School of Science, The University of Waikato, Hamilton, New Zealand; Hill Laboratories, Hamilton, New Zealand.
School of Science, The University of Waikato, Hamilton, New Zealand.
Talanta. 2025 Jan 1;281:126797. doi: 10.1016/j.talanta.2024.126797. Epub 2024 Sep 3.
Quantitation of sulfur (S) is vitally important for analysis of agricultural soil and plant samples due to the requirement of S in living organisms. Although inductively coupled plasma mass spectrometry (ICP-MS) is a commonly used and robust instrument for multi-elemental detection, S is usually analysed by ICP-optical emission spectroscopy (OES) since S quantitation poses a particular challenge for ICP-MS due to interferences on all S isotopes. The requirement for analysis by two instruments increases time and cost for sample analysis, hence analysis by one instrument is desirable. The use of reaction gases in ICP-MS can improve the performance by shifting S to a mass for detection where no interference is present. This work explored the potential of methane as a reaction gas for analysis of S in soil and plant samples to give users an alternative option to oxygen. The product ion clusters CHSH were monitored (m/z 47 and 49 on ICP-MS and with mass shift of +15 from Q1 → Q2 using 32 → 47 and 34 → 49 on triple quadrupole ICP-MS). As expected, triple quadrupole ICP-MS performed better than single quadrupole ICP-MS containing a reaction cell due to the ability to preselect the m/z of choice and remove ions that may react with methane in the reaction cell. The method detection limit (MDL) was 150 mg kg S for plants and 53 mg kg S for soils which is fit for requirements. This is the first-time methane has been reported as a reaction gas for analysis of S and shows promising results for agricultural samples when using a triple quadrupole ICP-MS. Results compared well to those obtained via the more commonly used ICP-optical emission spectroscopy (OES) method with results <20 % for all samples. Interlaboratory comparison samples were within 2 Z-scores of the consensus mean. In the absence of ICP-MS/MS, Q-ICP-MS with detection of cluster m/z 47 was deemed to be suitable for detection of S in plant samples, with acceptable MDL (250 mg kg S), acceptable precision (<20 % RSD) and <20 % variation to the reported ICP-OES result.
由于硫（S）是生物体所必需的，因此对农业土壤和植物样品进行 S 定量分析至关重要。尽管电感耦合等离子体质谱（ICP-MS）是一种常用且强大的多元素检测仪器，但由于所有 S 同位素的干扰，S 通常通过 ICP-发射光谱（OES）进行分析。由于 ICP-MS 对 S 定量分析提出了特殊挑战，因此需要使用两种仪器进行分析，这增加了样品分析的时间和成本，因此希望使用一种仪器进行分析。在 ICP-MS 中使用反应气体可以通过将 S 转移到没有干扰的检测质量上来改善性能。这项工作探讨了甲烷作为一种反应气体在分析土壤和植物样品中的 S 的潜力，为用户提供了一种替代氧气的选择。监测了产物离子簇 CHSH（在 ICP-MS 上为 m/z 47 和 49，在三重四极杆 ICP-MS 上使用 32→47 和 34→49 的质量位移为+15，从 Q1→Q2）。正如预期的那样，由于能够预先选择所需的 m/z 并去除可能在反应池中与甲烷反应的离子，因此具有反应池的三重四极杆 ICP-MS 比仅包含反应池的单四极杆 ICP-MS 性能更好。该方法的检测限（MDL）为植物中 150mg/kg S 和土壤中 53mg/kg S，符合要求。这是首次报道甲烷作为分析 S 的反应气体，并且当使用三重四极杆 ICP-MS 时，对农业样品显示出有希望的结果。结果与更常用的 ICP-发射光谱（OES）方法获得的结果相比，所有样品的结果均<20%。实验室间比较样品在共识平均值的 2Z 分数内。在没有 ICP-MS/MS 的情况下，具有检测簇 m/z 47 的 Q-ICP-MS 被认为适合于植物样品中 S 的检测，具有可接受的 MDL（250mg/kg S），可接受的精密度（<20%RSD）和与报告的 ICP-OES 结果的<20%变化。
