Efficient ensemble and IDA system based on the metal binding motif for highly sensitive and selective detection and determination of carbonate and citrate ions

ABSTRACT

Herein, we have reported a novel naked eye detection method which is based on the analyte competing for a metal reporter with a chromogenic indicator. This assay is based on the highly specific interaction between the anions and the metal ions and murexide (Mure) probe in a competition assay format. The resulting high sensitivity and selectivity for citrate and carbonate were achieved by changing the metal ions. The indicator is set free due to its displacement from the Mure/Cu²⁺ complex by citrate (Cit³ˉ) and the change in absorbance may be due to the further complexation of carbonate (CO₃²ˉ) with the additional coordination sites present in the zinc atom of Mure/Zn²⁺ complex. The dye-based ensemble systems are expected to be a potential and practical way for the detection of nanomolar concentrations of analytes in 100% aqueous solutions. The chemosensor enabled sensitive and selective detection of Cit³ˉ and CO₃²ˉ with detection limits of 19.1 and 9.4 nmol L⁻¹, respectively. These systems are simple in design, fast in operation and are more promising than previous methods. This novel method eliminated the need for separation processes, chemical modifications, organic cosolvents, and sophisticated instrumentations. Chiefly, the protocol offers high selectivity for the determination of Cit³ˉ and CO₃²ˉ among anions found in human urine samples in the presence of some biological species, including K⁺, Mg²⁺, Fe³⁺, Ca²⁺, Zn²⁺, Na⁺, glucose, urea, uric acid and ascorbic acid. Further, NAND and INHIBIT molecular logic gates were obtained using chemical inputs and UV–Vis absorbance signal as the output.

KEYWORDS:

• Colorimetric chemosensor
• metal ion-based ensemble
• aqueous media
• carbonate chemosensor
• citrate chemosensor
• molecular logic gates

Acknowledgments

The authors wish to acknowledge the support of this work by Shiraz Payame Noor University Research council with grant IDs d/7/47416 and Layout code 3146.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Shiraz Payame Noor University [d/7/47416]; [3146].