Qualitative study of ethanol content in tequilas by Raman spectroscopy and principal component analysis

Frausto-Reyes, Claudio; Medina-Gutiérrez, C.; Sato-Berrú, R. Y.; Sahagun, L. R.

doi:10.1016/j.saa.2004.10.008

Cited by 56 publications

(25 citation statements)

References 16 publications

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“…Previous work [22,23] has demonstrated that Raman spectroscopy can be used to quantify the volume percentage of ethanol in tequila samples and qualitatively distinguish distilled ("silver") and highly fluorescent, aged (or "golden") tequilas, even in the presence of fluorescence (more common in aged, so-called "golden" tequila). Here we show that our OB-CD fluorescence mitigation strategy can be used to quantify the volume percentage of ethanol in tequila, even for fluorescent "golden" tequila samples at speeds much greater than those previously reported for this application.…”

Section: Aqueous Ethanol and Fluorescent Tequilamentioning

confidence: 99%

Fluorescence modeling for optimized-binary compressive detection Raman spectroscopy

Rehrauer¹,

Mankani²,

Buzzard³

et al. 2015

Opt. Express

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The recently-developed optimized binary compressive detection (OB-CD) strategy has been shown to be capable of using Raman spectral signatures to rapidly classify and quantify liquid samples and to image solid samples. Here we demonstrate that OB-CD can also be used to quantitatively separate Raman and fluorescence features, and thus facilitate Raman-based chemical analyses in the presence of fluorescence background. More specifically, we describe a general strategy for fitting and suppressing fluorescence background using OB-CD filters trained on third-degree Bernstein polynomials. We present results that demonstrate the utility of this strategy by comparing classification and quantitation results obtained from liquids and powdered mixtures, both with and without fluorescence. Our results demonstrate high-speed Raman-based quantitation in the presence of moderate fluorescence. Moreover, we show that this OB-CD based method is effective in suppressing fluorescence of variable shape, as well as fluorescence that changes during the measurement process, as a result of photobleaching.

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Section: Aqueous Ethanol and Fluorescent Tequilamentioning

confidence: 99%

Fluorescence modeling for optimized-binary compressive detection Raman spectroscopy

Rehrauer¹,

Mankani²,

Buzzard³

et al. 2015

Opt. Express

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“…Raman spectroscopy is a very interesting alternative for applications in fuel analysis. It is non-destructive, potentially portable, requires no sample preparation, and is capable of furnishing compound-specific information [7,8]. On the other hand, Raman spectroscopy is plagued by intense background fluorescence signals.…”

Section: Introductionmentioning

confidence: 99%

Expanding the potentialities of standard dilution analysis: Determination of ethanol in gasoline by Raman spectroscopy

Fortunato

Vieira

Neto

et al. 2017

Microchemical Journal

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This work describes the application of standard dilution analysis (SDA) in Raman spectroscopy, demonstrating the versatility of this new calibration method. A flow system (FA) was developed for ethanol determination in gasoline employing liquid-liquid extraction (LLE) and acetone as the internal standard (IS). Applying LLE eliminated the intense fluorescence background, allowing for ethanol determination using a portable 785-nm-laser Raman system. The SDA-LLE-FA method was applied to commercial gasoline samples and the results were compared with values obtained using the ABNT NBR 13992 reference method. No statistically significant differences were observed for ethanol concentrations determined using the two methods (paired t-test at the 95% confidence level). SDA's accuracy was also evaluated by comparing results from analyses using the same LLE-FA system combined with the traditional calibration methods of matrix matching (MM), standard additions (SA) and internal standardization (IS). Recoveries from spike experiments were in 98.6-104.1% (SDA-LLE-FA), 94.7-171.1% (ABNT NBR 13992), 106.8-114.1% (MM-LLE-FA), 103.7-108.4% (IS-LLE-FA), and 114.7-125.8% (SA-LLE-FA) range. The relative standard deviation (RSD, n = 12, 25.5% v/v −1 ethanol in gasoline), limits of detection and quantification calculated for the SDA-LLE-FA method were 2%, 0.5% and 1.8% (v/v −1 ), respectively.

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“…[6][7][8][9][10][11][12] For tequila, both gas and liquid chromatography have been published for identifying some compounds (ethanol, methanol, higher alcohols, ethyl acetate, acetaldehyde, and others). [7,8,12] Raman spectroscopy [10] and Fourier transform infrared-spectroscopy [11] have been used to measure the alcohol content in tequila. UV-visible spectroscopy [6] has been applied as a verification method.…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of tequila in the microwave frequency range (0.5–20 GHz) using coaxial probe

Kataria

Sosa‐Morales

Olvera‐Cervantes

et al. 2017

International Journal of Food Properties

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In this work, an open-ended coaxial probe was used to characterize the dielectric properties of different tequilas and agave-distilled spirits in the range from 500 MHz to 20 GHz. The alcohol content of these beverages was clearly identified at these frequencies. From a Cole-Cole plot, the relaxation time (τ) was extracted and it was observed that there was a linear correlation between alcohol content and τ, where lower τ corresponds to lower ethanol content. In addition, dielectric differences were also found between silver, aged, and extra-aged tequilas. As aging increased, the real and imaginary parts of the permittivity increased (p < 0.05). These findings offered a new method for detecting alcohol content in tequila as well as for identifying tequila aging. ARTICLE HISTORY

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Qualitative study of ethanol content in tequilas by Raman spectroscopy and principal component analysis

Cited by 56 publications

References 16 publications

Fluorescence modeling for optimized-binary compressive detection Raman spectroscopy

Fluorescence modeling for optimized-binary compressive detection Raman spectroscopy

Expanding the potentialities of standard dilution analysis: Determination of ethanol in gasoline by Raman spectroscopy

Dielectric properties of tequila in the microwave frequency range (0.5–20 GHz) using coaxial probe

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