Optical spectroscopy is a powerful characterization tool with applications ranging from fundamental studies to real-time process monitoring. However, it can be difficult to apply to complex samples that contain interfering analytes which are common in processing streams. Multivariate (chemometric) analysis has been examined for providing selectivity and accuracy to the analysis of optical spectra and expanding its potential applications. Here we will discuss chemometric modeling with an in-depth comparison to more simplistic analysis approaches and outlining how chemometric modeling works while exploring the limits on modeling accuracy. Understanding the limitations of the chemometric model can provide better analytical assessment regarding the accuracy and precision of the analytical result. This will be explored in the context of UV-vis absorbance of neodymium (Nd3+) in the presence of interferents, erbium (Er3+) and copper (Cu2+) under conditions simulating the liquid-liquid extraction approach used to recycle plutonium (Pu) and uranium (U) in used nuclear fuel worldwide. The selected chemometric model, partial least squares regression (PLS), accurately quantifies Nd3+ with a low percentage error in the presence of interfering analytes and even under conditions that the training set does not describe.

光谱学是一种强大的表征工具，其应用范围从基础研究到实时过程监控。然而，它可能难以应用于包含在处理流中常见的干扰分析物的复杂样品。多变量（化学计量）分析已被检验，为光谱分析提供选择性和准确性，并扩大其潜在应用。在这里，我们将讨论化学计量建模，并与更简单的分析方法进行深入比较，并概述化学计量建模的工作原理，同时探索建模准确性的限制。了解化学计量模型的局限性可以对分析结果的准确性和精密度提供更好的分析评估。这将在模拟用于回收钚 (Pu) 和铀的液-液萃取方法的条件下，在存在干扰物、铒 (Er3+) 和铜 (Cu2+) 的情况下，在钕 (Nd3+) 的紫外-可见吸光度的背景下进行探索(U) 在全球使用过的核燃料中。选择的化学计量模型，偏最小二乘回归 (PLS)，即使在训练集未描述的条件下，也能以低百分比误差准确量化 Nd3+。