FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases

A Case Study on VOCs

Christian Bernd Hirschmann (Corresponding Author), Niina Susanna Koivikko, Jussi Raittila, Jussi Tenhunen, Satu Ojala, Katariina Rahkamaa-Tolonen, Ralf Marbach, Sarah Hirschmann, Riitta Liisa Keiski

Research output: Contribution to journalArticleScientificpeer-review

7 Citations (Scopus)

Abstract

This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements.
Original languageEnglish
Pages (from-to)5270-5289
Number of pages20
JournalSensors
Volume11
Issue number5
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

Fingerprint

Photoacoustic Techniques
Photoacoustic effect
volatile organic compounds
high temperature gases
Volatile organic compounds
Gases
Water
sensitivity
Wavelength
Calibration
Multivariate Analysis
Optical Devices
Methylene Chloride
subtraction
Dichloromethane
Signal-To-Noise Ratio
Ovens
water
Xylene
Microphones

Keywords

  • volatile organic compound (VOC)
  • photoacoustic spectroscopy (PAS)
  • science based calibration (SBC)
  • elevated temperature measurement

Cite this

Hirschmann, Christian Bernd ; Koivikko, Niina Susanna ; Raittila, Jussi ; Tenhunen, Jussi ; Ojala, Satu ; Rahkamaa-Tolonen, Katariina ; Marbach, Ralf ; Hirschmann, Sarah ; Keiski, Riitta Liisa. / FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases : A Case Study on VOCs. In: Sensors. 2011 ; Vol. 11, No. 5. pp. 5270-5289.
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title = "FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases: A Case Study on VOCs",
abstract = "This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2{\%} and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3{\%}, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements.",
keywords = "volatile organic compound (VOC), photoacoustic spectroscopy (PAS), science based calibration (SBC), elevated temperature measurement",
author = "Hirschmann, {Christian Bernd} and Koivikko, {Niina Susanna} and Jussi Raittila and Jussi Tenhunen and Satu Ojala and Katariina Rahkamaa-Tolonen and Ralf Marbach and Sarah Hirschmann and Keiski, {Riitta Liisa}",
note = "Project code: 41475",
year = "2011",
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Hirschmann, CB, Koivikko, NS, Raittila, J, Tenhunen, J, Ojala, S, Rahkamaa-Tolonen, K, Marbach, R, Hirschmann, S & Keiski, RL 2011, 'FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases: A Case Study on VOCs', Sensors, vol. 11, no. 5, pp. 5270-5289. https://doi.org/10.3390/s110505270

FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases : A Case Study on VOCs. / Hirschmann, Christian Bernd (Corresponding Author); Koivikko, Niina Susanna; Raittila, Jussi; Tenhunen, Jussi; Ojala, Satu; Rahkamaa-Tolonen, Katariina; Marbach, Ralf; Hirschmann, Sarah; Keiski, Riitta Liisa.

In: Sensors, Vol. 11, No. 5, 2011, p. 5270-5289.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - FT-IR-cPAS — New Photoacoustic Measurement Technique for Analysis of Hot Gases

T2 - A Case Study on VOCs

AU - Hirschmann, Christian Bernd

AU - Koivikko, Niina Susanna

AU - Raittila, Jussi

AU - Tenhunen, Jussi

AU - Ojala, Satu

AU - Rahkamaa-Tolonen, Katariina

AU - Marbach, Ralf

AU - Hirschmann, Sarah

AU - Keiski, Riitta Liisa

N1 - Project code: 41475

PY - 2011

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N2 - This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements.

AB - This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements.

KW - volatile organic compound (VOC)

KW - photoacoustic spectroscopy (PAS)

KW - science based calibration (SBC)

KW - elevated temperature measurement

U2 - 10.3390/s110505270

DO - 10.3390/s110505270

M3 - Article

VL - 11

SP - 5270

EP - 5289

JO - Sensors

JF - Sensors

SN - 1424-8220

IS - 5

ER -