Application Notes
A Diagnostic Tool for Smith-Lemli-Opitz Syndrome
Capillary GC/FID used to separate cholesterol and precursor molecule in plasma to identify genetic defect.
A Diagnostic Tool for Smith-Lemli-Opitz Syndrome, Alltech Application Note #AN104, July 6, 2004.
Smith-Lemli-Opitz syndrome is a hereditary biochemical disorder in which a gene responsible for converting 7-dehydrocholesterol to cholesterol is defective. The resulting lack of cholesterol causes severe birth defects. An elevated level of 7-dehydrocholesterol in plasma is a biochemical marker for this syndrome. Thus, a rapid method for determining both compounds in human plasma would be a useful diagnostic tool.
Both cholesterol and 7-dehydrocholesterol (33µg/mL in chloroform extracted plasma) were separated without derivatization on an Alltech Heliflex® AT-1ms, 15m x 0.25mm x 0.25µm capillary column (Part No. 15880) isothermally at 305°C using helium carrier gas and a split inlet flow. Detection was by FID at a temperature of 325°C. The separation of both compounds took about 4 minutes.
Key Analyte(s)
7-dehydrocholesterol7-dehydrocholesterol is a cholesterol precursor that is a biochemical marker in blood plasma for the genetic defect Smith-Lemli-Optiz Syndrome. It is most often measured using GC/FID.
cholesterolCholesrerol is a steroid produced naturally and obtained from animals in the diet. Its level in the blood is associated with cardiovascular disease. It is most often measured using HPLC, GC/FID and GC/MS.
Equipment
Alltech Heliflex® AT-1ms Capillary ColumnsAlltech Heliflex® AT-1ms capillary columns are a line of high performance low bleed, highly inert, non-polar fused silica GC columns manufactured and sold by Alltech Associates. They are specifically designed for use with mass spectrometers.
Technique
GC/FIDIn GC/FID, the FID or flame ionization detector detects analytes by measuring an electrical current generated by electrons from burning carbon particles in the sample.
Source
Alltech Associates, Inc.Alltech Associates, Inc., one of the leading suppliers of HPLC columns, manufactures and distributes HPLC, GC and IC columns, accessories and consumables and maintains a large searchable database of application notes and chromatograms on its website.
