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激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)适合于直接分析硫化物矿物中痕量元素的含量及空间分布,但硫化物矿物的激光剥蚀特性与硅酸盐及氧化物不同,受到的干扰也更严重,且由于硫化物标准物质(尤其是含铂族元素、Au、Ag等贵金属元素标准物质)极度缺乏,限制了LA-ICP-MS技术在硫化物微区分析中的广泛应用。本文以贵金属标准样品GPT-9和矿石标准物质为原料合成锍镍试金扣,并封入真空管中重熔,利用背散射电子图像和LA-ICP-MS分析元素分布的均匀性,探讨真空重熔锍镍试金扣制备硫化物原位微区分析标准样品的可行性。背散射电子图像(BSE)显示真空重熔后锍镍试金扣由单相S、Ni化合物组成。LA-ICP-MS线扫描和点扫描分析表明,锍镍试金扣中S、Ni、Cr、Co、Cu、Pb、Sb、Cd、Bi等主量及微量元素分析精密度(RSD)均小于10%,均匀分布;在镍扣制备过程中Zn相对于Cu、Pb、Sb更难进入硫化物相;贵金属元素Au、Ag、Pt均一性较好,其余贵金属元素由于含量低、仪器波动及质谱干扰等影响因素造成分析数据的RSD相对较大,但可通过提高原料中贵金属元素含量、降低熔融样品淬火温度等方法进一步提高其均匀性。锍镍试金扣的组成元素对铂族元素分析的质谱干扰研究表明,重铂族元素(Os、Ir、Pt)和Au受到的干扰可忽略不计;轻铂族元素(Ru、Rh、Pd)受金属氩化物干扰较为严重,需进行干扰校正。研究认为,真空重熔技术可有效提高锍镍试金扣中各元素(包括贵金属)的均一性,达到硫化物原位微区分析标准样品的要求,利用真空重熔锍镍试金扣制备LA-ICP-MS原位微区痕量及贵金属硫化物分析标准样品具可行性。
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is suitable for the direct analysis of the content and spatial distribution of trace elements in sulfide minerals. However, the laser ablation characteristics of sulfide minerals are different from that of silicates and oxides And the interference is more serious. Due to the extreme lack of sulfide standard materials (especially the noble metal element standard materials containing platinum group elements, Au, Ag and the like), the wide application of LA-ICP-MS technology in sulfide micro-area analysis is limited. In this paper, the gold-nickel-gold assay buckle was synthesized from the precious metal standard GPT-9 and the ore standard materials and sealed in a vacuum tube for remelting. The uniformity of the elemental distribution was analyzed by backscatter electron image and LA-ICP-MS, Feasibility of Preparing Standard Samples for Sulfide in Situ Microanalysis by Nickel Sulfide Assay Part. Backscattered electron image (BSE) shows that after the vacuum remelting, the nickel sulfonium test coupon consists of a single phase S, Ni compound. The results of LA-ICP-MS and scanning electron microscopy showed that the main contents of S, Ni, Cr, Co, Cu, Pb, Sb, Cd and Bi and the RSDs were less than 10%, uniform distribution; Zn in the nickel buckle preparation process more difficult to enter the sulfide phase than Cu, Pb, Sb; noble metal elements Au, Ag, Pt uniformity is good, the rest of the precious metal elements due to low content, instrument fluctuation and mass spectrometry The RSD of the analysis data is relatively large due to the interference factors and other factors. However, it can be further improved by increasing the content of precious metals in the raw materials and reducing the quenching temperature of the molten sample. The interferences of the heavy platinum group elements (Os, Ir, Pt) and Au are negligible; the composition of the light platinum group elements (Ru, Rh, Pd) Interference by metal hydride more serious, need to be corrected for interference. The study shows that vacuum remelting technology can effectively improve the uniformity of various elements (including precious metals) in the nickel sulfide test sample to meet the requirements of standard samples for in situ microanalysis of sulfides. The preparation of LA ICP-MS in-situ microdissection and noble metal sulfide standard samples are feasible.