Determination of nucleic acids by near-infrared fluorescence quenching of hydrophobic thiacyanine dye in the presence of Triton X-100.
A near-infrared (near-IR) fluorescence quenching method was developed for the determination of nucleic acids in aqueous solution by using a cationic heptamethylene thiacyanine as a probe. The near-IR cationic cyanine showed maximum excitation and emission wavelengths at 800 and 825 nm, respectively, in the presence of Triton X-100; the fluorescence of the cyanine could be greatly quenched by DNA. The calibration graphs were linear over the range of 10-400 ng/mL for CT (calf thymus) DNA and over the range 5-400 ng/mL for FS (fish sperm) DNA under optimal conditions. The corresponding detection limits were 5.2 ng/mL for CT DNA and 2.5 ng/mL for FS DNA. The relative standard deviation (n = 8) was 3.1% for 75 ng/mL CT DNA and 2.2% for 75 ng/mL FS DNA, respectively. Preliminary research showed that the fluorescence quenching might be ascribed to the formation of dye aggregate facilitated by DNA.
Zhu
Chang-Qing
CQ
The Key Laboratory of Analytical Science of MOE, Department of Chemistry, Xiamen University, Xiamen 361005, China.
Wu
Yu-Qin
YQ
Zheng
Hong
H
Chen
Jin-Long
JL
Li
Dong-Hui
DH
Li
Shun-Hua
SH
Xu
Jin-Gou
JG
D000818:Animals; D002232:Carbocyanines / Q000737:chemistry*; D004247:DNA / Q000032:analysis*; D005453:Fluorescence; D017830:Octoxynol / Q000737:chemistry*; D009994:Osmolar Concentration; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
D002232:Carbocyanines; D017830:Octoxynol; D004247:DNA