March Meeting Notice

Thursday, March 25, 2010

Dr. Andrew J. Alpert: Charge Effects in HILIC

Dr. Andrew J. Alpert

PolyLC

Abstract:

All silica-based materials used for HILIC have ionizable functional groups. The electrostatic effects affect the retention of charged solutes. Adjustment of the pH or addition of salt suppresses these effects. Alternatively, they can be exploited to afford unique separations. Performance of HILIC on an ion-exchange column of the same charge as the solutes is a combination termed Electrostatic Repulsion-Hydrophilic Interaction Chromatography (ERLIC). ERLIC can be used for:

1. Isocratic separation of highly varied mixtures of peptides, amino acids and nucleotides;
2. The selective isolation of phosphopeptides and glycopeptides from tryptic digests;
3. Fractionation of unmodified peptides from complex tryptic digests superior to that obtained with SCX.

Charged solutes are highly oriented during migration through ERLIC columns. This results in appreciable sensitivity to the location of a charged group in a solute, such as the position of a phosphate group in a peptide.

About the Speaker:

Andrew Alpert received his doctoral degree from Purdue U. (Ph.D. 1980), working in the lab of Fred Regnier to develop the first ion-exchange materials for HPLC of proteins. Following postdoctoral research at Baylor College of Medicine, Dr. Alpert started PolyLC in 1985 to manufacture HPLC materials for difficult protein and peptide separations. The company specializes in developing new approaches to separation problems, such as the introduction of SCX for fractionation of tryptic digests in proteomics. Dr. Alpert first described Hydrophilic Interaction Chromatography (HILIC) in 1990 as a technique suitable for analysis of polar solutes in general, just as reversed-phase HPLC is suitable for nonpolar solutes. Current interests include: 1) Development of techniques for analysis of particularly difficult proteins, including histone variants and proteomics analysis of both membrane and nonmembrane proteins; 2) Mixed-bed ion-exchange columns for proteins; 3) HILIC of solutes on columns of the same charge (a variant called ERLIC), which permits isocratic separations of solutes differing greatly in composition such as amino acids and nucleotides. It also affords isolation and resolution of phosphopeptides and glycopeptides for proteomics analyses.

Details:

Location:	Christiana Hilton
Times:	5:00 PM Executive Committee Meeting 5:45 PM Social "Hour" 6:30 PM Dinner 7:30 PM Presentation
Cost:	$30
Dinner Choices:	Breast of Chicken Dijonnaise Salmon with Dill Cream Sauce Grilled Portabella Mushroom Tower with Spinach, Mushrooms, Onions, tomatoes, Carrots, Zucchini and Peppers

NOTICE TO STUDENTS AND FACULTY: Full-time students with valid ID may attend dinner meetings at half-price. Faculty members at colleges and universities are urged to bring one or more students to the meeting. If they do, they also can attend at half-price.