UVM Agricultural and Environmental Testing Lab
Plant and Soil Science Department
219 Hills Bldg. 1/6/2000
Cation Method for Groundwater Analysis using a Perkin Elmer "Optima 3000DV" Inductively Coupled Plasma Atomic Emission Spectrometer.
1. All samples were stored in a refrigerator prior to analysis.
2. The instrument was calibrated prior and during analysis of the groundwater samples using a High and Low standard solution in 0.1M HNO3 and a Blank solution of the same matrix. All calibrations yielded linear curves on which to base all subsequent analyses. Calibration was re-initiated every 10 samples, or whenever Quality Conrol samples were +/- 10% out of range of known values.
3. Two different source Quality Control samples of known values were prepared in the same 0.1M HNO3 matrix and distributed throughout the sequence of analysis.
4. A 5ml aliquot of each groundwater sample was added in sequence after the calibration standards and 2 QC samples.
5. The pre-designed ICP method, "Radial Minerals Plus" was selected for calibration and analysis. This method used the "Radial" or side torch optical view mode, which is less sensitive but more stable over the full range of analytes in question than the "Axial" mode. This refers to the DV or "Dual View" feature of the instrument.
6. The standard values for this method are as follows: High Low Blank
Ca mg/L 100 50
K mg/L 100 50
Mg mg/L 25 12.5
Na mg/L 25 12.5
S mg/L 25 12.5
Al mg/L 10 5
Fe mg/L 4 2
Mn mg/L 4 2
Cu mg/L 2 1
B mg/L 2 1
Zn mg/L 2 1
Cd mg/L 2 1
Cr mg/L 2 1
Pb mg/L 2 1
Ni mg/L 2 1
Mo mg/L 2 1
7. No dilutions were required for these groundwater samples for cations.