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Electron capture dissociation, electron detachment dissociation, and collision-induced dissociation of polyamidoamine (PAMAM) dendrimer ions with amino, amidoethanol, and sodium carboxylate surface groups.

Kaczorowska MA, Cooper HJ - J. Am. Soc. Mass Spectrom. (2008)

Bottom Line: ECD and EDD of the PAMAM dendrimers resulted in simple mass spectra, which are straightforward to interpret, whereas CID produced complex mass spectra.CID of the PAMAM dendrimers showed a strong dependence on the nature of the surface group and occurred mostly in the outer generation.The results demonstrate the potential utility of ECD and EDD as a tool for the structural analysis of PAMAM dendrimers.

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.

ABSTRACT
Here, we investigate the effect of the structure (generation) and nature of the surface groups of different polyamidoamine (PAMAM) dendrimers on electron-mediated dissociation, either electron capture dissociation (ECD) or electron detachment dissociation (EDD), and compare the fragmentation with that observed in collision-induced dissociation (CID). ECD and EDD of the PAMAM dendrimers resulted in simple mass spectra, which are straightforward to interpret, whereas CID produced complex mass spectra. The results show that electron-mediated dissociation (ECD and EDD) of PAMAM dendrimers does not depend on the nature of the surface group but tends to occur within the innermost generations. CID of the PAMAM dendrimers showed a strong dependence on the nature of the surface group and occurred mostly in the outer generation. The results demonstrate the potential utility of ECD and EDD as a tool for the structural analysis of PAMAM dendrimers.

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Related in: MedlinePlus

EDD FT-ICR mass spectrum (top) and CID FT-ICR mass spectrum (bottom) of [M − 5Na + 2H]3− ions of PAMAMG0.5COONa.
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fig3: EDD FT-ICR mass spectrum (top) and CID FT-ICR mass spectrum (bottom) of [M − 5Na + 2H]3− ions of PAMAMG0.5COONa.

Mentions: The PAMAM dendrimer, generation 0.5, with eight sodium carboxylate surface groups and ethylenediamine core (PAMAMG0.5COONa), forms multiply charged anions via negative electrospray. The dendrimer ions have mixtures of sodium and proton counterions because protons present in the MeOH/NH4OH solution compete with sodium ions associated with the surface groups [16]. Within each charge state, mixtures of counterions were found according to the formula [M − (n + m)Na + mH]n−, where n is charge state (n = 2–4), and m is the number of protons replacing sodium in the surface groups. Figure 3 shows the EDD and CID mass spectra obtained from [M −5Na + 2H]3− ions. The EDD mass spectrum (Figure 3, top) is dominated by peaks corresponding to the loss of one, two, and three T fragments [CH2=CH—C(O)—O−] (Δm = 71.01333), which results from cleavage at an outer tertiary amine. Loss of T fragments is also observed following CID (Figure 3, bottom). The only peak present in the EDD mass spectrum, but not present in the CID mass spectrum, occurs at m/z 497.7054 and can be assigned to the [G1/2(in)]2− fragment (m/zcalc 497.7080). This fragment results from cleavage at the tertiary amine, which was also a major fragmentation channel in the ECD of PAMAM cations. No fragments corresponding to cleavage of the amide bond or c/z•-type cleavages were observed following EDD.


Electron capture dissociation, electron detachment dissociation, and collision-induced dissociation of polyamidoamine (PAMAM) dendrimer ions with amino, amidoethanol, and sodium carboxylate surface groups.

Kaczorowska MA, Cooper HJ - J. Am. Soc. Mass Spectrom. (2008)

EDD FT-ICR mass spectrum (top) and CID FT-ICR mass spectrum (bottom) of [M − 5Na + 2H]3− ions of PAMAMG0.5COONa.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2571976&req=5

fig3: EDD FT-ICR mass spectrum (top) and CID FT-ICR mass spectrum (bottom) of [M − 5Na + 2H]3− ions of PAMAMG0.5COONa.
Mentions: The PAMAM dendrimer, generation 0.5, with eight sodium carboxylate surface groups and ethylenediamine core (PAMAMG0.5COONa), forms multiply charged anions via negative electrospray. The dendrimer ions have mixtures of sodium and proton counterions because protons present in the MeOH/NH4OH solution compete with sodium ions associated with the surface groups [16]. Within each charge state, mixtures of counterions were found according to the formula [M − (n + m)Na + mH]n−, where n is charge state (n = 2–4), and m is the number of protons replacing sodium in the surface groups. Figure 3 shows the EDD and CID mass spectra obtained from [M −5Na + 2H]3− ions. The EDD mass spectrum (Figure 3, top) is dominated by peaks corresponding to the loss of one, two, and three T fragments [CH2=CH—C(O)—O−] (Δm = 71.01333), which results from cleavage at an outer tertiary amine. Loss of T fragments is also observed following CID (Figure 3, bottom). The only peak present in the EDD mass spectrum, but not present in the CID mass spectrum, occurs at m/z 497.7054 and can be assigned to the [G1/2(in)]2− fragment (m/zcalc 497.7080). This fragment results from cleavage at the tertiary amine, which was also a major fragmentation channel in the ECD of PAMAM cations. No fragments corresponding to cleavage of the amide bond or c/z•-type cleavages were observed following EDD.

Bottom Line: ECD and EDD of the PAMAM dendrimers resulted in simple mass spectra, which are straightforward to interpret, whereas CID produced complex mass spectra.CID of the PAMAM dendrimers showed a strong dependence on the nature of the surface group and occurred mostly in the outer generation.The results demonstrate the potential utility of ECD and EDD as a tool for the structural analysis of PAMAM dendrimers.

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.

ABSTRACT
Here, we investigate the effect of the structure (generation) and nature of the surface groups of different polyamidoamine (PAMAM) dendrimers on electron-mediated dissociation, either electron capture dissociation (ECD) or electron detachment dissociation (EDD), and compare the fragmentation with that observed in collision-induced dissociation (CID). ECD and EDD of the PAMAM dendrimers resulted in simple mass spectra, which are straightforward to interpret, whereas CID produced complex mass spectra. The results show that electron-mediated dissociation (ECD and EDD) of PAMAM dendrimers does not depend on the nature of the surface group but tends to occur within the innermost generations. CID of the PAMAM dendrimers showed a strong dependence on the nature of the surface group and occurred mostly in the outer generation. The results demonstrate the potential utility of ECD and EDD as a tool for the structural analysis of PAMAM dendrimers.

Show MeSH
Related in: MedlinePlus