以胰蛋白酶作为保护剂和还原剂,在胰蛋白酶和氯金酸混合溶液中合成了具有红色荧光的水溶性金纳米团簇(T-Au NCs)。考察了合成时间以及胰蛋白酶溶液的质量浓度对T-Au NCs荧光性能的影响,确立了最佳合成条件。荧光光谱表征说明T-Au NCs的最大激发和发射波长分别为500,640 nm,采用X射线光电子能谱表征了T-Au NCs中金的价态,并计算得到T-Au NCs的荧光量子产率为2.2%。基于过氧化氢对金纳米团簇的荧光猝灭作用,采用荧光光谱法测定食品中的过氧化氢残留量。过氧化氢的浓度的线性范围为0.050~1.00 mmol·L-1,检出限为7 μmol·L-1。对4种食品中过氧化氢残留量的测定结果与国家标准方法的测定结果一致。

Water-soluble gold nanoclusters (T-Au NCs) with red fluorescence were synthesized with trypsin as stabilizing and reducing agent in the mixed solution of trypsin and chloroauric acid. The optimum synthesis conditions for T-Au NCs were defined by investigating the reaction time and the mass concentration of trypsin solution. Fluorescence spectroscopy characterization indicated the maximum excitation and emission wavelengths of the prepared T-Au NCs were 500 nm and 640 nm respectively. The valence state of gold in T-Au NCs was estimated by X-ray photoelectron spectroscopy. The fluorescence quantum yield of T-Au NCs was 2.2%. Based on the fluorescence quenching effect of H2O2 to T-Au NCs, H2O2 residues in the food were determined by fluorescence spectroscopy. The linear range of H2O2 was 0.050-1.00 mmol·L-1, with detection limit of 7 μmol·L-1. The determination results of H2O2 in 4 kinds of food were in consistent with those obtained by standard method.