Editorial – Detection for Security

The detection of chemical, biological, radiological and explosive (CBR & E) material that can be used to harm poses analytical challenges which are exceptional both in quantitative and qualitative terms. There are certainly similarities with detection needs in other sectors, viz. medicine and the environment, but nowhere is there quite the same stringent requirement to identify and quantitate unknown entities with such speed, efficiency, and accuracy. Given, therefore, the pivotal role of the detection of CBR & E materials in security, both the theory and practice of detection here has attracted some considerable interest from established as well as new researchers. This, in the end is going to be our route to both innovation and practical delivery.

The first detector ‘systems’ for chemical weapons used what nature provided – the human senses of sight and smell. However, moves to colorimetric systems soon followed (including powders and papers) with the ultimate continued development of more and more sophisticated systems for CBR & E detection to this present day.

When developing a detection system there are a number of challenges that need to be overcome. For example, whilst the first colour-based detection systems were basic, they provided the user with a simple ‘yes/no’ answer. In developing equipment nowadays it must be still remembered that the user is almost certainly not a specialist, and indeed may not have any technical knowledge at all, and thus, whilst the technology employed will be significantly more complex and advanced than the original simple colorimetric tests, the detector output to the user still needs to be easy to interpret.

False positives (an instrumental indication of the presence of a material when there is none) and false negatives (no instrument response in the presence of a material at a concentration it is designed to see) can have a significant impact on user confidence, and could have a devastating effect on the response of support and emergency teams, and thus need to be reduced to a minimum, whilst increases in sensitivity and specificity are demanded against what is a tremendously complex and varying background of particulates (biological and non-biological) and chemical vapours. Add to this the fact that if the system needs to be portable it also has to be rugged, and you already have a major challenge – one technology alone is unlikely to solve.

Finally, another issue is that the CBR & E threat has changed in the last decade or so from a reasonably well-defined set to what seems like an ever-increasing range of materials, making the job of monitoring, detecting and identifying them very much more challenging.

This special set of papers includes the outcome of a high profile joint US–UK meeting on detection devices for security held in London in April 2007. They represent the diversity and scope for innovation that the field has engendered. As might be expected, represented here are both electrochemical (Wang et al., Kalaji et al.) and fibre optic (Hayes and co-workers) sensors, but there is also the example of the versatility and diversity possible using a surface waveguide (Lee et al.). As solid state devices, piezoelectric sensors (Hart et al.) have much to recommend them for eventual field use, and the incorporation of micro-/nano-sensing interfaces (Russell et al., Malosse et al.) imbued variously with biomimetic or biofunctionalised moieties are a likely way in which the field will move in the future. Indeed, an exciting aspect of detection work is the continued examination of what role nature can play today and in the future (Biggins et al.). Prospects and scenarios for advancing different systems for a real world are considered specifically here (Turl and Wood, and Smith et al.).

Ultimately it is not the innovation per se, nor whether the device is an intellectual or scientific advance that will determine utility, but how an end user, whose survival may depend on its ability to detect, would regard it. This series of papers makes a realistic move in this direction, and notably encompasses natural and artificial affinity systems, as well as the adaptation of mainstream techniques such as ion mobility spectrometry (Ross et al.), to highlight the need for a multiple set of perspectives on a measurement challenge set to increase this century.

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