Determination of adenine based on the fluorescence recovery of the L-Tryptophan–Cu2+ complex

• The method exhibited highly selective and real time response linear relationship to adenine.
• Adenine could be detected at low micromolar levels and was detected in ctDNA.
• Fluorescence quenching and recovery mechanism was discussed.

A simple and sensitive method for determination of adenine was developed based on fluorescence quenching and recovery of L-Tryptophan (L-Trp). The fluorescence of L-Trp could efficiently quenched by copper ion compared with other common metal ions. Upon addition of adenine (Ade) in L-Trp–Cu(II) system, the fluorescence was reoccurred. Under the optimum conditions, the recovery fluorescence intensity was linearly correlated with the concentration of adenine in the range from 0.34 to 25.0 μmol L−1, with a correlation coefficient (R2) of 0.9994. The detection limit (3σ/k) was 0.046 μmol L−1, indicating that this method could applied to detect trace adenine. In this study, amino acids including L-Trp, D-Trp, L-Tyr, D-Tyr, L-Phe, D-Phe were investigated and only L-Trp could well chelated copper ion. Additionally, the mechanism of quench and recovery also were discussed and the method was successfully applied to detect the adenine in DNA with satisfactory results.

The graphical presentation of the fluorescence quenching of L-Tryptophan (L-Trp) by copper ion and the recovery fluorescence occurred upon addition of adenine (Ade) in L-Trp–Cu2+ system.Figure optionsDownload as PowerPoint slide