Ichiro Kano

Ultrapure water blank for boron trace analysis

Weakly charged elements, or elements that are not well dissociated in water, are not removed efficiently by conventional water-purification technologies. In the production of high-purity water, silica and boron are generally the first ions to breakthrough into purified water when the ion-exchange resin approaches depletion. In this study, the behavior of these two elements was studied through various steps in a water-purification chain. An optimized system configuration is proposed that combines reverse osmosis and electrodeionization technologies in the pre-treatment phase, and results in the efficient removal of boron. These initial purification steps produce high-resistivity water, presenting a low ionic challenge to ultrapure polishing resins. In addition, a specific chelating adsorbent enhances the retention capacity of boron. Typical values achieved for the most important parameters assessed while producing ultrapure water are described.

Impact of purified water quality on molecular biology experiments.

Abstract Purified water is a reagent used in a variety of molecular biology experiments, for sample and media preparation, in mobile phases of liquid chromatography techniques, and in rinsing steps. The combination of several technologies in water purification systems allows delivering high-purity water adapted to each application and technique. Through a series of examples, the importance of water quality on biotechnology experiments, such as single nucleotide polymorphism (SNP) analysis by denaturating HPLC, RNA preparation and PCR, is presented. Results obtained on DNA mutation and single nucleotide polymorphism analysis using the denaturating HPLC (DHPLC) technique highlight the benefits of organic removal by UV photooxidation process. Comparative gel electrophoresis data show that ultrafiltration is as efficient as diethylpyrocarbonate (DEPC) treatment for suppressing RNase activity in water. Gel electrophoresis and densitometry measurement also point out the benefits of ultrafiltration to carry out reverse transcriptase-polymerase chain reaction quantitatively.