Selective ligand-doped liquid crystal-based sensor for detection of ferric cation

ABSTRACT

A liquid crystal (LC) sensing platform was developed for detection of ferric ion (Fe³⁺) in aqueous solutions. In this platform, a N and S comprising ligand (2E)-2-(naphthylmethylene)hydrazinecarbothioamide (CTA) was doped in 4-cyano-4’-pentyl biphenyl (5CB) as the Fe³⁺ selective LCs. When the platform was submerged in the solution comprising Fe³⁺, the complex between Fe³⁺ and CTA formed, which disturbed the orientation of LC and cause a dim-to-light conversion of the picture of LCs. Based on previous studies, it has been suggested that 2:1 Fe³⁺: CTA complex were formed. The limit of detection of the platform for Fe³⁺ is 0.03 µM. This sensing platform did not respond to Ca²⁺, Cd²⁺, Mg²⁺, Cu²⁺, Na+, Zn²⁺, Pb²⁺ and Hg²⁺ metal ions. Furthermore, we also represented that this sensing platform is able to detecting Fe³⁺ in piped water. Due to the fact, the sign of this sensing platform is coloured under environmental light, which is easily comprehended by ordinary operators, it could be utilised as a mobile device to check the quality of water in any one place.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystal
• sensor
• detection
• Fe(III)
• carbothioamide

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Partial financial support was received from the Islamic Azad University Bandar Abbas Branch for this study.