基于光热-激光背向散射干涉的生物分子定量检测技术

Quantitative detection technique of biomolecule based on photothermal effect and laser backscattering interferometry

针对传统的显色法中显色产物的定量检测问题,发展了1种结合光热效应和激光背向散射干涉(back-scattering interferometry,BSI)的生物分子定量检测技术。发生显色反应后的生物分子、离子溶液吸收激光会产生光热效应,使得溶液折射率发生改变,其改变量与待测的分子、离子浓度在一定范围内呈正相关。利用激光背向散射干涉技术可实现折射率变化的灵敏检测,从而实现待测物质浓度的定量检测。文中以亚硝酸盐为例,利用改进的格里斯重氮化反应,使得亚硝酸盐中的NO2-转变为紫红色偶氮化合物。采用波长为532nm的激光,利用显色反应后溶液的光热效应和BSI技术实现了NO2-质量浓度的定量检测,使用3σ方法得到检测限为0.05mg/L。

A method based on photothermal effect and laser back scattering interferometry(BSI)technology was developed for quantitative detection of biomolecule using traditional chromogenic reaction.After the color reaction of analyte in solution,the products can absorb the laser energy and induce the photothermal effect,which will induce a change of refractive index of the solution,and the amount of change is positively correlated with the concentration of the analyte.The change of refractive index and then the concentration of the analyte can be sensitively detected by the laser BSI technique.To prove this concept,nitrite was chosen as the analyte.The NO2-was changed to purplish red azo compound through the modified Griess diazotization reaction,and then the NO2-was detected quantitatively based on photothermal effect and BSI technique using laser with the wavelength of 532 nm,the 3σdetection limit was 0.05 mg/L.