Development and implementation of a flow injection analyser with chemiluminescence for detection of sub-nanomolar Fe in seawater

[摘要] ENGLISH ABSTRACT: Iron is an essential micronutrient for all phytoplankton and is found in seawater at picomolar-level concentrations. For the first time in South Africa, a technique that utilizes a flow injection analyser (FIA) coupled with a chemiluminescence reaction has been developed for the analysis of Fe in seawater samples. The developed method is an improvement on similar available methods and uses commercially available resin (IDA) as opposed to the one that requires synthesis in the laboratory. Furthermore, the method requires reduced reagent concentrations thereby providing better results in a cost-efficient and easy manner. The improvements resulted in better precision while eliminating the loss of resin through bleeding, a common problem when using 8-HQ resin as per prior methods. Method validation was performed using internationally calibrated reference material provided by GEOTRACES and the values obtained were within the error limits of certified range. An inter-laboratory calibration was also conducted as part of the verification of the system. Surface samples from the SANAE 51 cruise were analysed for dFe and TdFe. Subsequently, the method was implemented on the SANAE 53 voyage on board the SA Agulhas II, to assess trace metal sampling protocol for any contamination issues, as well as for the analyses of collected samples. Current results suggest some contamination during collection stages, but this is still to be verified by complementary data on macronutrients and chlorophyll. The method was successfully developed and implemented in a land based clean laboratory, as well as on board a vessel.

[发布机构] Stellenbosch University