oa Surface Enhanced Raman Spectroscopy (sers) Nanosensor For Ultrasensitive Detection Of Bromate In Drinking Water: State-of-the-art And Prospective

Surface Enhanced Raman Spectroscopy (SERS) nanosensor for ultrasensitive detection of bromate in drinking water: State-of-the-art and prospective Khaled A. Mahmoud Qatar Environment & Energy Research Institute (QEERI), [email protected] Sergey V. Gaponenko B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk 220072 Belarus, [email protected] The advances in Surface Enhanced Raman Spectroscopy (SERS) offer highly sensitive detection methods for monitoring drinking and potable water. The main experimental obstacle is the selective evaluation of a target pollutant in presence of the other pollutants. While single molecule detection is feasible in ultra-pure solutions with the known target molecules the trace detection of common pollutants in drinking and potable water remains a serious challenge. We consider the molecular recognition as the principal approach towards reliable development of plasmonic nanosensors for trace contaminations monitoring in water at the World Health Organization (WHO) prescribed levels. The molecular recognition approach has been recently shown to offer efficient selective analysis of certain target organic molecules in complex mixtures [4]. It is based on using specific binding of an additional agent (molecular compound) to the target molecules on complex solutions with the subsequent deposition of resulting conjugates on nanoplasmonic substrates and its Raman analysis. Specific binding can be tested additionally by predetermined modification of certain vibrational modes in conjugates as compared to free molecules. Desalinated water used in many countries including Qatar contains certain contaminants which does not present in ground water. Therefore analysts in these countries face the problem to develop affordable and reliable techniques for routine analysis of these contaminants in desalinated drinking and potable water. The representative examples are bromate, chlorate, and iodate anions. Bromate is supposed to possess carcinogenic properties with respect to humans and its content should thoroughly meet the WHO recommendation. We consider possible approaches to SERS sensor for trace level of bromate detection in desalinated drinking water. Herein we present novel analytical technique to trace bromate in drinking water based on novel molecular recognition and SERS sensor with detectability level improved by many orders of the magnitude. The novel and affordable technique for bromate detection in drinking water is expected to replace existing costly and bulky devices. This technique will offer bromate nanosensor test kit(s) to be used with the existing commercial Raman spectrometer and also will open an avenue towards portable desktop or even handheld bromate detection devices. The novel approach can be potentially foreseen to bromate extraction from drinking water. [1] S. V. Gaponenko, Introduction to Nanophotonics, Cambridge University, 2010. [2] K. Kneipp, M. Moskovits, H. Kneipp (Eds.) Surface-Enhanced Raman Scattering, Springer, 2006. [3] S. V. Gaponenko, D. V. Guzatov, Chem. Phys. Lett. 2009, 477, 411-414. [4] Kh. A. Mahmoud and M. Zourob, Analyst, 2013, 138, 2712-2719. [5] Bromate in Drinking-water, World Health Organization 2005.