title: Sensitive and background-free determination of thiols from wastewater samples by MOF-5 extraction coupled with high-performance liquid chromatography with fluorescence detection using a novel fluorescence probe of carbazole-9-ethyl-2-maleimide.
abstract: A sensitive and background-free pre-column derivatization method for the determination of thiol compounds using metal-organic framework material (MOF-5) as dispersive solid-phase extraction (DSPE) adsorbent followed by high-performance liquid chromatography fluorescence detection (HPLC-FLD) has been developed. In this paper, a novel labeling reagent, carbazole-9-ethyl-2-maleimide(CAEM), was synthesized and reacted with thiols at 40°C for 10min in the presence of PBS buffer (0.02mol/L, pH 7.5). Interestingly, CAEM itself had no fluorescence, while its derivatives exhibited intense fluorescence with an excitation maximum at λex274nm and an emission maximum at λem363nm, which greatly reduced the background interference and improved the sensitivity of the method. Furthermore, the MOF-5 was prepared and used as DSPE adsorbent for the selective adsorption of thiols from wastewater sample. Under the optimized experimental conditions, an excellent linearity for all analytes over their concentration ranges of 0.01-1.0μmol/L (R2>0.9986)were obtained with the limit of detection (LOD) ranging from 8 to 17.1pmol/L for nine tested thiols. The feasibility of this method for the determination of thiols in wastewater samples had been evaluated and satisfactory average recoveries (n=3) were achieved with the range of 86.6-98.5%.
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China.
authors: Zhengxian
authors: Z
authors: Lv
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China. Electronic address: sunzhiw@126.com.
authors: Zhiwei
authors: Z
authors: Sun
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China.
authors: Cuihua
authors: C
authors: Song
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China.
authors: Shuaimin
authors: S
authors: Lu
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China.
authors: Guang
authors: G
authors: Chen
authors: Key Laboratory of Life-Organic Analysis of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine of Shandong Province, Qufu Normal University, Qufu 273165, People's Republic of China; Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, People's Republic of China. Electronic address: jmyou6304@163.com.
authors: Jinmao
authors: J
authors: You
keywords: Carbazole-9-ethyl-2-maleimide (CAEM); High-performance liquid chromatography (HPLC); MOF-5; Thiols; Wastewater