Old silver mirror in qualitative analysis with new shoots in quantification: Nitrogen-doped carbon dots (N-CDs) as fluorescent probes for "off-on" sensing of formalin in food samples

Puttaraksa Naksen; Purim Jarujamrus; Wipark Anutrasakda; Vinich Promarak; Liyuan Zhang; Wei Shen

doi:10.1016/j.talanta.2021.122862

Old silver mirror in qualitative analysis with new shoots in quantification: Nitrogen-doped carbon dots (N-CDs) as fluorescent probes for "off-on" sensing of formalin in food samples

Talanta. 2022 Jan 1:236:122862. doi: 10.1016/j.talanta.2021.122862. Epub 2021 Sep 10.

Authors

Puttaraksa Naksen¹, Purim Jarujamrus², Wipark Anutrasakda³, Vinich Promarak⁴, Liyuan Zhang⁵, Wei Shen⁵

Affiliations

¹ Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand; Nanomaterials Science, Sensors & Catalysis for Problem-Based Projects, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand.
² Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand; Nanomaterials Science, Sensors & Catalysis for Problem-Based Projects, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190, Thailand. Electronic address: purim.j@ubu.ac.th.
³ Department of Chemistry, Faculty of Science, Chulalongkorn University, Payathai Road, Patumwan, Bangkok, 10330, Thailand.
⁴ Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand.
⁵ Department of Chemical Engineering, Monash University, Wellington Road, Clayton, VIC, 3800, Australia.

PMID: 34635244
DOI: 10.1016/j.talanta.2021.122862

Abstract

A novel fluorometric assay for selective and sensitive determination of formalin (FA) was developed based on nitrogen-doped carbon dots (N-CDs) coupled with silver mirror reaction. N-CDs was synthesized using the hydrothermal method with the ethylene glycol and ammonia solution as carbon and nitrogen precursors, respectively. The detection principle was based on "off-on" fluorescence switching. Specifically, the fluorescence signal of N-CDs was first turned off after incorporating the Ag⁺ and Tollens' reagents. Then, in the presence of FA, the Ag⁺ species on the N-CDs surface were reduced to Ag⁰ species and the fluorescence signal of N-CDs was switched back on. The fluorescence intensity due to the N-CDs signal linearly increased with the increasing FA concentrations in the range of 5-100 mg L^-1, with the detection limit of 1.5 mg L^-1. The proposed approach provides rapid, simple, sensitive, and selective detection of FA in various food samples.

Keywords: Fluorometric assay; Formalin (FA); Nitrogen-doped carbon dots (N-CDs); Silver mirror reaction; Tollens' reagent.

MeSH terms

Carbon*
Fluorescent Dyes
Formaldehyde
Nitrogen
Quantum Dots*
Silver

Substances

Fluorescent Dyes
Formaldehyde
Silver
Carbon
Nitrogen