Halogenated compound response in an oxygen doped ion mobility detector for capillary gas chromatography

Baim, Michael A.; Hill, Herbert H.

doi:10.1002/jhrc.1240060102

Cited by 20 publications

(2 citation statements)

References 22 publications

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“…Investigations into the response characteristics of the IMD have shown it to be extremely sensitive to organic compounds. Minimum detectable amounts are typically in the low picogram range and detector response is exponential with weight nnjected over approximately 2 orders of magnitude (usually 1-100 pg) (14).…”

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Ion mobility detector for gas chromatography with a direct photoionization source

Baim¹,

Eatherton²,

Hill³

1983

Anal. Chem.

118

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An Ion moblllty detector (IMD) for gas chromatography has been modltled to accept the use of a photolonlratlon source. Photolonlratlon offers a number of advantages over the commonly employed 63Ni lloll lncludlng the lack of reactant Ions, which are seen with the secondary lonlratlon source, enabllng use of the entire Ion rnoblllty spectrum1 from 0 to 20 ms for observatlon of product Ions. Test compounds contlnuousiy bled Into the detector are used to compare pertormance of the standard ""I foll to that of a low-pressure 10.0-eV krypton photolonlration lamp. Due to uncompkated fragmentatlon patterns produced via photoloniratlon, the tunable selectlve capabllitles of the dettsctor are enhanced. Selectlve moblllty monltorlng Is used to detect toluene, mesitylene, and naphthalene In a mixture of aromatlc compounds of slmllar structure following Separation on a fused slllca capillary column.Ion mobility spectrometry (IMS) has long been recognized as a potentially useful technique for eelective detection of organic compounds after separation by gas chromatography (1-7). First introduced in 1970 by Cohen and Karasek (8,9), the ion mobility spectrometer consists of two basic units: a 63Ni foil in an ionization cell analogous to that found in an electron capture detector (ECD) and an atmospheric pressure ion drift tube maintained at either a positive or negative uniform electric field gradient of 150-250 V/cm. Ions produced in the ionization cell are accelerated down the electric field where they are separated according to their mobilities in a countercurrent flow of nitrogen pas. As discussed by Revercomb and Mason (IO), a number of factors including the mass, size, and charge of an ion determine its mobility at atmospheric pressure.The prime advantage of IMS as a GC detection method is that the instrument imay be easily tuned to monitor ions of a preselected mobility, thereby tailoring response characteristics to fit the needs of a given separation problem. Ion mobility spectrometry can often provide selective detection between compounds of the same elemental content but differing in structural composition. Despite these advantages, however, IMS has not enjoyed wide-scale popularity as a GC detection technique largely due to limited success a t interfacing the instrument with chromatographic columns.A new GC detector based on the principles of IMS has been developed in this laboratory specifically to eliminate many of the limitations preventing use with high-resolution separations (11). Known as the ion mobility detector (IMD), this instrument has been used to selectively detect a wide range of compounds including substituted naphthalenes in gasoline (11) and terpenes in orange extract (12) using the positive ion mode and 2,4-dichlorophenoxyacetic acid in soil extracts (13) using the negative ion mode. Investigations into the response characteristics of the IMD have shown it to be extremely sensitive to organic compounds. Minimum detectable amounts are typically in the low picogram range and detector response is expone...

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Ion mobility detector for gas chromatography with a direct photoionization source

Baim¹,

Eatherton²,

Hill³

1983

Anal. Chem.

118

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“…An important challenge facing law enforcement and military personnel is the ability to detect, correctly identify, and interdict the illegal possession of explosives intended to initiate terror and harm citizens, both nationally and internationally. Ion mobility spectrometry (IMS) is a proven technology for trace screening of explosive compounds in field settings (1–16). Some of the advantages with IMS include the following: low detection limits for single‐component samples (nanogram detection limits); fast analysis time (provides output data in seconds); no required sample pretreatment of solids or analytes in solution; operates at atmospheric pressure eliminating bulky vacuum systems, detects both positive and negative ions, which provides good selectivity; can be miniaturized and battery operated; and is comparably less expensive to purchase and operate than other trace detection technologies (1,2,4,5,10,17,18).…”

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Using Gas Chromatography with Ion Mobility Spectrometry to Resolve Explosive Compounds in the Presence of Interferents*

Cook

LaPuma

Hook

et al. 2010

Journal of Forensic Sciences

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Ion mobility spectrometry (IMS) is a valued field detection technology because of its speed and high sensitivity, but IMS cannot easily resolve analytes of interest within mixtures. Coupling gas chromatography (GC) to IMS adds a separation capability to resolve complex matrices. A GC-IONSCAN® operated in IMS and GC⁄ IMS modes was evaluated with combinations of five explosives and four interferents. In 100 explosive/interferent combinations, IMS yielded 21 false positives while GC⁄ IMS substantially reduced the occurrence of false positives to one. In addition, the results indicate that through redesign or modification of the preconcentrator there would be significant advantages to using GC⁄ IMS, such as enhancement of the linear dynamic range (LDR) in some situations. By balancing sensitivity with LDR, GC⁄ IMS could prove to be a very advantageous tool when addressing real world complex mixture situations.

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Electron capture ion mobility spectrometry for the selective detection of chlorinated and brominated species after capillary gas chromatography

Louis

Hill

1990

J. High Resol. Chromatogr.

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This paper reports the first investigation of electron capture ion mobility spectrometry as a detection method for capillary gas chromatography. In previous work with negative ion mobility detection after gas chromatography, the principal reactant ion species were 02-or hydrated 02due to the presence of oxygen in the drift gas.These molecular reactant ions have a mobility similar to chloride and bromide ions, which are the principal product ions formed by most halogenated organics via dissociative ion-molecule reactions. Oxygenated reactant ions thus interfere with the selective detection of chloride and bromide product ions. A recently described ion mobility detector design efficiently eliminated ambient impurities, including oxygen, from infiltrating the ionization region of the detector; consequently, in the negative mode of operation, the ionization species with N2 drift gas were thermalized electrons.Therma1ized electrons have a high mobility and their drifl time occupies a region of the ion mobility spectrum not occupied by chloride, bromide, or other product ions. The result was improved selectivity for halogenated organics which ionize by dissociative electron capture.This was demonstrated by the selective detection of 4,4'-dibromobiphenyl from the components of a polychlorinated biphenyl mixture (Aroclor 1248).

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Halogenated compound response in an oxygen doped ion mobility detector for capillary gas chromatography

Cited by 20 publications

References 22 publications

Ion mobility detector for gas chromatography with a direct photoionization source

Ion mobility detector for gas chromatography with a direct photoionization source

Using Gas Chromatography with Ion Mobility Spectrometry to Resolve Explosive Compounds in the Presence of Interferents*

Electron capture ion mobility spectrometry for the selective detection of chlorinated and brominated species after capillary gas chromatography

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