Carbon dots are carbon-based nano materials that have been widely used as heavy metal ion detectors to replace quantum dot semiconductors such as CdS, CdSe, and CdTe which are dangerous to the environment. Cdots are known to be used as nanoparticle probe for the detection of heavy metal ions. Since the advantages of Cdots are sensitive and non toxic. Cdots also have some special properties such as biocompatible, high water solubility, and have high luminescence intensity. However, the detection of heavy metal ions using Cdots still have many limitations such as requiring doping materials Several techniques have been used to measure heavy metal by using CDots; however, their sensitivity needs to improve. We propose time-resolved photoluminescence (TRPL) measurement method to detect Fe³⁺ ions using CDots made of citric acid and urea. We conducted several other detection methods and compare the results to TRPL method. We found that TRPL method provides direct and high sensitivity compared with other methods. Concentration of Fe³⁺ ions as low as 0.23 nM can be easily detected using TRPL. Our TRPL measurement is also better than inductively coupled plasma optical emission spectrometry (ICP-OES) measurement system.

碳点是基于碳的纳米材料，已广泛用作重金属离子检测器，以替代对环境有害的量子点半导体，例如CdS，CdSe和CdTe。已知将点用作检测重金属离子的纳米粒子探针。由于Cdots的优点是敏感且无毒。Cdots还具有一些特殊的特性，例如生物相容性，高水溶性和高发光强度。但是，使用Cdots检测重金属离子仍然有很多局限性，例如需要掺杂材料。但是，它们的敏感性需要提高。我们提出了时间分辨光致发光（TRPL）测量方法来检测Fe ³⁺离子由柠檬酸和尿素制成的CDots。我们进行了其他几种检测方法，并将结果与​​TRPL方法进行了比较。我们发现TRPL方法与其他方法相比具有直接性和高灵敏度。使用TRPL可以轻松检测到低至0.23 nM的Fe ³⁺离子浓度。我们的TRPL测量也优于电感耦合等离子体发射光谱（ICP-OES）测量系统。