Micro- and nano-scale HPLC and LC/MS separations are the methods of choice for high sensitivity protein and peptide analysis. These methods only require a very small sample size and provide increased sensitivity and high resolution separations. CTI's PepSilTM capillary columns are packed with ultra pure 300A spherical silica bonded with ion exchange, and C18 or C8 stationary phase for the best possible LC/MS separation of proteins or peptides. All column housings, frits, fittings, and materials are designed to give an absolutely clean background in mass spectrometric analyses.

Fig. 1 shows the C18 reversed phase chromatogram of a tryptic digest of EGF Receptor (EGFR) protein. As shown, CTI columns provide excellent separations with high resolution and superb peak shapes.

Fig. 1 PepSil High Performance Capillary C18 Reversed Phase Separation of a tryptic digestion of the EGF Receptor. C18 column, 5 μm particle, 300 A, 150 μm x 100 mm.
Part number: CTICAP150100
Conditions:
Buffer A: 2% ACN, 97% water, 1% MeOH
Buffer B: 97% ACN, 2% water, 1% MeOH

Gradient: 0-150 min, 0-70% B

PepSil C18 – Capillary Columns
Particle Size (μm)	Column Dimension (mm)	Pore Size (A)	Part Number	Price
3	0.32 x 150	300	CTICAP3320150	$900.00
3	0.32 x 100	300	CTICAP3320100	$850.00
3	0.15 x 150	300	CTICAP3150150	$800.00
3	0.15 x 100	300	CTICAP3150100	$750.00
3	0.075 x 150	300	CTICAP3075150	$750.00
3	0.075 x 100	300	CTICAP3075100	$700.00

Sample Trap
Particle Size (μm)	Column Dimension (mm)	Pore Size (A)	Part Number	Price
5	0.15 x 30	120	CTITRAP15020(2/pkg)	$400.00
5	0.32 x 30	120	CTITRAP32020(2/pkg)	$550.00

Most peptides are retained on strong cation exchange (SCX) columns, making them uniquely useful for many protein/peptide analyses. SCX columns are commonly combined with reversed phase columns to achieve multidimensional separations of complex peptide mixtures. In such a method, peptides are separated off-line with SCX and then these fractions are re-injected into a reversed phase column for LC/MS analysis. Alternatively, both SCX and reversed phase columns are used simultaneously on a multidimensional LC/MS system – peptides are retained on the SCX column and then step- or gradient-eluted into the reversed phase column for further LC/MS separation. Using this method, it is possible to identify thousands of proteins in complex samples with a single LC/MS experiment.