First, 5 mL aqueous sample was placed in a 10 mL screwcap
glass conical tube without pH adjustment. Then the mixture of
65 μL [C6MIm][PF6], 120 μL [EMIm][BF4], and 30 μL [BSO3HMIm][OTf] were rapidly injected into the tube and the cloudy solution was formed.