ION CHROMATOGRAM METHOD FOR ANALYZING ANIONS AND CATIONS IN PORE WATER FROM MARINE SEDIMENTS

We use ion chromatogram technique to determine the anion and cation ion concentrations in pore waters. Metrosep A Supp4-250 type column and 1.8 mmol/L Na₂CO₃+1.7 mmol/L NaHCO₃mixed solution in anion system are used to determine concentrations of Cl^-,Br^-and SO₄^2- in pore water, and Metrosep C 2-150 type column and 4 mmol/L tartaric acid+0.75 mmol/L C₇H₅NO₄ mixed solution in cation system are used to determine concentrations of Na⁺,NH₄⁺,K⁺,Ca²⁺and Mg²⁺.The results indicate that correlation coefficient between measured and standard values for each ion in standard solutions preponderates over 0.999. The detection limit is less than 0.5 mg/L, and the relative standard deviation is better than 3%. In particular, we carried out special experiment to measure Br^-concentration under high Cl^- concentration background as well as NH₄⁺concentration under high Na⁺ concentration background. Right now, a tentative ion chromatograph method for analyzing concentrations of cations and anions in pore water from marine sediments has been established in our lab. This method has been proved to be rapid, simple, sensitive, and accurate.