Simulation of the single-vibronic-level emission spectrum of HPS.

We have computed the potential energy surfaces of the X¹A' and ùA" states of HPS using the explicitly correlated multi-reference configuration interaction (MRCI-F12) method, and Franck-Condon factors between the two states, which include anharmonicity and Duschinsky rotation, with the aim of testing the assignment of the recently reported single-vibronic-level (SVL) emission spectrum of HPS [R. Grimminger, D. J. Clouthier, R. Tarroni, Z. Wang, and T. J. Sears, J. Chem. Phys. 139, 174306 (2013)]. These are the highest level calculations on these states yet reported. It is concluded that our spectral simulation supports the assignments of the molecular carrier, the electronic states involved and the vibrational structure of the experimental laser induced fluorescence, and SVL emission spectra proposed by Grimminger et al. [J. Chem. Phys. 139, 174306 (2013)]. However, there remain questions unanswered regarding the relative electronic energies of the two states and the geometry of the excited state of HPS.

Simulated photodetachment spectra of AlH2(-).

We have carried out high-level ab initio calculations on AlH2 and its anion, as well as Franck-Condon factor calculations, which include anharmonicity and Duschinsky rotation, to simulate the photodetachment spectrum of AlH2(-), with the aim of assigning the very recently reported photodetachment spectrum of AlH2(-) [X. Zhang, H. Wang, E. Collins, A. Lim, G. Ganteför, B. Kiran, H. Schnöckel, B. Eichhorn, and K. Bowen, J. Chem. Phys. 138, 124303 (2013)]. However, our simulated spectra do not support the assignment of the reported experimental spectrum to AlH2(-).

Franck-Condon simulation of the photoelectron spectrum of AsCl2 and the photodetachment spectrum of AsCl 2⁻ employing UCCSD(T)-F12a potential energy functions: IE and EA of AsCl2.

The currently most reliable theoretical estimates of the adiabatic ionization energies (AIE(0)) from the X̃(2)B(1) state of AsCl(2) to the X̃(1)A(1) and ã(3)B(1) states of AsCl 2+, and the electron affinity (EA(0)) of AsCl(2) , including ΔZPE corrections, are calculated as 8.687(11), 11.320(23), and 1.845(12) eV, respectively (estimated uncertainties based on basis-set effects at the RCCSD(T) level). State-of-the-art ab initio calculations, which include RCCSD(T), CASSCF/MRCI, and explicitly correlated RHF/UCCSD(T)-F12x (x = a or b) calculations with basis sets of up to quintuple-zeta quality, have been carried out on the X̃(2)B(1) state of AsCl(2) , the X̃(1)A(1) , ã(3)B(1) , and Ã(1)B(1) states of AsCl 2+, and the X̃(1)A(1) state of AsCl 2-. Relativistic, core correlation and complete basis-set (CBS) effects have been considered. In addition, computed UCCSD(T)-F12a potential energy functions of relevant electronic states of AsCl(2) , AsCl (2)(+), and AsCl( 2)(-) were used to calculate Franck-Condon factors, which were then used to simulate the valence photoelectron spectrum of AsCl(2) and the photodetachment spectrum of AsCl (2)(-), both yet to be recorded. Lastly, we have also computed the AIE and EA values for NCl(2) , PCl(2) , and AsCl(2) at the G4 level and for SbCl(2) at the RCCSD(T)/CBS level. The trends in the AIE and EA values of the group V pnictogen dichlorides, PnCl(2) , where Pn = N, P, As, and Sb, were examined. The AIE and EA of PCl(2) were found to be smaller than those of AsCl(2) , contrary to the order expected from the IE values of P and As.

The enthalpies of formation of AsX(n) molecules, where X=H, F or Cl, and n=1, 2 or 3, by RCCSD(T) and UCCSD(T)-F12x calculations.

RCCSD(T) and UCCSD(T)-F12x calculations were performed on AsX(n) molecules, where X = H, F or Cl, and n = 1, 2 or 3, and related species, in order to evaluate their enthalpies of formation (ΔH(f)(Ø)). The recommended ΔH(f)(Ø) values obtained from the present investigation are AsH, 57.7(2); AsF, -7.9(3); AsCl, 27.2(4); AsH(2), 39.8(4); AsF(2), -96.6(9); AsCl(2), -17.8(10); AsH(3), 17.1(4); AsF(3)-196.0(5) and AsCl(3), -59.1(27) kcal mole(-1). These values are anchored only on one thermodynamic quantity, namely, ΔH(f)(Ø)(As) (= 70.3 kcal mole(-1)). In the calculations, the fully-relativistic small-core effective core potential (ECP10MDF) was used for As. Contributions from outer core correlation of As 3d(10) electrons were computed explicitly in both RCCSD(T) and UCCSD(T)-F12 calculations with additional tight basis functions designed for As 3d(10) electrons. Basis sets of up to augmented correlation-consistent polarized valence quintuple-zeta (aug-cc-pV5Z) quality were used in RCCSD(T) calculations and computed relative electronic energies were extrapolated to the complete basis set (CBS) limit. For the simplified, explicitly correlated UCCSD(T)-F12x calculations, basis sets of up to quadruple-zeta (QZ) quality were employed. Based on the RCCSD(T)/CBS benchmark values, the reliability of available theoretical and experimental values have been assessed.

Franck-Condon simulation, including anharmonicity, of the photodetachment spectrum of P2H(-): restricted-spin coupled-cluster single-double plus perturbative triple and unrestricted-spin coupled-cluster single-double plus perturbative triple -F12x potential energy functions of P2H and P2H(-).

Geometry optimization and harmonic vibrational frequency calculations have been carried out on the X̃(2)A(') state of P(2)H and the X̃(1)A(') state of P(2)H(-) using the restricted-spin coupled-cluster single-double plus perturbative triple excitation [RCCSD(T)] and explicitly correlated unrestricted-spin coupled-cluster single-double plus perturbative triple excitation [UCCSD(T)-F12x] methods. For RCCSD(T) calculations, basis sets of up to the augmented correlation-consistent polarized valence quintuple-zeta (aug-cc-pV5Z) quality were employed, and contributions from extrapolation to the complete basis set limit and from core correlation of the P 2s(2)2p(6) electrons were also included. For UCCSD(T)-F12x calculations, different atomic orbital basis sets of triple-zeta quality with different associated complementary auxiliary basis sets and different geminal Slater exponents were used. When the P 2s(2)2p(6) core electrons were correlated in these F12x calculations, appropriate core-valence basis sets were employed. In addition, potential energy functions (PEFs) of the X̃(2)A(') state of P(2)H and the X̃(1)A(') state of P(2)H(-) were computed at different RCCSD(T) and UCCSD(T)-F12x levels, and were used in variational calculations of anharmonic vibrational wavefunctions, which were then utilized to calculate Franck-Condon factors (FCFs) between these two states, employing a method which includes allowance for anharmonicity and Duschinsky rotation. The photodetachment spectrum of P(2)H(-) was then simulated using the computed FCFs. Simulated spectra obtained using the RCCSD(T)/aug-cc-pV5Z and UCCSD(T)-F12x(x = a or b)/aug-cc-pCVTZ PEFs are compared and found to be essentially identical. Based on the computed FCFs, a more detailed assignment of the observed vibrational structure than previously reported, which includes "hot bands," has been proposed. Comparison between simulated and available experimental spectra has been made, and the currently most reliable sets of equilibrium geometrical parameters for P(2)H and its anion have been derived. The photodetachment spectrum of P(2)D, yet to be recorded, has also been simulated.

Rapid simultaneous determination of major isoflavones of Pueraria lobata and discriminative analysis of its geographical origins by principal component analysis.

INTRODUCTION: Isoflavones are main bioactive components of Pueraria lobata (Willd.) Ohwi. Puerarin has been used as the marker compound in herb quality evaluation in the Chinese Pharmacopoiea. However, it is also important to include the other isoflavones present in the herb, such as daidzin, daidzein, genistin and genistein, in the evaluation as they also contribute to the overall bioactivity of the herb. OBJECTIVE: To develop a rapid and reliable method for simultaneous quantitation of isoflavones for P. lobata herb quality evluation. METHODOLOGY: The chromatographic separation was performed on an Agilent rapid resolution liquid chromatographic system through gradient elution. The developed method for the quantification of puerarin, daidzin, daidzein, genistin and genistein was fully validated. When it was applied to analyse the extracts of P. lobata, baseline separation was obtained within 10 min. RESULTS: The amounts of puerarin, daidzin, daidzein and genistin varied greatly among the samples although their chromatographic fingerprints were similar to each other. The 19 samples studied were classified into three clusters (I-III) by principal component analysis based on the amounts of puerarin, daidzin, daidzein and genistin. CONCLUSION: The classification result can be related to herbal origins, but the classification outcome from the chromatographic fingerprinting similarity approach did not provide any geographical origin information. This shows that bioactive constituents can reflect the intrinsic quality of P. lobata more accurately.

High-level ab initio calculations on HGeCl and the equilibrium geometry of the A1A'' state derived from Franck-Condon analysis of the single-vibronic-level emission spectra of HGeCl and DGeCl.

CCSD(T) and/or CASSCF/MRCI calculations have been carried out on the X(1)A' and A(1)A'' states of HGeCl. The fully relativistic effective core potential, ECP10MDF, and associated standard valence basis sets of up to the aug-cc-pV5Z quality were employed for Ge. Contributions from core correlation and extrapolation to the complete basis set limit were included in determining the computed equilibrium geometrical parameters and relative electronic energy of these two states of HGeCl. Based on the currently, most systematic CCSD(T) calculations performed in this study, the best theoretical geometrical parameters of the X(1)A' state are r(e)(HGe) = 1.580 +/- 0.001 A, theta(e) = 93.88 +/- 0.01 degrees and r(e)(GeCl) = 2.170 +/- 0.001 A. In addition, Franck-Condon factors including allowance for anharmonicity and Duschinsky rotation between these two states of HGeCl and DGeCl were calculated employing CCSD(T) and CASSCF/MRCI potential energy functions, and were used to simulate A(1)A'' --> X(1)A' SVL emission spectra of HGeCl and DGeCl. The iterative Franck-Condon analysis (IFCA) procedure was carried out to determine the equilibrium geometrical parameters of the A(1)A'' state of HGeCl by matching the simulated, and available experimental SVL emission spectra of HGeCl and DGeCl of Tackett et al., J Chem Phys 2006, 124, 124320, using the available, estimated experimental equilibrium (r(e)(z)) structure for the X(1)A' state, while varying the equilibrium geometrical parameters of the A(1)A'' state systematically. Employing the derived IFCA geometry of r(e)(HGe) = 1.590 A, r(e)(GeCl) = 2.155 A and theta(e)(HGeCl) = 112.7 degrees for the A(1)A'' state of HGeCl in the spectral simulation, the simulated absorption and SVL emission spectra of HGeCl and DGeCl agree very well with the available experimental LIF and SVL emission spectra, respectively.

Franck-Condon simulation of the photoelectron spectrum of AsF2 and the photodetachment spectrum of AsF2(-) using ab initio calculations: ionization energy and electron affinity of AsF2.

RCCSD(T) and/or CASSCF/MRCI calculations were carried out on the X(2)B(1) state of AsF(2), the X(1)A(1), ã(3)B(1) and A(1)B(1) states of AsF(2)(+), and the X(1)A(1) state of AsF(2)(-) employing the fully-relativistic small-core effective core potential (ECP10MDF) for As and basis sets of up to augmented correlation-consistent polarized valence quintuple-zeta (aug-cc-pV5Z) quality. Minimum-energy geometrical parameters and relative electronic energies were evaluated, including contributions from extrapolation to the complete basis set limit and from outer core correlation of the As 3d(10) electrons. In addition, simplified, explicitly correlated RHF/UCCSD(T)-F12x calculations were also performed employing different atomic orbital basis sets, and associated complementary auxiliary and density-fitting basis sets. The best theoretical estimates of the adiabatic ionization energies (AIE(0)) of AsF(2)(X(2)B(1)) to the X(1)A(1) and ã(3)B(1) states of AsF(2)(+), including corrections for zero-point vibrational energy (DeltaZPE), are 9.099(8) and 13.290(22) eV respectively. The best estimated electron affinity (EA(0)) of AsF(2) is 1.182(16) eV, also including Delta(ZPE). These are currently the most reliable AIE(0) and EA(0) values for AsF(2). Potential energy functions (PEFs) of the X(2)B(1) state of AsF(2), the X(1)A(1) and ã(3)B(1) states of AsF(2)(+) and X(1)A(1) state of AsF(2)(-) were computed at RCCSD(T)/aug-cc-pV5Z, RCCSD(T)/aug-cc-pCV5Z and RHF/UCCSD(T)-F12a/aug-cc-pCVTZ levels. These PEFs were employed in variational calculations of anharmonic vibrational wavefunctions, which were then utilised to calculate Franck-Condon factors (FCFs), using a method which includes allowance for anharmonicity and Duschinsky rotation. The computed FCFs were used to simulate the first two bands in the photoelectron spectrum of AsF(2) and the first band in the photodetachment spectrum of AsF(2)(-), both yet to be recorded. The simulated spectra obtained using different sets of PEFs were found to be almost identical, suggesting that the simplified explicitly correlated UCCSD(T)-F12x method with a relatively small basis set can be a reliable alternative to the conventional RCCSD(T) correlation methods with a relatively large basis set, but at a significantly lower cost.

Ab initio calculations on the X (2)B1 and A (2)A1 states of AsH2, and Franck-Condon simulation, including anharmonicity, of the A(0,0,0)-X single vibronic level emission spectrum of AsH2.

Restricted-spin coupled-cluster single-double plus perturbative triple excitation {RCCSD(T)} calculations were carried out on the X (2)B(1) and A (2)A(1) states of AsH(2) employing the fully relativistic small-core effective core potential (ECP10MDF) for As and basis sets of up to the augmented correlation-consistent polarized valence quintuple-zeta (aug-cc-pV5Z) quality. Minimum-energy geometrical parameters and relative electronic energies were evaluated, including contributions from extrapolation to the complete basis set limit and from outer core correlation of the As 3d(10) electrons employing additional tight 4d3f2g2h functions designed for As. In addition, simplified, explicitly correlated CCSD(T)-F12 calculations were also performed employing different atomic orbital basis sets of up to aug-cc-pVQZ quality, and associated complementary auxiliary and density-fitting basis sets. The best theoretical estimate of the relative electronic energy of the A (2)A(1) state of AsH(2) relative to the X (2)B(1) state including zero-point energy correction (T(0)) is 19,954(32) cm(-1), which agrees very well with available experimental T(0) values of 19,909.4531(18) and 19,909.4910(17) cm(-1) obtained from recent laser induced fluorescence and cavity ringdown absorption spectroscopic studies. In addition, potential energy functions (PEFs) of the X (2)B(1) and A (2)A(1) states of AsH(2) were computed at different RCCSD(T) and CCSD(T)-F12 levels. These PEFs were used in variational calculations of anharmonic vibrational wave functions, which were then utilized to calculate Franck-Condon factors (FCFs) between these two states, using a method which includes allowance for anharmonicity and Duschinsky rotation. The A(0,0,0)-X single vibronic level (SVL) emission spectrum of AsH(2) was simulated using these computed FCFs. Comparison between simulated and available experimental vibrationally resolved spectra of the A(0,0,0)-X SVL emission of AsH(2), which consist essentially of the bending (2(n)) series, suggests that there is a significant loss in intensity in the low emission energy region of the experimental spectrum.

Recipe for uncovering the bioactive components in herbal medicine.

Using whole chromatographic profiles and measurements of total bioactivity as input, a quantitative pattern-activity relationship (QPAR) approach is proposed as a general method for providing two pieces of crucial information about complex bioactive mixtures available: (i) a model for predicting total bioactivity from the chromatographic fingerprint and (ii) the features in the chromatographic profile responsible for the bioactivity. While the first piece of information is already available through existing approaches, the second one results from our ability to remove dominant features in the chromatographic fingerprints which mask the components specifically related to pharmacological activity. Our targeted approach makes information about bioactivity available at the molecular level and provides possibilities for assessment of herbal medicine (HM) possible beyond just authentication and total bioactivity. As an example, the antioxidant property of the HM Radix Puerariae lobatae is measured through its reducing power toward a ferric ion complex. A partial least-squares (PLS) model is created to predict the antioxidant activity from the chromatographic fingerprint. Using the antioxidant activity as a target, the most discriminatory projection in the multivariate space spanned by the chromatographic profiles is revealed. From this target-projected component, the chromatographic regions most strongly connected to antioxidant activity are identified using the so-called selectivity ratio (SR) plot. The results are validated by prediction of samples not included in the modeling step.

A combined ab initio and Franck-Condon factor simulation study on the photodetachment spectrum of ScO2(-).

Restricted-spin coupled-cluster single-double plus perturbative triple excitation {RCCSD(T)} potential energy functions (PEFs) of the X(2)B2 state of ScO2 and the 1A1 state of ScO2(-) were computed, employing the augmented correlation-consistent polarized-weighted core-valence quadruple-zeta (aug-cc-pwCVQZ) basis set for Sc and augmented correlation-consistent polarized valence quadruple-zeta (aug-cc-pVQZ) basis set for O, and with the outer core Sc 3s(2)3p(6) electrons being explicitly correlated. Franck-Condon factors, which include allowance for Duschinsky rotation and anharmonicity, were calculated using the computed RCCSD(T) PEFs, and were used to simulate the first photodetachment band of ScO2(-). The simulated spectrum matches well with the corresponding experimental 355 nm photodetachment spectrum of Wu and Wang, J Phys Chem A 1998, 102, 9129, confirming the assignment of the photodetachment spectrum and the reliability of the RCCSD(T) PEFs used. Further calculations on low-lying electronic states of ScO2 gave adiabatic relative electronic energies (T(e)'s) of, and vertical excitation energies (T(v)'s) to, the 2A1, 2B1, and 2A2 states of ScO2 (from the X(2)B2 state of ScO2), as well as electron affinities (EAs) and vertical detachment energies (VDEs) to these neutral states from the 1A1 state of ScO2(-).

Comparative analysis of essential oils from eight herbal medicines with pungent flavor and cool nature by GC-MS and chemometric resolution methods.

Systematic comparative research was conducted on essential oils from eight traditional Chinese medicines (TCM) of pungent flavor and cool nature because the essential oils are the main active ingredients of herbs of this kind. The work was based on their component analysis by gas chromatography-mass spectrometry (GC-MS), on their retention indices, as well as on chemometric resolution methods. A total of 144 compounds were tentatively identified, accounting for 69.0% to 91.8% of the total essential oils. It is worth noting that there are 67 compounds in at least three of these eight essential oils. Moreover, many biologically active compounds, such as hexanal, alpha-pinene, camphene, beta-pinene, p-cymene, limonene, eucalyptol, (Z)-ocimene, gamma-terpinene, camphor, p-menthone, 4-terpineol, alpha-terpineol, carvone, eugenol, caryophyllene, beta-farnesene, alpha-curcumene, beta-selinene, delta-cadinene, caryophyllene oxide, cedrol, n-hexadecanoic acid, benzaldehyde, benzeneacetaldehyde, phthalic acid diisobutyl ester, linoleic acid, tetradecanoic acid, (Z,Z,Z)-9,12,15-octadecatrienoic acid, eucalyptol, pentadecanoic acid, hexadecanoic acid methyl ester, linoleic acid methyl ester, exist in at least four of the eight essential oils. These results might help us to understand why the eight herbs are all of pungent flavor and cool nature according to the theory of TCM, and may provide a useful chemical basis for future research on herbs of this kind.

Difluorocarbene studied with threshold photoelectron spectroscopy (TPES): measurement of the first adiabatic ionization energy (AIE) of CF(2).

The first photoelectron band of difluorocarbene CF(2), has been studied by threshold photoelectron (TPE) spectroscopy. CF(2) was prepared by microwave discharge of a flowing mixture of hexafluoropropene, C(3)F(6), and argon. A vibrationally resolved band was observed in which at least twenty-two components were observed. In the first PE band of CF(2), the adiabatic ionization energy differs significantly from the vertical ionization energy because, for the ionization CF(2) (+) (X(2)A(1))+e(-) <-- CF(2) (X(1)A(1)), there is an increase in the FCF bond angle (by approximately 20 degrees ) and a decrease in the C--F bond length (by approximately 0.7 A). The adiabatic component was not observed in the experimental TPE spectrum. However, on comparing this spectrum with an ab initio/Franck-Condon simulation of this band, using results from high-level ab initio calculations, the structure associated with the vibrational components could be assigned. This led to alignment of the experimental TPE spectrum and the computed Franck-Condon envelope, and a determination of the first adiabatic ionization energy of CF(2) as (11.362+/-0.005) eV. From the assignment of the vibrational structure, values were obtained for the harmonic and fundamental frequencies of the symmetric stretching mode (nu(1)') and symmetric bending mode (nu(2)') in CF(2) (+) (X(2)A(1)).

Analytical comparison of different parts of Radix Angelicae Sinensis by gas chromatography coupled with mass spectrometry.

The three parts of Radix Angelicae Sinensis (Danggui) were reported to have different therapeutic effects. In order to investigate their chemical compositions of different parts of Danggui, gas chromatography-mass spectrometry (GC-MS) combined with chemometrics data analysis was applied to provide a more detailed study. Subwindow factor analysis (SFA) and a modified augmented evolving window orthogonal projection (AEWOP) method were used to resolve the batch GC-MS data sets from the Danggui samples. Then, t-test, Wilcoxon rank sum test, and principal component analysis (PCA) were applied to carry out the comparison job. The results indicate which components are found to have significant differences among the three parts. These findings may be helpful for further research of the pharmacological activities of Danggui.

An ab initio study of the low-lying electronic states of YO2 and Franck-Condon simulation of the first photodetachment band of YO2(-).

A variety of density functional theory and ab initio methods, including B3LYP, B98, BP86, CASSCF, CASSCF/RS2, CASSCF/MRCI, BD, BD(T), and CCSD(T), with ECP basis sets of up to the quintuple-zeta quality for Y, have been employed to study the X(2)B2 state of YO2 and the X(1)A1 state of YO2(-). Providing that the Y 4s(2)4p(6) outer-core electrons are included in the correlation treatment, the RCCSD(T) method gives the most consistent results and is concluded to be the most reliable and practical computational method for YO2 and YO2(-). In addition, RCCSD(T) potential energy functions (PEFs) of the X(2)B2 state of YO2 and the X(1)A1 state of YO2(-) were computed, employing the ECP28MDF_aug-cc-pwCVTZ and aug-cc-pVTZ basis sets for Y and O, respectively. Franck-Condon factors, which include allowance for Duschinsky rotation and anharmonicity, were calculated using the computed RCCSD(T) PEFs and were used to simulate the first photodetachment band of YO2(-). The simulated spectrum matches very well with the corresponding experimental 355 nm photodetachment spectrum of Wu, H.; Wang, L.-S. J. Phys. Chem. A 1998, 102, 9129, confirming the reliability of the RCCSD(T) PEFs used. Further calculations on low-lying electronic states of YO2 gave T(e)'s and T(vert)'s of the A(2)A1, B(2)B1, and C(2)A2 states of YO2, as well as EAs and VDEs to these states from the X(1)A1 state of YO2(-). On the basis of the ab initio VDEs obtained in the present study, previous assignments of the second and third photodetachment bands of YO2(-) have been revised.

Prediction of Radix Astragali Immunomodulatory Effect of CD80 Expression from Chromatograms by Quantitative Pattern-Activity Relationship.

The current use of a single chemical component as the representative quality control marker of herbal food supplement is inadequate. In this CD80-Quantitative-Pattern-Activity-Relationship (QPAR) study, we built a bioactivity predictive model that can be applicable for complex mixtures. Through integrating the chemical fingerprinting profiles of the immunomodulating herb Radix Astragali (RA) extracts, and their related biological data of immunological marker CD80 expression on dendritic cells, a chemometric model using the Elastic Net Partial Least Square (EN-PLS) algorithm was established. The EN-PLS algorithm increased the biological predictive capability with lower value of RMSEP (11.66) and higher values of Rp2 (0.55) when compared to the standard PLS model. This CD80-QPAR platform provides a useful predictive model for unknown RA extract's bioactivities using the chemical fingerprint inputs. Furthermore, this bioactivity prediction platform facilitates identification of key bioactivity-related chemical components within complex mixtures for future drug discovery and understanding of the batch-to-batch consistency for quality clinical trials.

Semiautomated Alignment of High-Throughput Metabolite Profiles with Chemometric Tools.

The rapid increase in the use of metabolite profiling/fingerprinting techniques to resolve complicated issues in metabolomics has stimulated demand for data processing techniques, such as alignment, to extract detailed information. In this study, a new and automated method was developed to correct the retention time shift of high-dimensional and high-throughput data sets. Information from the target chromatographic profiles was used to determine the standard profile as a reference for alignment. A novel, piecewise data partition strategy was applied for the determination of the target components in the standard profile as markers for alignment. An automated target search (ATS) method was proposed to find the exact retention times of the selected targets in other profiles for alignment. The linear interpolation technique (LIT) was employed to align the profiles prior to pattern recognition, comprehensive comparison analysis, and other data processing steps. In total, 94 metabolite profiles of ginseng were studied, including the most volatile secondary metabolites. The method used in this article could be an essential step in the extraction of information from high-throughput data acquired in the study of systems biology, metabolomics, and biomarker discovery.

Plasma fatty acid metabolic profiling and biomarkers of type 2 diabetes mellitus based on GC/MS and PLS-LDA.

Metabolic profiling has increasingly been used as a probe in disease diagnosis and pharmacological analysis. Herein, plasma fatty acid metabolic profiling including non-esterified fatty acid (NEFA) and esterified fatty acid (EFA) was investigated using gas chromatography/mass spectrometry (GC/MS) followed by multivariate statistical analysis. Partial least squares-linear discrimination analysis (PLS-LDA) model was established and validated to pattern discrimination between type 2 diabetic mellitus (DM-2) patients and health controls, and to extract novel biomarker information. Furthermore, the PLS-LDA model visually represented the alterations of NEFA metabolic profiles of diabetic patients with abdominal obesity in the treated process with rosiglitazone. The GC/MS-PLS-LDA analysis allowed comprehensive detection of plasma fatty acid, enabling fatty acid metabolic characterization of DM-2 patients, which included biomarkers different from health controls and dynamic change of NEFA profiles of patients after treated with medicine. This method might be a complement or an alternative to pathogenesis and pharmacodynamics research.

Pretreatments of chromatographic fingerprints for quality control of herbal medicines.

Pretreatments of chromatographic fingerprints are important for quality control of herbal medicines and they include data correction and data transformation. The data correction can reduce the variations of experimental procedures, and data transformation can put different weights on the different parts of the fingerprints. In this paper, a new target peak alignment (TPA) procedure has been proposed to correct the retention time shifts, multiplicative scattering correction (MSC) has been introduced for response correction. Then the similarity of the fingerprints with mean and median fingerprints is used to evaluate the quality of herbal medicines (HMs). Furthermore, different data transformation methods with kernel principal component analysis (PCA) have been applied to the data and their effects were discussed. The proposed approaches have been demonstrated by the essential oils data set of a herbal medicine, named Houttuynia cordata (HC), containing samples from different geographic origins. The experimental results indicate that the proposed approaches may be helpful in the quality control of herbal medicines by fingerprints.