A LED-based fiber-optic sensor integrated with lab-on-valve manifold for colorimetric determination of free chlorine in water.
In this work, a colorimetric methodology was developed for free chlorine determination by constructing a fiber-optic sensor (FOS) which was designed by using a small LED as light source and two silica fibers as light transmission elements. Then the FOS was integrated with the sequential injection lab-on-valve (SI-LOV) manifold to fabricate a FOS-SI-LOV system for free chlorine detection. The colorimetric determination was based on the reaction between N,N-diethyl-p-phenylenediamine (DPD) reagent and free chlorine, which would produce a chromophore showing maximum absorbance at 511 and 551nm and detected by a micro spectrometer detector. By choosing a green LED with emission wavelength at 520nm as light source, the chlorine concentration could be simply evaluated according to Beer's law. The developed FOS-SI-LOV system showed improved performances of wide linear range (10-400μgL-1), low detection limit (3.5μgL-1, 3σ), fast analysis (6.85s) and excellent repeatability (0.0083 RSD, n=8) for chlorine determination. The proposed FOS-SI-LOV system has been applied to on-line and real-time chlorine determination in different water samples with excellent selectivity. Furthermore, this FOS-SI-LOV methodology provided a colorimetric and fluorescence detection platform for other hazardous species monitoring in water environment based on Beer's law and Stern-Volmer relationship, respectively.
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China; Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu 610500, China. Electronic address: yanxiong207@aliyun.com.
Yan
Y
Xiong
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Jun
J
Tan
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China; Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu 610500, China.
Shenwen
S
Fang
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Chengjie
C
Wang
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Qing
Q
Wang
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Jiayi
J
Wu
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China.
Jie
J
Chen
School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China; Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu 610500, China. Electronic address: swpua124@126.com.
Ming
M
Duan
D002713:Chlorine / Q000032:analysis*; D003124:Colorimetry / Q000295:instrumentation*; D057230:Limit of Detection; D055100:Optical Fibers; D012666:Semiconductors; D013997:Time Factors; D014867:Water / Q000737:chemistry*
D014867:Water; D002713:Chlorine
Colorimetric determination; Fiber-optic sensor; Free chlorine concentration; Lab-on-valve; Sequential injection