Facile and Sensitive Detection of Nitrogen-Containing Organic Bases with Near Infrared C-Dots Derived Assays

Abstract

In this article, we have designed both colorimetric (including solution and test paper type) and spectral sensors (including UV-vis and PL type) for the quick and sensitive detection of general nitrogen-containing organic bases (NCOBs); the limit of detection could reach as low as 0.50 nM. NCOBs included 11 examples, covering aliphatic and aromatic amines, five- and six-membered heterocyclics, fused-ring heterocyclics, amino acids, and antibiotics. Furthermore, the assays demonstrated high reliability in sensing NCOBs and excellent ability to distinguish NCOBs from oxygen and sulfur containing organics. The assays developed could find important applications for the detection of NCOBs in the fields of biomedicine, chemistry, and agriculture.

Carbon Dots-Based Fluorescence Assay for the Facile and Reliable Detection of Ag+ in Natural Water and Serum Samples

“…In addition, unlike most reported C-dots, the fluorescence spectra showed that the emissions of C-dots were independent of the excitation wavelength. Specifically, regardless of the shift in the excitation wavelength, the emission always presented the main peaks at 621 nm and shoulder peaks at 675 nm ( Figure 2 b) [ 31 ].…”

“…Based on this linearity, a calibration curve ( Figure 3 c) with a linear equation of F/F 0 = 0.9186–0.01205 [Ag + ], R 2 = 0.9619 was established. According to the well-accepted 3σ method [ 31 ], the LOD of this assay was determined to be 0.37 μM, which was far below the maximum level of Ag + allowed in drinking water (0.93 μM) as specified by the World Health Organization (WHO) [ 10 ].…”

Sensitive, Selective and Reliable Detection of Fe3+ in Lake Water via Carbon Dots-Based Fluorescence Assay

“…Specifically, the first fitting curve (0–250 μmol/L) has a linear equation of F/F 0 = 1.00046–0.00157 [Fe 3+ ] with R 2 = 0.99807 ( Figure 3 c), and the second fitting curve (250–1200 μmol/L) has a linear equation of F/F 0 = 0.70532–0.00048 [Fe 3+ ] with R 2 = 0.99371 ( Figure 3 d). According to the well-accepted 3σ method, LOD = 3 σ/k, where σ is the standard deviation of the blank samples and k is the slope of the linear calibration plot [ 47 , 48 , 49 ]. The LOD for the assay based on the calibration curve presented in Figure 3 c was determined to be 1.68 μmol/L, which is well below the maximum permissible concentration of Fe 3+ in drinking water (3.57 μmol/L), as required by the European Union.…”