Fluorescent carbon dots sensor for highly sensitive detection of guanine

In the present work, unmodified carbon nanodots (CDs) can act as fluorescent probes for detection and measurement of guanine concentration. CDs were synthesized by using a facile one-step microwave-assisted method with DL-malic acid and ethylenediamine as the precursors. The fluorescence of CDs can be obviously quenched by copper(II) ions through nonradiative electron transfer. Meanwhile, due to the coordination of copper(II) ions with guanine, the fluorescence of the CDs was restored reversibly by the addition of guanine. Under optimized conditions, the prepared CDs demonstrate a linear range from 1.31 x 10(-8) to 7.27 x 10(-7) mol L-1 with the detection limit of 0.67 x 10(-8) mol L-1. The new fluorescence system has been applied for the determination of guanine in urine and DNA samples with the recoveries from 98.1% to 103.0%. (C) 2015 Elsevier B.V. All rights reserved.