Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian 350116, China.
Analyst. 2020 May 18;145(10):3543-3548. doi: 10.1039/d0an00302f.
Hydrogen sulfide (H2S) can regulate a variety of physiological functions, and the development of sensitive H2S detection methods is a requirement. In this study, a homogeneous photoelectrochemical (PEC) sensor for H2S detection was constructed based on the energy level matching of iron(iii) phthalocyanine-4,4',4'',4'''-tetrasulfonic acid ([Fe(iii)PcS4]+) and n-GaN. The photocurrent of n-GaN could be suppressed by monomeric [Fe(iii)PcS4]+ since the photogenerated electrons in the conduction band (CB) of n-GaN could be injected into the LUMO of [Fe(iii)PcS4]+. Under weak alkaline conditions, monomeric [Fe(iii)PcS4]+ can be converted to [Fe(i)PcS4]- after reacting with H2S with high selectivity. The LUMO of [Fe(i)PcS4]- was higher than the CB of n-GaN, so the photogenerated electrons in the LUMO of [Fe(i)PcS4]- could be injected back into the CB of n-GaN. The electron-hole pair recombination could be hindered, which resulted in the recovery of the system photocurrent. In the H2S concentration range of 10.0 nM-50.0 μM, a linear relationship was obtained between the photocurrent and the logarithm of H2S concentration with a detection limit of 3.40 nM. The proposed method avoids tedious electrode modifying procedures required in conventional PEC sensors and it was applied to detect extracellular H2S in rat brains coupled with microdialysis.
硫化氢（H2S）可以调节多种生理功能，因此开发灵敏的 H2S 检测方法是一项要求。在这项研究中，基于铁（III）酞菁-4,4',4'',4'''-四磺酸（[Fe（III）PcS4]+）和 n-GaN 的能级匹配，构建了一种用于 H2S 检测的均相光电化学（PEC）传感器。由于 n-GaN 导带（CB）中的光生电子可以注入[Fe（III）PcS4]+的最低未占轨道（LUMO），因此单体[Fe（III）PcS4]+可以抑制 n-GaN 的光电流。在弱碱性条件下，单体[Fe（III）PcS4]+可以与 H2S 反应后高选择性地转化为[Fe（I）PcS4]-。[Fe（I）PcS4]-的 LUMO 高于 n-GaN 的 CB，因此 LUMO 中的光生电子可以回注入 n-GaN 的 CB。可以阻碍电子-空穴对的复合，从而恢复系统的光电流。在 10.0 nM-50.0 μM 的 H2S 浓度范围内，光电流与 H2S 浓度的对数呈线性关系，检测限为 3.40 nM。该方法避免了传统 PEC 传感器所需的繁琐电极修饰程序，并应用于与微透析结合的大鼠脑细胞外 H2S 的检测。
