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. 2011;11(4):4060-72.
doi: 10.3390/s110404060. Epub 2011 Apr 6.

Bromocresol green/mesoporous silica adsorbent for ammonia gas sensing via an optical sensing instrument

Yu-Chang Chang  1 , Hsunling Bai, Shou-Nan Li, Chun-Nan Kuo
Affiliations

Bromocresol green/mesoporous silica adsorbent for ammonia gas sensing via an optical sensing instrument

Yu-Chang Chang et al. Sensors (Basel). 2011.

Abstract

A meso-structured Al-MCM-41 material was impregnated with bromocresol green (BG) dye and then incorporated into a UV-Vis DRA spectroscopic instrument for the online detection of ammonia gas. The absorption response of the Al-MCM-41/BG ammonia sensing material was very sensitive at the optical absorption wavelength of 630 nm. A high linear correlation was achieved for ppmv and sub-ppmv levels of ammonia gas. The response time for the quantitative detection of ammonia gas concentrations ranging from 0.25 to 2.0 ppmv was only a few minutes. The lower detection limit achieved was 0.185 ppmv. The color change process was fully reversible during tens of cycling tests. These features together make this mesoporous Al-MCM-41 material very promising for optical sensing applications.

Keywords: UV-Vis absorbance; ammonia gas; bromocresol green dye; mesoporous silica material; optical sensor.

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Figures

Figure 1.
Figure 1.
Schematic diagram of a UV-Vis DRA spectroscopic instrument for NH3 sensing.
Figure 2.
Figure 2.
Powder X-ray diffraction pattern of Al-MCM-41(50) and dye impregnated Al-MCM-41(50)/BG.
Figure 3.
Figure 3.
Nitrogen adsorption-desorption isotherms of dye impregnated Al-MCM-41(50).
Figure 4.
Figure 4.
Transmission electron micrographs of dye-impregnated Al-MCM-41(50).
Figure 5.
Figure 5.
UV-Vis Spectrograms of Al-MCM-41(50)/BG as time proceeded for adsorbing NH3. The ammonia gas concentration was 5 ppmv.
Figure 6.
Figure 6.
Time response on the absorbance difference of the Al-MCM-41(50)/BG for monitoring 4.3 ppmv NH3.
Figure 7.
Figure 7.
Reversibility tests of the Al-MCM-41(50)/BG material in the absorbance difference for sensing 1.0 ppmv NH3 after 20 min of NH3 adsorption.
Figure 8.
Figure 8.
Calibration curve of the Al-MCM-41(50)/BG for sensing sub-ppmv of NH3 gas concentration. The test time was 5 min for all NH3 concentrations.
Figure 9.
Figure 9.
Comparison of the correlation coefficient (R) as a function of NH3 sensing time using different amounts of Al-MCM-41(50)/BG materials.
Figure 10.
Figure 10.
Schematic sketches which show the diffusion effect across the sensing materials of different thickness. (a) thin sample (0.015 g). (b) thick sample (0.03 g).
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References

    1. Kanzawa K, Kitano J. A Semiconductor device manufacturer’s efforts for controlling and evaluating atmospheric pollution. Proceedings of 1995 IEEE/SEMI Advanced Semiconductor Manufacturing Conference and Workshop; Cambridge, CA, USA. 13–15 November 1995; pp. 190–193.
    1. Ruth JH. Odor thresholds and irritation levels of several chemical substances: A review. Am. Ind. Hyg. Assoc. J. 1986;47:A142–A151. - PubMed
    1. Agency for Toxic Substances & Disease Registry (ATSDR) Toxicological profile for ammonia. 2004. Available online: http://www.atsdr.cdc.gov/ (accessed on 1 October 2010) - PubMed
    1. The US Occupational Safety and Health Administration (OSHA) website. Available online: http://www.osha.gov (accessed on 1 October 2010)
    1. The US National Institute of Occupational Safety and Health (NIOSH) website. Available online: http://www.cdc.gov/niosh (accessed on 1 October 2010)

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