Faisal Hossain from the Department of Chemistry and Professor Dr. Mohammad Mosharraf Hossain from the Institute of Forestry and Environmental Science have been exploring electrochemical sensing of environmental analytes using ultraportable and highly sensitive platforms at low cost. Fortunately, Professor Hossain had a compact potentiostat that he bought from the company of his Ph.D. supervisor, Professor Eiichi Tamiya. Meanwhile, as Faisal started his Ph.D. at the University of Alberta, Canada, under Professor Michael J. Serpe, who has an interest in using readily available diabetic glucose sensors for phosphate sensing, we started trying to sense Phosphate and Arsenic in water on glucose sensor using compact potentiostat at IFESCU Lab. We all know that algal blooms are rapid and excessive growths of algae in aquatic environments are often triggered by elevated levels of orthophosphate, a form of phosphorus. Algal blooms affect aquatic ecology through eutrophication, necessitating management strategies to maintain water quality for aquatic ecosystem health. It depends on monitoring orthophosphate content in aquatic systems at a low-cost and easy-to-use device. We were successful in developing a sensor for orthophosphate (PO43–). It was based on the enzymatic cleavage of maltose in the presence of PO43– generating an equivalent amount of glucose. The glucose produced was quantified using a commercial glucometer test strip coupled to a miniature potentiostat using amperometry.

The limit of detection was excellent 1.45 μM (0.1 ppm) glucose/ PO43–, which is lower than that of a commercial glucometer (≥600 μM glucose) with a dynamic range of 10 μM–3 mM. The selectivity of the approach to PO43– was evaluated by determining the device’s response to known components in natural water samples. Finally, the approach was applied to determine PO43– in tap and river water samples successfully. This approach does not require any sensor fabrication as we used off-the-shelf glucose test strips, which are readily available anywhere in the world at low cost, to monitor orthophosphate in water. The research was published in the prestigious journal Analytical Chemistry of ACS publication (https://pubs.acs.org/doi/10.1021/acs.analchem.1c04121).

Later, one MS student of Professor Mosharraf from IFESCU, Ms. Etamoni Chakma, adapted the approach for the successful detection of As, and her poster won the first prize in the research showcasing event at the University of Chittagong. Etamoni is going to join Serpe Lab, and she will try to refine the As detection which is critical for Bangladesh laden with groundwater arsenic pollution. On the other hand, Faisal adapted the same system successfully to detect SARS-CoV-2 Spike RBD IgG Antibody and SARS-CoV-2 Virus in Saliva and Serum. This was published in the same journal (https://pubs.acs.org/doi/10.1021/acs.analchem.3c00481). If the technology is commercialized, the research outcomes will be able to make a significant contribution in democritizing environmental analysis and medical diagnosis.

Read the whole article: https://pubs.acs.org/doi/10.1021/acs.analchem.1c04121 and https://pubs.acs.org/doi/10.1021/acs.analchem.3c00481