Application of Hadamard transform to gas chromatography/nonresonant multiphoton ionization/time-of-flight mass spectrometry

✍ Scribed by Chao-Chiang Cheng; Hung-Wei Chang; Tomohiro Uchimura; Totaro Imasaka; Takashi Kaneta; Cheng-Huang Lin

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 310 KB
• Volume: 33
• Category: Article
• ISSN: 1615-9306
• DOI: 10.1002/jssc.200900662

✦ Synopsis

Abstract

The technique of Hadamard transform was successfully coupled with GC/nonresonant multiphoton ionization/TOFMS, for the first time. 1,4‐Dichlorobenzene and the fourth harmonic generation (266 nm) of a Nd:YAG laser were employed as a model sample and an ionization laser, respectively. A Hadamard‐injector coupled with a capillary‐based supersonic jet nozzle (capillary‐injector) was also developed in this study. The Hadamard‐injector was used to obtain the chromatogram, which was encoded by successive sample introduction based on Hadamard codes, and the capillary‐injector was used for injection of GC‐elutes into TOFMS. Compared with a conventional single injection method, the S/N ratios were substantially improved after inverse Hadamard transformation of the encoded chromatogram. Under optimized conditions, when Hadamard matrices of 103 and 255 were used, the S/N ratios of the signals for 1,4‐dichlorobenzene (concentration level, 4 μg/1 mL ACN) were substantially improved to 4.1‐ and 6.6‐fold, respectively, and those improvements are in good agreement with those obtained by theory (5.1‐ and 8.0‐fold).