Gas Chromatography

Story

Low Bleed Supelco GC Capillary Columns
The Supelco SLBms Story

From its humble beginnings in 1966, Supelco has exhibited a proven track record of GC innovation. Founders Walt Supina and Nick Pelick instilled in their fledging company their beliefs in innovation through a dedicated R&D program and backed up their products with quality manufacturing and unrivaled customer and technical service. These beliefs still flourish today, forty years later, with Supelco now being an important brand within the Sigma-Aldrich family.

Supelco has differentiated itself from other column manufacturers by focusing on columns for specific applications. The first of the specialty columns, SP-2560, was introduced in 1983. What followed is an impressive succession of columns for many different GC applications. The SLBms columns, designed for today’s most stringent GC and GC-MS applications, are among the newest members of the line.

1983 – SP-2560
1984 – SPB-608, SUPELCOWAX 10
1985 – SP-2331
1986 – VOCOL
1987 – Sup-Herb, SP-2380
1988 – Petrocol DH, Nukol
1989 – Petrocol DH 150, Petrocol 2887
1990 – Omegawax 320, Petrocol DH 50.2
1991 – Omegawax 250, SPB-1 SULFUR, Petrocol EX2887, Carbowax Amine
1993 – α-DEX 120, β-DEX 110, γ-DEX 120, SAC-5, TCEP
1994 – β-DEX 120, OVI-G43, Carboxen-1006 PLOT, Mol Sieve 5A PLOT, Supel-Q PLOT, SCOT Columns
1995 – SPB-624, SPB-PUFA, Petrocol DH Octyl, SPB-Octyl, PTA-5
1996 – α-DEX 225, β-DEX 225, γ-DEX 225, α-DEX 325, β-DEX 325, γ-DEX 325, Omegawax 530, SPB-1000
1997 – SPB-HAP, Carboxen-1010 PLOT
2003 – Equity-1701, Alumina chloride PLOT, Alumina sulfate PLOT
2005 – SLB-5ms
2007 – Astec CHIRALDEX column line, Omegawax 100
2008 – SLB-IL100, MET-Biodiesel
2009 – SLB-IL59, SLB-IL76
2010 – SLB-IL61, SLB-IL82, SLB-IL111
2012 – SLB-IL60
2015 – SLB-35ms

SLBms columns are designed for GC and GC-MS analysts who require a low bleed, inert, durable, and consistent capillary GC column for routine and trace analyses. By using SLBms, you will consistently achieve low detection limits, easy mass spectral identifications, less instrument downtime, great resolution, short analysis times, and long column life.


Unique Advances in Polymer Synthesis

The central innovation that gives SLBms its unsurpassed durability and performance is unique phase formulation. For example, a silphenylene polymer (shown in Figure 1) is used for some chemistries. The incorporation of a phenyl group into the backbone structure increases the stability of the polymer by sterically hindering the backbiting reaction (Figure 2) that occurs with conventional polymethylsiloxane polymers. Elution of cleaved phase from the backbiting reaction is the source of most column bleed. Additionally, the silphenylene polymers are extensively cross-linked, creating a phase molecule that is among the most rugged and lowest bleed we have tested.

SLBms columns exhibit Low Bleed and Durability because of the Unique Advances in Polymer Synthesis.

Figure 1. Structure of the Silphenylene Backbone of an SLBms Phase (R = either methyl or phenyl)
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Figure 2. Structure of a Siloxane Backbone, Column Bleed Resulting from the Backbiting Reaction
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Proprietary Surface Deactivation

Good capillary GC columns start with a uniformly inert fused silica surface. Active surfaces lead to poor peak shape, low efficiency, and reduced response levels of susceptible analytes. Deactivation and careful preparation of the fused silica surface prior to stationary phase coating are critical steps in the SLBms manufacturing process.

Typical GC column deactivation uses high temperatures to remove most of the water that is bound to the fused silica surface. However, thermal treatment can still leave residual silanol groups, which can act as hydrogen bonding sites, and strained siloxane bridges, which show activity toward alcohols. Additional chemical deactivation is necessary to neutralize these sites and create an inert surface.

SLBms columns employ a proprietary deactivation formulation and process developed by Supelco R&D chemists for superior deactivation of the fused silica surface. In addition to eliminating surface activity and improving inertness, the proprietary deactivation process also improves the wettability of the surface, which ensures a more uniform coating of the stationary phase film.

SLBms columns exhibit Inertness and Efficiency because of the Proprietary Surface Deactivation.


Innovative Manufacturing Processes

Supelco has over 30 years of expertise in the manufacture of high quality capillary GC columns. This expertise was applied to the production of SLBms columns to ensure our customers receive the best, most consistent product we can deliver. Our chemists painstakingly investigated every conceivable variable in the column manufacturing process using statistical modeling to help determine optimal manufacturing parameters. Many months were spent, many experiments were performed, and new equipment was purchased in order to refine the manufacturing processes. The results were worth the investment; SLBms columns have extremely tight specifications in all parameters that affect column performance.

Our investigations into SLBms manufacturing not only reduced performance variation, they also uncovered a new technique to chemically bond the phase to the fused silica surface. The durability of the phase as a result of this technique is such that when we add phase to the fused silica tubing, it stays there, drastically reducing column bleed and the associated problems of instrument fouling and loss of sensitivity.

SLBms columns exhibit Low Bleed, Durability, and Consistency because of our Innovative Manufacturing Processes.