Preservatives real-time monitoring

It would be difficult to underestimate the importance of the analysis of waters. It has long been recognized that the use of water for human consumption depended on its purity. More recently environmental considerations have led to recognition of the importance of water purity in preservation of the aquatic environment and food chains within it. Over the past few decades the importance of water quality has come to be appreciated in all of the applications to which water is put. The analyses that are required to ensure that the water is of the correct quality are numerous and legislative standards are in place for many of these analyses. Ion-selective electrodes play two kinds of role in water analysis, the first in those cases where the ion-selective electrode method is the most analytically suitable and the second where the ion-selective electrode is the most appropriate because of the dynamic real-time analytical capability of the ion-selective electrode which allows continuous monitoring of the water. 

An atomic or molecular beam of Ga, As, Al, and/or other elements is created thermally in a ultrahigh-vacuum chamber and directed at a specific, well-defined, atomically flat facet of a single-crystal substrate. A very low deposition rate, associated with a precisely controlled substrate temperature and various real-time techniques for monitoring the state of the surface, permit one to find growth conditions that preserve a coherent crystalline order or minimize the density of structural... 

---