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Simultaneous Determination of Nitrate, Chloride, Sulfate, and Phosphate in Natural Waters by Ion Chromatography
Author(s) -
Tabatabai M. A.,
Dick W. A.
Publication year - 1983
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1983.00472425001200020012x
Subject(s) - chemistry , ion chromatography , chloride , molybdenum blue , sulfate , column chromatography , nitrate , phosphate , ion exchange , chromatography , ion exchange resin , thermal conductivity detector , conductometry , ammonium , inorganic chemistry , ion , gas chromatography , organic chemistry
Simultaneous analysis of anions in water samples is needed. Studies to evaluate the Dionex Model 10 Ion Chromatograph (IC) for simultaneous determination of NO 3 − , Cl − , SO 4 2− , and PO 4 3− in water samples, including soil extracts, showed that the results by the IC method agreed closely with those obtained by the steam‐distillation method for NO 3 − , colorimetric method using mercuric thiocyanate and ferric ammonium sulfate for Cl − , reduction and colorimetric determination as methylene blue for SO 4 2− , and colorimetric molybdenum blue method for PO 4 3− . The IC method is based on separation of the anions by a separator column containing Dionex low‐capacity anion‐exchange resin in the HCO 3 − form and on converting the various anions to their corresponding acids by a suppressor column containing a strong acid cation‐exchange resin in the H + form. A solution 3.0 m M NaHCO 3 + 2.4 n M Na 2 CO 3 is used as the eluent, and electrical conductivity is used as the mode of detection. The method is precise and accurate, and can detect as little as 0.1 mg/L of NO 3 − ‐N, Cl − , SO 4 2− ‐S, or PO 4 3− ‐P in water samples. The coefficient of variation ranged from 0.44 to 8.6% for NO 3 − ‐N, from 0.14 to 4.3% for Cl − , from 0.13 to 1.1% for SO 4 2− ‐S, and from 0.55 to 8.6% for PO 4 3− ‐P. With the IC method, the 4 anions indicated can be determined simultaneously in 2 mL of water in approximately 10 min.