DETERMINATION OF CHEMICAL OXYGEN DEMAND IN WATER USING NEAR INFRAED TRANSMISSION AND UV ABSORBANCE METHOD

Guoqing Wu, Weihong Bi, Jiaming Lv, Guangwei Fu

Abstract

Chemical oxygen demand (COD) is a synthetical indicator which represents the degree of organic pollution in water. The near-infrared (NIR) transmission and the UV absorbance method based on photoelectric detection technology and spectroscopy analysis have some advantages such as high precision, fast, non-contact, no secondary pollution etc compared to conventional wet chemical method. The NIR transmission spectra and UV absorbance spectra of standard solution configured with phthalate hydrogen potassium were collected respectively by MPA FT-IR spectrometer (Bruker Optics Inc.) made in Germany and AvaSpec-2048-2 UV sepctrometer (Avantes Inc.) made in Netherlands. After different pretreatment to the spectra, COD quantitative analysis model was established using partial least squares regression (PLS) and linear regression. The statistical analysis of COD quantitative model was implemented, and the result showed that UV absorbance meathod had a higher relevance but lower forecast accuracy and precision than NIR transmission method.

Keywords

COD, NIR transmission spectra, UV absorbance spectra, Photoelectric detection, Regression, Quantitative analysis model

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DOI

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IMEKO TC

TC2 - Photonics

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