Abstract Elemental analysis of grass (Lolium perenne) is essential in agriculture to ensure grass quality and animal health. Energy-dispersive X-ray fluorescence (EDXRF) spectroscopy is a rapid, multi-element alternative to current methods using acid digestion and inductively coupled plasma optical emission spectrometry (ICP-OES). Percentage phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca), determined from grass samples using EDXRF, were within 0.035, 0.319, 0.025 and 0.061, respectively, of ICP-OES values. Concordance correlation coefficients computed using agreement statistics ranged from 0.4379 to 0.9669 (values close to one indicate excellent agreement); however, the level of agreement for each element depended on the calibrations used in EDXRF. Empirical calibrations gave excellent agreement for percentage P, K and Ca, but moderate agreement for percentage Mg due to a weaker correlation between standards and intensities. Standardless calibration using the fundamental parameters (FP) approach exhibited bias, with consistently lower values reported for percentage P and Mg, when compared with ICP-OES methods. The relationship between the methods was plotted as scatter plots with the line of equality included, and although correlation coefficients indicated strong relationships, these statistics masked the effects of consistent bias in the data for percentage P and Mg. These results highlight the importance of distinguishing agreement from correlation when using statistical methods to compare methods of analysis. Agreement estimates improved when a matching library of grass samples was added to the FP method. EDXRF is a comparable alternative to conventional methods for grass analysis when samples of similar matrix type are used as empirical standards or as a matching library.

中文翻译：

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一种使用能量色散 X 射线荧光光谱法分析禾本科（Lolium perenne）中主要营养素的快速多元素方法

摘要 草 (Lolium perenne) 的元素分析在农业中对于确保草质和动物健康至关重要。能量色散 X 射线荧光 (EDXRF) 光谱是当前使用酸消解和电感耦合等离子体发射光谱 (ICP-OES) 方法的快速多元素替代方法。使用 EDXRF 从草样品中测定的磷 (P)、钾 (K)、镁 (Mg) 和钙 (Ca) 的百分比分别在 ICP-OES 值的 0.035、0.319、0.025 和 0.061 以内。使用一致性统计计算的一致性相关系数范围从 0.4379 到 0.9669（接近 1 的值表示非常一致）；然而，每个元素的一致性水平取决于 EDXRF 中使用的校准。经验校准对 P、K 和 Ca 的百分比给出了极好的一致性，但由于标准和强度之间的相关性较弱，Mg 百分比的一致性适中。与 ICP-OES 方法相比，使用基本参数 (FP) 方法的无标准校准表现出偏差，报告的 P 和 Mg 百分比值始终较低。将这些方法之间的关系绘制为包含等式线的散点图，尽管相关系数表明存在很强的关系，但这些统计数据掩盖了 P 和 Mg 百分比数据中一致偏差的影响。这些结果强调了在使用统计方法比较分析方法时区分一致性和相关性的重要性。将匹配的草样本库添加到 FP 方法后，一致性估计得到了改进。