How Spectrophotometer Standards Work

The need to verify that an instrument is performing properly and is in calibration is becoming increasingly common for regulatory committees and internal QC procedures. 

By GFS Chemicals

Problem: The need to verify that an instrument is performing properly and is in calibration is becoming increasingly common for regulatory committees and internal QC procedures. This is particularly true when using UV/Vis spectrophotometers. These instruments can slowly drift out of spec as the lamp ages. In order to know that the data you are collecting is accurate, it is vital to verify the instrument’s performance.

Solution: By using a NIST-traceable standard, you can verify that an instrument is in fact performing as it should. This provides validity to the data that is collected using the instrument.

Many of the solutions that are available are either costly, toxic or not flexible and can’t meet your exact specifications. GFS Chemicals has the ability, with its In-Spec® Standards, to find a solution that will better fit your requirements.

GFS Chemical’s In-Spec product line has a broad range of solutions. For photometric accuracy, there are the In-Spec standards, which can be used from 200-900 nm. These standards are very easy to use since they are non-toxic, come completely premade with no dilutions or mixing required, and do not require special disposal procedures when you are finished using them. GFS Chemicals offers a broad range of absorbance values to match your tests, or custom values are available.

To use the In-Spec standards you would first baseline the instrument with the supplied Background Solution, then run the standard. You would compare the values obtainedon your instrument to the values listed on the Certificate of Analysis. If the values are within the greater of 5%, or +/- 0.004 added to your instrument’s stated accuracy, thenyour instrument is performing well.

GFS Chemicals also offers other standards that can be utilized to validate other aspects of an instrument’s performance. Wavelength, stray light and resolution filters are available. Together with the In-Spec photometric standards, these can be used to check the overall health of your spectrophotometer.

The In-Spec product line also has a solution designed specifically for the increasingly popular short pathlength (1 mm) instruments. The In-Spec Nano-Kit consists of two standards to check the absorbance values at 260, 280 and 320 nm. These wavelengths are the most common for DNA/RNA quantification tests. The kit comes with data for those wavelengths at a 1 mm pathlength.

When properly used and documented, a secondary, NIST-traceable standard can provide you with security and peace of mind in knowing that the data you collect with your instrument is in fact accurate.

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Categories: How it Works

Published In

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Published: November 1, 2008

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