将一种直接信号校正(DOSC)-小波包变换(WPT)-偏最小二乘法(PLS)(DOSC-WPT-PLS)新方法用于解析荧光光谱严重重叠的邻苯二酚?间苯二酚和对苯二酚混合物,并对其进行测定。该法将DOSC、WPT及PLS 3种方法结合从而提高了获取特征信息的能力和回归质量。DOSC方法用于除去与浓度无关的结构噪音。利用WPT的时域和频域局部化的特点改进了除噪质量和数据压缩及信息提取能力。PLS方法用于多变量校准和噪音消除。处理该3种组分的荧光光谱数据,并实现了3种化合物的同时测定。设计了PDOSCWPTPLS程序执行相关计算,并对以上3种化学计量学方法进行了比较,其总体相对预测标准偏差分别为4.3%、7.7%、11.5%,结果表明DOSC-WPT-PLS法优于WPT-PLS法和PLS法。将该法用于测定自来水中邻苯二酚?间苯二酚和对苯二酚的含量,其回收率分别为99%~110%?95%~108%和98%~104%,结果满意。
A DOSC-WPT-PLS method based on partial least squares(PLS) regression with direct orthogonal signal correction(DOSC) and wavelet packet transform(WPT) as preprocessing tools was proposed for the simultaneous fluorespectrophotometric determination of catechol,resorcinol and hydroquinone with overlapping peaks.The DOSC,WPT and PLS regression were combined to improve the ability of extraction of characteristic information and the quality of regression.DOSC was used to remove information in the response matrix.Wavelet packet representations of signals provided a local time-frequency description,thus in the wavelet packet domain,the quality of the noise removal,data compression,and relevant information extraction can be improved.PLS was applied in the multivariate calibration and the noise elimination by removing the less important latent variables.In this case,the simultaneous fluorespectrophotometric determination of catechol,resorcinol and hydroquinone in synthetic unknown samples was fulfilled based on the data processing of their fluorescene spectra.A program(PDOSCWPTPLS) was designed to execute the relative calculations.Three chemometric methods(DOSC-WPT-PLS,WPT-PLS and PLS) were applied in this study for comparison.The relative standard errors of prediction(RSEP) obtained for all components using DOSC-WPT-PLS,WPT-PLS and PLS were 4.3%,7.7% and 11.5%,respectively.Experimental results demonstrated that the DOSC-WPT-PLS method had the best result among the three methods and was successful applied in the determination of the contents of catechol,resorcinol and hydroquinone in the tap water.Their recoveries were 99%-110%,95%-108% and 98%-104%,respectively.