基于碳点的荧光探针“关-开”测定卡托普利

Sensitive Detection of Captopril Based on“Off-On”Carbon Dots as Fluorescent Probe

以柠檬汁和尿素为原料,通过一步简单的微波热解制得了含氮荧光碳点(NCDs)。所得碳点发蓝色荧光,量子产率高达53.1%。Hg^(2+)可以与NCDs表面基团络合形成非荧光的稳定化合物,导致荧光猝灭。通过荧光猝灭与寿命的关系和紫外-可见光谱的变化情况得出猝灭应属静态猝灭。另外,卡托普利的加入可以使NCDs荧光得以恢复,这是因为Hg^(2+)与卡托普利的成键作用强于NCDs,卡托普利的加入使Hg^(2+)脱离NCDs表面,荧光得以恢复。在最优化的实验条件下,卡托普利的检测范围是0.25~25μmol·L^(-1),检出限为0.17μmol·L^(-1)。该探针成功地用于卡托普利片剂中有效成分的测试并取得了满意的效果。

Fluorescent nitrogen-doped carbon dots(NCDs)were synthesized by a facile one-step microwave strategy using lemon juice and urea.The obtained NCDs show stable blue fluorescence with a high quantum yield of 53.1%.Hg^(2+) can efficiently coordinate onto the surface of NCDs by means of electrostatic interactions and remarkably quench the fluorescence of NCDs as a result of the formation of a non-fluorescent stable NCDs-Hg^(2+) complex(turn-off).Static fluorescence quenching towards Hg^(2+) is proved by the fluorescence lifetime measurements and the change of ultraviolet-visible absorption spectra.In addition,the fluorescence of NCDs-Hg^(2+) system was recovered with the addition of captopril(CAP)due to the ability of captopril to coordinate with Hg^(2+) and the formation of strong Hg^(2+)—S bond.When captopril was added,Hg^(2+) combined with captopril rather than with NCDs resulting in the remove of Hg^(2+) from the surface of NCDs and a significant fluorescence restore of NCDs was observed(turn-on).Under the optimized conditions,good linearity for detecting captopril was attained over the concentration range 0.25-25μmol·L^(-1) with a detection limit of 0.17μmol·L^(-1).Moreover,this NCDs-based sensor was successfully applied for quantitation of captopril in tablets with satisfactory recovery.