EQUIPMENT

  1. Thermo Jarrell-Ash model 61E ICP.
  2. Thermo Jarrell-Ash Autosampler 300.
  3. 48 position rectangular sample rack.
  4. Precision Scientific hot water shaking bath.
  5. Calibrated 5 gram scoop.
  6. 125 mL plastic erlenmeyer flasks.

STANDARDS

  1. Stock Solutions:
    1. BORON, 1000 ppm: Use NIST traceable single element plasma grade standard.
    2. BORON, 10 ppm: Pipet 10 mL of 1000 ppm boron standard into a 1 litervolumetric flask. Dilute to volume with deionized water and mix well. Store in a plastic bottle.
  2. Instrument calibration standards: Pipet the designated amounts of 10 ppm boronstandard into 100 mL volumetric flasks. Dilute to volume with deionized water and mix well. Store in plastic bottles.
mL
10 ppm B 		Final Concentration
ppm 		Instrument Readout
lbs/acre
1 0.10 1.00
3 0.30 3.00

EXTRACTION

  1. Scoop 5 grams soil into 125 mL plastic flasks.
  2. Add 25 mL deionized water.
  3. Stopper the flask and shake for 30 minutes at 80 °C on the hot water bath.
  4. Filter into 125 mL plastic erlenmeyer flasks, using Whatman #5 filter paper. The filtrate will often be turbid.
  5. Analyze the filtrate on the ICP emission spectrograph.
  6. Prepare one duplicate sample and one quality control sample with each set of samples analyzed.

ICP CALIBRATION

  1. Use deionized water and the 0.30 ppm B standard to calibrate the instrument.
  2. Use the 0.10 ppm standard as a curve verification check. Analyze this standard immediately after calibration and after the last soil sample. The acceptable range of values for this standard is 0.90 to 1.00 lbs/acre.

QUALITY CONTROL

  1. Values on the duplicate samples must agree within 20% of the average of the two values.
  2. Values on the quality control sample must lie within the established limits for this sample.

REFERENCES

  1. Gupta, U. C. 1967. A Simplified Method for Determining Hot Water-soluble Boron in Podzol Soils. Soil Sci. 103:424-428
  2. Odom, J. W. 1980. Kinetics of the Hot-water Soluble Boron Soil Test. Comm. Soil Sci, Plant Anal. 11(7): 750-769.
  3. Gestring, W.D. and P. N. Soltanpour. 1981. Boron Analysis in Soil Extracts and Plant Tissue by Plasma Emission Spectroscopy. Comm. Soil Sci. Plant Anal. 12(8): 733-742.