Water is the most widely used constituent of solvents and reagents for virtually every research application. Ultrapure water (designated as such based on resistivity characteristics, as well as low particulate and organic carbon levels) is a necessity for any analytical or theoretical lab. Although there is potentially a wide array of chemical and biological contaminants to any research protocol, this can be minimized by ensuring low organic carbon, particulate matter, pyrogen, and bacterial levels within the water used during experimentation. The Millipore brand offers several different systems that present different options based on the individual needs of a lab, featuring the new Milli-Q Biocel and Synthesis systems for life science applications. Although the Synthesis system has more options than the Biocel, I will comment on a recently acquired Biocel system used within our lab.
Specifications of water supplied from the Biocel are as follows: 18.2 megohms.cm resisitivity, organic compounds levels of 5-10, pyrogen levels <0.001 Eu/ml, bacterial content <1 cfu/ml, particulate/ml <1 and a flow rate of 1.0 l/min. The specifications of this system exceeded my research demands for water quality. Although I did not quantitate actual resisitivity or organic content values, there did not appear to be any contamination when the water was used in buffers, gels or molecular techniques (such as PCR). Nuclease levels were measured using a standard QC kit and I found that the water from the Biocel unit had a lower level of nucleases than the nuclease free water we had purchased for the lab (although both values were well below problematic levels). I believe that one of the key benefits of the Milli-Q Biocel is the ability to provide nuclease free water, eliminating the need for DEPC. DEPC has an adverse interaction with some assay components as well as being difficult to prepare and somewhat toxic. The flow rate of the system, although rather slow at 1 l/min, is sufficient if you plan ahead.
Mechanically, there are features I like about this system, including its compact size (18” x 10” x 12”). Our previous water system was larger, more cumbersome, and was not as well constructed. In order to maintain high quality purification or to address issues due to poor quality source water in your lab, a pre-filtration system may be used which prevents clogging of the Biocel filters. The system is user-friendly, with critical information clearly displayed and easily accessible. One of the features I like best about the system is the progammable fill amount which allows you to automate the volume of water you would like to dispense. This couples well with the low flow rate, since carboys may need to be filled often and the automation feature allows a carboy to be placed and left. The system itself is well built, with marked improvements in the design of the delivery arm and chassis as compared to older systems. Several optional accessories are available such as control pedals and remote quality monitoring systems (though not required for quality water purification).
Although expensive, the Biocel system is a fairly good value considering the frequency of use and the quality/longevity of construction. It is important to investigate the cost of various components and providers to get the best deal on a new system (the system lists for $8000). For comparison, similar products with comparable prices are available from Barnstead, Labconco and Aquamax, but I feel that the Millipore system is the best. In addition to the Biocel system, Millipore also offers the Synthesis model which provides options such as a UV photo-oxidation system, however, for the vast majority of laboratory applications the Biocel should be sufficient.
Daniel J. Schwartz
Scientist
Gentel Biosurfaces, Inc.
Madison, WI