RLS spectra of bindings of P1 and P1≈T1 with Cu (II)-TPP. The RLS intensitities of Cu (II)-TPP, P1 and P1≈T1 are weak. When P1≈T1 is mixed with Cu (II)-TPP, several enhanced RLS peaks can be observed at 362?nm, 410?nm and 471?nm(Curve 4), this enhancement is very significant, it indicate that a complex of Cu (II)-TPP-P1≈T1 is formed. With the increase of the concentration of P1≈T1, the RLS intensity increased, the enhanced RLS intensity is proportional to the concentration of P1≈T1 in an appropriate range (e.g.0.2–1.0?×?10?7?mol?L?1) ( Curve 5–7), so this method could be applied to determine oligonucleotide conveniently.