Fluorescent Determination of Succinylcholine Chloride by Naphthalimide/ Stilbazolium Dye ⊂ CP5A

Succinylcholine Chloride (SCC), a short-acting neuromuscular relaxant, is non-fluorescent in aqueous solutions. This property makes it impossible to be determined by direct fluorescent method. Naphthalimide dye (NA) exhibits very strong fluorescence emissions in aqueous solution, after complexing with carboxylatopillar[5]arene (CP5A) in aqueous solutions, the fluorescent quenched intensity of complex was observed. On the contraty, stilbazolium dye (SA) exhibits weak fluorescence emissions in aqueous solution, after being included by CP5A, a fluorescence enhancement was observed. However, adding SCC to the NA⊂ CP5A or SA⊂ CP5A complex solution led to the recovery of the fluorescence intensity, in the meantime, the color of SA⊂ CP5A solution changed from dark yellow to light yellow. The competitive supramolecular interaction between SCC, NA and SA for CP5A was studied by spectrofluorometry, ¹H NMR. Herein, a FID (fluorescence indicator displacement) system to detect SCC based on NA⊂ CP5A and SA⊂ CP5A complex was developed.