Smiths Detection-watford Limited

Henry McIntyre

Stephen John Taylor

Alastair Clark

Bruce Grant

Paul Douglas Arnold

Paul Grant Wynn

Matt Easton

Neal Thathapudi

The present application is directed to a process for calibrating a detection apparatus, especially an ion mobility spectrometer, using isoflurane (CAS Reg. No. 26675-46-7) as a chemical standard whereby calibrating the detection apparatus for a known target chemical is based on an evaluation of the experimental data collected for the negative isoflurane monomer ion against the experimental data collected for the negative isoflurane dimer ion.

Chemical calibration process, system and device

Systems and techniques for cleaning a corona discharge point are described. A controller () can be operatively coupled to a corona discharge point () to control the operation of the corona discharge point (. The controller () and the corona discharge point () can be included with, for example, an ion mobility spectrometry (IMS) system (). The controller () can be used to operate the corona discharge point () at an operating voltage for a first time interval, with or without an additional higher pulse voltage, to produce a corona discharge, and to operate the corona discharge point () at a cleaning voltage greater than the operating voltage for a second time interval subsequent to the first time interval to produce a corona discharge. The effectiveness of the corona discharge point () can be monitored by, for instance, measuring a voltage necessary to produce a corona discharge at the corona discharge point (), measuring a current produced at the corona discharge point () from a corona discharge, and so forth.

Cleaning of corona discharge ion source

An ion mobility spectrometer has a drift chamber () with an inlet () at one end by which a gas or vapor being analyzed is supplied to the chamber. After ionization, molecules are admitted through a gateand flow along a drift region () to a collector plate (). A drift gas is flowed through the drift region against the flow of ionized molecules and is circulated along a flow path () and (), which includes a chamber () including a dopant. The dopant is 2,4-pentanedione, which has been found to enhance the detection of a number of compounds especially toxic industrial chemicals and nitrogen compounds, such as those present in the breath of mammals.

Detection systems and dopants

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Watford, United Kingdom

Henry McIntyre