Every compound will absorb or transmit light over a certain range of wavelengths, and so the this can be used to measure the amount of a known chemical substance.
Most molecules will absorb radiation in the ultraviolet and visible range of the spectrum. Light is used in the UV range (185-400nm) and visible range (400-700nm). Radiation of a specific frequency will be passed through a cuvette containing a liquid sample and the amount of radiation measured on the other side of the cuvette is used to identify the sample.
Water is typically used in sample preparation or in blanks, as well as washing of the cuvettes. To ensure that there are no erroneous results, it is important that the water is free from contaminants which may interfere with the radiation by absorbing and scattering incoming radiation. Type II water is suitable for spectrophotometry.
Make sure that you are using the right water type for your application. Here are the requirements for spectrophotometry applications.
|Sensitivity required||Resistivity |
|Bacteria (CFU/ml)||Endotoxins (EU/ml)||Nucleases||Water grade|