With agaric as carbon source and urea as nitrogen source, this paper has successfully synthesized nitrogen-doped carbon quantum dots (N-CQDs) by simple one-step hydrothermal method. A series of analysis have been used to make characterization of the physical, chemical structures and optical performance of N-CQDs. The fluorescence stability was studied by examining the ionic strength, pH value and storage time and other conditions. The cytotoxicity and bacterial toxicity of N-CQDs were applied to biological imaging. Considering the quenching effect of 2,4-dinitrophenol (2,4 DNP) on the fluorescence generated by N-CQDs, N-CQDs have been used as fluorescence probe in detection of 2,4-DNP where N-CQDs showed high sensitivity, selectivity and strong disturbance resistance to 2,4-DNP based on the quenching mechanism of transfer of resonance energy. It can also be concluded that agaric-based N-CQDs can be used in bio-imaging due to a good inhibitory effect on but low toxicity to bacteria. Under the optimal experimental conditions, the probe has presented a good coefficient of determination (R2 = 0.9969) and a low limit of detection (15.78 nM). This method has been successfully applied to determine 2,4-DNP in environmental samples and provided a new idea for developing green and natural composite carbon materials.

Neste estudo foi desenvolvida uma metodologia analítica para determinação de 2,4-dinitrofenol (2,4-DNP) em amostras de águas de chuva de regiões de Santa Catarina utilizando a voltametria de onda quadrada (VOQ) e de forma ex situ. O estudo envolveu a aplicabilidade de utilizar o eletrodo de carbono vítreo modificado com filme de bismuto. A formação do filme de bismuto foi otimizada por voltametria cíclica e em seguida, estudos de pH e eletrólito de suporte foram investigados para a redução do 2,4-DNP. Os parâmetros analíticos que afetam a sensibilidade da VOQ foram otimizados. Na sequência, as figuras analíticas de mérito foram obtidas: faixa linear de trabalho de 3,2 x 10-7 - 4,6 x 10-6 mol L-1, coeficiente de correlação de 0,996, RSD% = 17,5 (1,3 x 10-6 mol L-1, n = 6), 11,7 (2,5 x 10-6 mol L-1, n = 6) e 6,4 ( 4,5 x 10-6 mol L-1, n = 6), limite de detecção de 1,2 x 10-7 mol L-1. E, finalmente estudos de recuperação foram realizados para avaliar a exatidão da metodologia. Valores obtidos ficaram entre 84-112% (2,5 x 10-6 mol L-1) e 89 - 113% (4,5 x 10-6 mol L-1).

In this study an analytical methodology for determination of 2,4-dinitrofenol (2,4-DNP) in rainwater samples of regions of Santa Catarina was developed using the square wave voltammetry (SWV). The study involved the applicability to use the modified glass carbon electrode with bismuth film. The formation of the bismuth film was optimized by cyclic voltammetry and after that, studies of pH and electrolyte support were investigated for the reduction of 2,4-DNP (ex situ form). The analytical parameters that affect the sensitivity of the SWW were optimized. In order, the analytical figures of merit were obtained: linear working range of 3,2 x 10-7 - 4,6 x 10-6 mol L-1; excellent coefficient of correlation of 0,996; RSD% = 17,5 (1,35 x 10-6 mol L-1, n = 6), 11,7 (2,5 x 10-6 mol L-1, n = 6) e 6,4 ( 4,6 x 10-6 mol L-1, n = 6); limit of detection of 1,2 x 10-7 mol L-1. Recovery studies were performed to evaluate the accuracy of the methodology. The values obtained were between 84 - 112% (2,7 x 10-6 mol L-1 ) and 89 - 113% (4,3 x 10-6 mol L-1).