Spectrophotometer calibration is a process in which a scientific instrument known as a spectrophotometer is calibrated to confirm that it is working properly. This is important, as it ensures that the measurements obtained with the instrument are accurate. The procedure varies slightly for different instruments, with most manufacturers providing a detailed calibration guide in the owner's manual so that people know how to calibrate the equipment properly. When this process is performed, the person doing it must make a note in the log attached to the equipment and in their experimental notes, so that people know when the device was last calibrated and handled, and by whom.
A spectrophotometer is capable of both transmitting and receiving light. The device is used to analyze samples of test material by passing light through the sample and reading the intensity of the wavelengths. Different samples impact the light in different ways, allowing a researcher or technician to learn more about the materials in the test sample by seeing how the light behaves as it passes through the sample. Spectrophotometer calibration is necessary to confirm that the results are accurate.
In spectrophotometer calibration, a reference solution is used to zero out the equipment. This solution provides a base or zero reading. The device is calibrated by placing the reference solution inside the spectrophotometer, zeroing out the settings, and running the instrument. Then, samples of an actual test material can be subjected to spectrophotometry in confidence that the machine has been calibrated and is working properly.
In a single beam spectrophotometer, a single beam of light is generated, and the device must be recalibrated for each use. In a double beam spectrophotometer, beams can be sent through a test sample and a reference sample at the same time to generate two sets of results which can be used for reference and calibration. In either case, spectrophotometer calibration can be done in the lab by someone working with the machine. If the machine develops serious problems, it may be sent to the manufacturer for maintenance, repair, and potential replacement.
In order for a spectrophotometer to work properly, it must be allowed to warm up before use. Many devices take around 10 minutes to warm up. It is important to avoid performing spectrophotometer calibration during the warmup phase as this will throw the settings off. It is also important to be aware that for certain types of wavelengths, special filters and attachments may be needed for the device to function.