UVM Agricultural and Environmental Testing Lab

Plant and Soil Science Department

219 Hills Bldg. 1/6/2000



Anion Method for Groundwater Analysis using a Dionex 2010I Automated Ion Chromatograph

1. The instrument was switched on and allowed to prime itself with diluent and buffer solutions for 10 minutes prior to calibration and analysis. All samples were stored in a refrigerator prior to analysis.

2. 5ml aliquots of High, Medium, and Low calibration standard solutions were placed in the first 3 tubes in sequence for calibration of the instrument and subsequent analysis of the unknown water samples. The instrument is re-calibrated every 12 samples.

Concentrations of standards are as follows: High Medium Low

Cl- mg/L 10 5 1

NO3-N 6.77 3.39 0.68

SO4-S 6.67 3.33 0.67

PO4-P 5 2.5 0.5

  1. A 5ml aliquot of each groundwater sample was placed in sequence after the first three calibration standards.
  2. After initial analysis, the un-diluted sample results were used to determine if dilutions for each anion species would be necessary.
  3. If results were greater than the High standard, samples were diluted using deionized Nanopure water as follows:
    1. 50 and 100x

    SO4-S 10x and 50x

    NO3-N and PO4-P generally did not need to be diluted, as they were often found to be below the lowest standard.