Spectrophotometer

Spectrophotometer is a lab equipment which used to measure light absorbance of a given sample with respect to different wave lengths.







Theory of operation.
Spectrophotometer consist of major five parts as shown bellow.

1. Light source used to generate light. They normally use a halogen bulb and deuterium lamp.
2. Collimator used to provide a focused sharp beam of light to the monochromator. Normally it would be a lens.
3. monocromator used to isolate the desired wave lengths. Normally it would be a prism or grating.
4. Sample compartment used to place liquid sample. normally the sample pore in to a container called Corvette  and place in the compartment.
5. Detector used to detect light intensity. Normally detector would be a photo-diode.
6. 

Safety.

1. In advanced machines used UV light so care must be taken to protect eyes.
2. electrical hazard when open.
3. Halogen, deuterium bulbs bulb are very hot while operate.

Planed Preventive Maintenance (PPM)

These are common things have to be considered on PPM but some mandatory things may include in manufacturer's service manual, they depend on the manufacturer and can't predefine for each and every production. 

1. Lifetime of halogen/deuterium bulbs must be check. Before end of lifetime better to replace with new one. Halogen bulbs should not touch with bare fingers and must fallow up given instruction by the manufacturer.
2. To achieve better performances light paths must be clean. Therefore keep free the light path without contamination and dust particles.
3. If any error accumulated with final readings you can clean the light path from bulb to detector with mild soap water. Don't use any kind of chemical if not recommended by products manufacture. prism, sample compartment,optical lenses are very sensitive devices if chemical deterioration happened it may caused errors to final readings.