Colorimetric and fluorometric dual-response system for rapid analysis of gentamicin in real samples

Gentamicin (GENTA) have been extensively used by humans and animals, however, excessive GENTA resulted in environment and food contamination, and finally threatened human health. Therefore, it is very necessary to establish novel method for quantitative determination of GENTA in real samples. In this investigation, carbon dots incorporated with nitrogen and boron elements (N,B-CDs) with large stokes shift (125 nm) and high fluorescence intensity was designed, synthesized and utilized. In the process, 18 μL of the mixed solution was dropped onto the test strip each time; the test strip was tested by a smartphone and/or a miniaturized fluorimeter to achieve red (R), green (G), blue (B) and fluorescence intensity values after 1 min. The color and fluorescence intensity of the mixture changed obviously with gold nanoparticles (AuNPs) and GENTA adding. The limit of detection (LOD) of colorimetric and fluorometric dual-response system for GENTA was 0.30 μmol/L and 14.7 nmol/L, respectively. Furthermore, the selectivity and practicality of the system was assessed for other analytes (metal ions and other antibiotics) and real samples, respectively. The system showed excellent recovery (98.4%–103.9%) and outstanding repeatability (relative standard deviation (RSD), 1.2%–4.0%) for fluorometric determination of GENTA in real samples. Moreover, this system was suitable for colorimetric detection of GENTA (recovery, 94.8%–113.4%, RSD, 1.9%–7.9%). The good properties of N,B-CDs and miniaturized fluorimeter were combined for fluorescence determination of GENTA in real samples. And simple colorimetric detection of GENTA could be realized. In brief, we anticipate that this hybrid system could be useful for rapid and onsite detection of GENTA in environment, food, and pharmaceutical samples.