Portable sampling devices

Portable sampling devices were categorised by Nielsen and Yeates (1985) as grab samplers, suction lift devices and positive displacement mechanisms. A brief review of each category is given below. 

If a dust hazard is suspected in the workplace, the first step is to monitor the working environment to determine the exposure of the worker. One of the better methods of achieving this is for the worker to wear a portable sampling device, which gives a measure of the type of particles and their size distribution in the air immediately around the worker. Such devices usually sample at a typical respiration rate and velocity and some devices are designed to capture directly only the respirable particles (particles capable of reaching the alveoli) or the inhalable particles (particles capable of being inhaled). 

Analyzer houses in today s facilities contain a wide range of instrumentation, including portable sampling devices, washing facilities, and sophisticated mass spectrometers. These structures can be as large as 200 sq ft and are often located in a controlled environment containing blowers and air-conditioning units. A typical analyzer house is shown in Exhibit 14-27. 

The Array Biosensor developed at the Naval Research Laboratory (NRL) is an automated, portable detection device for simultaneous analysis of up to six samples for multiple analytes with the size of a shoebox (Figure 10) 42-43. 

The relative simplicity of the sensor setup allows them to be implemented into portable automated devices or bed-side analyzers (Fig. 4.2), which are easily installed at patient beds, eliminating the time-consuming laboratory analyses. On the other hand, modem high throughput clinical analyzers may process more than 1000 samples per hour and simultaneously determine dozens of analytes, using a handful of analytical methods. Blood electrolyte analysis, however, remains one of the most important in... 

One of the major advantages of SPME is that it is a solventless sample preparation procedure, so solvent disposal is eliminated [68,131], SPME is a relatively simple, straightforward procedure involving only sorption and desorption [132], SPME is compatible with chromatographic analytical systems, and the process is easily automated [131,133], SPME sampling devices are portable, thereby enabling their use in field monitoring. 

Yeats s criteria for the ideal sampling tool. They can be dedicated to individual monitoring wells to avoid cross-contamination between boreholes, they are portable, simple to use and relatively easy to clean. They are, however, not suitable for purging large volumes of water, and it can be difficult even with double-ended bailers to determine accurately where the sample was collected. Compared with other sampling devices, the operator is also more at risk of coming into contact with contaminated sample, especially when emptying the bailer (Fig. 3.1). 

The high-volume sampler has become the most widely used tool for monitoring particulate matter air pollution. It is a low-cost, portable, easily maintained, and reasonably precise sampling device. Improvements in sampler performance have resulted from incorporation of automatic timers, flowrate recorders, and size separation devices into the basic system. Although hi-vols are the accepted standard in particulate matter monitoring, they inherently lack the ability to provide realtime particulate matter measurements. 

PDQ is a portable photodiode device for simultaneous analysis of up to eight samples (Fig. 3a). It uses commercially available 0.2 ml PCR tubes or 8-well PCR strips. In this machine, light is detected from the bottom of tubes. PDQ can be used in standalone mode or when connected to a PC through a USB-port. Power consumption is low enough for the machine to be run off a car battery if used in a field. PDQ is a low-cost distributed device suitable for point-of-care applications. Dedicated software offers a choice of tests with pre-set parameters (Fig. 3b) and analyses the data giving a final result for each sample at the end of the run, when used in the diagnostic mode (Fig. 3c). 

Copper has been measured in soil using a portable electroanalytical device based on stripping voltammetry. In marine chemistry, sediments have been sampled and analysed in real-time by in situ solid-state voltammetric micro-electrodes. The analyser was used to examine levels of various redox species and trace metals, e.g. iron and manganese, in salt marsh sediments and other matrices. 

Chip-based and other nanotechnology applications continue to excite much interest in analytical chemistry. Miniaturised devices offer the potential to shrink normal analytical systems with advantage of speed, initial cost, portability, sample size, lower consumables usage and disposability. ED would seem to be a natural choice for such systems since EC effects work fundamentally at a nanoscale. 

A novel one-sided NMR magnet has been developed for self-diffusion measurements in thin samples [7]. Using this technique, researchers have demonstrated measurements in bulk [BMIM][TFSI] and [BMIM][TFSI] confined in nanoporous anodized aluminum oxide membranes, as shown in Fig. 3. This operates at a proton Larmor frequency of 14.08 MFlz, and the expected appHcation is toward in situ measurements in portable energy devices. This method utilizes the fringe field to measure diffusion coefficients instead of conventional PFG-NMR. 

The sampling device is small, portable, and involved no liquids. Interferences are minimal, and most of those which do occur can be eliminated by altering chromatographic conditions. The samples are analyzed by means of a quick, instrumental method. 

If we are interested in what reaches the lower lung then sampling devices should collect dust on the same basis. Sampling devices have been designed which do this, such as the horizontal elutriator as the reference device (heavy and bulky), and the mini-cyclone (lightweight and portable). 

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. 

Economic Analysis is vital to justify the implementation of new diagnostic tests into resource limited health-care systems. POCTs are often more expensive on a test-by-test basis due to the scaling and portability of devices and not benefiting from the efficiency of large-scale multiplex laboratory testing of multiple samples. However, POCT can have benefits further down the clinical pathway such as those described in Table 2.1. These indirect cost savings can only be established by performing a comparative evaluation of the clinical pathway with and without the test. 

An estimated 2.8 million capacitors are in use in the USA. About 2000 of them rupture every year, causing spillage into the environment. As in the case of transformers, there are no tools to predict capacitor failure. Soil samples have to be tested for contamination, and the solid PCB-containing material must be shredded prior to incineration. The utility industry considers it to be cost-ineffective to recover the part/parts of the contaminated capacitors. Portable screening devices such as x-ray fluorescence meters for transformer oil, acoustical detectors to detect the ultrasonic sound from a faltering capacitor, and an infrared scanner to measure the temperature-rise of the faltering capacitor have been studied in the field (Miller, 1982). 

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