Colorimetric assay based on arginine-functionalized gold nanoparticles for the detection of dibutyl phthalate in Baijiu samples

In this paper, a simple and innovative colorimetric method is established, which is based on DBP-induced aggregation of arginine functionalized gold nanoparticles (ARG-AuNPs), and can be used for the sensitive determination of dibutyl phthalate (DBP) in Baijiu samples. The morphological characteristics and the color changes of ARG-AuNPs caused by aggregation show good sensitivity, and can be observed through ultraviolet-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential technology. The color change of ARG-AuNPs from red to blue is due to the strong non-covalent interactions between DBP and ARG-AuNPs (electrostatic, van der Waals force and hydrogen bonding), which leads to the reduction of the electrostatic repulsion between the nanoparticles and aggregation. A two-stage linear equation was established between the absorption ratio (A(690)/A(530)) and the DBP concentration (0.0-2.8 mg L-1); the correlation coefficient (R-2) was 0.9914-0.9940, and the detection limit (LOD) was estimated at 0.05 mg L-1. The designed ARG-AuNPs acting as a dependable sensor for the detection of Baijiu samples equally acquired satisfactory recoveries. When the concentration of DBP in the solution is more than 1.0 mg L-1, the color change can be clearly observed by the naked eye; so there is no need for sample preparation techniques and tedious operations to quickly and semi-quantitatively detect DBP. The successful application of the proposed method in Baijiu samples indicates its potential to detect DBP in more complex environment samples.

Automated summary

A simple and innovative colorimetric method based on the aggregation of ARG-AuNPs induced by DBP is established for the sensitive determination of DBP in Baijiu samples. The color change of the nanoparticles from red to blue due to the interaction between DBP and ARG-AuNPs allows for quick and semi-quantitative detection of DBP without the need for complex sample preparation techniques. The method shows potential for detecting DBP in more complex environmental samples.