TY - JOUR A1 - Traub, Heike A1 - Scharf, Holger T1 - NH4NO3 extractable trace element contents of soil samples prepared for proficiency testing - a stability study JF - Fresenius' journal of analytical chemistry N2 - In view of its intended use as a sample for proficiency testing or as a reference material the stability of the extractable trace element contents of a soil from an irrigation field was tested using the extraction with 1 mol/L ammonium nitrate solution according to DIN 19730. Therefore, changes of the extractability of sterilized and non sterilized soil samples stored at different temperatures were evaluated over a period of 18 months. Sets of bottles were kept at -20 °C, +4 °C, about +20 °C and +40 °C, respectively. The NH4NO3 extractable contents of Cd, Cr, Cu, Ni, Pb and Zn were determined immediately after bottling and then after 3, 6, 12 and 18 months with ICP-AES or ETAAS. Appropriate storage conditions are of utmost importance to prevent deterioration of soil samples prepared for the determination of NH4NO3 extractable trace element contents. Temperatures above +20 °C must be avoided. The observed changes in the extractability of the metals (especially for Cr and Cu) most likely could be related to thermal degradation of the organic matter of the soil. There is no need to sterilize dry soil samples, because microbiological activity in soils with a low moisture content appears to be negligible with regard to trace element mobilization. KW - Spurenelemente KW - Boden KW - Stabilität KW - Referenzmaterial PY - 2001 DO - https://doi.org/10.1007/s002160100748 SN - 0937-0633 VL - 370 IS - 2-3 SP - 270 EP - 274 PB - Springer CY - Berlin AN - OPUS4-1073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -