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While TARGA columns give exceptional performance without TFA buffer, it does not mean that you are precluded from using it. In fact, the changes in selectivity

that comes with changing buffer acids can be a powerful tool for separation optimization. Notice how the peptide elution orders change between the acetic acid (above) and TFA (below) buffered chromatogram.This is due to the diferences in pH of the acetic acid and TFA mobile phase.

TARGA

TARGA A Uniquely Shielded Surface

Phases C8 and C18 Par ticle Sizes 3, 4.5 and 10µm Pore Size 120Å Pore Volume 0.8mL/gm Surface Area 330m 2 /gm Carbon%(w/w) C18 = 18%

Phase type Monofuctional with a unique polar and

bulky end-capping Silica Class Type B

Applications

TARGA columns and car tridges are ideal for applications requiring an absence of secondary solute-silanol inter-action. Basic and acidic drugs and pep-tides can be chromatographed efficiently with little or no buffer. Targa columns are par ticularly well suited for LC/MS appli-cations where acetic acid or formic acid can be substituted for TFA resulting in significant increase in signal. While TFA is not required, it does not preclude its use on TARGA columns.TARGA exhibits extremely fast equilibration kinetics from high to low organic phase compositions. It works well in 100% aqueous condi-tions for hydrophilic applications also. Peptide Mapping without TFA

The following chromatograms illustrate the differences in selectivity for peptide maps of cytochrome-C when using 0.05% TFA or 0.05% acetic acid buffer in

1%/min acetonitrile gradient on a short 50x1.0mmTARGA C18 column. Both dilute buffer examples are characterized by sharp peaks and no tailing.

LC-MS without TFA

Researchers have shown that Higgins Analytical’s TARGA C8 and C18 phases have an extremely well protected silanol surface. An acetonitrile/water 1%/min gradients with as little as 0.05% acetic acid gives a very satisfactory peptide map on a short 5cm x 1mmTARGA C18 column. The ability to buffer with acetic or formic acid rather than TFA greatly enhances signals for LC/MS tech-niques.

Basic Peptides

with 0.1% Acetic Acid pH 3.1 TARGA C18 5µm 50x1.0mm

Basic Peptides

with 0.1% TFA pH 2.2 TARGA C18 5µm 50x1.0mm

Tryptic Map of Human Ocular Lens Proteins beta A1 crystallin and gamma S crystallin

TARGA C18 5µm 150x0.5mm P/NTS-15M5-C185

Solvent A: 0.1% Acetic Acid Solvent B: 0.1% Acetic Acid, 65% MeCN 0 - 50% B in 60min, 50 - 100%B in 15min

Sample is a tryptic digest of a 2D electrophoresis separat-ed spot digested from PDVF membrane. The two ocular proteins are ~25kD. The LC/MS zoom scan below con-firms the peak at 39.15min is singly charged, and software interpretation of the MS/MS scan at the bottom confirms the 1156.6 ion as residues 84-94 in human gamma S crys-tallin.

LC/MS Scan

LC/MS/MS Scan

Guide to TARGA Part Numbers

Tx-xxxx-C183 Targa C18 3µm Tx-xxxx-C185 Targa C18 5µm

See Page 23 for complete Part Number information