Abstract
7-Dehydrocholesterol is a biomarker of Smith-Lemli-Opitz syndrome, an autosomal recessive genetic disorder, caused by the inborn deficiency of 7-dehydrocholesterol reductase. In this study, procedures for its determination in artificial serum using flow injection analysis with electrochemical detection and voltammetric detection on boron doped diamond electrode were optimized.
The proteins were precipitated by acetonitrile and after centrifugation the supernatant used for analysis. For quantitation of 7-DHC by differential pulse voltammetry the optimal ratio acetonitrile-artificial serum 9:1 (v/v) was applied.
In FIA-ED, the ratio 3:1 (v/v), run electrolyte consisting of water-acetonitrile containing 0.01 mol L-1 NaClO in the same ratio 4 and detection potential of +1.3 V vs. Ag/AgCl (3 mol L-1 KCl) were used.
Quantitation of 7-DHC was possible using calibration depen- dence with limit detection of 20 μmol L-1 in artificial serum. Nevertheless, the method has low recovery and for sensitive determination in real matrices of human serum and amniotic fluid a liquid-liquid extraction needs to be applied to prevent presence of 7-dehydrocholesterol in the phase with precipitated proteins.