Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China.
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China.
Talanta. 2020 Jul 1;214:120814. doi: 10.1016/j.talanta.2020.120814. Epub 2020 Feb 8.
In this work, a rapid and sensitive ratiometric fluorescence sensing method for the detection of ascorbic acid (AA) and ascorbate oxidase (AA-Ox) was developed. MPA capped quaternary CuInZnS QDs with fluorescence emission wavelength of 580 nm was synthesized by hydrothermal synthesis. Thiamine (VB1) can be oxidized by KMnO to yield thiochrome (oxVB1) with a fluorescence emission peak at 459 nm. So positively charged thiamine and negatively charged MPA modified CuInZnS QDs can form a ratiometric fluorescence system via electrostatic interaction. The presence of AA will consume KMnO, which can inhibit the oxidization of thiamine, accompanied with a decrease of the fluorescence intensity at 459 nm, while the fluorescence of CuInZnS QDs at 580 nm remains the same when AA is present, so the fluorescence intensity ratio (I/I) decreased. When AA was oxidized by AA-Ox, KMnO could not be reduced by AA, which caused the fluorescence intensity of thiochrome at 459 nm restored, and the fluorescence intensity ratio (I/I) increased again. Therefore, AA and AA-Ox can be monitored by detecting the fluorescence intensities ratio at 459 and 580 nm. Moreover, the developed detection system for AA and AA-Ox displayed a good linear relationship from 0.05 to 0.25 μmol L and 0.1-5 mU·mL, and the detection limit are 0.011 μmol L and 0.078 mU·mL, respectively. The proposed method was applied to the determination of AA-Ox in human serum samples with satisfactory results.
在这项工作中，开发了一种用于检测抗坏血酸（AA）和抗坏血酸氧化酶（AA-Ox）的快速灵敏的比率荧光传感方法。通过水热合成合成了具有 580nm 荧光发射波长的 MPA 封端的四元 CuInZnS QDs。硫胺素（VB1）可被 KMnO 氧化生成荧光发射峰在 459nm 的硫色素（oxVB1）。因此，带正电荷的硫胺素和带负电荷的 MPA 修饰的 CuInZnS QDs 可以通过静电相互作用形成比率荧光系统。AA 的存在会消耗 KMnO，从而抑制硫胺素的氧化，同时伴随着 459nm 处荧光强度的降低，而当存在 AA 时，CuInZnS QDs 的荧光在 580nm 处保持不变，因此荧光强度比（I/I）降低。当 AA 被 AA-Ox 氧化时，KMnO 不能被 AA 还原，导致 459nm 处硫色素的荧光强度恢复，荧光强度比（I/I）再次增加。因此，可以通过检测 459nm 和 580nm 处的荧光强度比来监测 AA 和 AA-Ox。此外，所开发的用于检测 AA 和 AA-Ox 的检测系统在 0.05 至 0.25μmol·L 和 0.1 至 5mU·mL 的范围内显示出良好的线性关系，检测限分别为 0.011μmol·L 和 0.078mU·mL。该方法应用于人血清样品中 AA-Ox 的测定，结果令人满意。
