Perkin Elmer Lambda 35 ES UV/VIS Spectrophotometer is one of the many quality analytical instruments that offers the best solution for QC/QA on liquids, solids, pastes, and powders. When a wide range of sampling options and large number of samples are required, these spectrop- hotometers deliver trustworthy results. True double-beam operation provides the best possible stability and allows references to be measured and corrected in real time. Sealed and quartz-coated high-throughput optics ensure consistent performance throughout the meter's service life. Very low stray light provides a wide dynamic range. Prealigned deuterium and tungsten halogen lamps allow easy replacement. According to the intensity, position and shape of the absorption peak in the UV spectrum of the unknown, it is possible to determine which groups are contained in the unknown molecule and to deduce the structure of the unknown.