Effects of room temperature ionic liquids on fluorescence properties of bisphenol A in β-cyclodextrin

Fluorescence intensity of BPA (FBPA) was enhanced in the presence of β-CD and the maximum emission wavelength was blue-shifted (curves 1 and 3). Fluorescence intensity of BPA (FBPA or FBPA-β-CD) was diminished when RTILs were added (curves 2 and 4); and the ΔF1 = FBPA-β-CD − FBPA-β-CD-RTIL was larger than ΔF2 = FBPA − FBPA-RTIL at the same RTIL concentration. The FBPA-β-CD gradually decreased with increasing RTIL concentrations (auxiliary Fig. 2, curves 1-10). The fluorescence spectra of BPA-β-CD-RTILs with RTIL concentrations ranging from 0.001 to 0.01 mM are shown in curves 1-10. The ΔF1 was about 3-fold larger than ΔF2, demonstrating that there was a sensitizing effect in β-CD.