The acid–base properties of two novel 4-hydroxystyryl dyes were studied using colorimetric and spectrophotometric methods. The corresponding ionization and hydroxylation constants were determined. Changes of the water: DMSO ratio was shown to cause significant changes of the dye absorption spectra and the corresponding colorimetric functions. Use of the yellowness index allowed moderate water contents (1–30%) in DMSO to be determined. It was advisable to use the color saturation function for analyzing such mixtures in the entire range of possible contents because it was linear over a wider concentration range (0–99%).

中文翻译：

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4-羟基苯乙烯基染料比色法测定DMSO中的水

使用比色法和分光光度法研究了两种新型4-羟基苯乙烯基染料的酸碱性质。确定了相应的电离和羟基化常数。结果表明，水：DMSO比值的变化会引起染料吸收光谱和相应比色功能的显着变化。使用泛黄指数可以确定DMSO中的水分含量（1–30％）。建议使用色彩饱和度函数在所有可能的含量范围内分析此类混合物，因为它在较宽的浓度范围内（0-99％）是线性的。