Equipment designed for water-quality work commonly is constructed of a combination of materials, the most inert being used for components that will contact the sample. When planning equipment use, consider having several sets of precleaned equipment available. A clean set of equipment for each sampling site prevents cross contamination between sites, eliminates the need for time-consuming equipment cleaning in the field, and serves as backup should equipment break or become greatly contaminated.
Materials used in equipment can include plastics, glass, and metals.
Chemical reactivity varies widely within the same group of materials, depending on the chemical composition, the physical configuration, and the manufacturing process. The more polished the surface, the less reactive the material tends to be.