p/ace™ mdq detectors - Beckman Coulter

CE APPLICATION KITSC HIRALA NALYSISSince the chemical properties of enantiomers are identical, typical measurements and separation techniques cannot be usedto distinguish one from the other. The key to separating enantiomers is to first create diastereomers from the enantiomers.Diastereomers may be created through chemical derivatization with a “chiral” reagent, or they may be formed transiently throughinteractions with chiral selectors. The latter is usually the most desirable as it is the easiest to employ.Capillary electrophoresis has proven the most ideal analytical tool for this purpose, as it is simple to construct and modify a chiralenvironment within a capillary. The use of cyclodextrins for differential host-guest complexation of enantiomers is by far the mostcommon chiral selector and is the basis of the chiral separation strategy that we propose. Beckman Coulter’s primary strategyfocuses on the use of highly sulfated cyclodextrins (HSCDs) which are a family of three chiral reagents. This strategy first involvesscreening the compound for separation using all three (α, β, and γ) HSCDs and then optimizing on the reagent which yields thebest resolution. This initial screen involves the use of a single method and has been successful in greater than 90% of thecompounds that Beckman Coulter has analyzed.P RIMARYS TRATEGYPrimary Screen• 50 µm bare fused silica Capillary– 20 cm to Detector• Polarity – anode at detector• Detection – 200 nm• Buffer – 50 nM phosphate pH. 2.5• Selector – α, β and γ HSCD• 15 kV constant voltageYESDid youachieveResolution?NOUse CDwhich gavebestresolution andvaryconcentrationYESDecrease[HSCD}to 2%Did peakshapebroadenNOIncreaseHSCD to10% and tryall 3 HSCD’sFurtheroptimizetemperaturecolumnlength, fieldstrengthYESOptimizeFine-tune HSCDconcentrationTemperatureResolution?NOGo toSecondaryStrategyResolution?YESNOGo toSecondaryStrategyCapillary LengthField StrengthBeckman CoulterContentsIndex23