金纳米荧光团簇作为一种新型纳米材料, 毒性低, 光稳定性好, 斯托克位移较长。 作为荧光探针, 不容易由杂质造成干扰。 因此, 这类材料在环境监测领域引起了广泛的兴趣。 然而, 由于所选用的配体成本较高, 反应条件复杂, 目前绝大数合成金纳米荧光团簇的方法造价昂贵, 不利于广泛应用。 该工作建立了十分简便的方法, 利用市售鸡蛋蛋清为天然蛋白质配体, 价格低廉, 无毒性, 不需要任何复杂反应条件, 在 37℃的条件下孵化, 水浴加热24 h, 得到亮度很高的红色荧光金纳米团簇, 适合被普遍采纳。 根据实验研究发现, 所得到的金纳米团簇稳定性较好, 其中激发光谱的最大峰位于470 nm, 而发射光谱的最大发射峰位于680 nm, 为典型的红色纳米荧光团簇, 相应的荧光产率为8.76%。 通过进一步研究发现, 所得金纳米荧光团簇可设计为汞金属离子选择性探针。 并根据荧光选择性淬灭现象, 将其成功地应用于污水中Hg2+的检测。 检出限小于1 ppb, 满足安全饮用水的检出限要求。 校准曲线的线性相关线数在 99.8%以上。 同时研究了实际样品中Hg2+的加标回收测试。 并与原子吸收法进行对比。 在低浓度测试时, 该方法有显著的优越性。 在测定高浓度的Hg2+时, 两种方法的结果无明显差异, 进一步说明了方法的准确性。 该方法为天然水中 Hg2+的简便检测提供了有效而又经济实惠的手段。

As a new type of nanomaterials, fluorescent gold nanoclusters are low toxicity, good light stability, and long Storck shift. Based on these excellent properties, they are potentially applied as fluorescence sensors with less interference. These materials have attracted great attentions in the area of environment monitoring. However, due to the high cost and complicated reaction conditions, most methods for synthesizing gold nanoclusters are expensive and are not suitable for wide application. In consideration of the current requirement for more efficient methods for the preparation of fluorescent gold nanoclusters, egg white protein was obtained from market and employed as a green ligand for the synthesis of gold nanoclusters without the utilization of complicated procedures. The nanoclusters could be obtained at 37 ℃ through water bath for 24 h. The procedure was not only effective but also low toxicity during the synthesis process. After the synthesis, highly bright fluorescent gold nanoclusters were obtained. Based on our experiment, the As prepared gold nanoclusters had excellent stability and fluorescence properties. The excitation wavelength for the maximum emission was 470 nm and the wavelength for the emission was 680 nm with a quantum yield of 8.76%. It could be concluded that typical red emitted gold nanoclusters were synthesized, which was favorable for the environment analysis. After further investigation, the As prepared gold nanoclusters could be designed as Hg2+ selective sensor in water solution with little interference. Since the fluorescence could be quenched in the presence of Hg2+ with low concentration, it could be used for the determination of tracing amounts of Hg2+ in polluted water. The detection limit was smaller than 1 ppb, which met the requirement for the determination of Hg2+ for safe drinking water. The relative linear correlation coefficient value for the calibration was larger than 99.8%. Meanwhile, the recovery efficiency for the determination of Hg2+ was investigated. After the comparison with atomic absorption spectroscopy method, it could be concluded that the current method showed advantages for determination of tracing amounts of Hg2+. At the same time, the accuracy was satisfied for the detection of relative high concentration of Hg2+. By the employment of this method, an effective strategy can be expected for the determination of Hg2+ in natural water.