比率型红色荧光探针羧基铝酞菁对pH的长程响应及其应用

Tetracarboxy aluminum phthalocyanine,a novel ratiometric and red-emitting fluorescence probe responding to a wide-range of pH and its applications

对四羧基铝酞菁（AlC_4Pc）在大范围酸度介质中的荧光光谱行为进行了考察和分析,探索其作为pH测定比率型红色荧光探针的可行性。AlC_4Pc长波区域（红色）的特征荧光发射随着介质pH的增加而升高,对其荧光激发光谱进行深入分析,获得了重要的发现：AlC_4Pc在长波激发带（Q带）的荧光强度比率（激发波长分别为615nm和622nm）与介质的pH在大范围内（5.0~12.1）呈线性正相关。以参比法测定了AlC_4Pc的相对荧光量子产率,结果表明AlC_4Pc荧光量子效率较高,具有分析应用价值。结合吸收光谱研究探讨了AlC_4Pc对pH的长程响应机理,认为AlC_4Pc对pH的长程响应是由于AlC_4Pc的多步电离与分子间缔合综合作用而引起。上述研究提示AlC_4Pc有望成为新型比率型pH红色荧光探针。将该探针和建立的方法应用于多种实际样品的荧光比率测定,取得了较满意的结果。

The behavior of absorption and fluorescence spectra of four carboxyl aluminum phthalocyanine（ AlC_4Pc） in a wide range of acidity was investigated to explore the feasibility as a novel fluorescent probe for the determination of p H.Intensity of fluorescence emission of AlC_4Pc increased with the increase of p H.Namely,feature emission intensity of AlC_4Pc was positively correlated with the environmental p H.Important discovery was obtained through careful analysis of the fluorescence excitation spectra of the AlC_4Pc at 615 and 622 nm that the fluorescence intensity ratio showed a linear positive correlation with p H,implying that AlC_4Pc may be a novel fluorescent ratiometric p H probe emitting at red-region.The ratio of fluorescence intensity responses to p H in a broad range（ p H 5.5- 12.1） with positive relationship,indicating that AlC_4Pc has great potential to be a new ratiometric probe for p H detection by fluorimetry.The relative fluorescence quantum yield of AlC_4Pc was first determined by a reference method,and the results showed that AlC_4Pc is a fluorophore with high fluorescence quantum yield.The mechanism of AlC_4Pc responding to p H in wide range was also investigated,and responding effect could be attributed to the association and the multiple ionization of AlC_4Pc.The probe and the constructed method were employed to the determination of p H in real samples with satisfactory results.