No abstract

No abstract

Pure, mixed and doped metal oxides (MOX) have attracted great interest for the development of electrical and electrochemical sensors since they are cheaper, faster, easier to operate and capable of online analysis and real-time identification. This review focuses on highly sensitive chemoresistive type sensors based on doped-SnO2, RhO, ZnO-Ca, Smx-CoFe2−xO4 semiconductors used to detect toxic gases (H2, CO, NO2) and volatile organic compounds (VOCs) (e.g., acetone, ethanol) in monitoring of gaseous markers in the breath of patients with specific pathologies and for environmental pollution control. Interesting results about the monitoring of biochemical substances as dopamine, epinephrine, serotonin and glucose have been also reported using electrochemical sensors based on hybrid MOX nanocomposite modified glassy carbon and screen-printed carbon electrodes. The fundamental sensing mechanisms and commercial limitations of the MOX-based electrical and electrochemical sensors are discussed providing research directions to bridge the existing gap between new sensing concepts and real-world analytical applications.

No abstract

We report the fabrication and testing of a riboflavin (RF) biosensor based on the use of Cr doped SnO2 nanoparticles. The Cr-SnO2 nanoparticles with chromium concentration from 0 to 5 wt% were synthesised by a microwave irradiation method. Magnetic studies revealed that only 3 wt% Cr doped nano-SnO2 has ferromagnetic behaviour at room temperature. This Cr-SnO2 nanoparticles modified electrode responded to RF linearly over a concentration range of 0.2 × 10(-6) to 1.0 × 10(-4) M with a detection limit of 107 nM. The fabricated sensor showed an excellent anti-interference ability against electroactive species and metal ions and proved to be useful for the estimation of the RF content in pharmaceutical samples with satisfactory recovery.