Development of an ultrasensitive spectrophotometric method for carmine determination based on fluorescent carbon dots

ABSTRACT

A high-efficiency spectrophotometric method based on nitrogen-doped fluorescent carbon dots (N-FCDs) was developed for the ultrasensitive determination of carmine (CRM) in foodstuffs. The N-FCDs were fabricated via a one-pot hydrothermal method with m-phenylenediamine as the starting material. The detection principle was based on the fluorescence quenching effect of N-FCDs by CRM, where their interaction was due to the inner filter effect (IFE) and static quenching. A good linear relationship was established for CRM detection in a concentration range of 0.1–10.0 μM with a detection limit as low as 11.2 nM. The proposed method achieved satisfactory results for CRM determination in commercial food products with recoveries better than 98.6% and relative standard deviations (RSDs) less than 4.07%. The method established in this study was simple, ultrasensitive and reliable for rapid detecting CRM in a food matrix, which could be potentially used as a useful sensing agent for the analysis of additive food colourants.

Graphical Abstract

KEYWORDS:

• Carmine
• N-doped carbon dots
• spectrophotometric method
• inner filter effect

Supplemental data

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Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [21922202]; Jiangsu Key Research & Development Program, China [BE2019436-5]; LvYang Golden Phoenix Plan, Yangzhou City [2019]; Natural Science Fund for Colleges and Universities in Jiangsu Province, China [19KJB150042,20KJA550002]; Yangzhou Key R&D Project (Social Development), China (2020) [YZ2020063]; China Postdoctoral Science Foundation [2020M671625]; Opening Foundation of Jiangsu Dairy Bioengineering Technology Research Centre [KYRY2019002]; Natural Science Foundation of Jiangsu Province, China [BK20200949]; Yangzhou University Science and Technology Innovation Cultivation Fund [2019CXJ188]; National Key Research and Development Program of China [2016YFC1300201].