Continuous Determination of Trace Amounts of Humic Acid in Natural Water by Chemiluminescence Method

✍ Scribed by M. Kitano; Y. Ogasawara; X.C. Hu; N. Takenaka; H. Bandow; Y. Maeda

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 330 KB
• Volume: 49
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1994.1037

✦ Synopsis

A chemiluminescence (CL) method for the determination of humic acid (HA) based on the oxidation of HA with hydrogen peroxide in the presence of formaldehyde in alkaline solution is described. This method is sensitive and selective for the determination of (\mathrm{HA}) in natural water. (\mathrm{HA}) produces strong (\mathrm{CL}) in the oxidation of (\mathrm{HA}) with (\mathrm{MnO}{4}^{-}, \mathrm{Br}{2}, \mathrm{ClO}^{-}), and (\mathrm{Cr}{2} \mathrm{O}{7}{ }^{2-}), and the (\mathrm{H}{2} \mathrm{O}{2}). (\mathrm{HA}-\mathrm{H}{2} \mathrm{O}{2}-\mathrm{HCHO}) system is suitable for the determination of (\mathrm{HA}) because of its high sensitivity and high selectivity. The detection limit was (50 \mathrm{ppb}) and relative standard deviation for five measurements of (0.5 \mathrm{ppm}(\mathrm{w} / \mathrm{w}) \mathrm{HA}) was (1.8 %). Cations such as (\mathrm{Na}^{+}, \mathrm{K}^{+}, \mathrm{Mg}^{2+}, \mathrm{Cu}^{2+}), and (\mathrm{Fe}^{3+}) and anions such as (\mathrm{PO}{4}{ }^{3-}, \mathrm{NO}{3}{ }^{-}, \mathrm{CO}{3}{ }^{2-}), (\mathrm{SO}{4}{ }^{2-}, \mathrm{Cl}^{-}), and (\mathrm{Y}^{-})(EDTA-Na) did not interfere with the determination of HA. Addition of (\mathrm{Mn}) (II) increased the CL intensity. The concentration of HA in natural water determined with this method is in good agreement with that determined by fluorometric analysis. 1994 Academic Press, Inc.