Copper is found naturally in the earth's crust and in seawater. It is an excellent conductor of electricity, an alloying metal (brass and bronze) and a catalyst for oxidation reactions. This catalytic property renders it essential to plant and animal growth. Copper is also an important component of fungicides and insecticides.

Copper-containing fungicides are used to control biological growth in the water supply. The Maximum Contaminant Level Goal for copper is 1.3 mg/L in drinking water.  The measurement of copper is an important means of monitoring the corrosion of condensate systems and heat exchangers.

The Colorimetric Method. CHEMetrics' test kits employ the bathocuproine reagent. Bathocuproine disulfonate forms an orange-colored chelate with copper. The method measures total soluble copper as ppm (mg/L) Cu.  The test kits are applicable for analysis of drinking water, surface waters, ground water, wastewater and seawater.