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Overview

Overview. The efficiency of charge inversion depends strongly on properties of the analyte and the reagent ions. By choosing appropriate reagent ions, selective charge inversion can be achieved.

sheila-zimmerman
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Overview

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  1. Overview • The efficiency of charge inversion depends strongly on properties of the analyte and the reagent ions. • By choosing appropriate reagent ions, selective charge inversion can be achieved. • This poster particularly emphasizes the effect of dendrimer charge state on the efficiency of charge inversion of protonated drugs.

  2. Introduction • Gas-phase ion/ion reactions have been demonstrated to be effective in manipulating both the polarity and magnitude of charge of an ion.[1] • The ability to invert the polarity of gas-phase ions allows one to study species that may not be formed readily under available ionization conditions. • The goal of this study is to examine the efficiencies and selectivities of various reagent anions for the ion/ion charge inversion of small drug ions present in a complex mixture.

  3. n- - + - H + H Principle of Charge Inversion Ion/Ion Reaction Chemistry Polyamidoamine (PAMAM) Dendrimer (Metabolite Ion) Warfarin n+ - + - H + H 1,4-Diaminobutane (DAB) Dendrimer

  4. Proton Transfer Pathways • Red lines represent the desired product in charge inversion reactions.

  5. Reagent Ions - Dendrimers PAMAM Half Generations DAB Generation 4 [DAB]+7 m/z = 504 PAMAM-NH2 – Generation 3 (MW = 6909) [PAMAM-NH2]+10 m/z = 691 PAMAM – Generation 1.5 [PAMAM]-6 m/z = 429.5

  6. Analytes Warfarin [M+H]+ = 309 [M-H]- = 307 Aztreonam [M+H]+ = 436 [M-H]- = 434 Naproxen [M+H]+ = 231 [M-H]- = 229 Furosemide [M+H]+ = 331 [M-H]- = 329 Bromocriptine [M+H]+ = 654 [M-H]- = 652 Fosinopril [M+H]+ = 564.3 [M-H]- = 562.3 Glafenine [M+H]+= 373 [M-H]- = 371

  7. Methods • The charge inversion reagents, polypropylenimine diamino-butane (DAB) dendrimers and polyamidoamine (PAMAM) dendrimers were made in aqueous ~1-2% acetic acid and in aqueous ~1-2% ammonium hydroxide, respectively. • Drug, drug metabolites, and amino acids were provided by MDS|Sciex and had concentrations of 1mg/mL. • Biological matrix precipitated plasma was diluted 5x in water-methanol (50/50), 5mM NH4OAc, and 0.1% acetic acid. • All experiments were performed on modified Sciex QTRAP-2000/4000 mass spectrometers equipped with multiple nano-electrospray sources.

  8. Q0 Q1 Q2 Q3 Modified QTRAP 2000/4000[6] N2 CAD Gas AuxAC Dual ESIsources • Mutual storage mode reactions are performed by storing the reagent and analyte ions in the Q2 cell. • Reactions were allowed to proceed to the point where >95% of the analyte ions were depleted. RF Exit lens Skimmer IQ1 ST IQ2 IQ3 Deflector Orifice Triggered +HV Triggered -HV Ion/IonReaction Detector

  9. Reagent Analyte 2e7 3e7 positive ion spectrum of Warfarin cations [PAMAM-4H]4- [PAMAM-5H]5- anion only spectrum of PAMAM 1.5g [M+Na]+ + [M+H]+ [PAMAM-6H]6- [M+K]+ 200 400 200 300 400 500 600 800 5e5 post ion/ion - charge inversion of PAMAM and Warfarin in positive mode 1e7 post ion/ion - charge inversion in negative mode [M-H]- [M+Na]+ Products [M+H]+ [M+K]+ [PAMAM-5H]5- 200 300 400 500 200 300 400 500 600

  10. Charge Inversion Efficiency of PAMAM 1.5g

  11. [M+H]+ vs. [M+Na]+ Charge Inversion Efficiencies

  12. Negative  Positive Charge Inversion of Warfarin 2.6e7 Comparison of m/z before (red) and after (blue) charge inversion [M-H]- [M+H]+ [M+Na]+ [M+K]+ 400 300 Charge Inversion Efficiency 1.1e7 [M+H]+ z [M+Na]+ [PAMAM+8H]8+ [M+K]+ 900 300 500 700 Charge Inversion of [M-H]- with PAMAM-NH2 Gen 3

  13. Efficiencies for PAMAM 0.5g (pos  neg (analyte = warfarin) PAMAM 0.5 Charge States Charge Inversion Efficiency 1.5e8 [Z-3H]3- 2X Charge State [X=947] charge states [Y=1278] charge states [Z=1091] charge states [Z-2H]2- [Z+Na-3H]3- [Z+Na-2H]2- [Z+2Na-3H]3- [Z-3Na-3H]3- [Y-3H]3- [Z+2Na-2H]2- [X-3H]3- [Y-2H]2- [Y+Na-3H]3-v [Z-3Na-2H]2- [Z-3H]3- [Z+3Na-2H]2- [X-2H]2- [Y+Na-2H]2- [Z+4Na-2H]2- 200 300 400 500 600 700

  14. Efficiencies for PAMAM 2.5g (pos  neg (analyte = warfarin) PAMAM 2.5 Charge States non-isolated 9.4e6 [W=5959] charge states [X=5561] charge states [Y=5481] charge states [Z=5401] charge states Charge States of [X-6H]6- [Y-7H]7- [Z-7H]7- [X-7H]7- [Y-8H]8- [X-8H]8- [Y-6H]6- [X-6H]6- [P-8H]8- [W-8H]8- [W-9H]9- [W-12H]12- [Y-9H]9- [Z-6H]6- [W-10H]10- [W-7H]7- [W-13H]13- [Y-5H]5- [Z-5H]5- 400 600 800 1000

  15. Charge Inversion Efficiencies of Different Drug Compounds PosNeg Charge Inversion of metabolites Reagent: PAMAM1.5g NegPos Charge Inversion of metabolites Reagent: DAB gen4

  16. Direct Analysis of ProteinPrecipitated Plasma • Acetonitrile precipitated plasma • Monitor charge inversion of amino acids • Endogenous OR spiked • Amino acid selected due to their ability to form ions in both polarity with ESI source Arginine (ARG) Generic Amino Acid

  17. Positive to Negative Charge Inversion of Amino Acids Positive spectrum of Arginine 4.9e7 [Arg+H]+ 2.2e8 [PAMAM-6H]6- 2x [PAMAM-5H]5- 1.1x [PAMAM-4H]4- [Arg-H]- 50 150 350 550 700 Charge Inversion spectrum of Arginine and PAMAM1.5g

  18. Negative spectrum of Arginine Negative to Positive Charge Inversion of Amino Acids 1.6e7 [Arg-H]- 1.5e8 [PAMAM+10H]10+ 1.1x [Arg+H]+ 350 50 150 550 Charge Inversion spectrum of Arginine and PAMAM-NH2 Gen3

  19. Arg [M-H]- Arg [M+H]+ Negative Mode Spray Negative Mode Detection Positive Mode Spray Positive Mode Detection Ile/Leu His CHARGE INVERSION Positive Mode Spray Negative Mode Detection Asn Val Phe Thr Pro Inverting entire mass range

  20. Arg [M-H]- Arg [M+H]+ Negative Mode Spray Negative Mode Detection (isolation with Q1) Positive Mode Spray Positive Mode Detection (isolation with Q1) Positive Mode Spray Negative Mode Detection (isolation with Q1 used) CHARGE INVERSION Inverting SELECTED mass region (Arg+H – 3 amu wide)

  21. Infusion Experiments with Histidine and Arginine • Charge Inversion of precipitated plasma (Histidine m/z) ~ 18.2% • Histidine spiked in precipitated plasma ~ 29.4% 8e7 N-butyl- benzenesulfon- Amide 1.8x [PAMAM-5H]5- 1.8x [PAMAM-6H]6- 9.1x [His-H]- 150 350 550 700 8e7 N-butyl- benzenesulfon- Amide • Charge Inversion of precipitated plasma (Arginine m/z)~ 33.3% • Arginine spiked in precipitated plasma ~ 40.1% [PAMAM-5H]5- 2.3x [PAMAM-6H]6- 11.5x [Arg-H]- 50 150 350 550 700

  22. Conclusions • Dendrimers for a given analyte should be chosen based on charge, m/z of charge state, and functional terminated group. • [M+H]+ and [M+Na]+ charge invert with equal efficiency. • Amino acids charge invert in both polarities (i.e ability to lose or gain protons) based on their zwitterionic character. • Amino acids are selectivity found when charge inverting precipitated plasma. • Addition of plasma to the amino acid sample decreases the charge inversion efficiency because of “matrix suppression”. In this context, matrix suppression on the ion/ion reaction is due to the depletion of reagent anions by virtue of addition “chemical noise” cations in the positive ion population.

  23. References • He, M.; Emory, J. F.; McLuckey, S. A. Anal. Chem.2005, 77, 3173-3182. • McLuckey, S.A.; Stephenson, J. L., Jr. Mass Spectrom. Rev. 1998, 17, 369-407. • Bowie, J. H.; Brinkworth, C. S.; Dua, S. Mass Spectrom. Rev.2002, 21, 87-107. • Kaiser, R. E.; Cooks, R. G.; Stafford, G. C.; Syka, J. E. P.; Hemberger, P. H. Int. J. Mass Spectrom. Ion Processes.1991, 106, 79-115. • He, M.; McLuckey, S. A. J. Am. Chem. Soc.2003, 125, 7756-7757. • X. Liang, Y. Xia, S.A. McLuckey, Anal.Chem.,2006, 78, 3208-3212.

  24. Acknowledgements • MDS|Sciex • NIH GM 45372 • McLuckey group

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