COLORIMETRIC DETECTION OF MERCURY SPECIES BASED ON FUNCTIONALIZED GOLD

NANOPARTICLES

SRAVANTHI REDDY NAYINIL2036602611/30/2015

CHEM.COMM. FALL 2015

Chen, L. ; Li, J. ; Chen, L. Colorimetric Detection of Mercury Species Based on Functionalized Gold Nanoparticles. Appl. Mater. Interfaces. 2014, 6, 15897-15904.

INTRODUCTION• Heavy metal pollutants exhibit different toxicological effects and

mercury is one of them.

• Organic forms of mercury such as methylmercury (MeHg), ethylmercury (EtHg) have higher toxic effects than inorganic and elemental Hg.

• Inorganic mercury released in the ecosystem undergoes biogeochemical transformation process and can be converted into organic forms by microorganisms and microalgae in acquatic environments.

• Detection of organic mercury (Hg) is very important compared to measuring the total mercury

INTRODUCTION CONTD….• Atomic fluorescence spectrometry, gas chromatography and high

performance liquid chromatography are used for detection.

• But these conventional methods are complicated, costly and cannot discriminate organic mercury from inorganic mercury and measures the total mercury.

• Nanomaterial based calorimetric assays has been rapidly used as they are rapid, specific, cost effective .

• These are based on specific ligands, functionalized nanomaterials and nanosurface oxidation reduction reactions.

INTRODUCTION CONTD….• Determination of Hg species by using interparticle plasmon

coupling on analyte induced aggregation of gold nanoparticles (Au- Np) with specific recognition ligands.

• Mercury has high affinity towards the soft donors such as sulfur, a thiol containing ligand, diethyldithiocarbamate (DDTC) was employed..

• The Hg ions get displaced with the CU ions in the DDTC copper (II) complex.

• Au Np calorimetric nanosensor discriminates the organic mercury and inorganic mercury using ethylenediaminetetraaceticacid (EDTA) as masking agent.

EXPERIMENTAL SECTION• Au Np were synthesized by the citrate mediated reduction of

HAuCl4 and concentration is measured bu U.V-vis spectroscopy.

• For sensing of mercury ions, they were added to mixture of DDTC and cu +2 in buffer solution and Au Nps are added.

• Drinking water samples obtained are spiked with the standard Hg species at certain concentrations and mixed with stock solutions containing Au Np probe and buffer solution.

RESULTS AND DISCUSSION

. Schematic Illustrations of (A) Au NP-BasedColorimetric Strategy for Hg Species Sensing and (B) Hg−DDTC Complex Attached to the Surface Of Au NPs

RESULTS AND DISCUSSION CONTD…

Effect of polymer conc. On production of hybrid nanoparticles1. Higher the polymer concentration ,lareger the particle size.2. PDI dropped the same range.3. Polymer concentration is an important parameter in large-scale synthesis.

Fang, R.H. ; Chen, K.N.H. ; Aryal, S.; Hu, C.J.; Zhang,K.; Zhang, L. (2012) large-scale synthesis of lipid-polymer hybrid nanoparticles using a multi-inlet vortex reactor. Langmuir.DOI: 10.1021/Ia303012x.

RESULTS AND DISCUSSION CONTD…

Effect of total flow rate on production of hybrid nanoparticles

1. Particle size decreased as the flow rate was increased.2. Slight increase in PDI as the flow rate increased.

Fang, R.H. ; Chen, K.N.H. ; Aryal, S.; Hu, C.J.; Zhang,K.; Zhang, L. (2012) large-scale synthesis of lipid-polymer hybrid nanoparticles using a multi-inlet vortex reactor. Langmuir.DOI: 10.1021/Ia303012x.

RESULTS AND DISCUSSION CONTD…

Comparative physicochemical charaterisation of hybrid nanoparticles(A) UV−vis absorption spectra of Au NPs in the different conditions: (a) Au NPs, (b) Au NPs with CuDDTC2, and (c) Au NPs withCuDDTC2 + Hg species. (A, inset) color changes. (B) TEM images corresponding to the Au NPs in panel A.

ACKNOWLEDGMENTS

I sincerely acknowledge the authors of this article , Ling Chen, Jinhua Li, Lingxin Chen. I also thank all the professors for providing me this opportunity.

THANK YOU