Solid substrate-room temperature phosphorimetry for the determination of trace lead using p-nitro-phenyl-fluorone-multi-wall carbon nanotubes–Tween-80 micellae compound and diagnosis about human diseases

The structures of multi-wall carbon nanotubes (MWNTs) were modified by H 2SO 4–HNO 3 and H 2SO 4–H 2O 2, respectively. The corresponding products were water-soluble MWNTs-A and MWNTs-B. According to the experiment, it was found that MWNTs-B could emit stable solid substrate-room temperature phosphorescence (RTP) on the surface of paper with Ag + as perturber. Under the conditions of 70 °C and 15 min, MWNTs-B can react with Tween-80 and p-nitro-phenyl-fluorone (R) to form R-MWNTs-B–Tween-80 micellae compound, which could emit RTP of R and MWNTs-B on the surface of paper, respectively. Pb 2+ could cause the RTP of R and MWNTs-B enhanced sharply, respectively. Δ I p is directly proportional to the content of Pb 2+. A new solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace Pb 2+ has been established based on R-MWNTs-B–Tween-80 micellae compound containing double luminescent molecule. The detection limit of this method were 0.035 ag Pb 2+ spot −1 (8.8 × 10 −17 g Pb 2+ ml −1, MWNTs-B) and 0.028 ag Pb 2+ spot −1 (7.1 × 10 −17 g Pb 2+ ml −1, R). This method is of high sensitivity, good selectivity, high precision and accuracy. It could be applied to determine trace Pb 2+ in serum samples at wavelength of 453.7/623.0 nm (R) or 475.9/645.0 nm (MWNTs-B) with satisfactory results, showing that SS-RTP has flexibility and utility value. Simultaneously, this method can be used to diagnose human diseases. The reaction mechanism for the determination of trace Pb 2+ by SS-RTP based on R-MWNTs-B–Tween-80 micellae compound containing double luminescent molecule was also discussed.