偏最小二乘紫外分光光度法同时测定丁烯二酸的顺反异构体

将偏最小二乘法用于紫外分光光度分析,在pH=1.4的磷酸溶液中,同时测定了丁烯二酸的顺、反异构体。确定了测定的最佳波长范围为190～268nm;测得23个混合标样的吸光度值用于建立模型,顺、反丁烯二酸的浓度范围为3.0～14.0mg/L和1.0～13.0mg/L。所建立的测定二者模型的相关系数分别为0.9951和0.9983;平均回收率分别为100.8%和100.7%;均方根误差(RMSE)分别为0.3667和0.2233;预测相对误差(REP)分别为5.05%和3.49%。对3个批次反丁烯二酸样品的测定结果与高效液相色谱法的测定结果进行比较,经成对t检验表明,两种方法的测定结果无显著性差异。     

偏最小二乘光度法同时测定多种酚的研究及应用

利用Ｃｕ（Ⅱ）吡啶能与酚形成稳定的三元配合物的特点，研究了Ｃｕ（Ⅱ）－吡啶－酚三元显色新体系，并以偏最小二乘法建立模型预测，同时测定了模拟水样和环境水样中的对苯二酚、间苯二酚、邻苯三酚和对硝基苯酚，取得满意效果。     

偏最小二乘-分光光度法同时测定钢样中铬、锰

在石亢_磷混合酸介质中,钢铁样品中铬和锰在银离子存在下用过硫酸铵溶液分别氧化至六价和七价,用分光光度法同时测定样品中铬和锰的含量.在380～600 nm波长范围,每间隔10 nm测定一次吸光度.借计算机及Matlab语言编写程序,对所得吸光度数据用偏最小二乘计算法处理并获得结果.     

同时测定铜、镍、锌的非线性偏最小二乘分光光度法

建立了以1－[5-溴－2吡啶偶氮]－2,7－萘二酚（5－Br-PADN)为显色剂,TritonX-100为增溶增敏剂,用非线性偏最小二乘（NLPLS）－分光光度法同时测定Cu^ 、Ni^2 、Zn^2 的方法。用迭代偏最小二乘法（IPLS）选择测定波长,用自编原MATLAB计算机程序进行处理。结果表明,该法不仅克服了三组分之间相互干扰,而且较好地解决了非线性问题,所拟方法用人工样品的分析,准确度较好,结果令人满意。     

偏最小二乘分光光度法同时测定扑热息痛等五组分含量

本文将偏最小二乘分光光度法应用于感冒液中扑热息痛、扑尔敏、咖啡因、对氨基酚和愈创木酚甘油醚五组分含量的分析研究，介绍了基本原理和具体的分析步骤。实验结果表明，偏最小二乘分光光度法对样品各组分的平均回收率在96．4％－105．0％之间，样品不经分离即可同时测定，取得了满意的分析结果。     

偏最小二乘紫外分光光度法同时测定甲基苯甲醛三种同分异构体

将偏最小二乘法(PLS)用于紫外分光光度数据的解析,建立了同时测定甲基苯甲醛3种同分异构体的模型。在230～304 nm范围内,将测得的48个样品的吸光度值作为校正集,另18个样品的吸光度值作为预测集用于建模。所建立的邻、间、对甲基苯甲醛模型的平均回收率分别为101.2%、100.2%和98.9%;均方根误差(RMSE)分别为0.2667、0.3853和0.2118;预测浓度范围分别为4.6～16.2μg/mL、5.8～17.4μg/mL和6.5～20.6μg/mL。讨论了混合物中3种同分异构体浓度比例对测定结果的影响,并确定了最佳的浓度比例范围。对模拟样品进行加标回收率试验。并通过与顺、反丁烯二酸两种同分异构体测定结果的比较,得出了有意义的结论。     

主成分-偏最小二乘动力学分光光度法同时测定农药两组分

对氨基甲酸酯杀虫剂残杀威（PRO）和异丙威（ISO）的速差动力学光度法同时测定进行了研究。残杀威和异丙威均能在碱性条件下发生水解，水解生成的酚盐，均可以与对氨基苯酚及高碘酸钾混合物发生反应生成兰色化合物，且这是一个反应速率适中的动力学反应。本实验在538nm-700nm采集多个时间点下多个波长的动力学－－吸收光谱数据，构成量测矩阵。采用主成分－偏最小二乘法（PC－PLS）对测定数据进行了解析。本文对环境水样中残杀威和异丙威的含量进行了测定。取得了较好的分析结果。从而提出了一种易于实现，准确度高的残杀威和异丙威的同时测定新方法。     

偏最小二乘吸光光度法同时测定钡和锶的研究

二溴对甲基偶氮甲磺（ＤＢＭ－ＭＳＡ）在磷酸介质中能与Ｂａ（Ⅱ）、Ｓｒ（Ⅱ）形成稳定的络合物。研究了该显色体系的反应条件以及应用偏最小二乘法（ＰＬＳ）处理两者叠吸收峰,建立了光度法同时测定Ｂａ（Ⅱ）和Ｓｒ（Ⅱ）的方法。方法用于合成试样和除氧剂试样中两元素含量的测定,结果满意。     

偏最小二乘-分光光度法同时测定福美锌和代森锰农药残留量

利用紫外可见分光光度法研究了农药福美锌和代森锰与苯基荧光酮的相互作用,发现反应后的产物分别在波长为551和554 nm处最大有吸收,但光谱严重重叠.实验采集了450～700 nm波长范围吸光度数据,并对该数据进行一阶求导后用偏最小二乘法处理,据此建立了偏最小二乘-分光光度法同时测定福美锌和代森锰两种农药的新方法.福美锌和代森锰的线性范围分别为0.3～6.0和0.2～3.5 μg/mL;检出限分别为0.22和0.13 μg/mL.混合样品分析无需分离,方法简单、快速.用于水果、大米和自来水等实际样品测定.     

偏最小二乘分光光度法同时测定痕量铁、锰、铜、锌、钴和镍

痕量Fe^3 ,Mn^2 ,Cu^2 ,Zn^2 ,Co^2 ,Ni^2 与2－（5－溴－2－吡啶偶氮）－5－二乙氨基苯酚（5－Br-PADAP)和溴化十六烷基三甲基铵（CTMAB）在PH8．3时发生高灵敏显色反应，所形成的三元胶束络合的吸收光谱严重重叠，采用偏最小二乘法（PLS）辅助分光光度法测定了合成试样及饲料中上述6种痕量组分，结果表明，PLS法是化学计量学中一种可适用于基体较复杂的实际试样中痕量组分分光度同时测定的多元计算方法。     

偏最小二乘光度法同时测定铜和铁的研究及应用

７－（１－苯偶氮）－８－羟基喹啉－５－磺酸钠在ＰＨ＝４．７５ＨＡｃ－ＮａＡｃ缓冲溶液中能与Ｃｕ（Ⅱ）和ＦＥ（Ⅲ）形成稳定的络合物，本文研究了Ｃｕ（Ⅱ）－ＰＡＨＱＳ、Ｆｅ（Ⅲ）－ＰＡＨＱＳ体系的显色条件，以偏最小二乘法处理两者重叠吸收峰，建立了光度法同时测定铜和铁的方法。     

稳健偏最小二乘光度法同时测定贵金属元素锇和钌

本文将稳健偏最小二乘法用于贵金属元素锇、钌的光度法同时测定，较好地解决了实际校准模型由于实验误差偏离正态分布使计算结果的精度遭到破坏的问题。     

模糊聚类-偏最小二乘光度法同时测定锇和钌

将模糊聚类分析与偏最小二乘相结合，对锇、钌双组份重叠光谱进行解析；较好地解决了校正分析中校准模型的优化问题，提高了分析结果的准确度；研究了锇、钌－ＳｎＣｌ２－乳化剂ＯＰ－阿拉伯树胶（ＡＧ）－丁基罗丹明Ｂ（ＢＲＢ）高灵敏多元离子缔合物显色体系。锇、钌的检出限分别为 ０，６３２ μｇ／Ｌ和 ０．３６８ μｇ／Ｌ，模拟地质样品分析结果的相对误差小于±１０％。     

Comparison of Artificial Neural Networks with Partial Least Squares Regression for Simultaneous Determinations by ICP-AES

Simultaneous determination of several elements （U, Ta, Mn, Zr and W） with inductively coupled plasma atomic emission spectrometry （ICP-AES） in the presence of spectral interference was performed using chemometrics methods. True comparison between artificial neural network （ANN） and partial least squares regression （PLS） for simultaneous determination in different degrees of overlap was investigated. The emission spectra were recorded at uranium analytical line （263.553 nm） with a 0.06 nm spectral window by ICP-AES. Principal component analysis was applied to data and scores on 5 dominant principal components were subjected to ANN. A 5-5-5 （input, hidden and output neurons） network was used with linear transfer function after both hidden and output layers. The PI,S model was trained with five latent variables and 20 samples in calibration set. The relative errors of predictions （REP） in test set were 3.75% and 3.56% for ANN and PLS respectively.     

Determination of Quercetin and Luteolin in Paprika Samples by Voltammetry and Partial Least Squares Calibration

Quercetin and luteolin are flavonoids with beneficious properties, which are present in paprika. In this work, both have been determined in paprika by using electrochemistry combined with chemometrics. The electrochemical oxidation mechanisms of both analytes have been studied through sampled direct current (DC) voltammetry, differential pulse voltammetry (DPV) and Square Wave Voltammetry (SWV), making use of a glassy carbon electrode. The final technique selected for the quantification was DPV due to its high repeatability with respect SWV. The chemical variables and the instrumental parameters were optimized and the final conditions employed were ethanol: water (20 : 80), 0.75 mol dm⁻³ of HCl, and a pulse amplitude of 50 mV. Due to the facts that oxidation potential of both analytes were quite similar, their DPV peaks were overlapped, and also because the analytes interaction during the electrochemical process causes a non‐additivity of the signals, they could not be quantified separately by direct measurement of peak intensity. For this reason, a chemometric algorithm was applied (partial least squares (PLS) regression in its modality PLS‐2). In the case of validation samples, appropriate sets of calibration and validation were built and good results were obtained. This methodology was applied to real paprika samples and the results were similar to those obtained with a HPLC method previously reported.     

Genetic Algorithm Applied to Selection of Wavelength in Partial Least Squares for Simultaneous Spectrophotometric Determination of Nitrophenol Isomers

Abstract

Ternary mixtures of nitrophenol isomers have been simultaneously determined in synthetic and real matrix by application of genetic algorithm and partial least squares model. All factors affecting the sensitivity were optimized and the linear dynamic range for determination of nitrophenol isomers found. The simultaneous determination of nitrophenol mixtures by using spectrophotometric methods is a difficult problem, due to spectral interferences. The partial least squares modeling was used for the multivariate calibration of the spectrophotometric data. A genetic algorithm is a suitable method for selecting wavelength for PLS calibration of mixtures with almost identical spectra without loss prediction capacity. The experimental calibration matrix was designed by measuring the absorbance over the range 300–520 nm for 21 samples of 1–20 µg mL^?1, 1–20 µg mL^?1, and 1–10 µg mL^?1 of m‐nitrophenol, o‐nitrophenol, and p‐nitrophenol, respectively. The root mean square error of prediction for m‐nitrophenol, o‐nitrophenol, and p‐nitrophenol with genetic algorithms and without genetic algorithms were 0.3732, 0.5997, 0.3181 and 0.7309, 0.9961, 1.0055, respectively. The proposed method was successfully applied for the determination of m‐nitrophenol, o‐nitrophenol, and p‐nitrophenol in synthetic and water samples.     

偏最小二乘催化极谱法同时测定铂,钯,铑

应用Ｍ２７３Ａ电化学系统中的线性扫描技术，确定了０．７５ｍｏｌ／ＬＨ２ＳＯ４－１．５％ＮＨ４Ｃｌ－２．８ｍｍｏｌ／Ｌ（ＣＨ２）６Ｎ４－０．００２５％Ｎ２Ｈ４．Ｈ２ＳＯ４为偏最小二乘极谱法同时测定Ｐｔ、Ｐｄ、Ｒｈ的最佳极谱体系。Ｐｔ、Ｐｄ、Ｒｈ的线性范围为３．２ｍｇ／Ｌ、０－１５．０ｍｇ／Ｌ和０－１．０ｍｇ／Ｌ。模拟样品及实际样品的回收率在９０．３－１０７．７％之间。     

一阶紫外导数光谱PLS法直接同时测定硝酸根和亚硝酸根

用偏最小二乘（ＰＬＳ）法解析了ＮＯ_３~－和ＮＯ_２~－混合体系的一阶紫外导数光谱，提出了直接同时测定环境水样中ＮＯ_３~－－Ｎ和ＮＯ_２~－－Ｎ的计算分析法。该法对ＮＯ_３~－和ＮＯ_２~－来说，最低检测浓度分别为９×１０~（－８）和２×１０~（－７）ｍｏｌ·Ｌ~（－１），精密度（ＲＳＤ）分别为２．０５％和２．１２％。用于测定合成水样，平均相对误差在４％以内；用于测定环境水样，结果与标准法相吻合。