Studies on the Structure of Water Using Two-Dimensional Near-Infrared Correlation Spectroscopy and Principal Component Analysis

Segtnan, Vegard H.; Šašić, Slobodan; Isaksson, Tomas; Ozaki, Yukihiro

doi:10.1021/ac010102n

Cited by 286 publications

(278 citation statements)

References 21 publications

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“…These treatments are based e.g. on 2D correlation analysis (2DCOR) [22,23], mowing windows 2D concept (MW2D) [24,25], factor (FA) and principal component analysis (PCA) [26][27][28][29], etc.…”

Section: Resultsmentioning

confidence: 99%

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FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

Doroshenko

Balevičius

Pitsevich

et al. 2014

Low Temperature Physics

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FTIR spectra of 1-propanol in an argon matrix were studied in the range 11 to 30 K. Principal component analysis of dynamic FTIR spectra and nonlinear band shape fitting has been carried out. The peaks of monomer, open dimer, mixed propanol-water dimer and those of higher H-bond clusters have been resolved and analyzed. The attribution of certain FTIR peaks has been supported by proper density functional theory calculations. Analyzing dependences of the integral band intensities of various aggregates on temperature it has been deduced that in the initial stage of clustering monomers and dimers are the basic building blocks forming higher H-bond clusters. The peaks assigned to two conformers of monomers and mixed propanol-water dimers were investigated processing the temperature dependences of their integral intensities in Arrhenius plot. The obtained values of 0.18 kJ⋅mol -1 for propanol monomer and 0.26 kJ⋅mol -1 for mixed dimer are well comparable with the energy differences between the global minimum conformation of 1-propanol (Gt) and some other energetically higher structures (Tt or Tg). PACS

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Section: Resultsmentioning

confidence: 99%

“…This way of construction of Z is called the samplesample (SS) approach [28]. It differs from the variablevariable (VV) approach (Z = D T ·D), which is traditionally used in 2DCOR [14,22,23] or when 2DCOR and PCA are applied in tandem [29,30].…”

Section: Resultsmentioning

confidence: 99%

FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

Doroshenko

Balevičius

Pitsevich

et al. 2014

Low Temperature Physics

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“…基于不同氢键结构对温度响应的差异, 可利用近红外光谱的温度效应对氢键作用进行研究, 并分析分子间氢键的结合过程 [13] . Ozaki 等利用二维相关光谱、主成分分析 [14] 和自模式曲线分辨 [15] …”

Section: 近红外光谱的温度效应已得到广泛关注和研究unclassified

Temperature Dependent Near Infrared Spectroscopy for Understanding the Hydrogen Bonding of Amines

Zhu¹,

Cui²,

Cai³

et al. 2018

Acta Chim. Sinica

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Temperature dependent near-infrared (NIR) spectroscopy has been developed for structural analyses, especially for the study of hydrogen bonding, due to the distinct influence of temperature on both intra-and inter-molecular interactions. In this work, the hydrogen bonding of primary aliphatic amines (amylamine, hexylamine and heptylamine) were studied using the NIR spectra measured from 25 to 80 ℃ with a step of 5 ℃. Continuous wavelet transform (CWT) was applied to enhance the resolution of the NIR spectra, and independent component analysis (ICA) was adopted for analyzing the temperature effect. High resolution spectra were obtained by CWT, from which the peaks of free and hydrogen-bonded NH groups can be identified. The results obtained by ICA show that three independent components (ICs) can be obtained, corresponding to the spectral information of the free, linearly and cyclically hydrogen-bonded NH groups, respectively. Therefore, with the reconstructed spectra from the three ICs, the variation of the three forms of NH groups with temperature can be analyzed. When temperature increases, the hydrogen-bonded NH groups transform into the free form, and the cyclic form dissociates through the linear form. Furthermore, NIR spectra of the amines in carbon tetrachloride (CCl 4 ) solution were measured at 25 ℃ in the concentration range of 0.1～1.0 mol/L. The three ICs can also be obtained by ICA from the spectra after CWT. From the variation of the ICs with concentration, it was shown that NH groups in the amines prefer to be linearly aggregated at low concentration, but the cyclic aggregation increases with the increase of concentration. In addition, a comparison was performed on the results obtained by ICA from the spectra of the three amines measured at different temperatures. The result shows that there is no obvious difference for the temperature effect of the three amines, the variation of the three forms of NH groups with temperature, however, is different. With the increase of the carbon chain length, the variation of free and cyclically hydrogen-bonded NH group slows down, but there is a slight increase for the change rate of linearly hydrogen-bonded NH group. Therefore, temperature dependent near-infrared (NIR) spectroscopy may provide a new tool for studying the hydrogen bonding in liquid and solution samples with the help of chemometric calculations. The method may be promising for analyzing the complicated interactions in bio-systems, particularly the hydrogen bonding or inter-and intramolecular interactions.

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“…Accordingly, loading vector of PC1 (Fig. 2(b)) shows the dominance of water (OH 1st overtone) in the 1300-1600 nm spectral region, at 1386, 1416, 1452, and 1490 nm [21], while in the case of PC2 also the absorbance bands of lipids (CH 1st overtone) at 1726, 1764 nm [22] appear with high importance. PC1 representing water bands may refer to slight changes in temperature of samples during scanning and contains less information on variables in question since score plot does not show any separation by total lipid content along PC1.…”

Section: Basic Spectral Evaluationmentioning

confidence: 99%

“…OH) [21] and less by the lipid region (1st overtone of asymmetric and symmetric stretching vibrations of methylene group (-CH 2 -) at 1724 and 1764 nm, respectively) [22]. In the case of models on cholesterol concentration, the impact of lipid spectral region is increased.…”

Section: Tablementioning

confidence: 99%

Multicomponent blood lipid analysis by means of near infrared spectroscopy, in geese

Bázár

Éles

Kovács

et al. 2016

Talanta

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a b s t r a c tThis study provides accurate near infrared (NIR) spectroscopic models on some laboratory determined clinicochemical parameters (i.e. total lipid (5.57 71.95 g/l), triglyceride (2.59 71.36 mmol/l), total cholesterol (3.81 7 0.68 mmol/l), high density lipoprotein (HDL) cholesterol (2.45 70.58 mmol/l)) of blood serum samples of fattened geese. To increase the performance of multivariate chemometrics, samples significantly deviating from the regression models implying laboratory error were excluded from the final calibration datasets. Reference data of excluded samples having outlier spectra in principal component analysis were not marked as false. Samples deviating from the regression models but having non outlier spectra in PCA were identified as having false reference constituent values. Based on the NIR selection methods, 5% of the reference measurement data were rated as doubtful. The achieved models reached R 2 of 0.864, 0.966, 0.850, 0.793, and RMSE of 0.639 g/l, 0.232 mmol/l, 0.210 mmol/l, 0.241 mmol/l for total lipid, triglyceride, total cholesterol and HDL cholesterol, respectively, during independent validation. Classical analytical techniques focus on single constituents and often require chemicals, timeconsuming measurements, and experienced technicians. NIR technique provides a quick, cost effective, non-hazardous alternative method for analysis of several constituents based on one single spectrum of each sample, and it also offers the possibility for looking at the laboratory reference data critically. Evaluation of reference data to identify and exclude falsely analyzed samples can provide warning feedback to the reference laboratory, especially in the case of analyses where laboratory methods are not perfectly suited to the subjected material and there is an increased chance of laboratory error.

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Studies on the Structure of Water Using Two-Dimensional Near-Infrared Correlation Spectroscopy and Principal Component Analysis

Cited by 286 publications

References 21 publications

FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

FTIR/PCA study of propanol in argon matrix: The initial stage of clustering and conformational transitions

Temperature Dependent Near Infrared Spectroscopy for Understanding the Hydrogen Bonding of Amines

Multicomponent blood lipid analysis by means of near infrared spectroscopy, in geese

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