Portable sensors

Small, portable sensors are now available to monitor the air we breathe for such toxins as carbon monoxide, CO. As soon as the air contains more than a critical concentration of CO, the sensor alerts the householder, who then opens a window or identifies the source of the gas. 

In this book we will focus our attention on applications that require portable sensors, sensors that must be transported to the vicinity of the target. These applications include mine and UXO removal and the search for and identification of IEDs. Chapter 11 forms a notable exception to this focus, where fixed screening of airport portals is the principal application to date. Fixed sensing stations... 

The picture of the packaged unit reminds us of the ancillary systems necessary to form a useful portable sensor. In this unit they project a 4-hour battery life with a lithium ion battery. They have a pumping system that supplies air at 1.5 L per minute. It also contains an analog-to-digital converter capable of 200,000 samples per second at 14 bits and a personal digital assistant for control and data analysis. 

Wherever an antibody assay is used now, there will be the prospect of producing an immunosensor for the same analyte. Therefore, the development of immunosensors is directed to obtain sensors with fast response, low detection limits, little preparation efforts, low price availability and high specificity. Thanks to the possibility of fabricating fast portable sensors, immunosensors now constitute a potential alternative to centralized and sophisticated bioanalytical systems. 

With the advent of portable sensors, it has become common in recent years to bring the laboratory to the sample instead of bringing the sample back to the... 

Pre-coated crystals can be placed in a solution and give a direct result of the concentration of the specific analyfe in a maffer of minutes without any need for extra assay steps or washings. This approach is particularly useful for those developing portable sensors with a view to field analysis. Pre-prepared coafed crystals can be used with a portable instrument for direct analysis in minutes without the need for a skilled operator. 

Food safety Medical diagnostics Mobile sensor Portable sensor ... 

FIGURE 5.6 The portable sensor system for metal ions analysis. Screen-printed sensor (fabricated at Cranfield University) conpled to a portable electrochemical instrnment (PalmSense, Palm Instruments BV). 

Although a large level of success has been achieved with fluorescent-labeled DNA microarrays, these methods are difficult to implement in portable instrumentation, so that their use is limited to specialized laboratories. Electrical detection of biomolecular interactions is highly desirable due to its suitability to low-cost portable sensors that can be used in the field by non-specialized personnel. The use of label-free techniques has the added advantages of reducing costs and avoiding the need for sample pre-treatment. 

Some proton conductors have relatively high conductivities at room temperature. Introduction of these materials into electrochemical cells brings about attractive chemical sensors workable at room temperature. Potentiometric or amperometric detection of chemical components at room temperature would create new fields of application for sensors especially in bioprocess control and medical diagnosis. With an all-solid-state structure, the sensors would be compatible with micro-fabrication and mass production, and small power consumption associated with their ambient-temperature operation would be intrinsically suited for cordless or portable sensors. 

In field applications, the monitoring of the type and level of pollutants is also of great importance, and information is often required in real time rather than the several days of delay needed for sending samples to the laboratory. In response to this need, major advances have been made in the development and application of small-scale, portable sensors for in situ monitoring of pollutants [153-158]. Sensors can be of the solid-state, optical, bio-, and electrochemical types, examples of the latter being pH- and ion-selective... 

L.T. Rossetto, I. Muller, V. Bmsamarello, E. Fabris, C.E. Pereira, Wireless portable sensor for athletic monitoring, in Proc. IEEE International Instrumentation and Measurement Technology Conference (I2MTC) 2012, May 13-16, 2012, pp. 2371-2375. 

Lang HP, FUippi A, Tonin A, Huber F, Backmann N, Zhang J, Gerbe C (2009) Towards a modular, versatile and portable sensor system for measurements in gaseous environments based on microcantilevers. Procedia Chem 1 208-211 Lavrik NV, Sepaniak MJ, Datskosa PG (2004) Cantilever transducers as a platform for chemical and biological sensors. Rev Sci Instrum 75(7) 2229-2253... 

Volume-selective MRI using an adjustable, single-sided, portable sensor This sensor can probe the interior of samples nondestructively by collecting images and measuring relaxation and dilfusion constants, and even perform chemical analysis under conditions inaccessible to conventional NMR. MRI in axial and sagittal planes at dilferent depths of the sensitive volume and T-1-weighted contrast in a tissue sample are introduced. 

The United States needs to improve and expand the uses of sensors in preventing terrorism and to minimize the impact should an incident occur. Besides point sampling devices, sensors to help provide sensitive and rapid detection and advance warning of toxic vapor at fixed sites such as subways, buildings, financial centers, and airports are of utmost importance. These sensors need to be operable around the clock. For example, sensors installed in the ventilation system could be coupled with a rapid shutdown procedure. Portable sensors to allow assessment from a remote or on-site point can be used to map the potential extent of the chanical cloud cover to aid authorities in organizing the movement of people. Current sensors have limited capabilities and must be improved. 

However, in this fluorine sensor, the base electrolyte is composed of the lanthanum cation with the fluorine anion. In addition, one unusual property is that the sensor can operate even when directly immersed into aqueous solutions at room temperature. The realization of the application is greatly dependent on two facts Lap3 is stable in water and it shows an excellent fluorine conduction even at room temperature. These remarkable characteristics permit the use of Lap3 as a simple and portable sensor and have led to its commercial use on a worldwide scale. 

The application of an alcohol sensor to detect the concentration of alcohol in breath is very effective in enforcing the drinking and driving laws. The development of a portable sensor with simple and fast operation is desired for use in police vehicles to aid in apprehending offenders, and reduce the number of traffic offenses. 

A Hst of the components required for the construction of electrochemical analyzer, a brief description of them, and their functionality appears in Table 5.2. The total cost of this potentiostat is less than 50, making it cost effective for individual or small group experiments and special projects. The dimensions of the whole device are 10 x 13 cm on printed circuit boards (Figure 5.47). The simple circuit presented here is solid state, amenable to battery-powered operation, and if interficed to an appropriate electrochemical cell, can be used as a rugged, field-portable sensor system for monitoring... 

Electrochemical DNA arrays are unlikely ever to compete with existing fluorescence (or mass spectrometric) technologies directly, because those techniques allow fast readout of the arrays and high throughput. Nevertheless, fluorescence microscopes and mass spectrometers are best suited to applications that are carried out in a central laboratory and electrochemical devices (e.g., [126,127]) are potentially more useful for point-of-care diagnostics or as part of portable sensors for detection of bacteria in air, water, or food. 

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