Development of ambient sampling chemi/chemical ion source with dielectric barrier discharge

• Published in: Journal of mass spectrometry. 2010-08, Vol.45 (8), p.861-869
• Main Authors: Chen, Lee Chuin, Yu, Zhan, Furuya, Hiroko, Hashimoto, Yutaka, Takekawa, Kenichi, Suzuki, Hiroaki, Ariyada, Osamu, Hiraoka, Kenzo
• Format: Article
• Language: English
• Subjects: Air conditioning; ambient sampling; Analysis; Applied sciences; Aroma and flavouring agent industries; Biological and medical sciences; Chemical industry and chemicals; chemical ionization; Chemistry; Dielectric barrier discharge; Electrodes; Exact sciences and technology; Food industries; Fundamental and applied biological sciences. Psychology; General pharmacology; HMTD explosive; Industrial chemicals; Ingredients; Ion sources; Ionization; Ionization chambers; Mass spectrometry; Medical sciences; Organic chemistry; Penning ionization; Pharmacology. Drug treatments; Powders, propellants, explosives; Reactivity and mechanisms; Sampling
• ISSN: 1076-5174; 1096-9888; 1096-9888
• DOI: 10.1002/jms.1772

The development of a new configuration of chemical ionization (CI)-based ion source is presented. The ambient air containing the gaseous sample is sniffed into an enclosed ionization chamber which is of sub-ambient pressure, and is subsequently mixed with metastable species in front of the ion inlet of the mass spectrometer. Metastable helium atoms (He*) are used in this study as the primary ionizing agents and are generated from a dielectric barrier discharge (DBD) source. The DBD is powered by an AC high-voltage supply and the configuration of the electrodes is in such a way that the generated plasma is confined within the discharge tube and is not extended into the ionization chamber. The construction of the ion source is simple, and volatile compounds released from the bulky sample can also be analyzed directly by approaching the sample to the sampling nozzle. When combined with heated nitrogen or other desorption methods, its application can also be extended to non-volatile compounds, and the consumption for helium can be kept minimum solely for maintaining the stable discharge and gas phase ionization. Applications to non-proximate sample analysis, direct determination of active ingredients in drug tablets and the detection of trace explosive such as hexamethylene triperoxide diamine are demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.