Sniff methods

Detection. Many people can detect hydrogen cyanide by odor or taste sensation at the 1 ppm concentration in air, most at 5 ppm, but HCN does not have an offensive odor and a few people cannot smell it even at toxic levels. Anyone planning to work with hydrogen cyanide should be checked with a sniff test employing a known safe concentration. This test should be given periodically. Several chemical detection and warning methods can be employed. The most rehable are modem, electronic monitors based on electrolytes that react with hydrogen cyanide. 

Using sniff test method with container enclosed in poly/foil/poly pouch with 38 mm screw cap. 

Immediately following the initial assembly (and at any other time leaks are suspected), the box and purification train should be tested for leaks. A quick test for leaks is to pressurize the dry box until the gloves stick straight out. The gloves should remain in this position for several hours if no leaks are present. If leaks are indicated, testing is most easily accomplished while the box is pressurized. If the inert atmosphere is helium, the preferred method is the helium sniff test. All joints, welds, and connections should be checked. In the absences of a helium-sensitive probe or if the inert atmosphere is other than helium, the bubble method may be used a small amount of soapy water is placed on leak-prone welds and joints and the appearance of any bubbles is noted. 

The most elementary, nontechnical method of identifying a polysaccharide is to burn it, observe the yellow-to-brown color, and sniff the perfumelike aroma that should be reminiscent of the aroma of maple syrup, if the test is positive. If the caramelized residue is shaken with egg white and a visible reaction produces an insoluble, pigmented deposit (melanoidin), it is empirical proof that the sample was a polysaccharide. 

The most commonly used method to measure smells is with an organoleptic panel, i.e. a group of, typically, 4 to 8 people who sniff professionally the headspace of an odorant compound. In some cases, the headspace is first passed down a gas chromatography column and then the panel smells the separate compounds as they are slowly eluted Irom the end of the column - this is known as an olfactometer. However, organoleptic panels are expensive to train, take a considerable amount of time and effort to detect the compounds, and are subject to considerable variability -perhaps a factor of 3 or more Ifom panel to panel. Consequently, there has been considerable effort to employ other headspace techniques that are well known in the field of analytical chemistiy, such as ... 

It is clear that Plot had travelled all over the county (as he had in Staffordshire and elsewhere in England) examining its marls, earths, minerals and waters, and he mentions many local scientifically minded worthies, such as Dr Lane of Banbury and his brother Mr Lane of Deddington, both physicians, who were experts on the properties of their local environments. And inevitably, Plot must have lectured on these subjects in the Museum, and no doubt boiled, sniffed, and tasted a wide variety of specimens brought into his laboratory. One method by which a skilled experimenter or doctor often evaluated the chemical content of a mineral or medicinal spring was to have a quantity poured over a red-hot shovel or piece of iron, and to carefully sniff the resulting steam, for in an age when few reliable chemical tests existed the operator s sense of smell and taste buds were frequently crucial. 

A test for internal contamination must be performed on each cylinder used for oxygen or breathing gas prior to filling. The most common test is one described as an odor (sniff) test performed by the fill operator. Sniff test procedures are described in CGA P-15 and consist of smelling the effluent gas when the valve is cracked open [18]. Any cylinder that has an odor must not be filled, but set aside for removal of the contaminant. Alternate detection methods may also be used. 

The NIF (or SNIP) method was developed by PoIUen et. al. [73] (see also [74]). In this method, eight to ten untrained individuals sniff the GC effluent (one at a time). They simply note when they smell an odor. The aroma isolate used is adjusted... 

HACCP. A May 1987 National Academy of Sciences report urged USDA to shift from its traditional poke and sniff inspection method to a science-based approach, called hazard analysis at critical control points (HACCP), under which operators develop objective tests for contamination risk at various critical control points of the manufacturing process and adopt measures to... 

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