as stock solution. Then its standard solution was obtained by diluting the stock solution to the desired concentration with distilled water.