A nitrogen-doped fluorescent carbon dot for gallium occurrence investigation in environment

Gallium element had a good application prospect in semiconductor industry. The increase of gallium consumption led to elevated levels of gallium in the environment, so it was important to accurately explore gallium morphology in the environment and establish effective analytical methods. In this study, ammonium citrate was used as carbon and nitrogen sources to obtain water-soluble nitrogen-doped fluorescent carbon dots (N-CDs) under the hydrothermal synthesis condition of 160 °C. Fluorescence test showed that N-CDs has bright blue luminescence, pH-sensitivity and good stability under certain temperature, continuous ultraviolet irradiation and high salt concentration. There was a good linear relationship between Ga3+ concentration and fluorescence ratio (F0/F) when Ga3+ concentration was 1–10 μM, and the correlation coefficient was 0.999. Ion selectivity experiments showed that N-CDs had good selectivity and sensitivity to Ga3+ as fluorescent probes. Based on these characteristics, the fluorescence detection system of Ga3+ was established. Studies had shown that this method could be applied to the determination of Ga3+ in water samples and coal ash samples.