Purwadi Imam, Casey Lachlan W, Ryan Chris G, Erskine Peter D, van der Ent Antony
Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, St Lucia, QLD, 4072, Australia.
Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, QLD, 4072, Australia.
Plant Methods. 2022 Dec 19;18(1):139. doi: 10.1186/s13007-022-00958-z.
"Herbarium X-ray Fluorescence (XRF) Ionomics" is a new quantitative approach for extracting the elemental concentrations from herbarium specimens using handheld XRF devices. These instruments are principally designed for dense sample material of infinite thickness (such as rock or soil powder), and their built-in algorithms and factory calibrations perform poorly on the thin dry plant leaves encountered in herbaria. While empirical calibrations have been used for 'correcting' measured XRF values post hoc, this approach has major shortcomings. As such, a universal independent data analysis pipeline permitting full control and transparency throughout the quantification process is highly desirable. Here we have developed such a pipeline based on Dynamic Analysis as implemented in the GeoPIXE package, employing a Fundamental Parameters approach requiring only a description of the measurement hardware and derivation of the sample areal density, based on a universal standard.
The new pipeline was tested on potassium, calcium, manganese, iron, cobalt, nickel, and zinc concentrations in dry plant leaves. The Dynamic Analysis method can correct for complex X-ray interactions and performs better than both the built-in instrument algorithms and the empirical calibration approach. The new pipeline is also able to identify and quantify elements that are not detected and reported by the device built-in algorithms and provides good estimates of elemental concentrations where empirical calibrations are not straightforward.
The new pipeline for processing XRF data of herbarium specimens has a greater accuracy and is more robust than the device built-in algorithms and empirical calibrations. It also gives access to all elements detected in the XRF spectrum. The new analysis pipeline has made Herbarium XRF approach even more powerful to study the metallome of existing plant collections.
“植物标本馆X射线荧光（XRF）离子组学”是一种使用手持式XRF设备从植物标本中提取元素浓度的新定量方法。这些仪器主要设计用于无限厚度的致密样品材料（如岩石或土壤粉末），其内置算法和出厂校准在植物标本馆中遇到的干燥薄叶片上表现不佳。虽然事后已使用经验校准来“校正”测量的XRF值，但这种方法有主要缺点。因此，非常需要一种在整个定量过程中允许完全控制和透明度的通用独立数据分析管道。在此，我们基于GeoPIXE软件包中实现的动态分析开发了这样一种管道，采用基本参数方法，该方法仅需要对测量硬件进行描述，并基于通用标准推导样品面密度。
新管道在干燥植物叶片中的钾、钙、锰、铁、钴、镍和锌浓度上进行了测试。动态分析方法可以校正复杂的X射线相互作用，并且比内置仪器算法和经验校准方法表现更好。新管道还能够识别和量化设备内置算法未检测和报告的元素，并在经验校准不直接的情况下提供良好的元素浓度估计。
用于处理植物标本馆标本XRF数据的新管道比设备内置算法和经验校准具有更高的准确性和更强的鲁棒性。它还可以访问XRF光谱中检测到的所有元素。新的分析管道使植物标本馆XRF方法在研究现有植物标本的金属组方面更加强大。
