Influence of Dissolved Organic Matter on Determination of Iron in Solution and its Mechanism
Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2019, Vol. 40 ›› Issue (7): 1441-1448.DOI: 10.3969/j.issn.1000-2561.2019.07.028

• Agricultural Product Processing, Preservation, Storage, Analysis and Detection • Previous Articles     Next Articles

Influence of Dissolved Organic Matter on Determination of Iron in Solution and its Mechanism

WU Dongming1,2,LI Yi1,2,CHEN Yaohua1,2,DENG Xiao1,2,WU Chunyuan1,2,*()   

  1. 1. Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China
    2. Danzhou Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture & Rural Affairs, Danzhou, Hainan 571737, China;
  • Received:2018-08-19 Revised:2019-01-31 Online:2019-07-25 Published:2019-08-01
  • Contact: WU Chunyuan

Abstract:

Quantitative detection is a crucial technique for investigating the geochemical processes of ferric ion (Fe). However, due to the ubiquity of dissolved organic matter (DOM) in environmental medium, the combination of Fe with DOM may affect the determination of Fe in solution. Therefore, the effect of DOM between atomic absorption spectrometry (AAS) and colorimetry for Fe determination was tested. Precision of AAS was as good as colorimetry, both of them were less than 5%. However, AAS was more accurate with a recovery rate of 86.4%-97.8% and its detection limit was as low as 0.012 mg/L. DOM had a significant effect on colorimetry. The presence of DOM increased testing time and relative standard deviation of 11.5 h, 1.2%-22.2%, respectively. Moreover, the accuracy was also decreased by 28.3%-44.4%. As the concentration of DOM increasing, the accuracy was decreased in the tendency of exponential function, and the trend of the veracity fitted well with unary quadratic model. Moreover, the effect of DOM was greater with the decreasing concentration of iron. On the contrary, the presence of DOM had no significant influence on AAS. The results of EEMs and FTIR indicated that existed hydrogen bonding or π-π interaction occurred between DOM and Fe/phen that affected the interaction of Fe and colorimetry in a drive to influence the testing results.

Key words: ferric ion, determination, dissolved organic matter, veracity, accuracy

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