Help on: Use of Caffeine for Wavelength Accuracy

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Question:
“Can you tell me why caffeine is used for the calibration of HPLC systems? I know it shows two maxima (205 nm & 272nm) & minima at245, apart from this property why is it used?”

Answer:
“The main reason that caffeine is used for the wavelength accuracy test is as you have already identified, it contains chromophores which absorb at the wavelengths you have quoted. Other reasons are that it is easily available and relatively safe to handle, this makes it an ideal choice for this test. In addition organisations which certify calibration standards, such as NIST in America, specify the use of caffeine for the test and thus the calibration can be performed in a NIST-traceable manner.”