EMD Millipore

As instrumentation and analytical methods are becoming increasingly sensitive, the ability to perform trace and ultra trace analyses relies on the high quality and purity of the reagents used.

Chromatographers take great care in the selection of salts and organic solvents used in mobile phase preparation, but selecting the best type of water is sometimes an arduous task.

Ultrapure water is highly prone to contamination, e.g. it easily leaches contaminants out of container surfaces and absorbs contamination from the laboratory environment. As ultrapure water is the most frequently used solvent in any LC-MS laboratory, its purity plays a critical role in analyses. There are a number of high purity water handling pitfalls that result in degradation of its quality. To help analysts critically evaluate the potential risks involved in poor ultrapure water handling, we discuss here (I) the effect of laboratory environment and long high purity water storage, (II) the effect of the container material used to collect ultrapure water, (III) the effect of laboratory ware and equipment cleaning, and (IV) the effect of poor practices of water purification system usage.

As the sensitivity of analytical instrumentation is constantly improving, and ultra-traces of compounds are being analyzed, the purity of reagents is becoming of paramount importance. Trace impurities in the water used to prepare LC-MS mobile phases, standards or blanks may lead to erroneous results or difficulties in analyzing data.

UV technologies are being increasingly used in water purification systems, taking advantage of the germicidal properties of UV and also its effect in reducing organic contaminants. This paper discusses the effectiveness of using UV technologies along a water purification chain and the parameters and configurations to be considered when selecting UV lamps for water purification systems.

Volatile organic compounds (VOCs) are carbon containing compounds that evaporate easily at normal temperatures. They are typically generated from petroleum products, plastics, paints and solvents,. Other sources are the disinfecting agents used to control microbial contaminants in drinking water. Disinfecting agents react with naturally occurring organic matter in the source water to produce VOCs known as trihalomethanes. When VOCs are spilled or improperly disposed of a portion will evaporate, but some will soak into the ground and eventually end up in drinking water supplies

Ion chromatography (IC) has been recognized as one of the most competitive techniques for trace analysis, based on results from continuing research and development work into different types of instrumentation. Ultratrace analysis requires the use of extremely clean reagents, including water. The ionic content of water was monitored by IC along a water purification chain, from tap water to ultrapure water. This study shows that ultrapure water from a Milli-Q system is suitable for trace analysis by IC.

Following on our previous Dedicated Dialogue which discussed lab water contaminants and purification technologies, this Dedicated Dialogue will consider specific ways to handle and manage a lab water purification system and the product water from these systems in order to ensure consistent and reliable results.