Sniffers

Odor threshold The minimum concentration of an odorous gas which 50% of a panel of trained sniffers can detect. 

Gas Sniffer. This instrument can be hooked into the blooey line to detect very small amounts of natural gas entering the return flow from the annulus. 

Special populations at risk of high exposure to tetraethyl lead include workers at hazardous waste sites and those involved in the manufacture and dispensing of tetraethyl lead (Bress and Bidanset 1991). Recreational drug sniffers of leaded gasoline are also at risk (Edminster and Bayer 1985). 

Many sophisticated analytical techniques have been used to deal with these complex mixtures.5,45,46 A detailed description is not possible here, but it can be noted that GLC, often coupled with mass spectrometry (MS), is a major workhorse. Several other GLC detectors are available for use with sulfur compounds including flame photometer detector (FPD), sulfur chemiluminescence detector (SCD), and atomic emission detector (AED).47 Multidimensional GLC (MDGC) with SCD detection has been used48 as has HPLC.49 In some cases, sniffer ports are provided for the human nose on GLC equipment. 

J. J. Tyson, K. C. Chen, and B. Novak, Sniffers, buzzers, toggles and blinkers Dynamics of regulatory and signaling pathways in the cell. Curr. Opin. Cell Biol. 15, 221 231 (2003). 

One project that had great appeal was chemist Bob Ellin s development of a people sniffer. If consisfed of a sfeel fank large enough to accommodate a... 

Bob Ellin, Ph.D, discussing his people sniffer with his technician... 

I. Gazit and J. Terkel, Explosives detection by sniffer dogs following strenuous physical activity , Appl. Anim. Behav. Sci. 81 (2003) 149—161. 

The 1985 tragedy of Air India Flight 182, which exploded off Ireland en route from Montreal to London, stimulated an intensified effort to thwart terrorists. The International Security and Development Act of 1985 provided for air marshals and expanded FAA s R D for airport security. Thermal neutron analysis (TNA) and a number of sniffer technologies for trace explosives detection, which had been developed under FAA sponsorship, were accelerated toward commercial production. 

Figure 9 An ion mobility spectrometer called the Quantum Sniffer has an inlet with laser or flash-lamp to warm a surface and a vortex sampler (left frame) to pull sample into the analyzer without contact between analyzer and surface (right frame).

Severe but reversible liver and kidney injury occurred in a person who was a glue sniffer for 3 years. The chief component of the inhaled solvent was toluene (80% vol/vol) other ingredients were not listed. In workers exposed for many years to concentrations in the range of 80-3 00 ppm, there was no clinical or laboratory evidence of altered liver function. ... 

Botella, J. A., Ulschmid, J. K., Gruenewald, C., Moehle, C., Kretzschmar, D., Becker, K., and Scheuwly, S. (2004). The Drosophila carbonyl reductase sniffer prevents oxidative stress-induced neurodegeneration. Curr. Biol. 14, 782-786. 

When using the positive pressure method it is sometimes either impractical or in fact impossible to measure the leakage rate directly while it could certainly be sensed in an envelope which encloses the test specimen. The measurement can be made by connecting that envelope to the leak detector or by accumulation (increasing the concentration) of the test gas inside the envelope. The bombing test is a special version of the accumulation test (see Section 5.7.4). In the so-called sniffer technique, another variation of the of the positive pressure technique, the (test) gas... 

Today leak tests for vacuum systems are usually carried out with helium leak detectors and the vacuum method (see Section 5.7.1). The apparatus is evacuated and a test gas is sprayed around the outside. In this case it must be possible to detect (on the basis of samplings inside the apparatus) the test gas which has passed through leaks and into the apparatus. Another option is to use the positive-pressure leak test. A test gas (helium) is used to fill the apparatus being inspected and to build up a slight positive pressure the test gas will pass to the outside through the leaks and will be detected outside the device. The leaks are located with leak sprays (or soap suds, 5.4.5) or - when using He or H2 as the test gas - with a leak detector and sniffer unit (5.7.2). 

Universal sniffer leak detector Refrigerants, helium and other gases 10- 7.10-= Positive pressure Yes... 

Here the points suspected of leaking at the pressurized test specimen (see Fig. 5.4, d) are carefully traced with a test gas probe which is connected with the leak detector by way of a hose. Either helium or hydrogen can be detected with the INFICON helium leak detectors. The sensitivity of the method and the accuracy of locating leaky points will depend on the nature of the sniffer used and the response time for the leak detector to which it is connected. In addition, it will depend on the speed at which the probe is passed by the leak points and the distance between the tip of the probe and the surface of the test specimen. The many parameters which play a part here make it more difficult to determine the leak rates quantitatively. Using sniffer processes it is possible, virtually independent of the type of gas, to detect leak rates of about 10 mbar l/s. The limitation of sensitivity in the detection of helium is due primarily to the helium in the atmosphere (see Chapter 9, Table VIII). In regard to quantitative measurements, the leak detector and sniffer unit will have to be calibrated together. Here the distance from the specimen and the tracing speed will have to be included in calibration, too. 

Figure 4.5. The NP composition of a typical plant extract (in this case, a citrus hybrid) as revealed by gas chromatographic analysis. The peaks on the upper trace represent the different chemicals detected by the instrument, with the peak area being a measure of the amount of any substance. Note that there are a few major NP peaks but even more very minor ones. The spikes pointing down on the lower trace are the odours detected by a human sniffer with their perceived odour name. Note the human detection of odour does not always correspond to the emergence of a major chemical peak. For example near the start of the analysis, the green or burning smell detected by the human does not correspond to any instrument detection so those chemicals are below the level of detection of the instrument. (Modified from the data of Morton M, Smoot JM, Mahattanatawee K, Grosser] and Rouseff RL, Citrus Research and Education Center, University of Florida.)...

Hong, J.-J., Lin, J.-L., Wu, M.-S., Huang, C.-C. Verberckmoes, R. (1996) A chronic glue sniffer with hyperchloraemia metabolic acidosis, rhabdomyolysis, irreversible quadriplegia, central pontine myelinolysis, and hypothyroidism. Nephrol. Dial. Transpl., 11, 1848-1849... 

FID detector installed in parallel with an olfactometer capable of delivering the effluent from the column to the human sniffer. The column is installed in either the FID port or the olfactometer port, depending upon the mode of operation. Split effluents are not recommended. 

Temperature of the effluent reaching the sniffer 35° to 40°C Sample size 1 pi. 

Position a sniffer so as to provide comfortable access to the sniff port for the duration of the analysis. 

The sniffer should not sniff until the solvent has mostly eluted. 

Have the sniffer breathe in constant cycles at 20 breaths/min, record the exact moment an odor is first detected at the sniff port, associate it with a descriptor, and then record the moment the odor is no longer detectable. 

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