Instruments, odor

Minute Turbulence Continuous instrument Irritation (odor)... 

None of the foregoing methods will tell the frequency or duration of exposure of any receptor to irritant or odorous gases when each such exposure may exceed the irritation or odor response threshold for only minutes or seconds. The only way that such an exposure can be measured instrumentally is by an essentially continuous monitoring instrument, the record from which will yield not only this kind of information but also all the information required to assess hourly, daUy, monthly, and annual phenomena. Continuous monitoring techniques may be used at a particular location or involve remote sensing techniques. 

These objective, quantitative tests have shown that nitrile containers should protect the taste and odor of packaged foods and beverages. But the primary consideration in judging overall package performance, once safety is assured, rests on the subjective evaluations of taste, odor, and appearance. It is well known that the animal senses, in many instances, are far more sensitive than the best instruments and also are capable of integrating the individual effects of the several influences on product quality. 

Cross-reactive sensing arrays were developed to detect odors and vapors in an artificial nose manner. Solvatochromic dyes such as Nile Red are adsorbed on the surface or embedded into various polymeric or porous silica beads. The beads respond to analyte vapor by a change in fluorescence maxima or/and intensity due to changes of polarity inside the bead. A portable instrument and preliminary field test for the detection of petroleum products was recently described [106]. 

The joint session of both groups discussed the use of instrumental methods for evaluating odours, it was agreed that these methods could have advantages in terms of cost and labour input. In some cases identification of the odorous compounds was necessary to ensure that the correct treatment system is used. Cross reference to olfactometric measurements is necessary to ensure a good correlationship between the instrumental results, offensiveness ratings and odour concentration by panels. 

Elemental composition Cd 77.81%, S 22.91%. In crystalline state, it may be identified by x-ray diffraction measurement. In aqueous acid extract following digestion with nitric acid, cadmium may be measured by various instrumental techniques, (see Cadmium). Warming with dilute mineral acids liberates H2S, which may be identified by its odor or by browning of a white paper soaked in lead acetate solution. 

Guth, H. and Grosch, W. 1994. Identification of the character impact odorants of stewed beef juice by instrumental analyses and sensory studies. J. Agric. Food Chem. 42 2862-2866. 

The hydrocarbon standard provides a universal scale (retention index, RI) for the characterization of volatile odorants. Since a single determination may require the use of more than one instrument (GC, GC-O, GC-MS), it is crucial that every time a run is made using new operating conditions, a new calibration is recorded using the hydrocarbon standard. This is the only way that RI data from one instrument can be compared with that from another provided that the stationary phase is the same. RIs do not vary with the operating conditions, while retention times do. (See more on the use of hydrocarbon standards in unitgu.)... 

It should be kept in mind that most analytical instruments, such as gas chromatographs and mass spectrometers, do not discriminate between volatile compounds that do or do not possess odor activity. Some form of sensory analysis must be conducted in order to select which volatile compounds contribute to the flavor of the foods. Gas chromatography-olfactometry (GC/O) is an important tool to accomplish that task. 

An automated machine has been developed for sterilization of medical, surgical, and dental instruments. It uses buffered peracetic acid liquid of 0.1-0.5% concentration. Peracetic acid sterilization systems have been adopted for hemodialyzers. The food processing and beverage industries use peracetic acid extensively because the breakdown products in high dilution do not produce objectionable odor, taste, or toxicity. Since rinsing is not necessary in this use, time and money are saved. 

The great development of analytical techniques and instruments has allowed the advance from the first studies focused on the analysis of major volatile compounds to the analysis of compounds present in very low concentrations (even at levels below ng L-1) and with low odor thresholds. Due to the great complexity of the wine matrix, for the analysis of some minor, but key aroma compounds, different sample work-up procedures reported to determine volatile and semivolatile constituents,... 

Detector dogs still represent the fastest, most versatile, reliable, real-time explosive detection device available. Instrumental methods, while they continue to improve, generally suffer from a lack of efficient sampling systems, selectivity problems in the presence of interfering odor chemicals, and limited mobility/tracking ability [13]. 

The common VOCs observed in the SPME-GC headspace analysis of the explosive samples were presented individually, and combined, to previously trained and certified explosive detection canines that previously had only encountered actual explosives in training and certification. Chemicals that illicit a response from certified explosive detection canines can be considered explosive odorants, whereas chemicals to which canines do not alert may be considered as inactive VOCs. It should be noted that an inactive VOC might still have the potential to enhance the response by a canine to known odorants. In addition, inactive VOCs for the canines tested might be odorants to other canines trained in different ways and with different target materials. Finally, inactive VOCs might be useful target vapor chemicals for instrumental detectors. 

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