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Photonic sensing of organic solvents through geometric study of dynamic reflection spectrum.

Zhang Y, Fu Q, Ge J - Nat Commun (2015)

Bottom Line: Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices.There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents.With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

View Article: PubMed Central - PubMed

Affiliation: 1] Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China [2] Department of Chemistry, Tongji University, Shanghai 200092, China.

ABSTRACT
Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices. Here a sensing method based on the dynamic reflection spectra (DRS) of photonic crystal gel has been developed to distinguish even homologues, isomers and solvents with similar structures and physical properties. There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents. With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

No MeSH data available.


DRS patterns of alcohols.DRS patterns of homologues of alcohols including (a) ethanol, (b) propanol, (c) butanol and (d) pentanol.
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f4: DRS patterns of alcohols.DRS patterns of homologues of alcohols including (a) ethanol, (b) propanol, (c) butanol and (d) pentanol.

Mentions: The DRS method is capable of distinguishing homologues of alcohols according to their difference in polarity. It is known that ethanol, propanol, butanol and pentanol have nearly similar refractive indexes (Supplementary Table 1), which induce similar Δλ in traditional SRS detection. However, their DRS patterns are quite different, so that one can easily attribute them to specific alcohols (Fig. 4). The common characteristics include two to three ascending reflection bands with increased λ and R, the splitting of initial reflection bands, and their merging within or possibly after 10 min. When the alcohols diffuse into the gel, the colloidal crystals in surface layer expand more and faster than those in the inner layer due to prior swelling. Therefore, the reflection splits into two higher bands above the original, which can be attributed to reflection of the surface and inner layer, respectively. Once the diffusion and swelling reach a balanced state, the reflection bands will merge and go flat afterwards. Generally, the stronger the polarity that the alcohol has, the faster the rise in reflection band because the PEGMA/EG gel is more diffusible and swellable by polar solvents. In short, a sharp rise in the reflection band and an early appearance of merging point in the DRS pattern indicate a short-chain n-alcohol.


Photonic sensing of organic solvents through geometric study of dynamic reflection spectrum.

Zhang Y, Fu Q, Ge J - Nat Commun (2015)

DRS patterns of alcohols.DRS patterns of homologues of alcohols including (a) ethanol, (b) propanol, (c) butanol and (d) pentanol.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557364&req=5

f4: DRS patterns of alcohols.DRS patterns of homologues of alcohols including (a) ethanol, (b) propanol, (c) butanol and (d) pentanol.
Mentions: The DRS method is capable of distinguishing homologues of alcohols according to their difference in polarity. It is known that ethanol, propanol, butanol and pentanol have nearly similar refractive indexes (Supplementary Table 1), which induce similar Δλ in traditional SRS detection. However, their DRS patterns are quite different, so that one can easily attribute them to specific alcohols (Fig. 4). The common characteristics include two to three ascending reflection bands with increased λ and R, the splitting of initial reflection bands, and their merging within or possibly after 10 min. When the alcohols diffuse into the gel, the colloidal crystals in surface layer expand more and faster than those in the inner layer due to prior swelling. Therefore, the reflection splits into two higher bands above the original, which can be attributed to reflection of the surface and inner layer, respectively. Once the diffusion and swelling reach a balanced state, the reflection bands will merge and go flat afterwards. Generally, the stronger the polarity that the alcohol has, the faster the rise in reflection band because the PEGMA/EG gel is more diffusible and swellable by polar solvents. In short, a sharp rise in the reflection band and an early appearance of merging point in the DRS pattern indicate a short-chain n-alcohol.

Bottom Line: Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices.There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents.With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

View Article: PubMed Central - PubMed

Affiliation: 1] Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China [2] Department of Chemistry, Tongji University, Shanghai 200092, China.

ABSTRACT
Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices. Here a sensing method based on the dynamic reflection spectra (DRS) of photonic crystal gel has been developed to distinguish even homologues, isomers and solvents with similar structures and physical properties. There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents. With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

No MeSH data available.