Measurement of Trace Elements in Marine Environmental Samples using Solution ICPMS. Current and Future Applications

Abstract

The strengths and weaknesses of using inductively coupled plasma mass spectrometer (ICPMS) measurements of samples in solution for marine environmental analyses using real world examples is discussed.

ICPMS can detect nanogram per litre concentrations of trace elements but suffers from polyatomic interferences generated from the sample matrix. Most of the routine trace elements measured in marine biological tissue and sedimentdigests, with the notable exceptions of iron, chromium, vanadium, and selenium, are not subject to severe interferences. Low recoveries of trace elements from sediments are due to the inability of extraction acids to remove trace elements such as chromium and nickel from sediment matrices. The use of ICPMS offers the advantage that elements such as phosphorus, which previously required elaborate digestion procedures and a colorimetric determination, can be rapidly determined using nitric acid digestion alone.

The use of flow injection coupled with ICPMS allows on-line preconcentration of trace metals and metalloids using chelation by ion-exchange resins or hydride generation and trapping as well as separation from matrix elements. Thus, the routine determination of trace elements and inorganic and methylated arsenic, antimony, mercury, and germanium species in open-ocean waters is possible.

The coupling of HPLC and GC to ICPMS allows the measurement of metal and metalloid species in biological and sediment extracts. However, extraction of unaltered species from matrices presents a challenge. Many of the species found in the environmental samples are not known and analytical standards are not available. The concurrent use of HPLC-MS is needed to confirm these species.