Aerosol sprays, volatile

Aerosol sprays consist of a material dissolved or suspended in a liquid which when pressure is released volatilizes to produce a fine spray. The spray carries the active material. Used in hair lacquers, paints, etc. the propellant should be inert and non-inflammable. Chlorofluorocarbons have been used extensively but are now being replaced. 

For non-volatile sample molecules, other ionisation methods must be used, namely desorption/ionisation (DI) and nebulisation ionisation methods. In DI, the unifying aspect is the rapid addition of energy into a condensed-phase sample, with subsequent generation and release of ions into the mass analyser. In El and Cl, the processes of volatilisation and ionisation are distinct and separable in DI, they are intimately associated. In nebulisation ionisation, such as ESP or TSP, an aerosol spray is used at some stage to separate sample molecules and/or ions from the solvent liquid that carries them into the source of the mass spectrometer. Less volatile but thermally stable compounds can be thermally vaporised in the direct inlet probe (DIP) situated close to the ionising molecular beam. This DIP is standard equipment on most instruments an El spectrum results. Techniques that extend the utility of mass spectrometry to the least volatile and more labile organic molecules include FD, EHD, surface ionisation (SIMS, FAB) and matrix-assisted laser desorption (MALD) as the last... 

A recently commercialized U.L.V. (ultra-low volume) -type aerosol sprays a fixed volume of ultra-fine particles into the room and retains effectiveness for 12 h with one spray. The mechanism of the effectiveness was considered to be the contact of pyrethroid particles with mosquitoes in the air at the initial stage followed by re-volatilization into the air of pyrethroids attached to walls and floors however, according to experiments by the present author et al., it was confirmed that mosquitoes are knocked down by contact with pyrethroid particles in the air during the first 1 h and then the lethal effect on mosquitoes is achieved by their contact with pyrethroids adhering to walls. 

Under 16 years volatile inhalants, e.g. solvents of glues, aerosol sprays, vaporised (by heat) paints, solvent or substance abuse, gluesniffing. ... 

Volatile aerosol sprays, beloved by sportspeople, produce analgesia by cooling and by placebo effect. 

Aerosol Sprays Explain why volatile liquids are often used as propellants in aerosol spray cans of such things as paints and deodorants. 

ORIGIN/INDUSTRY SOURCES/USES not a natural product wastewater discharges stack fugitive emissions from production volatilization losses from use in cold cleaning of metals losses from vapor degreasing solvent, aerosol spray used in cleaning agents and pesticides... 

Silver(I) /3-diketonate derivatives have received significant attention due to the ease with which they can be converted to the elemental metal by thermal decomposition techniques such as metal organic chemical vapor deposition (MOCVD).59 The larger cationic radius of silver(I) with respect to copper(I) has caused problems in achieving both good volatility and adequate stability of silver(I) complexes for the use in CVD apparatus. These problems have been overcome with the new techniques such as super critical fluid transport CVD (SFTCVD), aerosol-assisted CVD (AACVD), and spray pyrolysis, where the requirements for volatile precursors are less stringent. 

Contained in engine-starting fluid purchased at automotive stores. To remove liquid ether from an engine-starting aerosol can, spray the contents of the can down a 12 inch ( 30cm) length of 3/4 inch PVC pipe. The ether will condense on the sides of the pipe and fall into the jar, while the inert propellant will be released into the air. Ether is extremely volatile. Ether floats to the top of the jar. 

As a reaction to the pressure imposed on refiners operating HF processes, licensors developed safety systems to reduce the inherent risks. Among the mitigation systems are high-volume water sprays to knock down an acid cloud, a low acid inventory, and a rapid acid de-inventory system. HF modifiers, which reduce the volatility and the aerosol-forming tendency of HF, are also offered. ConocoPhillips together with Mobil developed an HF modifier technology named ReVap to reduce the volatility of the acid. It is claimed that a 60-90% reduction in airborne acid release relative to that of the unmodified acid is... 

Cars and buses are fuelled by a volatile mixture of hydrocarbons. The mixture is called petrol in the UK, and gas (short for gasoline) in the USA. One of the main chemicals in petrol is octane, albeit in several isomeric forms. In the internal combustion engine, the carburettor first vaporizes the petrol to form an aerosol (see Section 10.2) comprising tiny droplets of petrol suspended in air (Figure 8.3). This vaporization process is similar to that which converts liquid perfume into a fine spray. 

Another procedure is to rapidly dry the solution at a rate that does not allow the elements to segregate. As an example, aerosols can be sprayed through a furnace heated at the reaction temperature of 900°C. This yields spherical submicronic particles that are most suitable to sinterable compacts. Another way is to spray the solution onto a substrate. This is a simple method of thick film deposition. Very ionic species such as nitrates dissolved in water can be sprayed onto a hot substrate. Long-chain carboxylates, soluble in volatile organic solvents, can be deposited as well, even at room temperature. 

A solvent is a substance that can dissolve another substance, and a volatile solvent is a liquid that vaporizes at room temperature. Volatile solvents include adhesives such as airplane glue and rubber cement aerosols such as spray paint, hair spray, and air freshener solvents such as nail polish remover, paint remover, and lighter fluid and cleaners such as dry cleaning fluid, spot remover, and degreasers. 

Aerosols used for inhalation therapy are generally packaged in containers with metered values. The standard procedure is to discharge the entire contents of the container for assay. For betamethasone dipropionate and betamethasone valerate topical aerosols, the contents are discharged into a volumetric flask and the propellants carefully boiled off. Precautions should be taken, as many of these propellants are flammable. The residue is diluted to volume with isopropanol-acetic acid (1000 1) and filtered [50]. Another approach is to discharge the contents into ethanol or dilute acid. An alternative is to immerse the canister in liquid nitrogen for 20 min, open the canister, evaporate the liquid contents, and dissolve the residue in dichloromethane. A unit spray sampling apparatus for pressurized metered inhalers has been described [51]. The components in an aerosol product that can be the cause of assay variance have been studied [52]. A method to quantify the volatile components of aerosol products has been developed [53]. 

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