determination of trace labile copper in environmental waters by magnetic nanoparticle solid phase extraction and highperformance chelation ion chromatography cobalt magnetic nanoparticles surface functionalised with iminodiacetic acid were evaluated as a nanoparticulate solid phase extraction absorbent for copper ions cu2 from environmental water samples using an external magnetic field the collector nanoparticles could be separated from the aqueous phase and adsorbed ions simply decomplexed using dilute hno3 effects of ph buffer concentration sample and sorbent volume extraction equilibrium time and interfering ion concentration on extraction efficiency were investigated optimal conditions were then applied to the extraction of cu2 ions from natural water samples prior to their quantitation using highperformance chelation ion chromatography the limits of detection lod of the combined extraction and chromatographic method were 01 ng ml1 based upon a 100fold preconcentration factor chromatographic performance lod92 ng ml1 cu2 analytical linear range from 20 to 5000 ng ml1 and relative standard deviations49 c1000 ng ml1 n7 accuracy and precision of the combined approach was verified using a certified reference standard estuarine water sample slew2 and comparison of sample determinations with sector field inductively coupled plasma mass spectrometry recoveries from the addition of cu2 to impacted estuarine and rain water samples were 1035 and 1085 respectively coastal seawater samples both with and without prior uv irradiation and dissolved organic matter removal were also investigated using the new methodology the effect of dom concentration on copper availability was demonstrated