The extraction of creatinine from a physiological medium by a microporous solid and its quantification by diffuse reflectance UV spectroscopy

Diffuse reflectance UV (DR-UV) spectroscopy was used for the first time to quantity the amount of creatinine adsorbed onto mordenite type zeolite from two different media: Phosphate Buffered Saline solution (D-PBS) and D-PBS solution containing albumin at a concentration corresponding to human serum conditions (50 g/L). The UV spectra of creatinine adsorbed onto mordenite zeolites was quantitatively treated using the Kubelka-Munk formalism. Quantification by diffuse reflectance UV spectroscopy after microporous solids extraction was linearly correlated with creatinine concentration whatever the medium. This study evidences that DR-UV spectroscopy may be an efficient method to directly quantify the amount of chosen molecules present in a liquid medium by pre-concentrating them on a specific solid adsorbent like in the solid phase extraction (SPE) procedure. The results on hand also prove that this is even possible in rather complex conditions. The method is simple, fast, and with a low detection threshold. (C) 2009 Elsevier Inc. All rights reserved.