单秒脉冲Sr同位素LA-MC-ICP-MS分析技术:在海水珍珠与淡水珍珠"无损"判别中的应用
Single-Second Pulse LA-MC-ICP-MS Analysis of Sr Isotope:Application to the Quasi"Non-Destructive"Discrimination between Seawater Cultured Pearl and Freshwater Cultured Pearl
廖秀红 1胡兆初 2刘丹 1曾显丽 2冯兰平 2张文2
作者信息
- 1. 中国地质大学(武汉)珠宝学院,湖北武汉 430074;中国地质大学(武汉)地质过程与矿产资源国家重点实验室,湖北武汉 430074
- 2. 中国地质大学(武汉)地质过程与矿产资源国家重点实验室,湖北武汉 430074
- 折叠
摘要
珍珠是一种广受欢迎的生物成因有机宝石.由于海水珍珠与淡水珍珠之间巨大的价格差异,市场上淡水珍珠冒充海水珍珠进行售卖的现象屡见不鲜,尤其是在某些外观特征如颜色、尺寸、大小和表面纹理等极为相似的珍珠中,如白色的"淡水Akoya珍珠"与白色的Akoya珍珠[1].海水珍珠与淡水珍珠的鉴别方法研究存在巨大的市场需求.本研究提出,Sr同位素组成可以作为区分海水珍珠与淡水珍珠的有效工具.为了实现珍珠样品中Sr同位素组成的高效测试,本研究开发了一种基于单秒激光剥蚀的LA-MC-ICP-MS Sr同位素分析方法,使用线性回归策略进行数据校正[2].该方法将剥蚀时间从30～60 s缩短至1 s,不仅加快了测试速度和降低成本,而且极大程度地减少了对珍珠这类宝石的损伤(图1).此外,本研究开发了一款用于珍珠微区原位Sr同位素分析的参考物质GIC-P,并对不同激光剥蚀束斑、频率和能量密度条件下的剥蚀行为进行了探索.总体来说,单秒脉冲Sr同位素LA-MC-ICP-MS分析方法,可在几近于"无损"的情况下满足海水珍珠与淡水珍珠的鉴定需求.基于所开发的分析方法与标准物质,本研究首次报道了海水珍珠和淡水珍珠的Sr同位素组成.结果发现,海水珍珠的87Sr/86Sr比值基本保持在0.709 2附近,与现代海水的Sr同位素比值吻合良好[3-4],而淡水珍珠则显示出相对较高且变化较大的87 Sr/86 Sr比值.从中国市场上收集到的淡水珍珠87 Sr/86 Sr比值范围在0.710 2～0.713 5,这与长江流域淡水样品中的Sr同位素组成呈现出高度一致性[5].这表明珍珠中的Sr同位素组成与其养殖水体中的Sr同位素组成紧密相关,利用Sr同位素区分海水珍珠与淡水珍珠的本质在于对其养殖水体Sr同位素组成的追溯,是一种极为可靠的鉴别技术.
Abstract
Pearls are popular organic gems formed by biological processes.The price differ-ences between seawater and freshwater cultured pearls create significant market demands for robust methods to differentiate between the two types.This demand is particularly impor-tant for pearls exhibiting similar characteristics,such as colour,shape,size,and surface texture,for example,those observed in white"freshwater Akoya pearls"and Akoya pearls[1].In this study,the utilization of Sr isotope composition is proposed as a tool for dis-tinguishing between freshwater and seawater cultured pearls.A single-second laser ablation protocol coupled with a linear regression calibration method[2]was developed for Sr isotope a-nalysis to differentiate pearl types(i.e.,freshwater pearls or seawater pearls)while causing minimum damage with the ablation time being reduced from 30-60 s to only 1 s(Fig.1).Additionally,a pearl reference material(RM),GIC-P,was developed for micro and in situ Sr isotope analysis.The ablation behavior,involving laser ablation spot sizes,repetition rates,and energy densities required for accurate Sr isotope analysis,was investigated.In general,the single-second pulse LA-MC-ICP-MS analytical method developed in this study minimizes sample consumption and offers identification between seawater pearls and freshwa-ter pearls with quasi"non-destructive"capabilities.With the proposed method and the newly developed RM,it was reported for the first time that seawater cultured pearls consistently exhibit the 87Sr/86Sr ratio around 0.709 2,consistent with modern seawater values,while freshwater cultured pearls display much high-er and variable 87 Sr/86 Sr ratios[3-4].The collected freshwater cultured pearls from the Chi-nese market yielded values ranging from 0.710 5 to 0.71 23,aligning well with the Sr iso-topes composition in freshwater samples along the Yangtze River[5].The results indicate that the Sr isotope in pearl samples depends largely on the Sr isotope composition of the ambient water environment,and discrimination between seawater cultured pearls and freshwater cul-tured pearls using the Sr isotopes ratio is indeed a method tracing the cultivation environ-ment,thus being robust and reliable.
关键词
海水珍珠/淡水珍珠/Sr同位素/LA-MC-ICP-MS/微区原位分析Key words
seawater cultured pearl/freshwater cultured pearl/Sr isotope/LA-MC-ICP-MS/in situ and microanalysis引用本文复制引用
出版年
2024
NETL
NSTL
万方数据