Abstract High-precision spectral analysis for complex liquid components has received much attention in recent years. However, the lack of systematic strategies of measurement and modeling notably appears when multiple internal and external factors vary—e.g., the sample parameters, instruments, and external environment. Many methods have been developed to eliminate these effects. According to the characteristics of error sources and its propagation rules, “M + N” theory integrates and classifies the internal and external factors that affect the analysis of complex liquid components into M factors and N factors systematically. “M” and “N” refers to the M components in a liquid and N interference factors, respectively, and “+” means that the spectral is a response to the interaction of M and N. In this review, “M + N” theory sums up five measurement and modeling strategies used to reduce the effect of various factors on spectral quantitative analysis of complex liquids. Finally, this review summarized the strategies used to improve the accuracy of quantitative analysis of complex liquids and discussed future research directions.

中文翻译：

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M+N理论及其提高复杂液体光谱化学成分分析精度的策略综述

摘要 近年来，复杂液体成分的高精度光谱分析备受关注。然而，当多种内部和外部因素（例如，样本参数、仪器和外部环境）发生变化时，就会出现缺乏系统的测量和建模策略。已经开发了许多方法来消除这些影响。“M+N”理论根据误差源的特点及其传播规律，将影响复杂液体成分分析的内外部因素系统地综合分类为M因素和N因素。“M”和“N”分别表示液体中的 M 分量和 N 干扰因子，“+”表示光谱是对 M 和 N 相互作用的响应。在这篇综述中，“M+N”理论总结了五种测量和建模策略，用于减少各种因素对复杂液体光谱定量分析的影响。最后，这篇综述总结了用于提高复杂液体定量分析准确性的策略，并讨论了未来的研究方向。