Portable multispectral fluorometer for determination of formalin in food samples using nitrogen-doped carbon dots as the fluorescence probe

Abstract

In this work, we developed a portable multispectral fluorometer for determining formalin (FA). We used nitrogen-doped carbon dots (N-CDs) as the fluorescence probe, based on right-angle fluorescence spectrometry with twin excitation high-power light emitting diode sources. The multispectral spectroscopy sensor was used as a detector for fluorescence intensity. The fluorescence intensity values were displayed from 0 to 65535 a.u. The FA determination results show a linear relationship in the FA concentration range of 10-75 mg L−1 with r2 = 0.9908. The limit of detection (LOD) was 2.09 mg L−1 (calculated from 3SDblank/slope (n = 3)). In addition, the percentage of relative errors compared with the standard method and standard instrument shows less than 10 percent. The performance of a portable multispectral fluorometer in actual samples exhibited no significant difference compared to the validation instrument results. Therefore, the development of a portable multispectral fluorometer can be used as a fluorometer, and the measurement performance is comparable to a standard fluorescence spectrometer.

Keywords

• Portable multispectral fluorometer
• Formalin
• High-power-light-emitting diode
• Nitrogen-doped carbon dots (N-CDs)
• Silver mirror reaction