Triethylammonium ion

Figure 7 The stability of liposomal VCR in liposomes prepared using different triethylammonium ion gradients. VCR can be deformylated under acidic conditions, similar to those found in the intraliposomal lumen of remote-loaded liposomes. (A) The deformylated product is inactive compared to the parent drug. (B) HPLC chromatograms show peaks for both VCR (rt = 9.5 minutes) and deformylated VCR (rt= 11.1 minutes) for liposomes prepared with either sulfate or citrate as the intraliposomal trapping agent and stored for three months at 4°C to 6°C. Abbreviation VCR, vincristine.

The other products, methoxide ion and triethylammonium ion, would equilibrate to give the weakest acid and weakest base (see Appendix C). 

For the simplest form of such reactions, palladium on charcoal is the catalyst and aqueous formate the hydrogen donor. Interfacial transport of formate is facilitated by an organophilic counter ion, and for the present purpose a triethylammonium ion is mostly used [48, 49]. 

Studies of the entropy changes attending the dissociation of the cations of these amines have led to somewhat conflicting results (Table 1). From measurements at only two temperatures Evans and Hamann found the value of —AS° decreased systematically from methylamine to n-butylamine, this being accompanied by a progressive increase in AH°. They also found —AS° for the dissociation of the diethylammonium ion to be less than for the dimethylam-monium ion. Fyfe , on the other hand, inferred from measurements at four temperatures that the values of —AS° for the ethylammonium, diethylammonium, and triethylammonium ions were all much higher than for the corresponding methylammonium ions. 

Adenosine 5"-[P-thio]diphosphate tri-lithium salt [73536-95-5] M 461.1. Purified by ion-exchange chromatography on DEAE-Sephadex A-25 using gradient elution with 0.1-0.5M triethylammonium bicarbonate. [Biochem Biophys Acta 276 155 7972.]... 

Workup (a) The product is isolated by passage through an ion exchange column (Dowcx AG1-X8, HCOf 100 mL) and consecutive elution with 200 mM triethylammonium bicarbonate solution. After ion exchange... 

Bromophenol Blue immobilized on [l,5-Bis(p-dimethylaminophenyl)-2,4-pentadienyl]-triethylammonium methylcellulose carbenium ion immobilised on Nation ... 

The ion-complex equilibrium position depends on the nature of the amine. This is clearly manifested in the case of triethylammonium and pyridinium 2,2,5-triphenyl-5-thio-1,3,2,5-dioxaborataphosphorinanes... 

For sufficient retention of these very polar sulfonated carboxylates on RP columns, the addition of an ion-pairing (IP) agent such as tetraethylammonium acetate (TEAA) to the LC buffer was compulsory [13]. To maintain the compatibility of the eluent with the MS interface, the use of such an involatile cationic additive entailed a cation exchanger to be placed between the column and the interface [13]. Alternatively, equimolar amounts (5 mM) of acetic acid and triethyl-amine, which form the volatile IP agent triethylammonium, were added to the mobile phase in order to improve the retardation of very polar SPC [14]. While the first approach with TEAA was effective in retaining even the very short-chain C3- and C4-SPC (Fig. 2.10.4), the weaker IP agent triethylammonium notably increased the retention of C5-SPC and higher, whereas C4-SPC elutes almost with the dead volume of the LC (Fig. 2.10.5). Addition of commonly used ammonium acetate as buffer component led to the co-elution of the short-chain SPC ([Pg.322]

When chromatographic resolution of species based on modifications located at the protein surface is desired, it may be advisable to use conditions that favor retention of native conformation.17 Here, the standard acidic conditions described in the preceding text may be inappropriate, and mobile phases buffered near neutrality may be required. Buffers based on ammonium acetate, ammonium bicarbonate, and triethylammonium phosphate may prove more useful in resolving polypeptide variants with differing posttranslational modifications, amino acid substitutions, or oxidation and deamidation products. The addition of more hydro-phobic ion-pairing agents may be needed to obtain polypeptide retention, and a variety of alkyl sulfonates and alkyl amines have been described for specific applications.17... 

Ion-pair chromatography has also been used for the separation of aspartame from other sweeteners. The ion-pair reagents commonly used are triethylammonium phosphate (32), tetra-ethylammonium hydroxyde (47), tetrapropylammonium hydroxide (40), pentanesulfonate (52), tetrabutylammonium phosphate (34), tetrabutylammonium hydrogen sulfate (66), and tetrabutyl-ammonium p-toluenesulfonate (24). 

Carbonate resins are generally used to neutralize strong mineral acids (e.g., HBr) when generated in situ as a by-product on certain reactions. These resins normally contain a quaternary ammonium carbonate salt functionality. Specific examples are triethylammonium carbonate (7) and trimethylammonium bicarbonate (8) resins (Fig. 5) ion exchanging the anionic halogen for carbonate. 

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