Key Laboratory of Optical Monitoring Technology for Environment

Taikang, China

Key Laboratory of Optical Monitoring Technology for Environment

Taikang, China
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Meng D.,CAS Anhui Institute of Optics and Fine Mechanics | Meng D.,Key Laboratory of Optical Monitoring Technology for Environment | Zhao N.,CAS Anhui Institute of Optics and Fine Mechanics | Zhao N.,Key Laboratory of Optical Monitoring Technology for Environment | And 15 more authors.
Applied Optics | Year: 2017

In this work, a mobile laser-induced breakdown spectroscopy (LIBS) system has been successfully applied to in situ analysis of heavy metals in soil samples. The LIBS system had two working methods, which were a fixed measuring method and a handheld method. For the fixed measuring method, a simple sample pretreatment was needed to reduce the soil matrix effect generated by moisture and porosity. Experiments proved that this method could be used to semi-quantitatively detect heavy metals when combined with the traditional calibration curve method. The limits of detection for copper, lead, and zinc were all below 10 mg/kg, which satisfied the need of heavy metal detection in soil. Principal component analysis was used for soil classification, which helped to build appropriate calibration curves. On the basis of soil classification, accurate and rapid detection of heavy metals in soil is feasible. For the handheld method, spectrum intensity and stability decreased significantly compared with the fixed measuring method. However, by using the internal standard method, the stability of LIBS data was improved significantly to 6%. For soil samples with serious heavy-metal pollution, the measurement errors were less than 12%, which indicated that handheld LIBS was effective to monitor heavy-metal pollution in soil. The research results provide application support for rapid and on-site monitoring of heavy metals in soil. © 2017 Optical Society of America.


Zhang K.,CAS Anhui Institute of Optics and Fine Mechanics | Zhang K.,Key Laboratory of Optical Monitoring Technology for Environment | Zhang Y.-J.,CAS Anhui Institute of Optics and Fine Mechanics | Zhang Y.-J.,Key Laboratory of Optical Monitoring Technology for Environment | And 16 more authors.
Journal of Water Supply: Research and Technology - AQUA | Year: 2011

In this paper, three common measuring methods for the principles of water turbidity, namely, scattering, transmission and the ratio method are introduced. A method combined with modulation and demodulation techniques based on pulse width modulation (PWM) pulse for turbidity measurement using light intensity modulation is proposed. The experimental system that is, the realizing circuit of modulation and demodulation is described in detail. The experimental system was used to measure Formazine Standard Solution turbidity of different values. The experimental results are shown, and then turbidity values are calculated using the three methods. Through the analysis and comparison of the experimental results, it is shown that when using the ratio method combined with the modulation technique, the interference of background light can be eliminated effectively, so the measuring accuracy is significantly improved. © IWA Publishing 2011.

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