Nitrates, organic interactions

Anionic and neutral polymers are usually analyzed successfully on Syn-Chropak GPC columns because they have minimal interaction with the appropriate mobile-phase selection however, cationic polymers adsorb to these columns, often irreversibly. Mobile-phase selection for hydrophilic polymers is similar to that for proteins but the solubilities are of primary importance. Organic solvents can be added to the mobile phase to increase solubility. In polymer analysis, ionic strength and pH can change the shape of the solute from mostly linear to globular therefore, it is very important to use the same conditions during calibration and analysis of unknowns (8). Many mobile phases have been used, but 0.05-0.2 M sodium sulfate or sodium nitrate is common. 

Evaporation by heating a filtrate from precipitation of potassium cobaltinitrite caused it to turn purple and explode violently [1]. This was attributed to interaction of nitrite, nitrate, acetic acid and residual cobalt with formation of fulminic or methylnitrolic acids or their cobalt salts, all of which are explosive [2], Mixtures containing nitrates, nitrites and organic materials are potentially dangerous, especially in presence of acidic materials and heavy metals. A later publication confirms the suggestion of formation of nitro- or nitrito-cobaltate(III) [3],... 

Several cases of interaction between anion exchange resins and nitric acid causing rapid release of energy or explosion have occurred [1]. The cause has been attributed to oxidative degradation of the organic resin matrix and/or nitration of... 

Scheme 2.1 Simplified mechanism whereby organic nitrates (RONO2) effect vasorelaxation. Thiols (R -SH) interact with organic nitrates to give nitrite (NO2-), which is converted successively to nitrous acid (HONO) and NO. NO then reacts with a thiol (R11 —SH) to give a nitrosothiol...

R11 —SNO), which upregulates sGC, leading to increase in cGMP and relaxation. In the course oftheir interaction with organic nitrate, thiols (R1—SH) are oxidised to disulfides (R1—S—S—R1). Adapted from Ignarro et ai. [11]. 

Fung, H-L., Chong, S., Kowaluk, E., Hough, K., Kakemi, M., Mechanisms for the pharmacological interaction of organic nitrates with thiols. Existence of an extracellular pathway for the reversal of nitrate vascular tolerance by N-acetylcytseine. J. Pharmacol. Exp. Ther. 245 (1988), 524-530... 

The mechanism of action of nitroglycerin and other organic nitrates is thought to involve an interaction with nitrate receptors that are present in vascular smooth muscle. Intact vascular endothelium is not necessary for... 

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