基于纳米金表面等离子体的高灵敏过氧化氢光学检测方法
High-Sensitivity Optical Hydrogen Peroxide Detection System Based on Surface Plasma of Gold Nanoparticles

在酸性2-吗啉乙磺酸介质中，建立基于纳米金表面等离子体的微量过氧化氢（H2O2）的比色检测体系，探讨裸眼检测途径下的分辨极限，提高体系稳定性并利用光谱分析精确定量H2O2浓度（c）. 结果表明，当c<100 μmol/L时，纳米金为团聚态，呈现蓝色；c>120 μmol/L时，纳米金为分散态，呈现红色. 该方法的裸眼检测极限可分辨浓度差为20 μmol/L. 反应溶液的显色结果并不稳定，在反应后45 min内变化较快，c为60~100 μmol/L的反应溶液也将逐渐由蓝色变为红色. 溶液在570 nm处的吸光度 (OD_570) 检测证明，反应体系在检测后3 h内仍持续变化. 反应10 min后，加入适量半胱甘肽终止反应，可使反应溶液的显色结果稳定，提高体系稳定性. 实验测定不同浓度H2O2反应产物的吸收光谱发现，c<100 μmol/L的反应孔产物在波长约550 nm处有吸收峰，且吸收强度与c成正相关. 而c>120 μmol/L的反应产物吸收峰逐渐往短波长方向偏移，最终峰值约为540 nm. 分析反应体系吸收光谱结果证明，各反应产物在630 nm和545 nm处吸光度的比值 (OD_630/545) 与c呈良好的线性关系. 实验对c为100~120 μmol/L的H2O2溶液进行检测，定量浓度差为2 μmol/L的H2O2溶液，降低裸眼检测途径下该方法的分辨极限，为微量样品检测提供更好的平台.
： A colorimetric method was developed for the determination of trace amount of H2O2 in acidic 2-(N-morpholino) ethanesulphonic acid buffer medium, based on surface plasma of gold nanoparticles. The detecting system, whose limit of detecting resolution with naked eyes was measured previously, was used to accurately quantify the concentration(c) of H2O2 by spectral analysis after stabilization enhancement. The results show that blue-coloured solutions with aggregated gold nanoparticles could be obtained when c<100 μmol/L, while the solutions were red-coloured with non-aggregated gold nanoparticles when c>120 μmol/L. The resolution limit of human eyes to this detection system was able to distinguish H2O2 concentration difference of 20 μmol/L. However, the color distinction of solutions was unstable and has a quick change in 45 mins. The blue solution with c of 60 to 100 μmol/L turned red gradually. The OD_570 of solutions also demonstrates that the reaction was constantly changing in 3 h after detection. Moderate L-glutathione was added to terminate the reaction after 10 min to improve the detection stability, which can stabilize the color distinction and effectively keep a constant OD_570. The spectra of the nanoparticle dispersions show the absorption peak at 550 nm and there is a positive correlation between intensity and the H2O2 concentration when c<100 μmol/L. The absorption peak shifted to 540 nm when c>120 μmol/L. By the spectral analysis, a linear relativity of regressive curves of OD_630/545 and the concentration of H2O2 was found. Then solutions with c from 100 to 120 μmol/L were detected and accurately quantified H2O2 with concentration difference of 2 μmol/L to break the limit of detecting resolution. The detection system could provide a preferential platform for trace detection