Using ICP-OES to determine rare earth elements (REE) in geological materials is one of the most complex analytical techniques.
The high matrix contents of digested samples require superior plasma robustness, frequently including large quantities of silica, alumina, refractory metals, and sulfur. This is particularly important when trace amounts of REE must be detected and sample dilution must be avoided.
The complexity of the technique is increased further by the high number of emission lines originating from both rare earth elements and the matrix, which can only be resolved by high spectral resolution.
本文概述了一种研究砂岩（GSR-4）和花岗岩（GSR-1）的两种地质参考材料的技术欧洲杯足球竞彩PR，SM，YB和ND。这是通过在带有HF试剂盒提供的9100质量9100 Elite上使用高分辨率ICP-OE来实现的。
Interference-free measurement in both sandstone and granite was viable for the majority of REE elements due to the novel resolving power of the PlasmaQuant 9100 Elite’s high-resolution optics.
The CSI-Software feature successfully corrected significant spectral interferences from erbium, cerium, neodymium, and iron on sensitive emission lines of erbium, dysprosium, samarium, and lanthanum.
The results for granite (GSR-1) and sandstone (GSR-2) demonstrated excellent agreement with the certified values and quality RSD values. This article provides matrix-specific detection limits.
Materials and Methods
Samples and Reagents
- Sodium peroxide
- Geological reference materials for granite (GSR-1) and sandstone (GSR-4)
- Nitric acid
- REE single element standards
- Deionized water
Sample Preparation
Alkaline fusion (0.1 g sample + 0.6 g Na2O2) was used to digest the samples. 2 mL of nitric acid was added to the fusions and was filled up to 50 mL afterward. The subsequent nominal matrix content was around 12 g/L. These solutions were directly injected into the PlasmaQuant 9100 Elite.
Calibration
Matrix matched calibration standards were created from a Sodium Peroxide digestion blank utilizing REE-single elements standards (1000 mg/L, Sigma Aldrich) in adherence with the predicted concentration range in the analyzed samples. The calibration levels that were prepared are provided in Table 1.
Table 1.校准标准的浓度。
| Element |
Unit |
Cal.0 |
Cal.1 |
Cal.2 |
Cal.3 |
Cal.4 |
| Ce |
mg/L |
0 |
0.040 |
0.100 |
0.250 |
0.500 |
| Dy |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Er |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Eu |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Gd |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Ho |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| La |
mg/L |
0 |
0.020 |
0.050 |
0.125 |
0.250 |
| Lu |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Nd |
mg/L |
0 |
0.040 |
0.100 |
0.250 |
0.500 |
| Pr |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| Sm |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
| YB |
mg/L |
0 |
0.004 |
0.010 |
0.025 |
0.05 |
Figure 1 – 8.Calibration curves.
Instrumentation
A质量9100精英was used to perform the analysis, along with the HF sample introduction kit and the ASPQ 3300 autosampler. Table 2 outlines the method settings along with a comprehensive description of the elements of the sample introduction system.
Table 2.样品简介系统的等离子体配置和设置。
| Parameter |
Settings |
| Power |
1250 w |
| Plasma gas flow |
12 L/min |
| 辅助气流 |
0.5 l/min |
| 雾化器气流 |
0.6 l/min |
| 喷雾器1 |
PFA parallel path nebulizer, 1.0 mL/min |
| 喷雾室1 |
PTFE cyclonic spray chamber, 50 mL |
| Outer tube/Inner tube1 |
Syalon /氧化铝 |
| 注射器1 |
Alumina, inner diameter 2 mm |
| Pump tubing |
PVC |
| Sample pump rate |
1.0毫升/分钟 |
| Read delay/ Rinse |
45 s/ 20 s |
| Auto Sampler |
Yes |
1Salt Kit may be used, too, for samples that do not contain hydrofluoric acid (HF)
评估参数
Table 3.Overview of method-specific evaluation parameters.
| Element |
Line [nm] |
Plasma view |
集成模式 |
Read time [s] |
Evaluation |
| No. of Pixel |
基线拟合 |
Polynomial degree |
Correction |
| Ce |
413.765 |
轴向 |
peak |
3 |
3 |
ABC1 |
auto |
- |
| Dy |
353.170 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
CSI2 |
| Er |
369.265 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
CSI3 |
| Eu |
412.970 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| Gd |
376.839 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| Ho |
379.675 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| La |
333.749 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
CSI2,4 |
| Lu |
291.139 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| Nd |
406.109 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| Pr |
532.276 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
| Sm |
442.434 |
轴向 |
peak |
3 |
3 |
static |
auto |
CSI2,5 |
| YB |
211.667 |
轴向 |
peak |
3 |
3 |
ABC |
auto |
- |
1automatic baseline correction (ABC)
2刚口的光谱干扰的数学校正
3mathematical correction of spectral interferences from Iron
4来自ERBIUM的光谱干扰的数学校正
5mathematical correction of spectral interferences from Cerium
Results and Discussion
Table 4 provides a summary of the results obtained for the investigation of the certified reference materials GSR-1 and GSR-4 compared to the certified values. The use of a Na2O2融合消化技术而不是酸性消化为分析样品中所有REE提供了完整的访问。
The accurate analysis (RSD values significantly less than 5%) of the as-prepared, matrix-rich digestions was provided by the high plasma stability along with the PlasmaQuant 9100 Elite’s smart torch design.
由于该仪器具有高分辨率（FWHM DY353.170≤5.5pm），因此可以在光谱上解析强干扰物，这提供了研究大多数REE的能力，而无需其他数学校正算法。
In this study, only the elements erbium, dysprosium, samarium, and lanthanum required additional mathematical correction using the CSI software feature. The superior precision and accuracy attained by the applied technique proves its efficacy for the routine analysis of geological materials for REE.
Table 4.Overview of results for two geological reference materials comprising of granite (GSR-1) and sandstone (GSR-4).
| Element |
GSR-1 |
GSR-4 |
DL1[µg/l] |
Measured value
[mg/kg] |
RSD2[%] |
Certified value
[mg/kg] |
Measured value3
[mg/kg] |
RSD
[%] |
Certified value
[mg/kg] |
| Ce |
112 ± 2.3 |
0.09 |
108 ± 7 |
52.6±2.2 |
0.92 |
48±4 |
0.85 |
| Dy |
10.6 ± 0.97 |
2.7 |
10.2 ± 0.4 |
4.18 ± 0.96 |
1.8 |
4.1 ± 0.4 |
0.32 |
| Er |
7.0 ± 0.099 |
0.87 |
6.5 ± 0.3 |
2.15 ± 0.10 |
0.48 |
2 ± 0.3 |
0.15 |
| Eu |
0.705 ± 0.56 |
3.0 |
0.85 ± 0.07 |
1.00±0.52 |
1.6 |
1.02 ± 0.08 |
0.04 |
| Gd |
10.3 ± 0.37 |
1.7 |
9.3 ± 0.7 |
4.76 ± 0.36 |
3.0 |
4.5±0.4 |
0.36 |
| Ho |
2.22±0.38 |
5.0 |
2.05 ± 0.17 |
0.841 ± 0.37 |
2.3 |
0.75 ± 0.12 |
0.11 |
| La |
53.4 ± 0.53 |
1.9 |
54±4 |
21.9±0.52 |
0.73 |
21±2 |
0.14 |
| Lu |
1.11±0.30 |
4.7 |
1.15±0.09 |
0.257 ± 0.29 |
5.9 |
0.3±0.03 |
0.19 |
| Nd |
48.6 ± 0.67 |
0.72 |
47 ± 4 |
23.8 ± 0.67 |
0.49 |
21±2 |
0.34 |
| Pr |
12.2±1.3 |
2.1 |
12.7 ± 0.8 |
5.65±1.2 |
1.3 |
5.4 ± 0.6 |
1.55 |
| Sm |
9.23 ± 0.20 |
1.4 |
9.7±0.8 |
4.70 ± 0.20 |
5.3 |
4.7±0.3 |
0.65 |
| YB |
7.67±0.36 |
1.3 |
7.4 ± 0.5 |
2.15 ± 0.38 |
1.6 |
1.9 ± 0.2 |
0.34 |
1Matrix-specific detection limit obtained from 3σ of SD for QC matrix blank (12 g/L Sodium peroxide),
2RSD values obtained from three replicate measurements per sample
3根据DIN 32645和DIN 38402的置信区间
Figure 9.CE 413.765 nm。
图10。Nd 406.109 nm.
图11。YB211.667 nm.
Figures 9-11.GSR-1（蓝色）和砂岩，GSR-4（红色）的高分辨率光谱数据的收集。自动基线拟合，ABC（绿色）。
Conclusion
分析时可能会出现多个挑战稀土元素（REE）, for example, it can be challenging to gain complete access to all REE, analyze the matrix-rich samples, and there is a high possibility of significant spectral interferences.
The research design outlined in this article involves a fusion digestion technique utilizing a Na2O2通量与高分辨率ICP-OES在质量9100精英上的分析结合在一起。
融合消化可实现复杂地质矩阵的无残留消化。所有分析物，包括重型REE，都可以轻松研究。
A sample introduction system and a highly stable plasma performance are required to perform an analysis that is highly accurate and precise because the solutions as prepared carry both the flux matrix and the sample.
与其他ICP-OES仪器相比，质量9100 Elite提供了高频发电机，以实现最佳血浆稳定性。使用其V-Shuttle Torch（一种完全可降低的垂直端部火炬）来确保对最高基质含量（例如12 g/L融合通量）的分析，从而消除了对REE检测限制的额外稀释需求。
可以达到Ng/L到低µg/L范围内的基质特异性检测极限。源自REE通常存在的其他REE或元素的重要光谱干扰，例如铁，使地质材料的精确测量变得复杂。欧洲杯足球竞彩
Plasmaquant 9100 Elite展示了两个有效的功能来解决这些光谱干扰：CSI-Software工具和光学系统的高分辨率。
The high resolution enables severe interferences to be spectrally resolved with no need for additional mathematical correction schemes, and the CSI-Software tool can correct for more challenging interferences by using a mathematical correction to achieve an interference-free result. These features make the PlasmaQuant 9100 Elite the ideal analytical technology for the determination of REE in any geological sample.
This information has been sourced, reviewed, and adapted from materials provided by Analytik Jena US.
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