Several novel water-soluble asymmetric pentamethine cyanine dyes were synthesized. The maximum absorption and emission wavelengths of the dyes in different solvents were in the range from 647 to 665 nm and exhibited negative solvatochromism with increasing solvent polarity. The fluorescence quantum yields of the dyes were about 0.1 in water, and were obviously higher than those of hydrophobic cyanine dyes. Dyes with N-benzyl groups and N-sulfo-groups displayed greater photostability than dyes with N-carboxypentyl groups in water. The limit of detection of dye 5a for BSA was 1.2 × 10⁻⁸ mol L⁻¹ by high performance liquid chromatography with fluorescent director about 100-fold lower than that by UV detection (1.0 × 10⁻⁶ mol L⁻¹). Therefore, Dye 5a could be used to improve photostability and detection sensitivity in protein analysis.

合成了几种新型的水溶性不对称五甲胺花青染料。染料在不同溶剂中的最大吸收和发射波长在647至665 nm范围内，并且随着溶剂极性的增加而呈现出负溶剂化现象。该染料在水中的荧光量子产率约为0.1，明显高于疏水性花菁染料。具有N-苄基和N-磺基的染料比在水中具有N-羧基戊基的染料表现出更高的光稳定性。BSA的染料5a的检出限为1.2×10 ^-8  mol L ^-1高效液相色谱仪的荧光指示剂比紫外检测（1.0×10 ^-6  mol L ^-1）低约100倍。因此，染料5a可用于提高蛋白质分析中的光稳定性和检测灵敏度。