Mercury and hydride element determination in seawater

Coastal and seawater matrices are considered some of the most difficult sample types to analyse because of the often-ultra-trace concentrations of target analytes, as well as the high total dissolved solids (TDS) that are present.

A normal analytical approach for trace metal determinations is to employ ICP-MS. However, high total dissolved solids can lead to salt precipitation within the nebuliser, torch and cones with associated operational problems. This is usually addressed by diluting the sample, but this has the undesired consequence of diluting the already ultra-trace concentration of Hg, As and Se making accurate and precise analysis very difficult. Additionally, elevated concentrations of sodium, magnesium and chloride, form polyatomic spectral interferences making the determination of elements, such as As and Se, more complicated (often addressed by employing a collision gas cell to try and overcome these interferences).

The employment of PS Analytical instruments, the Millennium Merlin 1631 (for Hg) and the Millennium Excalibur (for As and Se) for seawater analysis are useful as these systems are a) not subject the polyatomic spectral issues and b) can tolerate high TDS without the need for excessive dilution.

These systems offer excellent sensitivity (in the ppt range), wide linear working ranges, ease of use and rapid return on investment.

The analysers also allow the determination of these analysts in other environmental matrices; such as drinking water, wastewater, soils, sediments and sludges. 

With literally thousands of systems in the field today, and support networks in Europe, USA and SE Asia, PSA offers the ideal package of performance, reliability and support.  

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