Odors unknown

Odor Unknown upon combustion, smells like rotten horseradish Disagreeable odor No data No data... 

A linear chain polymer has no taste or odor, is a white powder, the specilic gravity is 1.12, is soluble among a wide variety of solutions, and has the unique characteristic of dissolving in aliphatic hydrocarbons that are low in price and have little odor. Unknown... 

Acetamide [60-35-5] C2H NO, mol wt 59.07, is a white, odorless, hygroscopic soHd derived from acetic acid and ammonia. The stable crystalline habit is trigonal the metastable is orthorhombic. The melt is a solvent for organic substances it is used ia electrochemistry and organic synthesis. Pure acetamide has a bitter taste. Unknown impurities, possibly derived from acetonitrile, cause its mousy odor (1). It is found ia coal mine waste dumps (2). 

This example demonstrates the most challenging problem of flavor chemistry, ie, each flavor problem may require its own analytical approach however, a sensory analysis is always required. The remaining unknown odorants demand the most sensitive and selective techniques, and methods of concentration and isolation that preserve the sensory properties of complex and often dehcate flavors. Furthermore, some of the subtle odors in one system will be first identified in very different systems, like o-amino acetophenone in weasels and fox grapes. 

L v ndin. Lavandin, Lavandula hjbrida as a plant species is of recent origin, unknown until the late 1920s. It is a hybrid of two common lavenders, l vandula officinalis and l vandula latifolia. Lavandin is cultivated mainly ia southern France and has become one of the most produced and used natural perfumery materials. The flowering tops of the shmb are used to produce a concrete, an absolute, and a steam-distilled oil the last is by far the most used. Low cost and refreshing odor quaUty allow lavandin to be employed ia a wide variety of perfume appHcations and at high concentrations. Chemically it is comprised of 30—32% linalool (3) and linalyl acetate (1), along with numerous other substances, mosdy terpenic. 

Health Hazards Information - Recommended Personal Protective Equipment Dust mask goggles or face shield protective gloves Symptoms Following Exposure Inhalation of dust irritates nose and throat. Contact with eyes causes irritation General Treatment for Exposure INHALATION move to fresh air. EYES flush immediately with physiological saline or water get medical care if irritation persists. SKIN flush with water Toxicity by Inhalation (Thresholdlimit Value) Data not available Short-Term Exposure Limits Data not available Toxicity by Ingestion Grade 1 oral LDjq 11.7 g/kg (rat) Late Toxicity Chronic effects in humans are unknown Vapor (Gas) Irritant Characteristics Not pertinent liqidd or Solid Irritant Characteristics Data not available Odor Threshold Data not available. 

As the name implies, the odor of urine in maple syrup urine disease (brancbed-chain ketonuria) suggests maple symp or burnt sugar. The biochemical defect involves the a-keto acid decarboxylase complex (reaction 2, Figure 30-19). Plasma and urinary levels of leucine, isoleucine, valine, a-keto acids, and a-hydroxy acids (reduced a-keto acids) are elevated. The mechanism of toxicity is unknown. Early diagnosis, especially prior to 1 week of age, employs enzymatic analysis. Prompt replacement of dietary protein by an amino acid mixture that lacks leucine, isoleucine, and valine averts brain damage and early mortality. 

Fig. 21.11. Mass spectra of the unknown off-flavor compound after spectral subtraction from the co-eluting peak and the matching spectrum from the NIST library. (Redrawn/redrawn from J. Chromatogr., 351, R.A. Sanders, and T.R. Morsch, Ion profiling approach to detailed mixture comparison. Application to a polypropylene off-odor problem, 525-531, Copyright (1986) with permission from Elsevier.)...

Commentary Ultimately, solving this problem was rather straightforward once the characteristic odor of mothballs was noted. (Keep in mind the safety aspects of smelling unknown chemicals, especially pesticides.) During the information gathering stage, perhaps interviews with elderly residents or perusal of the local newspaper at the time may have provided additional information to guide the analysis. 

New components, such as trans-fatty acids, sugar substituents, odorants, taste batterers, colorants and consistency equalizers, were unknown to the human organism enzyme systems of the latter were adapted to these... 

De Fraipont, M. and Thines, G. (1986). Responses of the czveftsh Astyanax mexicanus (Anop-tichthys antrobius) to the odor of known or unknown conspecifics. Experientia (Basel) 42,1053-1054. 

Caution. (r)3-Allyl)(r)s-cyclopentadienyl)palladium is volatile and has an unpleasant odor. As the toxity is unknown, all manipulations should be carried out in an efficient hood. All solvents are dried over sodium metal and distilled under nitrogen. 

The brown material, insoluble in water, examined more carefully [said he], was recognized to be the cause of the peculiar odor we mentioned above and by means of some experiments which we shall report soon, it was found that it was a combustible, elementary substance hitherto unknown, to which I have given the name selenium, derived from Selene (the moon), to recall its analogy with tellurium. According to its chemical properties, this substance belongs between sulfur and tellurium, although it has more properties in common with sulfur than with tellurium (9,17). 

In the following year, however, he concluded that tire mineral contained neither bismuth sulfide nor antimony, that the gold was an essential constituent of it, and that it contained an unknown metal. In an investigation lasting three years and consisting of more than fifty tests, he determined the specific gravity of the mineral and noted the radish odor of the white smoke which passed off when the new metal was heated, the red color which the metal imparts to sulfuric acid, and the black precipitate which this solution gives when diluted with water (3). 

Fig. 16.2 Flavour dilution (FD) chromatogram obtained by application of aroma extract dilution analysis on an extract prepared from parsley leaves. The odorants were identified as 1 methyl 2-methylbutanoate, 2 myrcene, 3 l-octen-3-one, 4 (2)-l,5-octadien-3-one, 5 2-isopropyl-3-me-thoxypyrazine, 6p-mentha-l,3,8-triene, 71inalool, 8 2-sec-butyl-3-methoxypyrazine, 9 (.Z)-6-dece-nal, 10 / -citronellol, 11 ( , )-2,4-decadienal, 12 / -ionone, 13 myristicin, 14 unknown. RI retention index. [30, 31]...

In the sample of parsley (Table 16.5), the analysis was started with a head-space volume of 5 mb, in which GCOH revealed 15 odorants. Then, the head-space drawn from the sample was reduced in a series of steps to find the most potent odorants. GCOH of volumes of 2.5 and 1.25 mb indicated only seven and five odorants, respectively (Table 16.5) after reduction to 0.6 mb, only methane-thiol, (Z)-3-hexenol and an unknown compound were the most potent, highly volatile odorants of parsley [31]. 

Males of a European species, Xysticus kochii, also were attracted to 12 and 13 (S. Toft and S. Schulz, unpublished data). The aldehydes 12 and 13 were not found in odors collected from females, although the saturated analogs octanal and decanal were present. However, neither they nor any of the other identified compounds attracted males (S. Schulz and S. Toft, unpublished data), and the reason for the attraction of male crab spiders to aldehydes 12 and 13 remains unknown. 

In the old days. chemists prided themselves on their ability to identify compounds by odor. Smelling unknown chemicals is a bad idea because some vapors are toxic. Chemists are developing electronic noses to recognize odors to assess the freshness of meat, to find out if fruit is internally bruised, and to detect adulteration of food products.13... 

The contribution to irradiation off-flavor of individual components was unknown, though the sulfur- and nitrogen-containing substances were suspected to be significant because of their inherent strong unpleasant odors. Merritt (9) suggested that dimethyl sulfide, 1-hexene, and n-hexane were important components of irradiation odor and pointed out that the quantity of these compounds produced increased directly with radiation dose. 

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