The spectrophotometer, also known as a spectrometer, is a scientific instrument that decomposes complex light into spectral lines. Spectrophotometer has become a routine instrument in modern molecular biology laboratories, and is often used for protein quantification and bacterial growth concentration quantification.

The following aspects need to be considered when selecting a lab spectrophotometer:

1. Wavelength detection range, wavelength selection method

Users need to choose the appropriate wavelength range according to their needs. The wavelength selection methods generally include manual search, automatic search or scan in setting mode.

2. Beam

The beam type is divided into single-beam type, double-beam type or quasi-double-beam type.

3. Light source

Tungsten lamps are mainly used in the visible light region, hydrogen lamps and deuterium lamps are mainly used in the ultraviolet region, and xenon lamps can be used as light sources in both ultraviolet and visible light regions.

4. Slit

The slit of simple instrument is usually a fixed width die. And the continuously adjustable slit can meet the needs of high resolution.

5. Optical performance indicators

The level of optical performance directly affects the accuracy of measurement, and the technical index of the grating is particularly important.

6. Detector

Usually photosensitive diodes, silicon photodiodes or high-sensitivity photomultiplier tubes and infrared detectors are used.

7. Measurement mode

Simple instruments mostly use fixed-point (fixed wavelength) absorbance or transmittance measurement methods, and mid-range instruments have more measurement modes, which can display transmittance, absorbance, direct reading of concentration, single beam, single point and scanning.

8. Measuring accessories

An important aspect to measure the quality of an instrument is to see whether it has a wealth of auxiliary measuring devices.

9. State of the sample

Visible and ultraviolet spectrophotometers generally measure liquid samples, and infrared spectrophotometers generally analyze samples in various states (gas, liquid, solid).