Spectrophotometer Diagram can be described as follows:
|Figure 1: Spectrophotometer Diagram|
Description of spectrophotometer above:
1 = Radiation sources
2 = Monochromator
3 = Sample / cuvette
4 = Detector
5 = Amplifier and Recorder
- Radiation sources
Some sources of radiation are often used in the spectrophotometer are: incandescent lamp with tungsten filament, hydrogen (deuterium) lamp, tungsten lamp, mercury lamp. Characteristics of energy that is emitted by each lamp varies whose function is to emit a radiation light that penetrates the sample that can later be read by recorder in which the source of the light radiation will pass through monochromator.
Sources of light is emitted from radiation source is focused onto entrance gap and then it is collected by gap or mirror and it is focused onto outer gap pass to the sample. The function of this monochromator is to obtain monochromatic radiation and then alter or transmit into polychromatic radiation.
- Samples / cuvette
Most spectrophotometers involve solution so it requires a container / cuvette for placing the liquid / solution. Cuvette that is used should emit radiant energy in the spectral region. Reviewed from the used materials, there are 2 (two) types to make cuvette, namely: cuvette made from fused silica and cuvette made from glass. Cuvette from fused silica can be used for qualitative and quantitative analysis on measurement of 190-1100 nm region, and cuvette from glass can be used for in measurement of 380-1100 nm because of glass material can absorb light radiation.
After passing through sample, light radiation is received by the detector. Detector is one of important spectrophotometer parts so the selected detector must have high sensitivity to received radiation, has ability to respond radiation at wavelengths in unison. The function of detector in spectrophotometer is transforms received radiation signals into electronic signals. Received signal is then passed through an amplifier and finally accepted by the reader (recorder).
- Amplifier and Recorder
Various tools can be used for reading generated signal by detector, including a calibrated meter to transmission or absorbance, digital readout systems, x-y recorder and computerized system.