Voltammetry of 7-dehydrocholesterol as a new and useful tool for Smith-Lemli-Opitz syndrome diagnosis

This study shows for the first time that electrochemical oxidation of 7-dehydrocholesterol can be used for its voltammetric determination. Two classes of supporting electrolytes in acetonitrile and a mixture of acetonitrile-water were used: inorganic acids known to promote structural changes of steroids and indifferent electrolytes. Oxidation of 7-dehydrocholesterol at ca +0.8 V (vs. Ag/AgNO3 in acetonitrile) in 0.1 mol L-1 NaClO4 in acetonitrile is useful for its voltammetric detection using common bare electrode materials. Detection limits for 7-dehydrocholesterol lie in the low micromolar range for all the working electrodes, including boron-doped diamond (0.4 μmol L-1) and disposable thin-film platinum electrodes (0.5 μmol L-1), which are advantageous because of the low volumes of studied solutions. After Bligh-Dyer extraction, quantification of 7-dehydrocholesterol concentration (boron-doped diamond) or concentration range (thin-film platinum) is easily attainable in artificial serum. The mere knowledge of the concentration range provides clinically valuable information, as 7-dehydrocholesterol levels are employed for SLOS diagnosis as a binary criterion (elevated, tens to hundreds μmol L-1 in symptomatic/non-elevated, typically bellow 1 μmol L-1 in healthy individuals in plasma). Moreover, it is shown that 7-dehydrocholesterol (provitamin D3) and cholecalciferol (vitamin D3) can be oxidized in 0.1 mol L-1 HClO4 in acetonitrile. Under these conditions, their voltamme...
Source: Talanta - Category: Chemistry Authors: Source Type: research