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1

Characterization and Quantitation of Aprepitant Drug Substance Polymorphs by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

Helmy, Roy, Zhou, George X., Chen, Yadan W., Crocker, Louis, Wang, Tao, Wenslow, Robert M., Vailaya, Anant

Journal:

Analytical Chemistry

Année:

2003

Langue:

english

Fichier:

PDF, 103 KB

english, 2003

2

Using miniature MS system with automatic blood sampler for preclinical pharmacokinetics study

Pu, Fan, Zhang, Wenpeng, Bateman, Kevin P, Liu, Yong, Helmy, Roy, Ouyang, Zheng

Journal:

Année:

2017

Langue:

english

Fichier:

PDF, 586 KB

english, 2017

3

Thermal stability of organic monolayers chemically grafted to minerals

Jeffrey McElwee, Roy Helmy, Alexander Y. Fadeev

Journal:

Journal of Colloid and Interface Science

Année:

2005

Langue:

english

Fichier:

PDF, 303 KB

english, 2005

4

Greening analytical chromatography

Christopher J. Welch, Naijun Wu, Mirlinda Biba, Robert Hartman, Tanja Brkovic, Xiaoyi Gong, Roy Helmy, Wes Schafer, James Cuff, Zainab Pirzada, Lili Zhou

Journal:

TrAC Trends in Analytical Chemistry

Année:

2010

Langue:

english

Fichier:

PDF, 1006 KB

english, 2010

5

‘REAL’ TRANSACTIONS COSTS ARE INESSENTIAL

Helmy Baligh, Daniel A. Graham, E. Roy Weintraub, Morris Weisfeld

Journal:

Année:

1976

Langue:

english

Fichier:

PDF, 161 KB

english, 1976

6

Self-Assembled Monolayers Supported on TiO 2 : Comparison of C 18 H 37 SiX 3 (X = H, Cl, OCH 3 ), C 18 H 37 Si(CH 3 ) 2 Cl, and C 18 H 37 PO(OH) 2

Helmy, Roy, Fadeev, Alexander Y.

Journal:

Année:

2002

Langue:

english

Fichier:

PDF, 95 KB

english, 2002

7

Development and Application of a User-Friendly Automated HPLC Dilution Macro for API Route Optimization

Zang, Jia, Sirota, Eric, Moment, Aaron, Williams, J. Michael, Tellers, David M., Helmy, Roy

Journal:

Organic Process Research & Development

Année:

2012

Langue:

english

Fichier:

PDF, 497 KB

english, 2012

8

Ambient Pressure Desorption Ionization Mass Spectrometry in Support of Preclinical Pharmaceutical Development

Helmy, Roy, Schafer, Wes, Buhler, Leah, Marcinko, Stephen, Musselman, Brian, Guidry, Erin, Jenkins, Herb, Fleitz, Fred, Welch, Christopher J.

Journal:

Organic Process Research & Development

Année:

2010

Langue:

english

Fichier:

PDF, 975 KB

english, 2010

9

A novel compact mass detection platform for the open access (OA) environment in drug discovery and early development

Gao, Junling, Ceglia, Scott S., Jones, Michael D., Simeone, Jennifer, Antwerp, John Van, Zhang, Li-Kang, Ross, Charles W., Helmy, Roy

Journal:

Journal of Pharmaceutical and Biomedical Analysis

Année:

2016

Langue:

english

Fichier:

PDF, 2.00 MB

english, 2016

10

ChemInform Abstract: Excited-State Acid—Base Chemistry of Coordination Complexes

Charles Hicks, Guozhong Ye, Chaim Levi, Marlyn Gonzales, Irina Rutenburg, Jainwei Fan, Roy Helmy, Abe Kassis, Harry D. Gafney

Journal:

Année:

2001

Fichier:

PDF, 25 KB

2001

11

Improving sensitivity in chiral supercritical fluid chromatography for analysis of active pharmaceutical ingredients

Roy Helmy, Mirlinda Biba, Jia Zang, Bing Mao, Kimber Fogelman, Vaso Vlachos, Paul Hosek, Christopher J. Welch

Journal:

Année:

2007

Langue:

english

Fichier:

PDF, 549 KB

english, 2007

12

Selectivity of amylose tris(3,5-dimethylphenyl-carbamate) chiral stationary phase as a function of its structure altered by changing concentration of ethanol or 2-propanol mobile-phase modifier

Roy Helmy, Tao Wang

Journal:

Journal of Separation Science

Année:

2005

Langue:

english

Fichier:

PDF, 332 KB

english, 2005

13

Exploiting pH mismatch in preparative high-performance liquid chromatographic recovery of ertapenem from mother liquor streams

Anant Vailaya, Peter Sajonz, Osama Sudah, Vincent Capodanno, Roy Helmy, Firoz D. Antia

Journal:

Journal of Chromatography A

Année:

2005

Langue:

english

Fichier:

PDF, 198 KB

english, 2005

14

Development of a gradient elution preparative high performance liquid chromatography method for the recovery of the antibiotic ertapenem from crystallization process streams

Peter Sajonz, Anant Vailaya, Osama Sudah, Lynette McPherson, Vincent Capodanno, Theresa K. Natishan, Roy Helmy, Firoz D. Antia

Journal:

Journal of Chromatography A

Année:

2006

Langue:

english

Fichier:

PDF, 171 KB

english, 2006

15

Excited-state acid–base chemistry of coordination complexes

Charles Hicks, Guozhong Ye, Chaim Levi, Marlyn Gonzales, Irina Rutenburg, Jainwei Fan, Roy Helmy, Abe Kassis, Harry D. Gafney

Journal:

Coordination Chemistry Reviews

Année:

2001

Langue:

english

Fichier:

PDF, 130 KB

english, 2001

16

Concentration determination of methyl magnesium chloride and other Grignard reagents by potentiometric titration with in-line characterization of reaction species by FTIR spectroscopy

Yadan Chen, Tao Wang, Roy Helmy, George X. Zhou, Rosario LoBrutto

Journal:

Journal of Pharmaceutical and Biomedical Analysis

Année:

2002

Langue:

english

Fichier:

PDF, 188 KB

english, 2002

17

Identification of a trace colored impurity in drug substance by preparative liquid chromatography and mass spectrometry

Peng Wang, Y.-J. Shi, Roy Helmy, Robert Reamer, Anant Vailaya

Journal:

Rapid Communications in Mass Spectrometry

Année:

2005

Langue:

english

Fichier:

PDF, 168 KB

english, 2005

18

Metabolic flexibility revealed in the genome of the cyst-forming α-1 proteobacteriumRhodospirillum centenum

Yih-Kuang Lu, Jeremiah Marden, Mira Han, Wesley D Swingley, Stephen D Mastrian, Sugata Roy Chowdhury, Jicheng Hao, Tamer Helmy, Sun Kim, Ahmet A Kurdoglu, Heather J Matthies, David Rollo, Paul Stothar

Journal:

Année:

2010

Langue:

english

Fichier:

PDF, 4.31 MB

english, 2010

19

Process Development and Large-Scale Synthesis of a PDE4 Inhibitor

Conlon, David A., Drahus-Paone, Antoinette, Ho, Guo-Jie, Pipik, Brenda, Helmy, Roy, McNamara, James M., Shi, Yao-Jun, Williams, J. Michael, Macdonald, Dwight, Deschênes, Denis, Gallant, Michel, Mastra

Journal:

Organic Process Research & Development

Année:

2006

Langue:

english

Fichier:

PDF, 155 KB

english, 2006

20

Adsorption Properties of SAMs Supported on TiO 2 and ZrO 2

Marcinko, Stephen, Helmy, Roy, Fadeev, Alexander Y.

Journal:

Année:

2003

Langue:

english

Fichier:

PDF, 64 KB

english, 2003

21

Looking Beyond the Column: An Investigation into Method Irreproducibility for an Active Pharmaceutical Ingredient

Frank Bernardoni, Peter Sajonz, Jia Zang, Claire Lee, Steven Marcinko, Ahmed Abrahim, Roy Helmy

Journal:

Chromatographia

Année:

2009

Langue:

english

Fichier:

PDF, 566 KB

english, 2009

22

Application of LC/MS to determine specific activity variation in a series of sulfonamide tracers from the [ 35 S]methane sulfonate reagent

Schenk, David J., Hesk, Dave, Marques, Rosemary, Helmy, Roy, Cheung, Patty

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2012

Langue:

english

Fichier:

PDF, 109 KB

english, 2012

23

Application of Heart-Cutting 2D-LC for the Determination of Peak Purity for a Chiral Pharmaceutical Compound by HPLC

Lee, Claire, Zang, Jia, Cuff, James, McGachy, Neil, Natishan, Theresa K., Welch, Christopher J., Helmy, Roy, Bernardoni, Frank

Journal:

Chromatographia

Année:

2013

Langue:

english

Fichier:

PDF, 396 KB

english, 2013

24

Design and Application of an Easy to Use Oligonucleotide Mass Calculation Program

Yang, Jiong, Leopold, Peter, Helmy, Roy, Parish, Craig, Arvary, Becky, Mao, Bing, Meng, Fanyu

Journal:

Journal of the American Society for Mass Spectrometry

Année:

2013

Langue:

english

Fichier:

PDF, 356 KB

english, 2013

25

Wetting in Hydrophobic Nanochannels: A Challenge of Classical Capillarity

Helmy, Roy, Kazakevich, Yuri, Ni, Chaoying, Fadeev, Alexander Y.

Journal:

Journal of the American Chemical Society

Année:

2005

Langue:

english

Fichier:

PDF, 107 KB

english, 2005

26

Preparation and Solid-State Characterization of Nonstoichiometric Cocrystals of a Phosphodiesterase-IV Inhibitor and l -Tartaric Acid

Variankaval, Narayan, Wenslow, Robert, Murry, Jerry, Hartman, Robert, Helmy, Roy, Kwong, Elizabeth, Clas, Sophie-D., Dalton, Chad, Santos, Ivan

Journal:

Crystal Growth & Design

Année:

2006

Langue:

english

Fichier:

PDF, 732 KB

english, 2006

27

Using pure shift HSQC to characterize microgram samples of drug metabolites

Liu, Yong, Green, Mitchell D., Marques, Rosemary, Pereira, Tony, Helmy, Roy, Thomas Williamson, R., Bermel, Wolfgang, Martin, Gary E.

Journal:

Tetrahedron Letters

Année:

2014

Langue:

english

Fichier:

PDF, 872 KB

english, 2014

28

Removal of Electrophilic Potential Genotoxic Impurities Using Nucleophilic Reactive Resins

Lee, Claire, Helmy, Roy, Strulson, Christopher, Plewa, Jolanta, Kolodziej, Elizabeth, Antonucci, Vincent, Mao, Bing, Welch, Christopher J., Ge, Zhihong, Al-Sayah, Mohammad A.

Journal:

Organic Process Research & Development

Année:

2010

Langue:

english

Fichier:

PDF, 1.22 MB

english, 2010

29

Excited-State Acid−Base Chemistry: Evidence for a Dissociative Excited State

Fan, Jianwei, Helmy, Roy, Kassis, Abe, Grunseich, Amanda, Mangubat, Peter, Hicks, Charles, Stevens, Nathan, Gafney, Harry D.

Journal:

Inorganic Chemistry

Année:

2003

Langue:

english

Fichier:

PDF, 56 KB

english, 2003

30

Self-Assembled Monolayers of Organosilicon Hydrides Supported on Titanium, Zirconium, and Hafnium Dioxides

Fadeev, Alexander Y., Helmy, Roy, Marcinko, Stephen

Journal:

Année:

2002

Langue:

english

Fichier:

PDF, 181 KB

english, 2002

31

Reaction of Organosilicon Hydrides with Solid Surfaces: An Example of Surface-Catalyzed Self-Assembly

Helmy, Roy, Wenslow, Robert W., Fadeev, Alexander Y.

Journal:

Journal of the American Chemical Society

Année:

2004

Langue:

english

Fichier:

PDF, 102 KB

english, 2004

32

Effect of Injection Diluent on a Chiral Separation on an Amylose S-α-Methylbenzylcarbamate Chiral Stationary Phase (Short Communication)

Price, Kathi, Clausen, Andrew M., Helmy, Roy

Journal:

Journal of Liquid Chromatography & Related Technologies

Année:

2008

Langue:

english

Fichier:

PDF, 256 KB

english, 2008

33

Chromatographic resolution of closely related species: Drug metabolites and analogs

Regalado, Erik L., Helmy, Roy, Green, Mitchell D., Welch, Christopher J.

Journal:

Journal of Separation Science

Année:

2014

Langue:

english

Fichier:

PDF, 1.15 MB

english, 2014

34

Development of an automated system for preparation of liquid scintillation counting samples for radiolabeled pharmaceuticals

Marques, Rosemary, Bernardoni, Frank, Pollack, Scott, Helmy, Roy

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2014

Langue:

english

Fichier:

PDF, 315 KB

english, 2014

35

Use of Pressure in Reversed-Phase Liquid Chromatography To Study Protein Conformational Changes by Differential Deuterium Exchange

Makarov, Alexey A., Schafer, Wes A., Helmy, Roy

Journal:

Analytical Chemistry

Année:

2015

Langue:

english

Fichier:

PDF, 603 KB

english, 2015

36

Coupling of Ultrafast LC with Mass Spectrometry by DESI

Cai, Yi, Liu, Yong, Helmy, Roy, Chen, Hao

Journal:

Journal of the American Society for Mass Spectrometry

Année:

2014

Langue:

english

Fichier:

PDF, 375 KB

english, 2014

37

Using Oxidation–Reduction Chemistry in Sample Preparation for Sub-PPM Quantitation by LC/MS

Al-Sayah, Mohammad A., Liu, Yong, Helmy, Roy, Yehl, Peter

Journal:

Journal of Liquid Chromatography & Related Technologies

Année:

2015

Langue:

english

Fichier:

PDF, 161 KB

english, 2015

38

Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry

Mei Lu,Yong Liu,Roy Helmy,Gary E. Martin…

Journal:

Journal of the American Society for Mass Spectrometry

Année:

2015

Langue:

english

Fichier:

PDF, 1.54 MB

english, 2015

39

Capture of Reactive Monophosphine Ligated Palladium(0) Intermediates by Mass Spectrometry

Zheng, Qiuling, Liu, Yong, Chen, Qinghao, Hu, Mei-Hong, Helmy, Roy, Sherer, Edward C., Welch, Christopher J., Chen, Hao

Journal:

Journal of the American Chemical Society

Année:

2015

Langue:

english

Fichier:

PDF, 561 KB

english, 2015

40

Applications of TiCl 3 as A Diagnostic Reagent for the Detection of Nitro and N-oxide Containing Compounds as Potentially Mutagenic Impurities (PMIs) using Ultra-High Performance Liquid Chromatography Coupled with High Resolution Mass Spectrometry

Yang, Rong-Sheng, Beard, Adam, Sheng, Huaming, Zhang, Li-Kang, Helmy, Roy

Journal:

Organic Process Research & Development

Année:

2015

Langue:

english

Fichier:

PDF, 749 KB

english, 2015

41

Combining size-exclusion chromatography with differential hydrogen–deuterium exchange to study protein conformational changes

Makarov, Alexey A., Helmy, Roy

Journal:

Journal of Chromatography A

Année:

2016

Langue:

english

Fichier:

PDF, 1.07 MB

english, 2016

42

Use of hydrostatic pressure for modulation of protein chemical modification and enzymatic selectivity

Makarov, Alexey A., Helmy, Roy, Joyce, Leo, Reibarkh, Mikhail, Maust, Mathew, Ren, Sumei, Mergelsberg, Ingrid, Welch, Christopher J.

Journal:

Organic & Biomolecular Chemistry

Année:

2016

Langue:

english

Fichier:

PDF, 743 KB

english, 2016

43

Enhancing radiolytic stability upon concentration of tritium-labeled pharmaceuticals utilizing centrifugal evaporation

Marques, Rosemary, Helmy, Roy, Waterhouse, David

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2015

Langue:

english

Fichier:

PDF, 515 KB

english, 2015

44

Application of HPLC mixed-mode chromatography in determining radiochemical purity of [ 14 C] labeled metformin hydrochloride

Truong, Van, Helmy, Roy, Ren, Sumei, Schenk, David, Waterhouse, David

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2015

Langue:

english

Fichier:

PDF, 266 KB

english, 2015

45

Moisture determination of tritium tracers utilizing near-infrared spectroscopy

Marques, Rosemary, Waterhouse, David J., Helmy, Roy

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2016

Langue:

english

Fichier:

PDF, 287 KB

english, 2016

46

Synthesis of [ 14 C]omarigliptin

Ren, Sumei, Gauthier, Donald, Marques, Rosemary, Helmy, Roy, Hesk, David

Journal:

Journal of Labelled Compounds and Radiopharmaceuticals

Année:

2016

Langue:

english

Fichier:

PDF, 733 KB

english, 2016

47

Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry

Cai, Yi, Zheng, Qiuling, Liu, Yong, Helmy, Roy, Loo, Joseph, Chen, Hao

Journal:

European Journal of Mass Spectrometry

Année:

2015

Langue:

english

Fichier:

PDF, 2.00 MB

english, 2015

48

Characterization of impurities of HIV NNRTI Doravirine by UHPLC-high resolution MS and tandem MS analysis

Zhang, Li-Kang, Yang, Ross, Sheng, Huaming, Helmy, Roy, Zheng, Jinjian, Cao, Yang, Gauthier, Donald R.

Journal:

Journal of Mass Spectrometry

Année:

2016

Langue:

english

Fichier:

PDF, 1.95 MB

english, 2016

49

Mechanistic Study of the Gas-Phase In-Source Hofmann Elimination of Doubly Quaternized Cinchona-Alkaloid Based Phase-Transfer Catalysts by (+)-Electrospray Ionization/Tandem Mass Spectrometry

Yang, Rong-Sheng, Sheng, Huaming, Lexa, Katrina W., Sherer, Edward C., Zhang, Li-Kang, Xiang, Bangping, Helmy, Roy, Mao, Bing

Journal:

Journal of the American Society for Mass Spectrometry

Année:

2017

Langue:

english

Fichier:

PDF, 1.20 MB

english, 2017

50

Unusual (+/-)-electrospray ionization induced fragmentation: Structural elucidation of an in-process synthetic intermediate of doravirine (MK-1439) using liquid chromatography/high-resolution tandem mass spectrometry and two-dimensional nuclear magnetic r

Sheng, Huaming, Lexa, Katrina W., Zhang, Li-Kang, Yang, Rong-Sheng, Wright, Timothy J., Sherry, Benjamin D., Helmy, Roy, Martin, Gary E.

Journal:

Rapid Communications in Mass Spectrometry

Année:

2017

Langue:

english

Fichier:

PDF, 872 KB

english, 2017