Determination of heavy metals in environmental matrices sampled inside the Park of the Po Delta.

Analytical results are reported for the determination of heavy metals in environmental matrices, sampled in an ecosystem inside a protected area: the Park of the Po Delta, located near the thermoelectric power station ENEL of Porto Tolle, one of the greater in Italy. The elements determined, in sediments and superficial water, are Ni and V, linked to the fuel oil combustion. However, in order to obtain a complete picture enough of heavy metals polluting load in the study areas, the following elements: Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn are also determined. For all the elements, in addition to the detection limits, precision and accuracy are also given: the former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.

Determination of traces of iron in indium phosphide by electrothermal atomic absorption spectrometry combined with solvent extraction.

An electrothermal atomic absorption (ETAAS) method for the determination of traces of iron (0.1-1.0 microgram g-1) in Fe-doped indium phosphide (InP) has been developed. In order to overcome the indium matrix-effect and to achieve a useful detection limit, a preliminary solvent-extraction of Fe(III) with acetylacetone (HAA) is necessary. After sample dissolution with hydrochloric acid (1 + 1) the digest is evaporated to dryness, Fe(II) is oxidized to Fe(III) with nitric acid, the residue is dissolved in 0.01 mol L-1 HCl and the iron is extracted at pH 2.0 with 0.5 mol L-1 HAA in toluene. The organic phase is injected into the graphite furnace and the iron is directly evaluated by external organic standard calibration. The limit of detection (3SB) resulting from further in-situ preconcentration is 0.03 microgram g-1. When the method was applied to the analysis of real samples containing 0.2-0.7 microgram g-1 Fe, the RSD was in the range 8-21%. Results were compared with those independently obtained on the decomposed sample solution with inductively coupled atomic emission spectrometry (ICP-AES). The detection limit of the ICP-AES method, that needs matrix-matched standards, is 0.20 microgram g-1.