EMD Millipore | Authors

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.