Spectra-Structure Correlations for Near-Infrared Region

Goddu, R. F.; Delker, Dorothy

doi:10.1021/ac60157a048

Cited by 53 publications

(53 citation statements)

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“…Algumas absorções não estão na região característica de sobretons (ST), sendo possível que as mesmas tratem-se de bandas de combinação (BC) de grupos característicos dos polímeros [5] .…”

Section: Caracterização Das Bandas Principais Das Resinas Nc E Pu -Anunclassified

“…Entretanto, a região do infravermelho próximo (NIR) tem um mérito quantitativo interessante, podendo em alguns casos, melhorar a precisão da metodologia desenvolvida para diferentes tipos de materiais [5][6][7][8] . Deste modo, as características da análise NIR devem ser abordadas para melhor entendimento da metodologia proposta neste trabalho.…”

Section: Introductionunclassified

“…Os números de onda dos sobretons são, aproximadamente, múltiplos dos números de onda fundamentais e as de combinação correspondem à soma dos números de onda de seus componentes [5] . A maior energia da região NIR do que a do MIR excita sobretons e combinações de vibrações moleculares, fundamentais ou não, em materiais ao invés de excitar bandas fundamentais [5] . Técnicas de análise de superfície podem também ser usadas em auxílio à técnica de Transmissão, tanto na região MIR quanto na região NIR, para uma avaliação qualitativa mais completa do material [9] .…”

Section: Introductionunclassified

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Quantificação por NIR/MIR de resina poliuretânica em misturas binárias com nitrocelulose, utilizadas em tintas

Rodrigues¹,

Dutra²,

Diniz³

et al. 2014

Polímeros

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Resumo: Foi elaborada uma nova metodologia nas regiões do infravermelho médio (MIR) e do infravermelho próximo (NIR), usando-se técnicas de Reflexão e/ou Transmissão para a determinação do teor de resina poliuretânica (PU) em misturas binárias com nitrocelulose (NC), utilizadas em formulações de tintas. A técnica de Reflexão Total Atenuada Universal (UATR) se mostrou útil na região MIR, para tal fim. Após a avaliação de diferentes bandas analíticas, de referência e de linhas de base, a banda relativa (A 1541 / A 1645 ) foi escolhida para a elaboração da curva de calibração, com erro de metodologia de 1,42%. As técnicas de Transmissão e Reflexão (DRIFT) foram utilizadas na região NIR (banda relativa A 5902 / A 5262 ) para validação, apresentando erros de metodologia de 1,42% e 1,60 %, respectivamente. Todos os erros relativos nas metodologias apresentaram-se dentro dos limites de precisão da análise quantitativa FT-IR, para as condições usadas (≤2%). A análise de amostras teste confirmou a precisão das metodologias desenvolvidas, que também apresentam praticidade, baixo custo e tempo reduzido de análise. Palavras-chave: Tintas, PU, NC, NIR, MIR, UATR, DRIFT e quantificação. Measurement by NIR/MIR of Polyurethane Resin in Binary Mixtures with Nitrocellulose Used in Paints FormulationsAbstract: A new methodology was developed in the mid-infrared (MIR) and near infrared (NIR) regions by using techniques of Reflection and / or Transmission for the determination of polyurethane resin (PU) in binary mixtures with nitrocellulose (NC), used in paint formulations. The Universal Attenuated Total Reflection (UATR) technique proved useful in the MIR region for this purpose. From an evaluation of analytical bands and reference baselines, the relative band (A 1541 /A 1645 ) was selected for the calibration curve, whose error was 1.42%. The Transmission and Reflection (DRIFT) techniques were used in the NIR region (relative band A 5902 / A 5262 ) for validation, and both showed good precision with an error of methodology of 1.42 and 1.60% respectively. All relative errors are within the accuracy of FT-IR quantitative analysis for the conditions used (≤ 2%). Analysis of test samples confirmed the accuracy of the methodologies, which also show practicality, low cost and reduced analysis time.

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Section: Caracterização Das Bandas Principais Das Resinas Nc E Pu -Anunclassified

Section: Introductionunclassified

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Quantificação por NIR/MIR de resina poliuretânica em misturas binárias com nitrocelulose, utilizadas em tintas

Rodrigues¹,

Dutra²,

Diniz³

et al. 2014

Polímeros

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“…Consequently, the charac teristic features in their NIR spectra are overtones and combinations of the stretching and deformation modes of the O -H and the C -H groups. For alcohols, the first and second overtone of the O -H stretching vibration should occur at about 1.4 pm and 0.9 pm, respectively, whereas the combination band appears at about 2.1 pm [9][10][11][12][13], The funda mental C -H stretching vibration gives rise to an absorption band at about 3.3 pm to 3.5 pm, and the first and second overtone at about 1.7 pm and 1.2 pm, respectively [9][10][11][12][13]. Another band with relatively high intensity exists near 2.3 pm, which belongs to the second overtone of the carbonhydrogen "bending" vibration at about 6.9 pm [10,12,13].…”

Section: / Vibration Spectra Of Functional Groupsmentioning

confidence: 99%

“…Similar to the alcohols case, the combinations of the fundamental carbon-hydrogen vibrations are observed for both liquids in the spectral range 2300 nm to 2600 nm. The spectrum of acetone shows a further absorption band at about 1913 nm due to the second overtone of the C = 0 fundamental stretching vibration [11].…”

Section: / Vibration Spectra Of Functional Groupsmentioning

confidence: 99%

The Absorption Behavior of Water and Some Organic Liquids in the Near Infrared Studied by Photoacoustic Spectroscopy

Haas

Seiler

1984

Zeitschrift Für Naturforschung A

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Automated chemical imaging identification of illegal drugs in correctional facilities mail

Schweitzer

Treado

Olkhovyk

et al. 2018

Journal of Chemometrics

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The current opioid epidemic represents a significant health and security threat. This epidemic has affected correctional facilities with an increased smuggling of illicit drugs concealed in envelopes, letters, greeting cards, and business cards to inmates. Short‐wave infrared chemical imaging sensors are being successfully applied to the automated, high confidence detection of drugs concealed in prison mail. Once detected, end users have a need to confirm the detection and to identify the specific drug being detected. The challenge for identification is that the spectral signature of the concealed drug is often convolved with the spectral signature of the piece of mail (substrate) in which the drug is concealed. This paper presents a method to remove the substrate signal from the substrate/drug mixture signal followed by a set of 3 spectral identification methods. The substrate signature is estimated by a region of interest that is spatially local to the detection, and linear unmixing uses this substrate signature to calculate the residual spectra in the detection pixels. These residual spectra represent the isolated drug spectra, and they are compared with a spectral drug library via Euclidean distance, target factor analysis, and adaptive cosine estimator methods. This methodology was applied to a set of 116 positive‐ and negative‐control samples spanning a range of drugs and concealment methods with the result that 90 of the 104 positive‐control samples were identified correctly (86.5%) and 0 of the 12 negative‐control samples were incorrectly identified as a drug in the library (0%).

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Spectra-Structure Correlations for Near-Infrared Region

Cited by 53 publications

References 1 publication

Quantificação por NIR/MIR de resina poliuretânica em misturas binárias com nitrocelulose, utilizadas em tintas

Quantificação por NIR/MIR de resina poliuretânica em misturas binárias com nitrocelulose, utilizadas em tintas

The Absorption Behavior of Water and Some Organic Liquids in the Near Infrared Studied by Photoacoustic Spectroscopy

Automated chemical imaging identification of illegal drugs in correctional facilities mail

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