酸溶-电感耦合等离子体发射光谱法和燃烧-红外吸收法测定不同类型地球化学样品中的硫

石友昌; 陈贵仁; 赵萌生; 吕振龙; 杨金国

doi:10.15898/j.cnki.11-2131/td.202108200104

酸溶-电感耦合等离子体发射光谱法和燃烧-红外吸收法测定不同类型地球化学样品中的硫

Determination of Sulfur in Different Types of Geochemical Samples by ICP-OES with Acid Dissolution and Combustion-Infrared Absorption Spectrometry

摘要

摘要: 测试地质样品中的硫含量，以电感耦合等离子体发射光谱法(ICP-OES)和燃烧-红外吸收光谱法应用最为广泛。ICP-OES法灵敏度高、稳定性好，但受样品预处理和基体干扰的影响较大；燃烧-红外吸收光谱法便捷高效，但受结晶水红外吸收干扰，分析硫含量低的样品稳定性较差。本文采用5种酸溶方式处理样品ICP-OES测定硫含量，同时采用燃烧-红外吸收光谱法测定低中高含量的硫，综合比较了两类方法的检出限、检测范围、精密度和准确度、分析效率等，明确了各方法的适用范围。实验中确定了燃烧-红外吸收光谱法最佳测试条件为：称样量0.0500g，燃烧时间25s，分析时间40s，氧气流量4.0L/min；通过标准物质验证，该方法检出限为10×10^-6，检测范围为10×10^-6~470000×10^-6，相对标准偏差(RSD) < 6%(n=12)，相对误差绝对值小于8%。实验结果表明，ICP-OES分析效率高，但是样品处理时间长，检测范围不如燃烧-红外吸收光谱法宽；燃烧-红外吸收光谱法采用固体直接进样，成本低，用高氯酸镁作为干燥剂可解决结晶水红外吸收干扰问题。总体上，ICP-OES法适用于分析硫含量低的样品或作为测试结果佐证的手段，可实现多元素联测；批量样品或基体类型复杂的样品宜采用燃烧-红外吸收光谱法测试，更加便捷。

Abstract:
BACKGROUND Inductively coupled plasma-optical emission spectrometry (ICP-OES) and combustion-infrared absorption spectrometry are the most widely used methods to measure sulfur content in geological samples. The ICP-OES method has high sensitivity and good stability, but it is greatly affected by sample pretreatment and matrix interference. Combustion-infrared absorption spectrometry is convenient and efficient, but due to the interference of crystal water infrared absorption, the analysis of samples with low sulfur content has poor stability.
OBJECTIVES To study the application scope of the two methods in geological sample analysis.
METHODS The sulfur content of samples was determined by ICP-OES and combustion-infrared absorption spectrometry. The detection limit, detection range, precision, accuracy and analysis efficiency of the two methods was compared in order to study and understand the performance of the two methods in sulfur measurement of geological samples.
RESULTS The best test condition of combustion-infrared absorption spectrometry was determined thus: optimal sample weight of 0.0500g, combustion time of 25s, analysis time of 40s and oxygen analysis flow rate of 4.0L/min. The detection limit of combustion-infrared absorption spectrometry was 10×10^-6 and the detection range was 10×10^-6-470000×10^-6. The accuracy relative standard deviation (RSD) of the method was less than 6% (n=12) and the absolute value of relative error was less than 8%.
CONCLUSIONS For the analysis of low-sulfur samples, ICP-OES method can be used to analyze or compare, and multi-element simultaneous measurement can be determined. Batch samples or samples with a complex matrix can be analyzed by combustion-infrared absorption spectrometry, which is more convenient and efficient.

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