Calibration of Spectrophotometers and Basic Information

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Many research, biology, chemistry, and industrial laboratories have spectrophotometers. Spectrophotometers are utilized in a variety of scientific domains for data processing and study. Physics, molecular biology, chemistry, and biochemistry labs are just a few fields where a spectrophotometer is utilized. This moniker commonly refers to atomic absorption spectroscopy basics.

A spectrophotometer is a device that transmits and receives light. By sending light through the sample and measuring the intensity of the wavelengths, the spectrophotometer is used to examine test material samples. Various samples alter the behavior of light in various ways, allowing researchers to learn more about the test material by observing the changes in light behavior as it passes through the sample. These results must be correct; otherwise, the researcher will be squandering time by relying on a faulty instrument. Calibration of the spectrophotometer is the only way to ensure accuracy.

What Is Calibration of a Spectrophotometer?

A researcher or scientist calibrates a spectrophotometer using a calibration standard to check the light source’s accuracy. This step is important to confirm that the spectrophotometer is operating properly and that the measurements are accurate. It’s also vital to keep a calibration log to show when and who did the last calibration. For each device, the calibration technique differs differently. In the owner’s manual, most major manufacturers include a detailed calibration guide so that researchers can properly calibrate their equipment.

Spectrophotometer Calibration Tools

Spectrophotometer calibration filters, also known as neutral density filters, are generated from NIST and calibrate various transmittance values (National Institute of Standards and Technology). SRM 2031, 2034, NIST930e, and others are examples of NIST standards. Researchers should send their spectrophotometers in to be calibrated, according to some spectrophotometer manufacturers. The issue with sending the equipment in is the expense of research time, transportation charges, and other external factors. Without sending the spectrophotometer out of the lab, it is best and most convenient to calibrate it.

Calibration of a Spectrophotometer with Neutral Density Filters

Liquid calibration standards have been used for decades. Solid-state filters began to replace liquid filters in 2010 due to their capacity never needing re-calibrated or replaced. Solid neutral density filters are very simple to handle and will not break if dropped or handled incorrectly. The neutral density filters used in solid-state spectrophotometer calibration can be used to check for photometric accuracy and stray light. A minimum of five test points is used to achieve 100 percent accuracy.


A spectrophotometer must be allowed to warm up before calibration and usage to ensure accurate results. Calibration of spectrophotometers should not be performed while the machines are warming up. If the spectrophotometer is calibrated during the warming period, the settings will be thrown off. You can learn more about atomic absorption spectroscopy basics by visiting any official spectrophotometer site.

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