A sensitive spectrofluorimetry method based on S and N dual-doped carbon nanoparticles for ultra-trace detection of ferrocyanide ion in food salt samples

ABSTRACT

An ultra-sensitive spectrofluorimetry method was developed and validated for the rapid determination of ferrocyanide ions (hexacyanidoferrate(II), FeCN₆^4-, FCNs) by using sulphur (S) and nitrogen (N) dual-doped fluorescence carbon nanoparticles (S,N-FCNPs) as nanoprobe. The fluorescence of S,N-FCNPs was strongly reduced due to the dynamic interaction between S,N-FCNPs and FeCNs. The developed method proved to be highly sensitive and selective for FeCNs detection with linearity in three concentration ranges over four orders of magnitude, covering 0.01–200.0 μg/mL.

A limit of detection (LOD) of 2.8 ng/mL was obtained. The method was successfully applied for the determination of FeCNs in a series of dietary food salt samples and gave satisfactory results; the spiked recoveries were 97.6‒104.6% with standard uncertainty less than 5.8%. The method proved to be applicable for ultra-trace detection of FeCNs in food salt samples, having advantages in great simplicity, rapid response, low cost, favourable selectivity, and high sensitivity.

Graphical Abstract

KEYWORDS:

• Fluorescence probe
• FeCNs
• carbon nanoparticles
• food analysis
• hexacyanidoferrate(II)
• ferrocyanide

Acknowledgments

This work was supported by the LvYang Golden Phoenix Plan, Yangzhou City (2019), China Postdoctoral Science Foundation [2020M671625]; National Natural Science Foundation of China [21922202]; Yangzhou Key R&D Project (Social Development), China (2020) [YZ2020063]; Natural Science Fund for Colleges and Universities in Jiangsu Province, China [19KJB150042]; Yangzhou University Technology Innovation Cultivation Fund [2019CXJ188]; Opening Foundation of Jiangsu Dairy Bioengineering Technology Research Center [KYRY2019002].

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This work was supported by the China Postdoctoral Science Foundation [2020M671625]; National Natural Science Foundation of China [21922202]; Yangzhou Key R&D Project (Social Development), China (2020) [YZ2020063]; Natural Science Fund for Colleges and Universities in Jiangsu Province, China [19KJB150042]; Yangzhou University Technology Innovation Cultivation Fund [2019CXJ188]; Opening Foundation of Jiangsu Dairy Bioengineering Technology Research Center [KYRY2019002].