Sulfonphthaleins are one of the most interesting families of anionic dyes and have attracted scientific attention; this is attributed to their molecular structure which allows formation of ion-associate complexes with various drugs, where ion pair
or ion association complexes are those complexes in which the analytical species associates with oppositely charged ions to form neutral compounds [9-12].
So far, analysis of this compound by GC/MS method was performed after ion pair
extraction combined with derivatization process and this technique seemed to be the most effective one; however some recent studies showed the possibility of 4-MeI analysis by solid phase microextraction (SPME) method without derivatization .
Metabolites M1 and M1' (retention times at 8.9 and 9.8 min, resp.) were detected (Figures 1(b) and 1(c)) in both HLMs and MLMs incubations by scanning of an ion pair
of m/z 946 [right arrow] 817, and M1 and M1' showed identical mass fragmental patterns with indicative characteristic secondary ion signals associated the cleavage of the GSH moiety (Figure 1(e)).
This behavior is not observed in any of the mixtures where toluene is present, thus indicating a strong role of toluene in facilitating the access of ethylene to the catalyst/cocatalyst ion pair
. The profiles for solvent mixtures 25/75 and 50/50 T/H are intermediate between the two solvents, while for any mixture containing more than 50% of toluene the uptake profiles show a faster reaction and a higher total consumption, even compared to the pure solvents.
The purity of ion pair
as electroactive material ensures correct ion exchange between the solution and the membrane of electrode.
The ionizing voltage was -4200 V in the negative ion mode, the ion pair
of the parent ion (Q1)/daughter ion (Q3) was set up as the unit of discernment, and the dwell time of each ion pair
was 150 ms.
However; the absorbance of both complexes were decreased gradually at 40C indicating the destruction of ion pair
AQUEOUS SUBSTANCES Aqueous copper(II) nitrate Hydrated copper and (-1M), C[u.sup.2+](aq) + nitrate ions, and water 2N[0.sub.3](aq) molecules, in a 1:3:55 ratio, roam amongst the water molecules, with the occasional formation of a transient ion pair
, followed by its dissociation.
On mixing aqueous solutions of bismuth(III) tetraiodide complex and the cited drugs in an acidic medium, a reddish orange precipitate instantaneously appeared that is attributed to the ion pair
formed in the reaction (Scheme 1).
For instance, complexation of crown ether derivatives with viologen dicationic guests having univalent counterions included two modes: (1) dissociation of the ion pair
prior to interaction of the free dication with the host to produce a complex that is not ion-paired and (2) direct complexation of the ion-pair to produce an ion paired
In addition, the effects of soil dissolved ion pair
were determined by use of MINTEQ geochemical software program.
Each TAD yielded 2 separate product ions with good intensity, either of which was suitable as a confirmation ion pair
. The ring formed during the reaction also prevents cleavage of the derivatized portion of the molecule during fragmentation in Q2, forcing breaks to occur through the vitamin D backbone (Fig.