Caffeine intake by pregnant women, adults and children can be harmful to
the health of all particularly fetuses if the intake exceeds the permissible
limits. Therefore, it is of fundamental importance to measure its concentration
accurately using certified reference materials (CRMs). In the literature, no
scientific details are published about the certification of caffeine standard
solutions, and therefore, the present article covers this gap. A batch of
caffeine solution was prepared in concentration of 1000 mg/kg and bottled.
Homogeneity and stability of the candidate reference material were assessed by HPLC-UV and the results showed that the material is
homogenous and stable enough. Characterization of the caffeine reference
material was performed by HPLC-UV, LC-MS/MS and UV-VIS-NIR spectrophotometer in
three different days and the characterization uncertainty was estimated in
accordance with the requirements of ISO GUM. The certified value (999.86 ± 8.54 mg/kg)
was derived as a weighted mean from the gravimetry and the three
characterization methods and the certified uncertainty was calculated according
to ISO Guide 35. The produced CRM is of strong interest to the food and drug
analytical laboratories for the validity and credibility of their caffeine
measurement results.
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