[Determination of brix and POL in sugar cane juice by using near infrared spectroscopy coupled with BP-ANN].

The models of quantitative analysis of brix and pol in sugar cane juice were established by using near infrared spectroscopy (NIR) coupled with the back propagation-artificial neural network method (BP-ANN). The spectra of cane juice samples were obtained by the way of 2 mm optical length transmission and using the NIR spectrometer of 1,000-1,800 nm wavelength. Firstly, the data of original spectra were pretreated by Savitzky-Golay derivative and mean-centering. Secondly, the wavelength range of model was optimized by using correlation coefficient method coupled with the characteristic absorbance of the spectrum. Finally, the principal components, obtained by PLS dimension-reducing, were inputed into BP-ANN. The calibration models were established by calibration set and validated by prediction set. The results showed that the related coefficients (R2) of prediction for brix and pol were 0.982 and 0.979, respectively; and the standard errors of prediction (SEP) for brix and pol were 0.159 and 0.137, respectively. BP-ANN was more accurate in the prediction of brix and pol compared with the partial least square method (PLS). The method can be applied to fast and accurate determination of brix and pol in sugar cane juice.

[Real-time monitoring of industrial acetic acid production process using a new type of online NIR analysis system].

The safe and real-time monitoring of the production process of acetic acid is always a key technical problem. The conventional online chromatographic analysis can't satisfy the requirements of real-time analysis for its inherent disadvantages. A new type of on-line near-infrared analysis system has been developed for real-time analysis of the concentration of each component in acetic acid reaction kettles instantly. Its features and configuration were described in detail. Both the laboratory modeling and field application results have confirmed that this system is of high stability and accuracy. The proposed system can effectively solve the key technical problems in the manufacture and ensure the safety and stability of production process of acetic acid.

Quantitative analysis of epinephrine in human plasma samples using kinetic fluorometric method combined with second-order calibration.

A kinetic fluorometric method was proposed for the quantitative determination of epinephrine (EP) in human plasma samples with the aid of second-order calibration methods based on alternating trilinear decomposition (ATLD) and alternating fitting residue (AFR) algorithms. It was based on that EP could be gradually converted to a highly fluorescent intermediate product by an oxidation reaction, and further to a non-fluorescent degradation product (o-quinone). These methodologies fully exploit the second-order advantage of the employed three-way kinetic fluorescence data, allowing the concentrations of EP to be quantified even in the presence of uncalibrated interferences. The average recoveries obtained from ATLD and AFR with a factor number of 2 (N = 2) were 100.7 +/- 3.3 and 100.4 +/- 2.2%, respectively. In addition, elliptical joint confidence region (EJCR) tests as well as figures of merit (FOM) were employed to evaluate the accuracy of the two algorithms.

Excitation-emission-kinetic fluorescence coupled with third-order calibration for quantifying carbaryl and investigating the hydrolysis in effluent water.

A novel method for determination of carbaryl in effluent was proposed in this study. The kinetic evolution of excitation-emission matrix fluorescence (EEM) for the pesticide were recorded and come into being a four-way data array. The four-way fluorescence data were analyzed using the parallel factor analysis (PARAFAC). The methodology exploits the second-order advantage of three-order calibration based on quadrilinear parallel factor analysis, allowing analyte concentrations to be estimated even in the presence of an uncalibrated fluorescent background. It gave the satisfactory results for determination of the carbaryl in effluent samples. In addition, the kinetic study of degradation of carbaryl was performed according to the kinetic profile provided by the calibration.

Determination of psoralen in human plasma using excitation-emission matrix fluorescence coupled to second-order calibration.

A new algorithm, an alternating normalization-weighted error (ANWE) method, and the parallel factor analysis (PARAFAC) have been used to directly determine psoralen (PSO) in human plasma. The two methods fully exploit the second-order advantage of the applied three-way fluorescence data. Interestingly, the calibration samples need only the components of interest, and the prediction samples allow containing not only the components of interest, but also unknown interferents. Consequently, the determination of PSO in plasma becomes no longer troublesome or time-consuming. The results are satisfying. Furthermore, compared with PARAFAC, the newly introduced ANWE method can obtain more satisfactory results.

Determination of pesticides in honey using excitation-emission matrix fluorescence coupled with second-order calibration and second-order standard addition methods.

The present paper presents a novel method for simultaneous determination of the three pesticides, carbaryl, carbendazim and 1-naphthol in honey. The excitation-emission matrix fluorescence data from calibration and prediction samples composed a three-way data array and then were analyzed using the second-order calibration method based on the self-weighted alternating trilinear decomposition (SWATLD). The second-order advantage of the SWATLD-based second-order calibration method was exploited, which makes it possible that calibration can be performed even in the presence of unknown interferences. The method was applied to determine the pesticides in the complex matrix of the honey sample. After the calibration step the recoveries of carbendazim and 1-naphthol were satisfactory. The quantification of carbaryl using the second-order standard addition method (SOSAM) based on SWATLD and the high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) were performed to validate the concentration of carbaryl in honey samples.

Quantitative analysis of hydrolysis of carbaryl in tap water and river by excitation-emission matrix fluorescence coupled with second-order calibration.

A novel method was proposed to determine simultaneously carbaryl and its degradation product 1-naphthol in river and tap water in this paper. The parallel factor analysis (PARAFAC) algorithm was adopted to analyze the excitation-emission matrix (EEM) fluorescence data. The second-order advantage of the PARAFAC-based second-order calibration algorithm was exploited, which make it possible that calibration can be performed even in the presence of unknown interferences. Good recoveries were obtained although the excitation and emission spectral profiles of the analytes were overlapped with background in the river water. It was also applied to investigate the hydrolysis kinetics of carbaryl in river water and tap water. The rate equation, the rate constant and the half life were calculated.

Determination of sulpiride in human urine using excitation-emission matrix fluorescence coupled with second-order calibration.

This paper proposes a new and effective approach for the quantitative analysis of sulpiride, a significant antipsychotic drug, in human urine samples by the incorporation of excitation-emission matrix (EEM) fluorescence and second-order calibration methodologies based on the alternating fitting residue (AFR) and self-weighted alternating trilinear decomposition (SWATLD) algorithms. With the application of a second-order advantage, the proposed strategy could be utilized for a direct concentration determination of sulpiride with a simple pretreatment step, even in the presence of serious natural fluorescent interferences. The average recoveries of sulpiride in complex urine samples by using AFR and SWATLD with an estimated component number of three were 101.2 +/- 2.1 and 94.4 +/- 0.7%, respectively. Moreover, the accuracy of the two algorithms was also evaluated through elliptical joint confidence region (EJCR) tests as well as the figures of merit, such as sensitivity (SEN), selectivity (SEL) and limit of detection (LOD). The experimental results demonstrated that both algorithms, as promising quantitative alternatives, have been satisfactorily applied to the determination of sulpiride in human urine, but the performance of AFR was slightly better than that of SWATLD.

Determination of carbendazim in bananas by excitation-emission matrix fluorescence with three second-order calibration methods.

A novel method for determination of carbendazim in bananas is proposed in this study. After the bananas were simply extracted, the carbendazim was quantified under the interference of banana extract using the second-order calibration algorithms based on the parallel factor analysis (PARAFAC), the self-weighted alternating trilinear decomposition (SWATLD) and the alternating penalty trilinear decomposition algorithms (APTLD), respectively. For analysis of the complex samples, the so-called second-order advantage was adequately exploited and good results were obtained. Figures of merit, such as limit of detection, sensitivity and selectivity, were calculated to compare the performances of the three algorithms.

Trilinear decomposition method applied to removal of three-dimensional background drift in comprehensive two-dimensional separation data.

A novel technique for removal of three-dimensional background drift in comprehensive two-dimensional (2D) liquid chromatography coupled with diode array detection (LCxLC-DAD) data is proposed. The basic idea is to perform trilinear decomposition on the instrumental response data, which is based on the alternating trilinear decomposition (ATLD) algorithm. In model construction, the background drift is modeled as one component or factor as well as the analytes of interest, hence, the drift is explicitly included into the calibration. The method involves performing trilinear decomposition on the raw data, then extracting the background component and subtracting this background data from the raw data, leaving the analytes' signal on a flat baseline. Simultaneous evaluation of three-dimensional background drift and true signals may improve the quality of the data. This method is applied to the determination and removal of three-dimensional background drifts in simulated multidimensional data as well as experimental comprehensive two-dimensional liquid chromatographic data. It is shown that this technique yield a good removal of background drift, without the need to perform a blank chromatographic run, and required no prior knowledge about the sample composition.

A novel efficient way to estimate the chemical rank of high-way data arrays.

A novel method, a subspace projection of pseudo high-way data array (SPPH), was developed for estimating the chemical rank of high-way data arrays. The proposed method determines the chemical rank through performing singular value decomposition (SVD) on the slice matrices of original high-way data array to produce a pseudo high-way data array and employing the idea of the difference of the original truncated data set and the pseudo one. Compared with traditional methods, it uses the information from eigenvectors combined with the projection residual to estimate the rank of the three-way data arrays instead of using the eigenvalue. In order to demonstrate the excellent performance of the new method, simulated and real three-way data arrays were carried out by the proposed method. The results showed that the proposed method could accurately and quickly determine the chemical rank to fit the trilinear model. Moreover, the newly proposed method was compared with the other four factor-determining methods, i.e. factor indicator function (IND), ADD-ONE-UP, core consistency diagnostic (CORCONDIA) and two-mode subspace comparison (TMSC) approaches. It was found that the proposed method can deal with more complex situations with existence of severe collinearity and trace concentration than many other methods can and performs well in practical applications.

Estimating the chemical rank of three-way data arrays by a simple linear transform incorporating Monte Carlo simulation.

Estimating an appropriate chemical rank of a three-way data array is very important to second-order calibration. In this paper, a simple linear transform incorporating Monte Carlo simulation approach (LTMC) to estimate the chemical rank of a three-way data array was suggested. The new method determines the chemical rank through performing a simple linear transform procedure on the original cube matrix to produce two subspaces by singular value decomposition. One of two subspaces is derived from the original three-way data array itself and the other is derived from a new three-way data array produced by the linear transformation of the original one. Projection technique incorporating the Monte Carlo approach acts as distinguishing criterion to choose the appropriate component number of the system. Simulated three-way trilinear data arrays with different noise types (homoscedastic and heteroscedastic), various noise level as well as high collinearity are used to illustrate the feasibility of the new method. The results have shown that the new method could yield accurate results with different conditions appended. The feasibility of the new method is also confirmed by two real arrays, HPLC-DAD data and excitation-emission fluorescent data. All the results are compared with the other three factor-determining methods: factor indicator function (IND), core consistency diagnostic (CORCONDIA) and two-mode subspace comparison (TMSC) approach. It shows that the newly proposed algorithm can objectively and quickly determine the chemical rank to fit the trilinear model.

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.

Study of the interactions of berberine and daunorubicin with DNA using alternating penalty trilinear decomposition algorithm combined with excitation-emission matrix fluorescence data.

Studies of interactions between drugs and DNA are very interesting and significant not only in understanding the mechanism of interaction, but also for guiding the design of new drugs. However, until recently, mechanisms of interactions between drug molecules and DNA were still relatively little known. It is necessary to introduce more simple methods to investigate the mechanism of interaction. In this study, the interactions of daunorubicin (DNR) or berberine (BER) with DNA and the competitive interactions of DNR and BER with DNA have been studied by alternating penalty trilinear decomposition algorithm (APTLD) combined with excitation-emission matrix fluorescence data. The excitation and emission spectra as well as the relative concentrations of co-existing species in different reaction and equilibrium mixtures can be directly and conveniently obtained by the APTLD treatment. The results obtained are valuable for providing a deeper insight into the interaction mechanism of DNR and BER with DNA. It is proved that the fluorescence spectrum of complex DNR-DNA is different from that of DNR. Furthermore, the present method provides a new way to search for a new non-toxic, highly efficient fluorescent probe. For controversial interaction mechanism of the drugs and DNA, it can provide a helpful verification.

Fluorescence determination of metoprolol in human plasma by trilinear decomposition-based calibration techniques.

In this study a new spectrofluorimetric method for the direct determination of metoprolol in human plasma is presented and discussed. It is based on the use of fluorescence excitation-emission matrices (EEMs) and second-order calibration performed with parallel factor analysis (PARAFAC) or alternating trilinear decomposition (ATLD). This methodology enables accurate and reliable discrimination of the analyte signal, even in the presence of unknown and uncalibrated fluorescent component(s), which is often referred to as the second-order advantage. No separation or sample pretreatment steps were required. Satisfactory results were obtained. Metoprolol recoveries in plasma were determined as 87+/-2% and 90+/-4% with PARAFAC and ATLD, respectively. All RSD values of intra- and interday assays were below 5%.

Determination of daunomycin in human plasma and urine by using an interference-free analysis of excitation-emission matrix fluorescence data with second-order calibration.

Daunorubicin (DNR) is a significant antineoplastic antibiotic, which is usually applied to a chemotherapy of acute lymphatic and myelogenous leukaemia. Unfortunately, cardiotoxicity research in animals has indicated that DNR is cardiotoxic. Therefore, it is important to quantify DNR in biological fluids. A new algorithm, the alternating fitting residue (AFR) method, and the traditional parallel factor analysis (PARAFAC) have been utilized to directly determine DNR in human plasma and urine. These methodologies fully exploit the second-order advantage of the employed three-way fluorescence data, allowing the analyte concentrations to be quantified even in the presence of unknown fluorescent interferents. Furthermore, in contrast to PARAFAC, more satisfactory results were gained with AFR.

Simultaneous determination of cortisol and prednisolone in body fluids by using HPLC-DAD coupled with second-order calibration based on alternating trilinear decomposition.

A novel method for simultaneous determination of cortisol and prednisolone in body fluids has been developed in this paper. Three-way data recorded by high-performance liquid chromatography with a diode array detector (HPLC-DAD) have been analyzed by second-order calibration based on the alternating trilinear decomposition (ATLD) algorithm. The chemometric methodology selected exploits the second-order advantage of the three-way data arrays, which allows one to obtain concentrations of individual calibrated analytes even in the presence of interferences not present in the calibration samples (e.g. background in urine or plasma). It was applied to simultaneous determination of cortisol and prednisolone in both plasma and urine samples. Though the chromatographic and spectral peaks of the analytes were heavily overlapped and interferents coeluted with the compounds studied, good recoveries of the analytes could be obtained with HPLC-DAD coupled with second-order calibration based on ATLD. Sample preparation was based on solvent extraction (SE), and quantification can be carried out with simple mobile phase. The time required for the quantification process is shorter than other methods.

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.