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Stheno 1000-or magneto-optical enatiomeric detection
Stheno 1000-OR Magneto-Optical Enatiomeric Detection
MOPED Chiral purity is a key factor in the efficacy of many agrochemicals, flavor & fragrance ingredients, and pharmaceuticals. Hence, the production of single enantiomers of chiral intermediates and final products has become increasingly important over the last several decades. However, the detection of these chiral analytes remains a daunting challenge especially in cases where a convenient UV chromophore is not present. While some progress in laser-based polarimetry and Circular Dichroism HPLC detectors has been achieved in the past decade, the current demands for rapid detection of enantiomeric purity on small volume and low concentration samples remains largely unresolved.
To address these acute industry needs for novel chiral detection technologies, we have developed a next-generation chiral analysis instrument that is suitable for non-contact, rapid, accurate, and highly sensitive screening of chiral samples. This instrument utilizes several experimentally simple, but scientifically sophisticated, techniques from "state of the art" optics research first developed for nonlinear optical spectroscopy, but which is now applied to simple polarimetry. The method transforms the detection of optical rotation into a dual-beam double-modulation technique that utilizes the advantages of differential signals, heterodyne mixing, direct modulation of the sample Verdet constant via the Faraday effect, electronic noise cancellation, and phase sensitive detection for additional noise rejection and enantiomer identification.
We call this set of techniques and the resulting system Magneto-Optical Enantiomeric Detection (MOPED ).
MOPED 1000-OR: Stheno s Answer to Real-Time LC Chiral Detection Stheno s initial device is a bench top, inline detector designed to monitor the output from a high pressure liquid chromatography unit. Currently, most manufacturers do not have the technology available for real-time measurement of chiral liquid reagents and chiral products. The MOPED 1000-OR has the following unique attributes that give the device tremendous utility:
an order of magnitude increase in sensitivity over current state-of-the-art chiroptical detectors;
active baseline stabilization that results in extremely stable baseline for unattended operation;
detects and analyzes compounds in real-time using a non-contact inline method.
The current flow cell volume is 40 l and the current flow rate range is 0.1 mL/min to 5 mL/min, but adaptation for flow rates up to 2 L/min are under development.
The MOPED instrument has been configured for inline analysis of liquid samples and would typically be located downstream of an HPLC for analytical applications involving separation or flow injection analysis of target compounds. However, the instrument can also be utilized for process monitoring as the non-contact nature of the flow cell allows online monitoring of process conditions involving chiral substrates or products.
The following is a partial listing of MOPED 1000-OR chiral measurement applications:
achiral stationary phase HPLC separations monitoring for optical activity
chiral stationary phase HPLC separations monitoring for chiral signature
gradient method HPLC separation monitoring
online process monitoring for wide dynamic range applications (i.e. high concentrations)
HPLC/MS chiral signature determination
Species identification for analytes lacking accessible chromophore
The following traces show examples of both chiral and non-chiral samples along with ideal and actual detector responses. The chromomatographic examples utilize an isocratic separation with a Agilent 1100 system utilizing a reverse phase C8 column (Zorbax SB-C8) under the following conditions: 85% 0.1 vol% phosphoric acid + 15% acetonitrile, 60 C, and 2 ml/min. The following traces show examples of 10 ml injections of a test mixture including mandelic acid, phenylethanol, and acetophenone at a concentration of ~1 mg/ml for each species.
Ideal optical activity response
+Mandelic acid (chiral), +Phenylethanol (chiral), and Acetophenone (non-chiral)
