Dry Ash Procedure for P, K, Ca, Mg, Zn, Cu, Fe

Reagents

  1. 1 N HYDROCHLORIC ACID - Dilute 83.3 mL conc. HCl to 1 L Deionized H20.
  2. 6 N HYDROCHLORIC ACID - Dilute 50 mL conc. HCl to 100 mL deionized H20.

Apparatus

  1. MUFFLE FURNACE
  2. "HIGH FORM" PORCELAIN CRUCIBLES
  3. 100 mL VOLUMETRIC FLASKS
  4. 13 X 100 mm FLINT GLASS TEST TUBES

    Procedure

    1. Weigh 1.000 g sample into "high form" porcelain crucible.
    2. Place sample into furnace and increase temperature gradually until temperature reaches 500oC.
    3. Ash for 3 h after reaching temperature.
    4. Wet sample with a small amount of dH20, then add 5-10 mL of 6 N HCl and bring to near dryness on hot plate.
    5. Dissolve ash by adding 10 mL 1 N HCl to crucible.
    6. Quantitatively transfer dissolved ash into 100 mL volumetric flasks.
    7. Wash down sample with dH20.
    8. Dilute to volume with dH20 and shake.
    9. Place aliquot into ICP test tube.

    References

    1. Ellis, R. J., Jr., J. J. Hanway, G. Holmgren, D. R. Keeney, and O. W. Bidwell. Sampling and Analysis of Soils, Plants, Waste Waters, and Sludge-Suggested Standardization and Methodology. Agricultural Exp. Station, Kansas State University, Manhattan, Res. Pub. 170. North Central Regional Pub. 230.
    2. Haynes, R. J. 1980. A Comparison of Two Modified Kjeldahl Digestion Techniques for Multi-Element Plant Analysis with Conventional Wet and Dry Ashing Methods. Comm. in Soil Sci. and Plant Anal. 11(5): 459-467.