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Sensing free sulfur dioxide in wine.

Monro TM, Moore RL, Nguyen MC, Ebendorff-Heidepriem H, Skouroumounis GK, Elsey GM, Taylor DK - Sensors (Basel) (2012)

Bottom Line: These processes and others consume the SO(2) over time, resulting in wines with little SO(2) protection.This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte.We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring.

View Article: PubMed Central - PubMed

Affiliation: Institute for Photonics & Advanced Sensing and School of Chemistry & Physics, The University of Adelaide, Adelaide, SA 5005, Australia. tanya.monro@adelaide.edu.au

ABSTRACT
Sulfur dioxide (SO(2)) is important in the winemaking process as it aids in preventing microbial growth and the oxidation of wine. These processes and others consume the SO(2) over time, resulting in wines with little SO(2) protection. Furthermore, SO(2) and sulfiting agents are known to be allergens to many individuals and for that reason their levels need to be monitored and regulated in final wine products. Many of the current techniques for monitoring SO(2) in wine require the SO(2) to be separated from the wine prior to analysis. This investigation demonstrates a technique capable of measuring free sulfite concentrations in low volume liquid samples in white wine. This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte. We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring.

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(a) Experimental set up for the in-fiber absorption measurement (not to scale). (b) Schematic of the filling phase of the absorption measurement.
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f3-sensors-12-10759: (a) Experimental set up for the in-fiber absorption measurement (not to scale). (b) Schematic of the filling phase of the absorption measurement.

Mentions: The schematic of the in-fiber experimental set up is shown in Figure 3(a). The two ends of the fiber were placed in fiber holders on three-axis nano-translation stages for accurate alignment of the light into and out of the fiber. Light from the 25 mW 532 nm laser (CrystaLaser, Reno, NV, USA) was attenuated using a neutral density filter (ND 2) and launched into the core of the fiber using a 60× objective lens. At the other end of the fiber, a pinhole was used to ensure that any light guided within the cladding of optical fiber (rather than the core) is not incident on the detector. The transmitted light guided by the core was focused at the pinhole plane using a 60× objective lens. The pinhole was set to let the light from the fiber core to pass through to the detector, which was connected to a power meter.


Sensing free sulfur dioxide in wine.

Monro TM, Moore RL, Nguyen MC, Ebendorff-Heidepriem H, Skouroumounis GK, Elsey GM, Taylor DK - Sensors (Basel) (2012)

(a) Experimental set up for the in-fiber absorption measurement (not to scale). (b) Schematic of the filling phase of the absorption measurement.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472855&req=5

f3-sensors-12-10759: (a) Experimental set up for the in-fiber absorption measurement (not to scale). (b) Schematic of the filling phase of the absorption measurement.
Mentions: The schematic of the in-fiber experimental set up is shown in Figure 3(a). The two ends of the fiber were placed in fiber holders on three-axis nano-translation stages for accurate alignment of the light into and out of the fiber. Light from the 25 mW 532 nm laser (CrystaLaser, Reno, NV, USA) was attenuated using a neutral density filter (ND 2) and launched into the core of the fiber using a 60× objective lens. At the other end of the fiber, a pinhole was used to ensure that any light guided within the cladding of optical fiber (rather than the core) is not incident on the detector. The transmitted light guided by the core was focused at the pinhole plane using a 60× objective lens. The pinhole was set to let the light from the fiber core to pass through to the detector, which was connected to a power meter.

Bottom Line: These processes and others consume the SO(2) over time, resulting in wines with little SO(2) protection.This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte.We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring.

View Article: PubMed Central - PubMed

Affiliation: Institute for Photonics & Advanced Sensing and School of Chemistry & Physics, The University of Adelaide, Adelaide, SA 5005, Australia. tanya.monro@adelaide.edu.au

ABSTRACT
Sulfur dioxide (SO(2)) is important in the winemaking process as it aids in preventing microbial growth and the oxidation of wine. These processes and others consume the SO(2) over time, resulting in wines with little SO(2) protection. Furthermore, SO(2) and sulfiting agents are known to be allergens to many individuals and for that reason their levels need to be monitored and regulated in final wine products. Many of the current techniques for monitoring SO(2) in wine require the SO(2) to be separated from the wine prior to analysis. This investigation demonstrates a technique capable of measuring free sulfite concentrations in low volume liquid samples in white wine. This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte. We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring.

Show MeSH