Analiza comparativă a concentraţiilor ionilor metalici în condiţiile utilizării de aparatură de laborator diferită [The comparison between the concentrations of metallic ions obtained in the same laboratory using different apparatus]

Abstract

In the framework of ICP Forests, within the period 1997-1999, the concentrations of Na and Mg in precipitation samples collected in open field and under the wood canopy were determined in the laboratory of ICAS Campulung by atomic absorption spectrophotometry, using a spectrophotometer produced in Romania in 1980. The concentrations of Ca and K for the same period and samples were determined by flame ionization, using an apparatus produced in Est Germany in 1970. Beginning with 2000 untill 2004, the concentrations of the four metallic ions were determined only by atomic absorbtion spectophotometry, using a spectrophotometer produced in USA in 1975 and donate to the laboratory of ICAS Campulung by INRA Nancy. In order to provide the comparability of the results obtained in time, the detection limits obtained were compared and 38 samples were analysed in parallel with the specific apparatus used within the two periods of mesurements. The detection limit was the same for Mg, but much lower for Na (twice), K (tree times) and Ca (ten times) with the apparatus used in 2000-2004 than that used in 1997-1999. The lowest deviations were obtain for Mg (< ∓ 20%) and Na ((< ∓ 30), because for these ions was used the same method (atomic absorption spectrophotometry), but different apparatus. For K and Ca were used different methods (flame ionization and respectively, atomic absorption spectrophotometry) and apparatus, so the deviations were higher ( up to ∓ 100 and respectively up to ∓ 40%).

Keywords

• : metallic ions
• atomic absorbtion spectrophotometry
• flame ionization