在金纳米棒(AuNRs)-Ag+-甲醛(HCHO)体系中，HCHO快速将Ag+还原为Ag，Ag包裹在AuNRs表面形成Au@AgNRs，改变了AuNRs周围的电介质环境，导致纵向最大吸收波长（LPAB）红移，同时伴随着溶液的颜色发生显著的变化。据此，发展了一种测定HCHO的快响应、简便、灵敏、选择性的AuNRs比色传感器。该比色传感器的检出限为6.3×10-11(g mL−1)，比表面增强拉曼光谱法低，显示很高的灵敏度；尤其是本比色传感器用于水样品中HCHO的测定，结果与固体基质室温磷光法相吻合，展示较高的实用性。此外，探讨了测定HCHO的机理。%Formaldehyde (HCHO) could reduce Ag+to Ag on the surface of gold nanorods (AuNRs) to form Au core-Ag shell nanorods (Au@AgNRs) in AuNRs-Ag+-HCHO system, which caused dielectric function to change. Thus, a responsive, simple, sensitive and selective AuNRs colorimetric sensor for the determination of HCHO has been developed based on the linear relationship between∆λLPAB and the concentration of HCHO. The limit of detection (LOD) of this sensor is 6.3×10-10 (g mL−1), which is much lower than that of resonance fluorescence spectrometry, showing its high sensitivity. What’s more, the sensor has been applied to the detection of HCHO in water samples with the results agreeing well with resonance fluorescence spectrometry, showing its great practicality. Furthermore, mechanism for the detection of HCHO was also discussed.
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