Sniff test

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. 

For comparing the relative loss of a flavor component from a container, we have found the sniff test (6) very useful, especially when gas concentration measuring techniques were not available. Typical results of this type of test are shown in Table II. Each filled container was held in a glass jar for approximately 48 hours. The results are stated in qualitative, subjective terms such as slight, strong, or undetectable. The... 

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. 

Even partial resolution of these very complex samples requires the use of very efficient columns. In general, separation efficiency varies inversely with column capacity. Sniff-testing of the column effluent can be very useful to the flavor chemist, but this demands columns of even larger sample capacity. Hence the flavor chemist has been faced with a difficult choice 1) better resolution of volatile flavor compounds in amounts too small for their sensory evaluation, or 2) sniff testing of poorly resolved multi-component peaks. 

Data Sheet 16.5 One student s choices in sniff test... 

Occupational illness no mention is made in the CER or annual report of any group-wide strategy for reducing occupational illness. Mention is made in the annual report, however, of the replacement of a sniff test with an analytical procedure. 

Hess et al., 1983) were correlated with a daily regime of "sniff tests during which a bull was allowed limited access to each cow for several minutes flehmen responses and checks were recorded. The data obtained established an inverse correlation of serum progesterone levels with the male flehmen response (Hess et al., 1983). 

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. 

Danger Cylinders that may contain nitrous oxide, toxic, or flammable gases should not be subjected to an odor (sniff) test. 

PS-3 CGA Position Statement on Odor Testing for Cylinder Contaminants. Describes CGA s position on the question of whether compressed gas cylinders should be odor (sniff) tested prior to filling. (2... 

The gravitational field affects olfaction as it does vision, audition, or vestibular function. It could impair detection of dangerous fumes or burning electrical equipment in airplanes or space vehicles. Astronauts also report altered perception of food flavors under weightless conditions. Men and women tested with four scratch-and-sniff odor samples of the University of Pennsylvania Smell Identification Test identified odors more poorly when in an upside-down position (Mester eta/., 1988). 

I Pul. 5 g v/s TEASPOON) MANGANESE DIOXIDE INTO TEST TUBE. ADD 3 ml (ft TEST TUBE) UNDILUTED HYDROCHLORIC ACID. HEAT GENTLY. CHLORINE FORMS. WaFT A LITTLE CAREFULLY TOWARD YOU FOR A SNIFF. 

IN A TEST TUBE, MIX 3 ml ETHANOL WITH 2 g SODIUM BISULFATE AND 3 ml WHITE VINEGAR. HEAT IT GENTLY. SNIFF CAREFULLY. THE SOUR SMELL OF VINEGAR HAS TURNED INTO THE FRUITY SMELL OF ETHYL ACETATE (CHJCOOC,Hs). IT IS A MUCH-USED SOLVENT. 

IN A DRY TEST TUBE. MIX A SMALL AMOUNT OF SALICYLIC ACID WITH AN EQUAL AMOUNT OF CALCIUM OXIDE. HEAT GENTLY. REMOVE TUBE FROM HEAT. SNIFF. YOU GET THE ODOR OF PHENOL—ALSO KNOWN AS CARBOLIC ACID. 

IN A DRY TEST TUBE ADD i/4 TEASPOON SODIUM BISULFATE TO 1 ml VEGETABLE OIL AND HEAT GENTLY. WAFT THE IRRITATING ODOR TOWARD YOU AND SNIFF CAUTIOUSLY. THE SMELL IS FROM ACROLEIN WHICH IS PRODUCED BY BREAKING DOWN THE GLYCERIN IN THE FAT. 

This research involves the testing of human response to odors they detect sniffing whole foods (cola beverages and cheeses), synthetic models of foods or extracts of foods. Standardized sets of odorants designed to stimulate all odor receptors in the subjects will be used in a device called a GC/O to test for sensory acuity. You will be asked to sit in front of a gas chromatograph combined with an olfactometer and sniff purified humidified air in an isolated environment. The experiment will consist of four sniffing sessions conducted on different days. The maximum number of samples you will be asked to sniff in any one day is six. Each session will take 30 to 45... 

In 1986 the largest ever smell survey was carried out involving 1.5 million people from all over the world. They were given scratch and sniff cards and a questionnaire to answer. The scents tested were androstenone, isoamyl acetate (banana), glaxolide (a synthetic musk), eugenol (cloves), rose, and a mercaptan (the one added to natural gas to make it detectable). Of those who took part, 50% were able to detect all six smells and only 1% could detect none of them. Women were found to be better than men. The smell that was sensed the least was androstenone, and if this really is a human pheromone then it does not operate by having an irresistible odour. 

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. 

Fig. 7.59 In the detector-probe technique, the tested piece is filled with helium and the sniffer probe sniffs the areas in question to detect leaks. Always sniff from bottom to top.

A sense as basic as pain could be abolished. In spite of the number of times 1 have seen it, a test procedure we called anosmia to ammonia still amazes me. I would tell a subject that he could no longer smell anything. Then I would hold a bottle of household ammonia an inch under his nose and ask him to take a good sniff. The smell of ammonia is not only a strong smell, it is an extremely painftil sensation, as if your nostrils were set on fire. A talented hypnotic subject would take a deep sniff, while 1 winced. No reaction. No tears would form in his eyes, and he wouldn t jerk his head away or show any other reaction. Did you smell anything. No. ... 

David Laing has shown that nobody is able to distinguish more than 3-5 molecules in a single sniff. This can be explained by the detection limits in triangle tests relative concentration differences below 20% in a mixture are very difficult to differentiate. 

The experiments with H. M. employed a battery of tests. One set of experiments measured his sensitivity by means of a technique derived from signal detection theory (Corbit Engen, 1971), in which I asked H. M. to sniff 20 presentations of dilute odorant solution randomly interspersed with 20 presentations of odorless blank. The odor was so faint as to make it hard to tell it apart from blank. Figure 1 compares some of the data for H. M. with a male normosmic (P. D.) matched for age and race. After each presentation I asked H. M. whether he could smell an odor. His pattern of responding was the same as that of normosmics sometimes he gave affirmative responses to blanks (false alarms, symbolized by open symbols in fig. 14.1), but he did not always respond affirmatively to the dilute sample (correct affirmatives are symbolized by solid symbols in fig. 14.1). 

Responses of mitral cells to odors are typically complex during odor exposure, units may be initially excited then inhibited, inhibited then excited, or may exhibit more complex responses. The character of these responses may alter with odor concentration. Individual units may more reliably discriminate between odors if unit activity is recorded in relation to an artificial sniff cycle (Macrides and Chorover, 1972). Recent authors have emphasized the necessity of testing the response of each cell over a range of odor concentrations (Meredith, 1986 Harrison and Scott, 1986). Testing with several odors, each at several different concentrations, showed that a significant number of cells respond differently to at least two odors at all odor concentrations (Wellis et al. 1989). Similar results in the salamander led to the concept of concentration tuning of bulb units individual cells appeared to respond best to a particular concentration of each odorant (Kauer, 1974). 

---