Field Preconcentration of Trace Metals from Seawater and Brines Coupled with Laboratory Analysis Using Flow Injection and ICP-AES Detection

Abstract

A simple but robust battery powered field sampling unit for the selective in situ preconcentration of trace elements (Cd, Co, Cu, Mn, Ni, Pb and Zn) from natural waters on a commercially available iminodiacetate resin is described. Water samples were filtered (0.45 μm) on-line and passed through twin microcolumns containing the resin Metpac CC-1. This allowed duplicate samples to be preconcentrated in parallel. The microcolumns were then taken to the laboratory and placed in a flow injection manifold coupled to an inductively coupled plasma – atomic emission spectrometer (FI – ICP–AES) for elution and quantitation. The results for CASS-2, a coastal seawater CRM, preconcentrated for 2 h at 0.5 ml min⁻¹, gave good agreement with certified values for Cd, Co, Cu, Mn, Ni and Zn. The preconcentration column has been shown to be applicable to samples in the salinity range 39–156% for Cd, Co, Mn and Zn and the field sampling unit is therefore suitable for the analysis of seawaters and industrial brines (such as those associated with North Sea oil field production waters).

Key Words:

• Flow injection
• in situ preconcentration
• ICP-AES
• seawater
• brines
• trace metals