Negative flame ions

The negative-ion-molecule reactions in flames can be conveniently classified, as were positive ions, into naturally occurring flame ions, and ions produced by the addition of halogens or metals. 

Determination of Na " and Na" ions in raw cosmetic materials was conducted with the developed method of flame photometry. A necessity of development of method of samples preparation arose up in the work process, as this spicily-aromatic raw material contained pectin in amount 0.1-0.5% and that prevented preparation of samples by standard method of extracts dilution and required incineration of analyzed sample, time of analysis was increased in 60 times. It was established that CaCl, solution with the concentration 0,4 % caused destmctions of the carbopol gel. It was established that the addition of 0,1% CaCl, and 0,1% NaCl salts solutions into the system intensified the effect of negative action of these salts onto the gel stmcture and the gel destmcted completely. 

Origin of Ions in Hydrocarbon Flames. Many ions, both positive and negative, are observed in hydrocarbon flames studied by mass spectrometric methods (9, 14, 26). Most of these are produced by ion-molecule reactions following the formation of primary ions from neutral species. 

Negative Ions. Negative ions in flames have been studied less widely than positive ions because they are present in much smaller concentrations typically, n+//i 100. The primary source of negative ions has been suggested (20) to be Reaction 3, comparable to Reaction 4 (see the section on flames with halogen additives). 

The above values of kz may be compared with that required to explain Green s results (20) (obtained from measurements on an atmospheric pressure H2/02/Ar flame at 2180°K. to which had been added 2.8% by volume of CoH2) in terms of Reaction 3. Under steady-state conditions the rates of production and loss of negative ions are equal. (Steady-state conditions are those under which ion concentrations maxi-... 

The negative ion concentrations all show very definite maxima on the fuel-rich side of stoichiometric flame composition. 

The work of Bleekrode and Nieuwpoort (3) suggests that at 1 torr in a stoichiometric C2H2/02 flame, tic2 1013 cm.-3 The observed rate of production of negative ions would thus necessitate a three-body rate constant for attachment of electrons to C2 of about 5 X 10-28 cm.6 molecule-2 sec.-1 This seems somewhat high but is not altogether impossible. 

As expected, the addition to the flame of the electronegative species Cl (from HC1) or CN (from CH3CN) produces Cl or CN. At low pressures, the total negative ion population may be increased (9) while at 1 atm. all the negative ions can be replaced by Cl (14). Thus, both direct attachment and charge transfer are involved. 

Figure 3. Negative ion profiles in an ethylene/oxygen flame at...

Collisional Detachment. Reactions of negative ions in flames not containing hydrocarbons have not been widely studied, although OH -ion formation is important in flames containing high electron concentrations. The rate constant k l of the reaction... 

Flames, either with or without metallic additives, are rich in ion-molecule reactions of both positive and negative ions. The use of flames as media in which these reactions may be studied over broad ranges of temperature and pressure is in its infancy. Most of the phenomena observed can be explained qualitatively, and some quantitative results have been obtained. 

Interference occurs when compounds co-elute with the analytes and are not detected directly by a specific detector. The effect is to create negative peaks or an erratic response for the analyte. This problem can be identified by using a non-specific detector such as an ion trap MS detector, an MS in the electron impact ionization mode, or a flame ionization GC detector. 

Repeated TLC of active, pooled fractions from Red Flame grapes revealed major spots with Ry s corresponding to those of catechin and epi-catechin, identical color reaction with p-toluenesolfonic acid spray reagent, and coelution of trimethylsilane (TMS) derivatives by GC with reference samples of these flavans. However catechin and epicatechin were assayed with the bacterial strains described and no activity was detected. TMS-derivatized samples of active grape flavans were examined by GC-MS, but a search for the molecular ions of a number of known wr-inducing phenolics yielded negative results. 

High speed emission spectroscopy has been used to study free radicals and positive, negative, and multiple ions produced in explosions and flames. Many excited states would exist for many different species from coal subjected to high energy. Complex spectra would result. The combination of electronic-vibration-rotation transitions observable in emission spectroscopy... 

When careful measurements are made in a flame, very little HCO+ or e is found. This is because these species further react very quickly. The first loses H+ (proton abstraction) to any of a variety of species on collision. The most stable product is and its polymerized form (H2O) H+. It is such polymerization about a charged species which makes raindrops. Such watery charge is what is collected. The free electron can be captured by radicals, most importantly, OH, but also by H2O and O2. Thus the negative ionic species weighs about the same as the final positive ion. 

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