Water Purification
Water purification systems provide consistent and pure sources of water that meet NCCLS, ASTM, and CAP specifications. Laboratory water purification systems range from simple filtration to more extensive treatment techniques. Combining water purification systems with UV lamps is the most extensive and complex. Techniques include:
- Distillation
- Ion exchange, also called deionization or demineralization
- Ultrafiltration and microporous filtration
- Reverse osmosis
- Ultraviolet (UV) radiation
Source or feed water may be tap water, water that is pre-treated by the system, or pretreated water that is drawn from a reservoir or tank. Water systems typically produce water rated as Type I, II, III, or IV.
Type I or “ultrapure” Type I water is defined by resistivity and TOC levels (total organic compounds, measured in parts per billion (ppb). Type I water is required for ICPMS, AAS, FAAS, GFAAS, HPLC, IC, and ICPAES methods, molecular biology, cell and tissue culture, electrochemistry, and electrophoresis.
Type II water is suitable for ELISA and RIA test methods, buffer and reagent preparation, and spectrophotometry. It also has a specific requirement for resistivity. Type III water is used for media preparation, glassware washing and rinsing, and other non-critical applications. Type IV water is typically used as feed water for Type I and Type II water purification systems.
Water purification systems also range in size based on capacity. Some units are small enough to fit on a benchtop; others are free-standing or wall-mounted and may have multiple, remote reservoirs for convenience.
Replacement water purification parts — filters and cartridges — are key component of these systems and must be changed according to specifications to maintain the promised water quality. Replacement tubing, spigots, reservoirs, and other water system parts and accessories are available to keep the system in good working order.