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Technology without sacrificing their ability to ensure water quality. Real-Time Analysis Of Multiple Compounds With A Single Instrument By analyzing multiple wavelengths or perhaps the full spec- tral absorbance of the water, a single spectrophotometric instrument can provide detection of multiple chemical com- pounds in the water, thereby reducing upfront costs and long-term maintenance requirements, and reagents are often not required. Often for less than the cost of a lab spectro- photometer, a real-time spectrophotometric instrument can provide immediate detection in real-time of multiple con- taminants. For example, until relatively recently, a plant that needed to measure both nitrates and organics at one location in real time has had to purchase a nitrate monitor and an organic monitor, whereas it is now becoming commonplace to purchase a real-time spectrum analyzer for less cost than just the nitrate analyzer alone. The Right Spectrophotometric Instrument For The Application Once it has been determined that real-time spectrophotometric analysis can improve the efficiency of a given process, the right instrument must be chosen for that application. The latest generation of real-time spectrum analyzers now comes in several varieties. The price point for a spectrum analyzer can vary widely, primarily due to the technology, light source, path length, options and features desired, and the water quality range of testing required. The light source and wavelength range of spectrum analyzers is an important consideration. Importance Of The Technology Inside Spectrophotometric instrumentation measures light within the UV and/or visible light range. To be able to do this in real time on a continuous basis, these analyzers must provide some accommodations or compensation mechanism for dealing with the drift and fluctuations of the system's light source and sensor. There are several technologies being implemented in spectrophotometric analyzers and all have varying degrees of effectiveness. The success of the technology utilized in the analyzer will greatly impact the accuracy, reliability, maintenance, and cost of the system. Most analyzers on the market today have chosen the traditional dual beam principal for compensation, which requires additional optics increasing expense while often adding even more potential for inaccuracy. New technologies are now on the market that provide compensation for the inherent challenges associated with spectrophotometric instrumentation in a more simple and effective manner. These new technologies are creating solutions at price points unmatched by other analyzers while improving performance. Light Source Customization The light source and wavelength range of spectrum analyzers are another important consideration. Deuterium light sources, which are the kind most 14 Water Online The Magazine, Cleanwater Edition ■ wateronline.com