How do the HACH Spectrophotometers work?
Spectrophotometers measure the amount of light that is passing through the sample at a given wavelength. Hach has prepared tests where the user combines a packet of chemicals with a sample that reacts with a specific parameter(Nitrate, Iron, Sulphate, etc.) that the research wants to measure. The reaction is designed so the sample will turn a darker color based on the amount of the parameter the sample contains. Therefore, the more of the parameter a sample contains, the less light that passes through the vial (see above picture). The company has done a series of tests to determine how much light passes through different concentrations of the parameter at given wavelengths and stored these values in a computer program. The light measurement of a sample is converted into the concentration reading that appears on the screen of the spectrophotometer using an equation saved in the instrument’s memory.
