ABSTRACT
Seawater, with its high concentration of ions and the presence of Ca and Mg, whose salts are insoluble at high pH, represents a sample matrix that is many times more complex than that of typical freshwater samples. The nutrients that form the basis of life in the ocean are present at concentrations up to 100 million times lower than the typical salt content, and this presents a great challenge to the analyst. Measuring low levels of dissolved nutrients requires careful attention to detail in cleanliness, sample handling, laboratory technique, and instrument design.
