“爱迪生”珍珠及染色处理有核珍珠的谱学特征

颗粒大、圆度高并具有浓郁颜色的淡水有核养殖珍珠（商贸名称为“爱迪生”珍珠）为珍珠市场提供了更高的品质与价值，然而受利益的驱使，染色的有核养殖珍珠也逐渐流入市场，扰乱了消费者的健康消费，在一定程度上阻碍了“爱迪生”珍珠产业的良性发展。本文利用红外光谱仪、紫外-可见分光光度计和光致发光光谱仪对养殖和染色“爱迪生”珍珠进行了系统的谱学研究，并将其与海水珍珠、染色海水珍珠进行了比较。结果表明：（1）染色与养殖“爱迪生”珍珠在红外光谱上均显示1 445，882和725 cm-1处的文石振动峰，其中染色“爱迪生”珍珠在3 800 cm-1处均出现宽缓的弱吸收峰；（2）染色“爱迪生”珍珠的紫外可见光光谱中280 nm处的吸收峰明显弱于养殖“爱迪生”珍珠，染色后的“爱迪生”珍珠整体反射率降低，可能与染剂使珍珠中的蛋白质分子受损有关。染黄色“爱迪生”珍珠缺失养殖橙黄色“爱迪生”珍珠在360～380 nm处的吸收峰，而与染色海水金珠430 nm处的强吸收峰相似。染黑色“爱迪生”珍珠在425 nm处有吸收峰，染色海水黑珍珠在480和645 nm处有吸收峰，养殖海水黑珍珠在702 nm处有吸收峰，三者图谱的差异可能为各自的染料不同所致；（3）养殖“爱迪生”珍珠在光致发光光谱中450～550 nm范围内可见一组吸收峰，染色“爱迪生”珍珠的发光中心向红区偏移且在650 nm附近出现强度不等的与染色剂相关的吸收峰，染色海水金珠也在600 nm处有和染色剂有关的吸收峰。

The Spectral Characteristics of “Edison” Pearls and Nucleated Pearls With Dyeing Treatment

Fresh water nucleated cultured pearls with large grain size, high roundness and rich color (the commercial name is “Edison” Pearl) provide higher quality and value for the pearl market. However, due to the trend of interests, dyed nucleated cultured pearls gradually flow into the market, which disturbs the healthy consumption of consumers and hinders the sound development of “Edison” pearl industry to a certain extent. In this paper, infrared spectrometer, ultraviolet-visible spectrophotometer and photoluminescence spectrometer were used to systematically study the spectra of cultured and dyed “Edison” pearls and compared with seawater pearls and dyed seawater pearls. The results showed that: (1) the dyed and cultured “Edison” pearls showed aragonite vibration peaks at 1 445, 882 and 725 cm-1 in the infrared spectrum, and the dyed “Edison” pearls showed a broad and weak absorption peak at 3 800 cm-1; (2) The absorption peak at 280 nm of dyed “Edison” pearls is obviously weaker than that of cultured “Edison” pearls, which may be related to the damage of protein molecules in pearls caused by dyes. After dyeing, the overall reflectivity of “Edison” pearls decreased. Dyed yellow “Edison” pearl lacks the absorption peak at 360~380 nm of cultured orange-yellow “Edison” pearl, which is similar to the strong absorption peak at 430 nm of dyed seawater gold beads. Dyed black “Edison” pearls have absorption peaks at 425 nm, dyed sea water black pearls have absorption peaks at 480 and 645 nm, and cultured sea water black pearls have absorption peaks at 702 nm. The difference between the three patterns may be due to their different dyes; (3) A group of absorption peaks can be seen in the range of 450~550 nm in the photoluminescence spectrum of cultured “Edison” pearls. The luminous center of dyed “Edison” pearls shifts to the red zone, and absorption peaks related to dyes appear around 650 nm with different intensities. Dyed seawater gold beads also have absorption peaks related to dyes at 600 nm.