Sample preconcentration techniques practical applications

Copper is invariably determined by AAS in a lean air-acetylene flame, using the main resonance line at 324.7 nm. The detection limit is generally around 10 ng ml-1, which is marginally better than that generally achievable by flame AFS, and comparable to that reported for AES using a carefully optimized nitrous oxide-acetylene flame.2 Provided samples are not excessively diluted, this value is adequate for many practical applications in environmental analysis, such as the measurement of plant copper concentration or EDTA- or DTPA-extractable copper in soils. Interferences are rare, and unlikely to be a problem from concomitant elements present in most environmental samples, but matrix matching is still advisable. The sensitivity is inadequate for the direct determination of copper in natural water samples, for which a suitable preconcentration technique must be employed.1,23,24... 

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