Chemical Reaction Gas Chromatography

Polymers being, with few exceptions, solid snbstances, cannot be directly analysed using gas chromatography (GC). However, it is possible by the application of well-controlled chemical reactions to decompose polymers to simpler volatile substances that are amenable to GC and thereby one can obtain information concerning the original polymer, the chemical structnre composition and end group analysis. 

In this procedure the polymer is reacted with a suitable reagent which produces a derivative or breakdown product. 

A further special case of reaction GC involves pyrolysis (or photolysis) of the polymer in the absence of oxygen and examination of the volatiles produced by GC to provide information on the structure of the original polymer. 

Further complementary techniques can be applied to obtain even more information. Thus, pyrolysis - gas chromatography (Py-GC) can be coupled with mass spectrometry (MS see Chapter 6). 

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Continuous reaction gas chromatography The dehydrogenation of cyclohexane over Pt/g-A1203 (with A.W. Wardwell and R.W. Carr, Jr.). American Chemical Society Symposium Series no. 196. Washington, D.C. American Chemical Society (1982). 

Chemical Analysis. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) techniques were used to analyze 4-chlorophenol and its oxidation intermediates. For GC-MS analysis, the samples were acetylated in pyridine. The samples were first evaporated to dryness. Then 200 xL of pyridine and 200 (xL of acetic anhydride were added to the dry residue. The samples were heated at 65 °C for 2-3 h to ensure the complete acetylation reaction, and then gently evaporated to dryness in a nitrogen stream. Finally, the residue was redissolved in 0.1 mL of hexane for GC analysis. A GC (HP model 5890) equipped with mass selective detector (HP model 5971) and SPB-5 capillary column (Supelco Co., PA., 25- X 0.2-mm i.d. X 0.33-p.m film thickness) was used. To separate different intermediate products, various oven-temperature programs were performed. The GC-MS interface line was maintained at 300 °C. The mass-... 

Characteristic Classical phyacal chromatography Analytical reaction gas chromatography (physico-chemical chromatography)... 

The methods of analytical reaction gas chromatography, making use of the differences in the chemical, chromatographic and detection properties of the main and trace components, in some instances offer simple solutions even to such complex situations where, for example, the zone of the main component completely masks the trace zones. The general methods of analytical reaction GC, developed for trace analysis (with the assumption that the trace and main components have different reactivities) are listed in Table... 

Reaction gas chromatography. Identification of a series of groups of substances can be performed by carrying out a chemical reaction with the sample either before it enters the column or after its passage through it. A reaction should be chosen which occurs selectively with only a certain... 

Reaction GC is a variation of GC in which chemical reaction is coupled with the chromatographic separation. Chemical transformations in analytical reaction gas chromatography always take place in an integral chromatographic system, in a reaction syringe, a precolumn reactor, or the column itself. The combination of the chemical and the chromatographic methods is a more efficient tool for... 

Reaction gas chromatography 58—61) has become one of the most convenient methods for performing chemical reactions at the microgram level. In this technique, the unknown compound is injected into the GC system and is retained or transformed, frequently at the injection port on a precolumn. The products that elute can be collected and analyzed. 

Figure 8. Rate of carbon monoxide oxidation on calcined Pt cube monolayer as a function of temperature [27]. The square root of the SFG intensity as a function of time was fit with a first-order decay function to determine the rate of CO oxidation. Inset is an Arrhenius plot for the determination of the apparent activation energy by both SFG and gas chromatography. Reaction conditions were preadsorbed and 76 Torr O2 (flowing). (Reprinted from Ref. [27], 2006, with permission from American Chemical Society.)...

Gas chromatography is one of the most powerful analytical techniques available for chemical analysis. Commercially available chemiluminescence detectors for GC include the FPD, the SCD, the thermal energy analysis (TEA) detector, and nitrogen-selective detectors. Highly sensitive detectors based on chemiluminescent reactions with F2 and active nitrogen also have been developed. 

Much less work has been focused on the effect of polymer structure on the resist performance in these systems. This paper will describe and evaluate the chemistry and resist performance of several systems based on three matrix polymers poly(4-t-butoxycarbonyloxy-a-methylstyrene) (TBMS) (12), poly(4-t-butoxycarbonyloxystyrene-sulfone) (TBSS) (13) and TBS (14) when used in conjunction with the dinitrobenzyl tosylate (Ts), triphenylsulfonium hexafluoroarsenate (As) and triphenylsulfonium triflate (Tf) acid generators. Gas chromatography coupled with mass spectroscopy (GC/MS) has been used to study the detailed chemical reactions of these systems in both solution and the solid-state. These results are used to understand the lithographic performance of several systems. 

Isotopes of hydrogen. Three isotopes of hydrogen are known H, 2H (deuterium or D), 3H (tritium or T). Isotope effects are greater for hydrogen than for any other elements (and this may by a justification for the different names), but practically the chemical properties of H, D and T are nearly identical except in matters such as rates and equilibrium constants of reactions (see Tables 5.1a and 5.1b). Molecular H2 and D2 have two forms, ortho and para forms in which the nuclear spins are aligned or opposed, respectively. This results in very slight differences in bulk physical properties the two forms can be separated by gas chromatography. 

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