Determination of iron-porphyrin-like complexes at nanomolar levels in seawater.
A new method for the non-specific determination of iron-porphyrin-like complexes in natural waters has been developed. It is based on the chemiluminescent oxidation of the luminol in the presence of dioxygen (O2) at pH 13. The method has been implemented in a FIA manifold that allowed the direct injection of seawater. The limit of detection is 0.11 nM of equivalent hemin (Fe-protoporphyrin IX). Fe2+, Fe3+, H2O2, siderophore (deferoxamin mesylate), humic acid and phytic acid did not interfere when they were present at the concentrations expected in seawater. Metal free porphyrin and Mg, Cu, Co porphyrin complexes did not induce a significant chemiluminescent signal. Poisoned unfiltered samples could be stored for several weeks before analyses. The new method was successfully applied to the determination of the Fe-porphyrin complexes contained in cultured phytoplankton and in natural samples.
Vong
Lilita
L
Laboratoire d'Océanographie et de Biogéochimie, Université de la Méditerranée, Centre d'Oceanology de Marseille, Unité Mixte de Recherche CNRS 6535, Campus de Luminy, Case 901, 163, Avenue de Luminy, F-13288 Marseille Cedex 09, France.
Laës
Agathe
A
Blain
Stéphane
S
D007501:Iron / Q000032:analysis* / Q000737:chemistry; D049449:Luminescence; D011166:Porphyrins / Q000032:analysis* / Q000737:chemistry; D012623:Seawater / Q000737:chemistry*; D012680:Sensitivity and Specificity
D011166:Porphyrins; D007501:Iron