Atmosphere quantitative determination

Mobile phase 3 may be used for the detection and semi-quantitative determination of residual N-bromosuccinimide. Thereby, the plate is sprayed with water and then placed in a chlorine atmosphere for 10 minutes. Excess chlorine is removed by placing the plate in a stream of warm air for another 10 minutes. After spraying with o-toluidine reagent, the evaluation is made against a dilution of N-bromosuccinimide. 

The Aspirator.—Since the closely packed absorption vessels offer a resistance equivalent to several centimetres of water to the gas stream there must be sufficient pressure at the junction of the constricted part of the combustion tube with the calcium chloride tube to overcome this resistance when the absorption apparatus is opened. But to create this pressure would seriously endanger the quantitative determination of the products of combustion because the high concentration of these set up at this point would increase the possibility of leakage. The most effective remedy consists in maintaining within the junction a pressure as near as possible to the atmospheric pressure. For this purpose an aspirator is attached to the apparatus so that a determined, easily variable diminished pressure can be maintained in the absorption apparatus. 

Negative atmospheric pressure chemical ionization (APC) low-energy collision activation mss spectrometry has also been employed for the characterization of flavonoids in extracts of fresh herbs. Besides the separation, quantitative determination and identification of flavonoids, the objective of the study was the comparison of the efficacy of the various detection systems in the analysis of flavonoids in herb extracts. Freeze-dried herbs (0.5g of chives, cress, dill, lovage, mint, oregano, parsley, rosemary, tarragon and thyme) were ground and extracted with 20 ml of 62.5 per cent aqueous methanol. After sedimentation the suspension was filtered and used for HPLC analyses. Separations were carried out in an... 

Alpert D. J. Hopke, P. K. A Quantitative Determination of Sources in the Boston Urban Aerosol, Atmospheric Environ.,... 

A variation of eq. (5.453) has been proposed by Fuentes et al. (1991) for quantitatively determining the effect of temperature, time, and atmosphere on the sintering rate of supported metal catalysts ... 

In addition to being oxidized by the hydroxyl radical, alkenes may react with the N03 radical as has been described by several investigators (52, 56, 66). Listed in Table I are some of the organic nitrates that have been predicted to be produced via reaction of OH and N03 with isoprene and pro-pene. Analogous compounds would be expected from other simple alkenes and from terpenes such as a- and (3-pinene. Other possible organic nitrates may be produced via the oxidation of aromatic compounds (53, 54) and the oxidation of carbonaceous aerosols (67). Quantitative determination of these species has not been made in the ambient atmosphere. 

Hultman et al. [130] developed a LC/MS/MS method for the quantitative determination of esomeprazole and its two main metabolites 5-hydro-xyesomeprazole and omeprazole sulfone in 25 /il human, rat, or dog plasma. The analytes and their internal standards were extracted from plasma into methyl ferf-butyl ether-dichloromethane (3 2). After evaporation and reconstitution of the organic extract, the analytes were separated on a reversed-phase liquid chromatography column and measured by atmospheric-pressure positive ionization mass spectrometry. 

Keski-Rahkonen, R et al. Quantitative determination of acetylcholine in microdialysis samples using liquid chromatography/atmospheric pressure spray ionization mass spectrometry. Rapid Commun. Mass Spectrom. 2007, 21, 2933-2943. 

Jensen, A. G. Ndjoko, K. Wolfender, J. L. Hostettmann, K. Camponovo, E Soldati, F. Liquid chromatography-atmospheric pressure chemical ionisation/mass spectrometry A rapid and selective method for the quantitative determination of ginkgolides and hilohalide in Ginkgo leaf extracts and phytopharmaceuticals. Phytochem. Anal., 2002, 13 31-38. 

The quantitative determination of small concentrations of organic solvents in a working place atmosphere by IR spectroscopy has been reported by Schacke et al. (1972). The measurements were carried out using a multipass gas cell with a maximum pathlength of 10 m. Such cells allow the determination of compounds in the ppm or even ppb region. 

A further requirement for measurement of absolute concentrations of excited species in flames is that the volume from which emission is collected be known. The simplest experimental arrangement for flames at atmospheric pressures is to focus the radiation from the flame onto the entrance slit of a spectrograph. Reasonable assumptions can be made about the thickness of the emitting layer, and Ausloos and van Tiggelen have used the arrangement successfully in semi-quantitative determinations of excited OH, NH, NO and NH2 in flames emitting the bands of these species. 

HG Fouda, RP Schneider. Quantitative determination of the antibiotic azithromycin in human serum by high-performance liquid chromatography (HPLC)-atmospheric pressure chemical ionization mass spectrometry Correlation with a standard HPLC-electrochemical method. Ther Drug Monitor 17 179, 1995. 

Ciccioli, P., E. Brancaleoni, M. Possanzini, A. Brachetti, and C. Di Palo (1984). Sampling, identification and quantitative determination of biogenic and anthropogenic hydrocarbons in forested areas. In Physicochemical Behaviour of Atmospheric Pollutants, (B. Versino and G. Angeletti, eds.) Proc. Symp. 3rd, Varese, Italy pp. 62-73. Reidel, Dordrecht. 

Nelson, P. F., S. M. Quigley, and M. Y. Smith (1983). Sources of atmospheric hydrocarbons in Sidney a quantitative determination using a source reconciliation technique. Atmos. Environ. 17, 439-449. 

Charsley and Dunn (102) and Dunn (103) have applied TG to the characterization and quantitative determination of carbon black in rubber. The analysis involves volatilization of the oil and pyrolysis of the polymer in an inert atmosphere followed by oxidation of free carbon black in the rubber. 

Table 17-5 shows potential applications of IR lilter photometers (such as that shown in Figure 16-13) for the quantitative determination of various chemicals in the atmosphere for the purpose of assuring compliance with Occupational Safety and Health Administration (OSHA) regulations. 

Pommier, R. and Frigola, R. (2003). Quantitative determination of Riva,stigminc and its major metabolite in human pla.sma by liquid chromatography with atmospheric-pres.sure chemical-ionization tandem mass. spectrometry. J. Chromaiogr. B Anal. Techno , Biomed. Life Sci, 784(2). 301-313. 

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