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Selectable Ultrasensitive Detection of Hg(2+) with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor.

Wang Z, Yang M, Chen C, Zhang L, Zeng H - Sci Rep (2016)

Bottom Line: An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg(2+)-Au(+) interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity.The optical sensor has a detection sensitivity down to 0.6 pM for Hg(2+) and CH3Hg(+) ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles.Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.

ABSTRACT
An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg(2+)-Au(+) interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg(2+) and CH3Hg(+) ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

No MeSH data available.


Selectivity test of the R6G/MPA-NPG sensor.(a) Normalized fluorescence change of R6G with individual metal ions at various concentrations. (b) The normalized fluorescence intensities with various mixed ions at different concentrations. The rhomb dots indicate the solution only contains Hg2+. The inverted triangle dots (mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, and Ba2+ with the same concentrations, and the square dots (super-mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, Ba2+, Cu2+, Cr2+, Na+, Co2+, Zn2+, and Pb2+ with the same concentration. Excitation wavelength is 532 nm.
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f3: Selectivity test of the R6G/MPA-NPG sensor.(a) Normalized fluorescence change of R6G with individual metal ions at various concentrations. (b) The normalized fluorescence intensities with various mixed ions at different concentrations. The rhomb dots indicate the solution only contains Hg2+. The inverted triangle dots (mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, and Ba2+ with the same concentrations, and the square dots (super-mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, Ba2+, Cu2+, Cr2+, Na+, Co2+, Zn2+, and Pb2+ with the same concentration. Excitation wavelength is 532 nm.

Mentions: The high specificity of Hg2+-Au+ interactions provided the excellent selectivity of this method towards detecting Hg2+ in river water which may contains several environmentally relevant metal ions31. To confirm the selectivity of the sensor, other 13 different metal ions (including Mg2+, Ag+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+ and K+ ions) with the same concentrations (1 μM, 1 nM and 1 pM) of Hg2+ were separately added into the water, and the response of the fluorescence sensor is depicted in Fig. 3a. As shown in the figure, the sensor shows appreciable intensity change in the response to Hg2+. The more Hg2+ ions are introduced into the solution, the lower the fluorescence intensity is. For Mg2+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+, and K+, within the dynamic range (1 nM and 1 pM) the fluorescence intensity does not change perceptibly (less than ±10%). The fluorescence intensities slightly fluctuate with the adding of the other 13 kinds of metal ion (including Mg2+, Ag+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+, and K+ ions). However, even at 1 μM higher concentration, the largest change of the intensity is around 20%, where Hg2+ ions led to almost 100% dropping of R6G/MPA-NPG fluorescence. The intensity decreases slightly for Ag2+, but the variation less than 20% even with a concentration of 1 μM.


Selectable Ultrasensitive Detection of Hg(2+) with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor.

Wang Z, Yang M, Chen C, Zhang L, Zeng H - Sci Rep (2016)

Selectivity test of the R6G/MPA-NPG sensor.(a) Normalized fluorescence change of R6G with individual metal ions at various concentrations. (b) The normalized fluorescence intensities with various mixed ions at different concentrations. The rhomb dots indicate the solution only contains Hg2+. The inverted triangle dots (mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, and Ba2+ with the same concentrations, and the square dots (super-mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, Ba2+, Cu2+, Cr2+, Na+, Co2+, Zn2+, and Pb2+ with the same concentration. Excitation wavelength is 532 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940742&req=5

f3: Selectivity test of the R6G/MPA-NPG sensor.(a) Normalized fluorescence change of R6G with individual metal ions at various concentrations. (b) The normalized fluorescence intensities with various mixed ions at different concentrations. The rhomb dots indicate the solution only contains Hg2+. The inverted triangle dots (mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, and Ba2+ with the same concentrations, and the square dots (super-mixed) indicate the solution contains Hg2+, Ag+, Mn2+, Mg2+, Ca2+, K+, Ba2+, Cu2+, Cr2+, Na+, Co2+, Zn2+, and Pb2+ with the same concentration. Excitation wavelength is 532 nm.
Mentions: The high specificity of Hg2+-Au+ interactions provided the excellent selectivity of this method towards detecting Hg2+ in river water which may contains several environmentally relevant metal ions31. To confirm the selectivity of the sensor, other 13 different metal ions (including Mg2+, Ag+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+ and K+ ions) with the same concentrations (1 μM, 1 nM and 1 pM) of Hg2+ were separately added into the water, and the response of the fluorescence sensor is depicted in Fig. 3a. As shown in the figure, the sensor shows appreciable intensity change in the response to Hg2+. The more Hg2+ ions are introduced into the solution, the lower the fluorescence intensity is. For Mg2+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+, and K+, within the dynamic range (1 nM and 1 pM) the fluorescence intensity does not change perceptibly (less than ±10%). The fluorescence intensities slightly fluctuate with the adding of the other 13 kinds of metal ion (including Mg2+, Ag+, Na+, Zn2+, Ca2+, Co2+, Cu2+, Ba2+, Mn2+, Cr2+, Ti4+, Pb2+, and K+ ions). However, even at 1 μM higher concentration, the largest change of the intensity is around 20%, where Hg2+ ions led to almost 100% dropping of R6G/MPA-NPG fluorescence. The intensity decreases slightly for Ag2+, but the variation less than 20% even with a concentration of 1 μM.

Bottom Line: An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg(2+)-Au(+) interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity.The optical sensor has a detection sensitivity down to 0.6 pM for Hg(2+) and CH3Hg(+) ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles.Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.

ABSTRACT
An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg(2+)-Au(+) interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg(2+) and CH3Hg(+) ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

No MeSH data available.