高斯多峰拟合用于烷基葡萄糖苷临界胶束浓度测量

Determination of Critical Micelle Concentration of Alkyl Polyglucoside (APG) Nonionic Surfactant Aqueous System By Multi-Peaks Gaussian Fitting of Visible Absorption Spectra Line Shape

报道了可见吸收光谱线型的高斯多峰拟合用于新型非离子表面活性剂烷基葡萄糖苷（APG）,如辛基--βD-葡萄糖单苷（C8G1）和癸基--βD-葡萄糖单苷（C10G1）的临界胶束浓度（CMC）的测定。具体作法是以结晶紫（crystal violet,CV）为探针,测量一系列不同浓度的APG-CV水溶液体系的可见吸收光谱。其光谱特征是CV单体吸收峰598~609 nm和二聚体吸收峰538~569 nm叠合在一起。用高斯多峰拟合法实现了体系可见光谱吸收叠合峰的分峰、峰面积（积分吸光度）、频移及半高宽等光谱线型参数计算。单体和二聚体峰面积比（相对积分吸光度A2/A1）、频移（Δλ）及半高宽（w1,w2）对APG浓度图形在CMC处发生突变。首次发现可见吸收光谱线型参数半高宽对APG聚集行为敏感,并成功用于APG的CMC测量。

A multi-peaks Gaussian fitting on the line shape of visible spectra was used to determine the critical micelle concentration （CMC） of alkyl polyglucoside（APG） nonionic surfactant aqueous system such as octyl beta D mono-glueoside（C8G1 ） and decyl beta D mono-glucoside（C10G1 ）. Visible electronic absorption spectra of a series of different concentration C8G1 or C10 G1 with crystal violet（CV） used as a probe were measured respectively and characterized by the overlap of the principal peak with λmax at 598-609 nm and a shoulder at 538-569 nm assigned to monomer and dimer CV respectively. A multi-peaks Gaussian fitting was used to interpret the spectra and give relative integrating absorbance（A2/A, ） of two peaks, red-shift（△λ） and half-width. A sudden change occurred at CMC in the curves of the relative integrating absorbance（A2/A1 ）, red-shift（△λ.） and half-width （w1, w2 ） versus the C8 Cn or C10G1 sudactant concentrations. Significantly the dependence of the CMC upon the half-width was observed for the first time and successfully used to determine CMC of nonionic surfactant such as APG.