‘All that glitters is gold’: CEITEC scientists design an ultrasensitive heavy metal detection system


A nanoscale system that can efficiently detect heavy metal impurities in water has been developed by CEITEC researchers 1 



 

Water, water everywhere (Credit: Photo by Linus Nylund on Unsplash)


It can precisely identify the minuscule amount of contaminations, envisioning an easy and effective pollution monitoring system.


The upcoming Horizon Europe program has earmarked ‘Clean air and clean environment’ as one of their missions, which makes the credibility of this research even higher.


Horizon Europe program: 

‘Clean air and clean environment’


Cleaning biological and human-made contaminations could be easy, but the microscopic presence of toxic heavy metals are hard to be skimmed out. So, this invention will certainly assist in solving this problem.


Potable Water (Credit: Photo by  mrjn Photography on Unsplash


In the present day, many heavy metal detectors are mercury (Hg) based.

But the non-biodegradability and its accumulation in the tissues of organisms on the food-chain; e.g., fish and human led to the curtailing 2 (total ban in Scandinavia) of Hg use in European Union.

Hence, innovations in Hg-free detection systems are in high demand.

At the center of the invention, sits the shiny precious mineral, Gold (Au)!


‘But don’t worry, the cost will not exceed a few hundred Czech crowns,’ said the primary researcher Dr. Pavel Neužil.


That’s just like buying 200 rohliks (the famous Czech bread rolls)!


Although, the presence of heavy metals in the water/soil of the Czech Republic has never invaded the risk-zone, in certain regions alarming contaminations were detected 3, 4.



An easier monitoring system, such as this will prove to be a savior



Till date, out of the known toxic heavy metals, arsenic (As) - a confirmed carcinogen - has created most of the nuisance 5.

Dr. Podešva from Dr. Neužil’s team stated, ‘The World Health Organisation (WHO) has fixed the minimum level of arsenic ions in drinkable water to be 10 micrograms/litre (10 parts per billion, ppb), and to sense even lower concentrations we are using the technique named anodic stripping voltammetry (ASV), for quantitative determination of ionic species, here of As.’


Dr. Neužil added, ‘to avoid Hg, and associated technical problems with use of silver, we picked Au, which has already proven to be an excellent electrode material.’ 



The nanostructured gold islands (Source: Dr. Pavel Neužil)



Podešva and Neužil made their device on a multi-layered hybrid platform, with an equally spaced array of nanostructured gold microelectrodes in a gelatin matrix.


That creates random nanostructures of gold, generating islands of electrodes with a ~1400 fold greater surface area compared to existing gold-based electrodes.


Dr. Neužil explained, ‘the increased surface area beautifully allows ultrasensitive detection of heavy metals.’ It can detect 0.0212 ppb of As ions, i.e. 470× below the WHO threshold, is hitherto the lowest reported limit of detection value.


Additionally, other metals, namely, cadmium, mercury, copper or antimony can be identified; making it suitable for the detection of a wide range of elements.


Taking the proceedings forward, Neužil and colleagues are now developing another system, published recently 5, employing a non-toxic amalgam of microstructured gold and mercury, ideally detecting DNA and protein, potentially examining biological interactions.

By complementing the rich history of analytical chemistry in the Czech Republic, Dr. Neužil’s team is playing an important role featuring CEITEC’s interdisciplinary research nature.


Here, what glitters, is really gold!



References

  1. Nanostructured Gold Microelectrode Array for Ultrasensitive Detection of Heavy Metal Contamination, Podesva et al, Anal. Chem. 90, 1162 – 1167 (2018).
  2. Regulation (EU) 2017/852 of the European parliament and of the council of 17 May 2017 on mercury, and repealing Regulation (EC) No 1102/2008.
  3. Contamination of potentially toxic elements in streams and water sediments in the area of abandoned Pb-Zn-Cu deposits (Hrubý Jesenník, Czech Republic). Lichnovský et al., 2017.
  4. Robust assessment of moderate heavy metal contamination levels in floodplain sediments: a case study on the Jizera River, Czech Republic. Grygar et al. 2013.
  5. Single Nanostructured Gold Amalgam Microelectrode Electrochemiluminescence: From Arrays to a Single Point. Podesva et al, Sensors and Actuators B: Chemical 284 (2019).



Written by  Somsuvro Basu


Publication date: 29.03.2019