A simple in-house dry ashing chamber for the rapid determination of total mercury in organic-rich solid materials by oxidative pyrolysis followed by CVAAS and FI-ICPMS detection

A simple in-house pyrolysis chamber made of quartz material is described for the determination of total mercury content in a wide variety of organic-rich solid materials (plant, fish tissues and polymer based) by oxidative pyrolysis and cold vapour atomic absorption spectrometry (CVAAS). Oxidative pyrolysis was carried out by means of a Bunsen burner in the presence of an oxygen stream. Mercury liberated from the sample was collected in 0.1% KMnO4 trapping solution. Determination of mercury was achieved by CVAAS. Under optimal conditions, the limit of detection (LOD), calculated as the concentration of mercury yielding a signal equivalent to three times of the standard deviation of the blank value (3 sigma), obtained for CVAAS in conjunction with the oxidative pyrolysis method was found to be 0.08 ng g(-1). Flow injection inductively coupled plasma mass spectrometry (FI-ICPMS) was used to validate the developed method. The results obtained for several reference materials, such as mussel tissue (CE-278), tuna fish (CE-463), tuna fish (464), polyethylene (EC-681), plankton (CRM-414), lichen (CRM-482) and human hair (CRM-397), by the developed method agreed well with the certified values. These studies clearly demonstrate the capabilities of the pyrolysis set-up that can potentially be used for the rapid determination of total mercury in a wide variety of organic-rich matrices.