Construction of disposable biosensors for nitrite monitoring in food and beverages

Nitrite salts are regularly used as fertilizers and food preservatives. Excessive levels have raised awareness from public regulation agencies, since nitrite can have an adverse impact on public health and on ecological systems. Therefore, it is important to develop sensitive assays to monitor this ion in foodstuff products and waters. This work presents a nitrite biosensor based on a highly selective nitrite reducing enzyme incorporated on carbon ink based screen-printed electrodes. The resulting device enabled the quantification of nitrite in different samples (milk, water) in a straightforward way and with small error (1-6%). The sensitivity of the biosensor towards nitrite reduction under optimized conditions was 0.55 A M-1 cm-2 with a linear response in the range 0.7-370 jM.Grant: This work was supported byCiiEM - Centro de Investigaçao Interdisciplinar Egas Moniz, and Unidade de Ciencias Biomoleculares Aplicadas-UCIBIO, which is financed by national funds from FCT/MEC (UID/Multi/ 04378/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007728). CM. Silveira and T. Monteiro acknowledge Fundaçao para a Ciencia e Tecnologia the fellowships SFRH/BPD/79566/2011 and PD/BD/109687/2015, respectively.