Quantitative Analysis of Allantoin

The allantoin content was measured with a method described previously [41 (link)] with some further modification [24 (link)]. An Agilent 7100 Capillary Electrohoresis set coupled with a diode-array detector (UV-Vis/DAD, 190–600 nm; Agilent Technologies, Santa Clara, CA, USA) was used for separation and determination of allantoin. The analysis was carried out in fused silica 50 µm i.d., capillaries with a total length of 64.5 cm. The background electrolyte with pH 9.2 consisted of a 50 mM borate solution. The quantitative analysis of allantoin was performed at λ = 192 nm. Allantoin was identified based on comparison of the retention time and absorption spectrum similarity in a 190–400 nm range with allantoin standards purchased in Sigma-Aldrich (St. Louis, MO, USA).