Premium
Sensitivity improvement of circular dichroism detection in HPLC by using a low‐pass electronic noise filter: Application to the enantiomeric determination purity of a basic drug
Author(s) -
Lorin Marie,
Delepee Raphael,
Maurizot JeanClaude,
Ribet JeanPaul,
Morin Philippe
Publication year - 2007
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20352
Subject(s) - chemistry , enantiomer , chromatography , repeatability , detection limit , analytical chemistry (journal) , high performance liquid chromatography , resolution (logic) , calibration curve , circular dichroism , stereochemistry , artificial intelligence , computer science
The quality control of chiral drugs requires the determination of their enantiomeric purity. Nowadays, circular dichroism (CD) spectroscopy is gaining increasing importance in pharmaceutical analysis because of the commercially available CD detector in liquid chromatography. The separation of the two enantiomers of a basic drug (efaroxan) was achieved by high performance liquid chromatography using an amylose‐derivated column with both UV and CD detections. A baseline‐resolved separation (resolution: 5) was obtained after optimization of the mobile phase composition with hexane‐ethanol‐diethylamine (90:10:0.05; v/v/v). The use of a commercial low‐pass electronic noise filter of the CD signal has improved the signal‐to‐noise ratio by a factor twelve and allowed the quantitation of each enantiomer in the 1.25–300 μg ml − 1 concentration range. The CD linear calibration curve, expressed in terms of stereoisomer height ratio versus concentration ratio, was plotted over the 0.4–6% range. A correlation coefficient greater than 0.999 was obtained by least‐squares regression and the limit of detection for the distomer/eutomer ratio was estimated at 0.14%. Although the method validation showed good repeatability on the retention times (RSD < 0.9%), on the peak height ratios (RSD < 8.7%) of each enantiomer only up to 99.2% enantiomeric purity was achieved. Chirality, 2006. © 2006 Wiley‐Liss, Inc.