Progress in circular dichroism laser mass spectrometry

• Published in: Analytical and bioanalytical chemistry Vol. 395; no. 6; pp. 1631 - 1639
• Main Authors: Logé, Christoph, Bornschlegl, Alexander, Boesl, Ulrich
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.11.2009; Springer-Verlag
• Subjects: Analytical Chemistry; Biochemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Circular Dichroism - instrumentation; Circular Dichroism - methods; circular dichroism spectroscopy; Cyclopentanes - chemistry; Dichroism; energy; Food Science; ionization; Ions - chemistry; Laboratory Medicine; Lasers; Limit of Detection; mass spectrometry; Mass Spectrometry - instrumentation; Mass Spectrometry - methods; Mathematical analysis; mixtures; Monitoring/Environmental Analysis; Original Paper; quantitative analysis; Repetition; Samples; Statistical analysis; Statistical methods; Wavelengths; Enantiosensitive ionization; Laser mass spectrometry; Multiphoton ionization; Chiral ketones; Circular dichroism
• ISSN: 1618-2642; 1618-2650; 1618-2650
• DOI: 10.1007/s00216-009-2956-9

Circular dichroism in ion yield has promising new potentials for chiral analysis. Our progress of its development is described here. Circular dichroism in ion yield is achieved by resonance-enhanced multiphoton ionization. The feasibility of circular dichroism spectroscopy and quantitative determination of circular dichroism by this method is demonstrated. Several excitation schemes have been applied using different types of lasers, which vary in wavelength and repetition rate. Progress to improve the statistical error and thus the lower limit of measurable circular dichroism is described. This is achieved by adding achiral compounds or racemic mixtures of chiral compounds to the sample gas as reference substances and ionizing them by the same laser pulse. Therefore, in the mass spectrum of every single laser pulse, ion signals of sample and reference species appear both being subject to the same kind of instrumental fluctuations (in particular of laser pulse energy). In another approach, a laser repetition rate of 200 Hz allowed averaging of large numbers of laser pulses. [graphic removed]