Pharmacokinetic Analysis of Four Bioactive Iridoid and Secoiridoid Glycoside Components of Radix Gentianae Macrophyllae and Their Synergistic Excretion by HPLC-DAD Combined with Second-Order Calibration

An HPLC-DAD method combined with second-order calibration based on the alternating trilinear decomposition (ATLD) algorithm with the aid of region selection was developed to simultaneously and quantitatively characterize the synergistic relationships and cumulative excretion of the four bioactive ingredients of Radix Gentianae Macrophyllae in vivo. Although the analytes spectra substantially overlapped with that of the biological matrix, the overlapping profiles between analytes and co-eluting interferences can be successfully separated and accurately quantified by the ATLD method on the basis of the strength of region selection. The proposed approach not only determined the content change but also revealed the synergistic relationships and the cumulative excretion in vivo of the four ingredients in urine and feces samples collected at different excretion time intervals. In addition, several statistical parameters were employed to evaluate the accuracy and precision of the method. Quantitative results were confirmed by HPLC-mass spectrometry. Satisfactory results indicated that the proposed approach can be utilized to investigate the pharmacokinetics of Radix Gentianae Macrophyllae excretion in vivo.

A road map for multi-way calibration models

A road map is proposed for the selection of a multi-way calibration model according to the data properties.

Label-free fluorescent catalytic biosensor for highly sensitive and selective detection of the ferrous ion in water samples using a layered molybdenum disulfide nanozyme coupled with an advanced chemometric model

The synergistically enhanced catalytic effect of a Fe²⁺/molybdenum disulfide (MoS₂) nanosheet was exploited to construct a nanozyme biosensor for Fe²⁺.

Application of parallel factor analysis to total synchronous fluorescence spectrum of dilute multifluorophoric solutions: addressing the issue of lack of trilinearity in total synchronous fluorescence data set

In recent years, total synchronous fluorescence (TSF) spectroscopy has become popular for the analysis of multifluorophoric systems. Application of PARAFAC, a popular deconvolution tool, requires trilinear structure in the three-way data array. The present work shows that TSF based three-way array data set of dimension sample × wavelength × Δλ does not have trilinear structure and hence it should not be subjected to PARAFAC analysis. This work also proposes that a TSF data set can be converted to an excitation-emission matrix fluorescence (EEMF) like data set which has trilinear structure, so that PARAFAC analysis can be performed on it. This also enables the retrieval of PARAFAC-separated component TSF spectra.

Luminescence sensors applied to water analysis of organic pollutants--an update

The development of chemical sensors for environmental analysis based on fluorescence, phosphorescence and chemiluminescence signals continues to be a dynamic topic within the sensor field. This review covers the fundamentals of this type of sensors, and an update on recent works devoted to quantifying organic pollutants in environmental waters, focusing on advances since about 2005. Among the wide variety of these contaminants, special attention has been paid polycyclic aromatic hydrocarbons, pesticides, explosives and emerging organic pollutants. The potential of coupling optical sensors with multivariate calibration methods in order to improve the selectivity is also discussed.

Chemometrics-assisted fluorimetry for the rapid and selective determination of heavy polycyclic aromatic hydrocarbons in contaminated river waters and activated sludges

The most concerned polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene, dibenz[a,h]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene and benz[a]anthracene were simultaneously determined in the presence of other 10 interfering PAHs, applying second-order multivariate calibration to the data obtained with a flow-through optosensor interfaced to a fast-scanning spectrofluorimeter. Using a sample volume of 2.5 mL, detection limits in the range 5-115 ng L(-1) were obtained in interfering samples, with a sample frequency of ca. 15 samples per hour, and with a minimum use of organic solvents, competing very favorably with chromatographic methods. The significance of this study lies in the solution of the quantitative analysis problem of six PAHs in real matrices of unknown composition. The unfolded partial least-squares/residual bilinearization (U-PLS/RBL) algorithm showed the best performance in resolving the complex studied system.