多环芳烃混合物的快速导数-恒能量同步荧光光谱分析

多环芳烃混合物的快速导数-恒能量同步荧光光谱分析;导数技术     

多元线性回归—同时单点沉淀滴定同时测定卤素及硫氰酸盐混合物中各组分

本文将多元线性回归分析用于单点沉淀滴定法，同时测定了卤素及硫氰酸盐混合物各组分深度，讨论了方法原理、回归方程、对１５个二元、三元及四元混合样品进行了测定，均得到满意结果。     

分枝定界算法用于有机混合物的同时定性定量分析

分枝定界法用于多组分同时定性定量分析，只需解析一份试样测得的数据，即可同时得到待测样品中所含组分的种类、数目及含量，具有简单、快速、准确等优点。此文对分枝定界法在判据应用方面进行了改进，应用四个判据，解决了最佳子集难判断的问题。建立了精蒽中不经分离同时测定蒽、菲和咔唑的方法。     

小波潜变量回归和广义回归神经网络同时测定三组分混合物

本文采用小波潜变量回归（WLVR）方法，同时测定重叠的光谱信号。结合小波阈值法和主组分分析（PCA）改进除噪质量。八个误差判据用于推断因子数目。潜变量由小波处理过的信号投影到正交基矢量而获得。广义回归神经网络（GRNN）被应用于多组分同时测定。依据算法原理编制了三个程序（PWMRA、PWLVR和PGRNN）执行有关计算。三个方法（WLVR、LVR（潜变量回归）和GRNN）同时测定三组分混合物，获得满意的结果。     

基于LASSO算法的光谱变量选择方法研究

光谱分析技术由于具有简单、快速、无损等优势,在复杂体系的定性和定量分析中得到了广泛应用。然而光谱中往往包含成百上千的波长点,有些波长点与研究的目标性质并不相关,加大了计算量并降低了模型的预测准确度。因此,在建立模型前需要进行变量选择。最小绝对收缩与选择算子（LASSO）可将回归系数收缩为0,进而达到变量选择的目的。该研究将LASSO用于三元调和油样品近红外光谱和生物样品拉曼光谱的变量选择,基于偏最小二乘（PLS）和多元线性回归（MLR）模型,分别对香油和肌氨酸的含量进行定量分析,并与无信息变量消除－PLS（UVE－PLS）、蒙特卡罗结合UVE－PLS（MCUVE－PLS）和随机检验－PLS（RT－PLS）3种变量选择方法进行比较。结果表明,基于LASSO的变量选择方法保留的变量数最少,运算速度最快。对三元调和油样品,LASSO－PLS预测的准确度最高;对生物样品,LASSO－MLR预测的准确度最高。因此,基于LASSO的变量选择算法有望在光谱分析领域中得到良好应用。     

基于交互式自模型混合物分析的近红外光谱波长变量优选方法

为了提高近红外光谱定量分析的预测精度和建模效率,提出了一种基于交互式自模型的混合物分析的波长优选方法,根据光谱各波长变量的纯度值和标准差值,选择含有用信息的波长变量,并引入相关权函数解决变量间共线性问题.通过依次迭代选择的变量建立定量校正模型,由交互验证均方根预测误差(RMSECV)确定最佳波长变量个数.应用该波长变量优选方法对具有不同葡萄糖含量的两组(四成分葡萄糖水溶液实验和人体血浆实验)近红外光谱数据进行分析,两组数据中分别只选择了全部变量的0.3%建立定量校正模型,其验证集葡萄糖浓度的均方根预测误差(RMSEP)分别减少为669和15 mg/L.与全谱范围及优选波段建立的定量校正模型比较,本方法能够通过波长变量优选最小化冗余信息、提高预测精度及建模效率.     

多组分体系同时定性定量测定的逐步回归分析法

阐述了逐步回归分析法用于多组分体系同时定性定量分析的原理、实验及数据处理方法。分析了硝基酚类人工样、未知样及合成样。该法可用于仅知可能含有的组分范围的样品分析。     

混合物定性定量分析的分枝定界算法

已知被测体系可能存在的物种范围, 但其确含何种物质及相应浓度必须经分析方可确定, 实为分析化学实践中常见的一类分析体系。基于分枝定界原理, 本文提出一种直接对其进行定性定量解析的光谱多元分析算法, 可显著减少计算量,却无失去真实信息的风险。对实际紫外可见及荧光混合物光谱进行解析, 均获满意结果。     

“灰色”分析体系的定性定量分析

已知组成范围的“灰色”分析体系的校正,其首要步骤是鉴定出体系中实际存在的物种.本文对由所有可能存在组分的标准光谱与样品光谱构成的矩阵进行了奇异值分解,根据对应奇异向量的元素判断样品的组成,继而做定量分析.计算机模拟与实际分析表明方法令人满意.     

Simultaneous Multivariate Spectrophotometric Analysis of Binary and Ternary Mixtures of Sulfamethoxazole,Trimethoprim and Phenazopyridine in Tablets

ABSTRACT

The use of multivariate spectrophotometric calibration is reported for the analysis of tablets containing the antibiotics sulfamethoxazole and trimethoprim, and a combination of the former two drugs with the analgesic phenazopyridine. The resolution of these mixtures has been accomplished without prior separation, derivatisation or use of nonaqueous solvents, with the aid of partial least-squares (PLS-1) regression analysis of electronic absorption spectral data. The analytes have been simultaneously determined with high accuracy and precision, and with no interference from tablet excipients.     

一类用于多元光度分析的小波基主成分回归法

通过将变尺度小波分解滤噪与特征信息提取相结合,提出一类新的多元光度分析算法－小波基主成分回归（ＰＣＲＷ）方法。该法可有效地减小主成分向量残留噪声所引 误差显著提高多元校正准确性。将其用于分析氯霉素、醋酸对塞米松、尼泊金乙脂体系、得到满意的回收率,与ＰＣＲ法相比,分析结果的总平均相对误差从３．３８％降低到０．８３％。     

氟胺氰菊酯的定性定量分析

氟胺氰菊酯是一种用于蜜峰的高效杀螨剂。从20%商品氟胺氰菊酯粉剂中通过硅胶柱层板分离得到了96.6%的纯品并用FTIR和GC/MC进行定性量测定。采用GC/MS定量分析的方法，氟胺氰菊酯的浓度在0.05-10mg/L范围为线性响应，最低检测极限为 0.01mg/L。采用R（-）N-3，5-二硝基苯甲酰-苯基甘氨酸和长链烃的硅胶微粒手性柱，可成功地分离氟胺氰菊酯的二种旋光异构体，它们在商品氟胺氰菊酯中的比例近似为1：1。     

Application of Multivariate Calibration Techniques to HPLC Data for Quantitative Analysis of a Binary Mixture of Hydrochlorathiazide and Losartan in Tablets

New multivariate approaches have been applied to high-performance liquid chromatography (HPLC) with multiwavelength photodiode-array (PDA) detection. Multivariate calibration techniques such as partial least squares (PLS), principal component regression (PCR), classical least squares (CLS), and inverse least squares (ILS) was subjected to HPLC data for simultaneous quantitative analysis of synthetic binary mixtures and a commercial tablet formulation containing hydrochlorothiazide (HCT) and losartan potassium (LST). The combined use of HPLC and multivariate calibrations has been denoted HPLC–CLS, HPLC–ILS, HPLC–PCR, and HPLC–PLS. Successful chromatographic separation of the two active compounds and enalapril maleate, used as internal standard (IS), was accomplished by means of a 4.6 mm i.d. × 250 mm, 5 m particle, Waters Symmetry C₁₈ reversed-phase column and a mobile phase consisting of 60:40 acetate buffer (0.2 M, pH 4.8)–acetonitrile (v/v, 60:40). HPLC data based on the ratio of analyte peak areas to IS peak area were obtained by PDA detection at five-wavelengths (250, 255, 260, 265, and 270 nm). The HPLC–CLS, HPLC–ILS, HPLC–PCR, and HPLC–PLS calibration plots for hydrochlorothiazide and losartan potassium were constructed separately by using the peak-area ratios corresponding to the concentrations of each active compound. The HPLC multivariate calibrations obtained were tested for different synthetic mixtures containing HCT and LST in the presence of the IS. These multivariate chromatographic methods were also applied to a commercial pharmaceutical dosage form containing HCT and LST. The results obtained from the multivariate calibrations were compared with those obtained by use of another, classical HPLC method using single-wavelength detection.Revised: 29 September 2004 and 4 January 2005     

Simultaneous Determination of Timolol Maleate and Pilocarpine Hydrochloride in Ophthalmic Solutions by First Derivative UV Spectrophotometry and PLS-1 Multivariate Calibration

ABSTRACT

The use of UV spectrophotometry (first-derivative/zero-crossing and zero-order spectra/multivariate calibration) is reported for the analysis of two miotic agents in ophthalmic solutions. The resolution of these mixtures has been accomplished without prior separation or derivatisation by using: 1) first-derivative measurements at two appropriate zero-crossing points: λ₁ = 222 nm, where the absorption corresponding to excipients is negligible, and λ₂ = 307 nm, where the contribution of pilocarpine and excipients to the overall absorption is negligible, and 2) partial least squares (PLS-1) regression analysis of zero-order spectral data. Although the components show an important degree of spectral overlap, they have been simultaneously determined with high accuracy, and with no interference from ophthalmic solution excipients.     

Rapid and Simple Method for Simultaneous Determination of Escin and Diethylamine Salicylate in Pharmaceutical Preparations by Partial Least-Squares Multivariate Calibration

Summary. A partial least-squares calibration (PLS) method has been developed for simultaneous quantitative determination of escin (ES) and diethylamine salicylate (DAS) in pharmaceutical preparations. The resolution of these mixtures has been accomplished without prior separation or derivatisation, by using partial least-squares (PLS-2) regression analysis of electronic absorption spectral data. The experimental calibration matrix was constructed with 9 samples. The concentration ranges considered were 10, 20, 30 (ES) and 40, 50, 60 (DAS) μg cm⁻³. The absorbances were recorded between 200 and 325 nm every 5 nm. Proposed method was compared with conventional spectrophotometric method. The results show that PLS-2 is a simple, rapid, and accurate method applied to the determination of these compounds in pharmaceuticals.     

多组分烟用香精定量分析方法的研究进展

综述了近年来烟用香精、香料各组分化合物的定量分析方法的研究进展。面积归一化法、内标法、外标法和标准加入法等常用色谱定量分析方法主要用于烟用香精、香料中目标化合物或单个组分的测定;多标定量法、特征峰-内标定量法和多元校正法能深入剖析烟用香精复杂体系中各组分含量(引用文献48篇)。     

模型诊断用于近红外光谱建模校正集中奇异样本的识别

由于校正集样本的质量决定校正模型的质量,校正集中奇异样本的检测在多元校正建模中具有非常重要的意义.本研究建立了一种用于近红外光谱多元校正建模时校正集中奇异样本的检测方法.本方法基于奇异样本的定义和偏最小二乘方法的原理,通过考察每个校正集样本在模型的每个因子(或主成分)中对模型的贡献,将与多数样本表现不同的样本识别为奇异样本.采用218个橘汁样本构成的近红外光谱数据进行了分析,结果表明,校正集中存在6个奇异样本,扣除奇异样本后,校正集的交叉验证均方根误差由16.870减小为4.809,预测集的均方根误差从3.688减小为3.332.     

拉曼光谱同时测定乙醇与葡萄糖的方法研究

以共焦拉曼光谱技术为基础,结合96孔板,对比利用一元线性回归法、多元线性回归法、主成分回归法和偏最小二乘法建立定量分析模型,探索同时定量检测乙醇和葡萄糖的快捷方法。对同一组乙醇和葡萄糖混合标准溶液进行定量检测,并用木薯淀粉发酵液进一步验证。结果表明,偏最小二乘法定量结果的平均标准误差(SE)为0.179,平均相对标准偏差(RSD)为0.029,结合二阶导数后分别降至0.106和0.021,说明偏最小二乘法具有良好的紧密度和稳定性;t检验表明,在置信度为95%的条件下,实测值与标准值间不存在显著性差异。研究表明基于拉曼光谱技术的偏最小二乘回归定量方法,能满足实验和生产对乙醇和葡萄糖检测精度的要求,可用于乙醇和葡萄糖相关成分的同时快速检测。     

多元分辨校正模型与方法研究—无机多组份分析

系统研究了各种多元分辨校正模型、方法及其应用，以模拟体系、病态体系有态体系为对象，考察了它们的多元校正能力与多元分辨效果，给我机多组份分析态体系实例。