Design of a cyanide ion optode based on immobilization of a new Co(III) Schiff base complex on triacetylcellulose membrane using room temperature ionic liquids as modifiers

A new cyanide optode was designed using [N,N′-bis(salicyliden)-2,3-diaminopyridine]tributylphosphine cobalt(III) percholorate monohydrate complex, which was coated on transparent triacetylcellulose film as membrane. The reduction in the absorbance value of the optode at the maximum wavelength of 380 nm was related to cyanide concentration in aqueous samples. The sensitivity of the method was improved by using room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, [C4MIM][PF6], introduced in constructing the optode membrane. The linear dynamic range for the determination of cyanide was 1.0 × 10−5 to 2.5 × 10−4 M with a limit of detection of 4.2 × 10−6 M (n = 10) and a response time range of 7–10 min. The optode was successfully applied for the determination of cyanide in drinking water.