Surface ionization mass spectrometry of organic compounds Part 4. Oxygen-containing organic compounds

Fujii, Toshihiro; Kakizaki, Koichi; Mitsutsuka, Yoshihiro

doi:10.1016/0168-1176(91)80004-7

Cited by 9 publications

(9 citation statements)

References 7 publications

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“…Another important difference relative to conventional MOX gas sensors is that SI gas detectors can, in principle, be realized using simple metal electrodes as ion emitters. In the early work on SI gas detection, both noble-metal and refractory-metal electrodes were investigated [1,2,3,4]. As refractory metals tend to get oxidized upon high-temperature operation in air, the actual ion emission in most cases is likely to have occurred from some sort of MOX material, which moves SI gas detectors somewhat closer to conventional MOX gas sensors.…”

Section: Surface Ionization: Principle Sensing Mechanismmentioning

confidence: 99%

“…Fuji et al [3,4] have studied surface ionization processes by applying mass spectroscopic analysis to the emitted ions. In this work, they found that surface ionization mainly proceeds through three different reaction channels:Direct ionization: → M + Dissociative ionization: → (M − H) + Associative ionization: → (M + H) + .…”

Section: Surface Ionization: Principle Sensing Mechanismmentioning

confidence: 99%

“…Surface ionization (SI) is a form of gas detection, which relies on the chemisorption of analyte molecules on heated solid surfaces and on the extraction of the formed analyte ions from the adsorbent surface towards an oppositely biased counter electrode. A very interesting feature of the SI process is that it is largely insensitive to small, high-ionization-energy molecules, like N 2 , O 2 , H 2 O, CO 2 , and methane, but very sensitive towards low-ionization-energy analytes, such as secondary and tertiary amines [1,2,3,4,5,6,7]. This kind of selectivity makes SI detection interesting for the detection of organic decay products, illicit drugs, and a range of other hazardous materials [8,9,10].…”

Section: Introductionmentioning

confidence: 99%

“…While much of the pioneering work on SI gas detection had been performed on macroscopic versions of noble and refractory metal ion emitters [1,2,3,4], more recent work concentrated on miniaturized kinds of SI devices, including MEMS and NEMS versions [11,12,13]. In these latter devices, different kinds of electrode arrangements were used to read out SI signals from noble-metal and metal oxide (MOX) emitters.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity-Selectivity Trade-Offs in Surface Ionization Gas Detection

et al. 2018

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Surface ionization (SI) provides a simple, sensitive, and selective method for the detection of high-proton affinity substances, such as organic decay products, medical and illicit drugs as well as a range of other hazardous materials. Tests on different kinds of SI sensors showed that the sensitivity and selectivity of such devices is not only dependent on the stoichiometry and nanomorphology of the emitter materials, but also on the shape of the electrode configurations that are used to read out the SI signals. Whereas, in parallel-plate capacitor devices, different kinds of emitter materials exhibit a high level of amine-selectivity, MEMS (micro-electro-mechanical-systems) and NEMS (nanowire) versions of SI sensors employing the same kinds of emitter materials provide significantly higher sensitivity, however, at the expense of a reduced chemical selectivity. In this paper, it is argued that such sensitivity-selectivity trade-offs arise from unselective physical ionization phenomena that occur in the high-field regions immediately adjacent to the surfaces of sharply curved MEMS (NEMS) emitter and collector electrodes.

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Section: Surface Ionization: Principle Sensing Mechanismmentioning

confidence: 99%

Section: Surface Ionization: Principle Sensing Mechanismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sensitivity-Selectivity Trade-Offs in Surface Ionization Gas Detection

et al. 2018

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“…A clue to the exceptional role of amine functional groups is provided by the work of Fuji [57,58], who found, using mass spectroscopic analysis, that surface ionization mainly proceeds through three reaction channels. In decreasing order of probability, these are:

Dissociative ionization: (M − H) + ;

Associative ionization: (M + H) + ;

Direct ionization: M + .

…”

Section: Metal-oxide-based Security Sensor Systemsmentioning

confidence: 99%

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

et al. 2016

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The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

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