Rapid determination of thiabendazole in orange extract using excitation-emission matrix fluorescence and second-order calibration based on alternating trilinear decomposition/alternating normalization-weighted error algorithms

A novel approach is proposed for direct quantitative analysis of thiabendazole in the orange extract by using excitation-emission matrix fluorescence coupled with second-order calibration methods based on the alternating trilinear decomposition(ATLD) and the alternating normalization-weighted error(ANWE) algorithms,respectively. The average recoveries of thiabendazole in the orange extract by using ATLD and ANWE with an estimated component number of two were 99.7 ± 3.3% and 103.5 ± 4.1%,respectively. Furthermore,the accuracy of the two algorithms was also evaluated through elliptical joint confidence region(EJCR) tests as well as figures of merit,such as sensitivity(SEN),selectivity(SEL) and limit of detection(LOD). The experimental results demonstrate that both algorithms have been satisfactorily applied to the determination of thiabendazole in orange extract,and the perform-ance of ANWE is slightly better than that of ATLD.     

Strategies for solving matrix effects in the analysis of sulfathiazole in honey samples using three-way photochemically induced fluorescence data

A widely employed compound for honey treatment, sulfathiazole (ST), was determined in commercial honey samples, employing a combination of photochemically induced fluorescence excitation-emission matrices (EEMs) and chemometric processing of the recorded second-order data. Parallel Factor Analysis (PARAFAC) and Self-Weighted Alternating Trilinear Decomposition (SWATLD) methods were used for calibration. An appropriately designed calibration with a set of standards composed of 18 samples, coupled to the use of the second-order advantage offered by the applied chemometric techniques, allowed quantitation of sulfathiazole in spiked commercial honey samples. No previous separation or sample pretreatment steps were required. The results were compared with other calibration methods such as N-PLS and PLS-1 that produced good results on synthetic samples but not on the investigated commercial honey samples.     

Simultaneous determination of tyrosine and dopamine in urine samples using excitation-emission matrix fluorescence coupled with second-order calibration

A "green" and quick analytical method for complex compounds was developed for simultaneous determination of tyrosine (Tyr) and dopamine (DA) in urine samples in this paper. The three-way responsive data recorded by excitation-emission matrix fluorescence (EEM) spectrometer was analyzed using second-order calibration methods based on both parallel factor analysis (PARAFAC) and selfweighted alternating trilinear decomposition (SWATLD) algorithms. The EEM spectra of the analytes were overlapped with the background in urine samples. However the second-order advantage of both PARAFAC and SWATLD methods was exploited, even in the presence of unknown interferences and the satisfactory results can be obtained. Furthermore, the linear ranges of Tyr and DA were determined to be 0.042-6.42 μg/mL and 0.18-4.43 μmg/mL, respectively, and the accuracies of both methods were validated by the analytical figures of merit (FOM).     

三维荧光二阶校正法快速测定块茎类蔬菜、土壤和污水中克百威残留量

克百威是一种高效内吸广谱氨基甲酸酯类杀虫剂.本文充分利用荧光光谱仪操作简单、灵敏度高,化学计量学二阶校正算法具有的"二阶优势",将三维荧光(EEM)与化学计量学交替三线性分解(ATLD)算法相结合,实现了红薯、土豆、红萝卜、土壤和污水5种实际复杂体系中克百威残留量的直接快速定量测定.当选取组分数为2时,用ATLD获得的平均回收率分别为(99.0±5.3)%、(97.2±4.2)%、(102.7±5.9)%、(101.1±3.8)%和(91.3±1.9)%.另外,还用椭圆置信区间(EJCR)测试和品质因子,如灵敏度(SEN)、选择性(SEL)、检测下限(LOD)和预测均方根误差(RSMEP)评估了该种算法的准确性.实验结果表明,该方法能以"数学分离"代替繁琐的"化学分离",成功地解决实际复杂体系中内源干扰物质与分析物光谱重叠所引起的难分辨的问题,可用于未知干扰共存下克百威含量的直接快速定量测定.     

Interference-free determination of fluoroquinolone antibiotics in plasma by using excitation-emission matrix fluorescence coupled with second-order calibration algorithms

Fluoroquinolones or so-called second-generation quinolones, in particular, ofloxacin (OFL), norfloxacin (NOR), and enoxacin (ENO), with therapeutic advantages possess strongly overlapped fluorescence spectra. In this paper, two strategies were proposed for simultaneous direct determination of OFL, NOR and ENO in plasma by combining fluorescence excitation-emission matrix (EEM) with second-order calibration based on the alternating trilinear decomposition algorithm (ATLD) and parallel factor analysis (PARAFAC). The results showed that both algorithms could solve the problem of serious fluorescence spectral overlapping of the sought-for analytes even in the presence of uncalibrated interferents. However, ATLD has advantages of being insensitive to overestimated component number and fast convergence. The results by using ATLD with an estimated component number of five were reasonably acceptable for clinical analysis. The average recoveries of OFL, NOR and ENO in synthetic samples were 99.7 ± 2.4, 101.5 ± 2.4 and 97.3 ± 3.8%, respectively; the average recoveries of OFL, NOR and ENO in complex plasma were 94.3 ± 2.6, 85.6 ± 3.3 and 103.3 ± 3.0%, respectively.     

Simultaneous determination of 6-methylcoumarin and 7-methoxycoumarin in cosmetics using three-dimensional excitation-emission matrix fluorescence coupled with second-order calibration methods

This paper reports a simple, rapid, and effective method for quantitative analysis of 6-methylcoumarin (6-MC) and 7-methoxycoumarin (7-MOC) in cosmetics using excitation–emission matrix (EEM) fluorescence coupled with second-order calibration. After simple pretreatments, the adopted calibration algorithms exploiting the second-order advantage, i.e., parallel factor analysis (PARAFAC) and self-weighted alternating tri-linear decomposition (SWATLD), could allow the individual concentrations of the analytes of interest to be predicted even in the presence of uncalibrated interferences. In the analysis of facial spray, with the external calibration method, the average recoveries attained from PARAFAC and SWATLD with the factor number of 3 (N = 3) were 101.4 ± 5.5 and 97.5 ± 4.1% for 6-MC, and 103.3 ± 1.7 and 101.7 ± 1.8% for 7-MOC, respectively. Moreover, in the analysis of oil control nourishing toner, the standard addition method (SAM) was suggested to overcome the partial fluorescence quenching of 6-MC induced by the analyte–background interaction, which also yielded satisfactory prediction results. In addition, the accuracy of the two algorithms was also evaluated through elliptical joint confidence region (EJCR) tests as well as figures of merit (FOM), including sensitivity (SEN), selectivity (SEL) and limit of detection (LOD). It was found that both algorithms could give accurate results, only the performance of SWATLD was slightly better than that of PARAFAC in the cases suffering from matrix effects. The method proposed lights a new avenue to determine quantitatively 6-MC and 7-MOC in cosmetics, and may hold great potential to be extended as a promising alternative for more practical applications in cosmetic quality control, due to its advantages of easy sample pretreatment, non-toxic and non-destructive analysis, and accurate spectral resolution and concentration prediction.     

Simultaneous determination of naphazoline and pyridoxine in eye drops using excitation–emission matrix fluorescence coupled with second-order calibration method based on alternating trilinear decomposition algorithm

A novel method is developed for the direct determination of naphazoline hydrochloride(NAP) and pyridoxine hydrochloride(VB6) in commercial eye drops. By using excitation–emission matrix(EEM)fluorescence coupled with second-order calibration method based on the alternating trilinear decomposition(ATLD) algorithm, the proposed approach can achieve quantitative analysis successfully even in the presence of unknown and uncalibrated interferences. The method shows good linearity for NAP and VB6 with correlation coefficients greater than 0.99. The results were in good agreement with the labeled contents. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring(MRM) based on LC–MS/MS method.T-test demonstrated that there are no significant differences between the prediction results of the two methods. The satisfactory results obtained in this work indicate that the use of the second-order calibration method coupled with the EEM is a promising tool for industrial quality control and pharmaceutical analysis due to its advantages of high sensitivity, low-cost and simple implementation.     

三线性分解方法用于激发-发射矩阵荧光数据中一阶瑞利散射的扣除

由于荧光分析具有检测灵敏度高、数据容易获得等优点,近年来二阶张量校正方法与激发-发射矩阵荧光光谱技术的联用正受到人们越来越多的关注.但是,在三维荧光分析中,经常出现的一阶瑞利散射干扰往往容易导致建立的三线性模型存在较大的偏离,进而直接影响复杂体系中感兴趣组分的定性、定量分析.针对该问题,我们提出了一种基于对组分数不敏感的三线性分解算法扣除一阶瑞利散射干扰的新思路.该方法的特点是根据一阶瑞利散射分别在水平切片矩阵和侧面切片矩阵所处位置相同,沿I-模和J-模同时构建含一阶瑞利散射的三维数据阵,利用三线性分解算法对此各自建模,将一阶瑞利散射当作一个响应组分或因子拟合后从三维数据阵中扣除掉.通过对模拟和实际三维激发发射矩阵荧光光谱实验数据进行讨论,结果表明该方法能有效地扣除体系中的一阶瑞利散射干扰.改进后的方法不仅操作简单,而且不受组分数选取不当的困扰.另外,由于同时从两个方向进行一阶瑞利散射扣除,因此不会出现因边缘瑞利散射峰形不完整而扣除不完全的情况.该方法为三维荧光光谱的无损分析提供了新思路,为进一步进行三维荧光光谱的定量分析奠定了良好的基础.     

Determination of testosterone propionate in cosmetics using excitation-emission matrix fluorescence based on oxidation derivatization with the aid of second-order calibration methods

A sensitive excitation-emission fluorescence method was proposed to determine testosterone propionate (TP) in several cosmetics with the aid of second-order calibration methods based on the self-weighted alternating trilinear decomposition (SWATLD) and parallel factor analysis (PARAFAC) algorithms. TP can be transformed into a highly fluorescent derivative through oxidation reaction with concentrated sulfuric acid (H₂SO₄). Both algorithms have been recommended to enhance the selectivity and attain TP concentration in cosmetics free from interference from potential interfering matrix contaminants introduced during simple cosmetic pretreatment procedure, even in the presence of other homogeneous drugs. Satisfactory results have been achieved for TP in complicated cosmetics, fully exploiting “second-order advantage”. The correlation coefficients of TP obtained by using both SWATLD and PARAFAC with N = 3 are 0.9968 and 0.9974, and the average recoveries, 99.3 ± 4.7% and 101.3 ± 5.9%, respectively. Furthermore, in order to investigate the performance of the proposed methods, some statistical parameters and figures of merit of SWATLD and PARAFAC, i.e., sensitivity (SEN), selectivity (SEL) and limit of detection (LOD) were evaluated, and the accuracy of both algorithms was also validated by the elliptical joint confidence region (EJCR) test.     

三维荧光光谱结合交替三线性分解二阶校正法同时测定血浆样中三种抗癌药物含量

姜黄素、阿霉素和白藜芦醇对多种恶性肿瘤的治愈皆有一定的疗效,且其联合用药对癌细胞的抑制效果更加显著．本文采用三维激发发射荧光光谱结合基于交替三线性分解（Alternating Trilinear Decomposition,ATLD）算法的化学计量学二阶校正法,同时对血浆样中姜黄素、盐酸阿霉素和白藜芦醇的含量进行了定量分析研究．当量测体系的组分数预估计取4时,ATLD方法解析得到的血浆样中姜黄素、盐酸阿霉素和白藜芦醇的平均回收率分别为（91．4±1．1）％、（104．5±2．8）％和（103．4±4．7）％．实验结果表明,此法能够解决干扰共存和荧光光谱重叠下血浆样中姜黄素、盐酸阿霉素和白藜芦醇的直接、快速、同时定量分析的难题．     

三维荧光校正法直接测定尿液中的利血平

利用化学计量学三维数据校正方法中的交替三线性分解算法(ATLD)和自加权交替三线性分解算法(SWATLD), 不经化学分离, 对采用激发-发射矩阵荧光法所得到的三维响应数据阵进行三线性成分分解, 再基于标样已知浓度, 利用简单回归法直接测定尿液中利血平(Reserpine)的含量. 结果表明, 当体系的主要组分数取3时, 两种方法均可迅速、 快捷地得到待测物的浓度, 有效地解决了荧光法定量测定时未知背景及干扰物光谱严重重叠而引起的问题.     

三维荧光二阶校正方法快速检测香蕉中双苯三唑醇含量

利用交替三线性分解(ATLD)、交替拟合残差(AFR)和自加权交替三线性分解(SWATLD)等3种二阶校正算法分别对三维荧光光谱数据进行解析,实现了香蕉中的双苯三唑醇含量的直接快速定量测定.当被分析体系的组分数取2时, ATLD、AFR和SWATLD获得的平均回收率分别为(98.2±2.6)%、(97.6±2.1)%和(91.5±3.5)%.另外,采用椭圆置信区间测试(EJCR)和品质因子,如灵敏度(SEN)、选择性(SEL)和检出限(LOD)评估了3种算法的准确性.实验结果表明:3种算法均能成功用于直接分析香蕉中双苯三唑醇的含量.     

三维荧光二阶校正方法用于体液和细胞培养基中五味子甲素含量的快速测定

采用三维激发发射荧光光谱结合自加权交替三线性分解(SWATLD)二阶校正方法, 对人体液样(血浆样及尿液样)和细胞培养基样中五味子甲素的含量进行了直接快速定量分析. 在血浆背景、尿液背景和细胞培养基背景共存下, 当分析体系的组分数分别选择2时, 用SWATLD二阶校正方法获得相应五味子甲素的平均回收率分别为(100.4±1.6)%, (100.5±6.3)%和(103.6±4.5)%. 实验结果表明, 此方法不仅能够较好地解决这些复杂分析体系因背景内源荧光性物质与待分析物光谱严重重叠所引起的难分辨的问题, 还可以用于直接快速准确定量分析.     

交替三线性分解算法用于水杨酸和2,5-二羟基苯甲酸的荧光法同时测定

水杨酸 (SA)、2 ,5 二羟基苯甲酸 (GA)和对 氨基苯甲酸 (PABA)的荧光光谱相互重叠。用交替三线性分解二阶校正法对PABA共存下的SA和GA进行了同时荧光测定 ,SA和GA的回收率分别为 (1 0 1 2± 1 9) %和 (97 1 6±1 0 4 ) %。     

Interference-free determination of Sudan dyes in chilli foods using second-order calibration algorithms coupled with HPLC-DAD

This paper presents a new method for the determination of Sudan dyes contained in hot chilli samples. The method employs second-order calibration algorithms to handle the recorded data. The second-order calibration algorithms are based on the popular parallel factor analysis (PARAFAC), alternating trilinear decomposition (ATLD) and self-weighted alternating trilinear decomposition (SWATLD), respectively. These chemometric methodologies have the second-order advantage, which is the ability to get accurate concentration estimates of interested analytes even in the presence of uncalibrated interfering components. The results on a set of spiked chilli test shows that low contents of Sudan I and Sudan II in complex chilli mixtures can be accurately determined using the new method. The sample preparation was based on solvent extraction, and internal standard was not required. Quantification was carried out with simple mobile phase.     

Analysis of amoxicillin in human urine by photo-activated generation of fluorescence excitation-emission matrices and artificial neural networks combined with residual bilinearization

Fluorescence excitation-emission data recorded for amoxicillin after photo-activated reaction with periodate have been processed by a novel second-order multivariate method based on the combination of artificial neural networks and residual bilinearization (ANN/RBL), since the signals bear a strong non-linear relation with the analyte concentration. The selected chemometric methodology is employed for the first time to evaluate experimental non-linear second-order spectral information. Due to severe overlapping between the emission profiles for the analyte reaction product and for the urine background, calibration was done using different spiked urine samples. This allowed for the determination of amoxicillin in test spiked urines, other than those employed for calibration. When new urine samples containing a fluorescent anti-inflammatory were analyzed, accurate prediction in the presence of unexpected components required the achievement of the second-order advantage, which is provided by the post-training RBL procedure. Amoxicillin was also determined by ANN/RBL in a series of real urine samples, which allowed one to perform a comparison study with the reference high-performance liquid chromatographic technique.     

交替拟合残差算法与高效液相色谱-二极管阵列检测方法结合同时测定两种抗结核药物

本文利用化学计量学交替拟合残差(AFR)算法与高效液相色谱-二极管阵列检测(HPLC-DAD)方法相结合,同时测定两种抗结核药物异烟肼和吡嗪酰胺的含量。该法与交替三线性分解算法(ATLD)、自加权交替三线性分解(SWATLD)算法相比较,从预测均方差、预测相对误差以及平均回收率等结果来看,其预测结果更接近实际值。研究表明,基于交替拟合残差等算法的二阶校正法,可以迅速准确地给出色谱重叠情况下两个组分的预测结果,是复杂体系成分直接定量分析的一个有力的化学计量学工具。     

三维荧光光谱结合二阶校正方法测定细胞培养基中阿霉素的含量

本文采用交替三线性分解(ATLD)和交替归一加权残差三线性分解(ANWE)两种二阶校正方法结合激发发射矩阵荧光光谱对完全不经任何预处理的细胞培养基中的阿霉素进行简单、快速、直接的定量测定.当算法选取组分数为2时,解析得到细胞培养基中阿霉素的平均回收率分别为(100.5±1.8)%和(100.3±1.9)%.在细胞培养基中加入烟酰胺腺嘌呤二核苷酸(NADH)、烟酰胺腺嘌呤二核苷酸磷酸(NADPH)、黄素腺嘌呤二核苷酸(FAD)和黄素单核苷酸(FMN)四种细胞内的自发荧光物后,选取组分数为4时,解析得到细胞培养基中阿霉素的平均回收率分别为(99.1±2.9)%和(99.2±3.1)%.结果表明该分析方法能够准确、快速地直接测定细胞培养基中阿霉素的含量,并且在模拟细胞内荧光干扰环境下可定量测定阿霉素,且能获得令人满意的结果.     

两种荧光方法分析血样中锌原卟啉和原卟啉

利用N,N-二甲基甲酰胺同时萃取血样中痕量的锌原卟啉和原卟啉,以三维荧光-交替三线性分解算法和导数恒基体同步荧光法同时分析血样中的锌原卟啉和原卟啉.前者中锌原卟啉和原卟啉分别在0.6～35 μg/L和0.4～27 μg/L范围内呈良好的线性,检出限分别为0.18和 0.12 μg/L;后者中锌原卟啉和原卟啉在0.14～45 μg/L和0.056～28.5 μg/L范围内呈良好的线性,检出限分别为0.12和 0.045 μg/L.实际血样中两种方法的平均回收率分别为(82±9)%和(85±10)%,且两种方法测定20份血样时获得的相关性良好.     

Interaction of epicatechin with bovine serum albumin using fluorescence quenching combined with chemometrics

The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure.