Development of a method for mercury speciation by diffusive gradient in thin films (DGT)

  • Sam De Craemer ((PhD) Student)

Scriptie/masterproef: Master's Thesis

Uittreksel

In this research such a method for sampling and analysing methylmercury (MeHg) and total mercury at their low ambient concentrations has been developed and characterised.
Mercury species were collected from solution by using the diffusive gradients in thin films (DGT) technique, with an agarose (AG) gel as a diffusive gel and a 3-mercaptopropyl functionalised silica resin gel to bind mercury. The difference with the MeHg DGT method described in the literature is the use of the AG gel in MeHg probes, instead of polyacrylamide (PA) gels. The viability and characteristics of AG gel as a diffusive gel for MeHg determination were researched and a comparison between AG- and PA gels was made. For short deployments AG gels seemed to be the better choice, whereas for longer deployments more research is needed. The diffusion coefficient of MeHg in AG gel was determined, and linear dependency between the amount of MeHg that accumulates of the resin gel and both deployment time and gel thickness were demonstrated. Experiments showed that this DGT method could be used in most natural waters, as accumulation of MeHg was efficient in solutions with a pH between 3 and 9, and independent of ionic concentrations in the range
of 100nM and 1M.
An obstacle to overcome was the apparent incompatiblity between the literature procedure for eluting MeHg from the resin gel and the available equipment for analysing MeHg in environmental samples. To this end an alternative extraction procedure was developed.
Limited sampling results were achieved due to a combination of limited time and technical problems. Nevertheless the results show that the developed method has good potential as a tool for speciation studies.
Datum Prijs20 jun 2013
TaalEnglish
Toekennende instantie
  • Ghent University
BegeleiderMartine Leermakers (Promotor) & Yue Gao (Promotor)

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