Advances in Capillary Columns For Gas Chromatographic Applications Shawn Reese, Roy Lautamo, Chris Cox Gianna Barlupi, Rick Morehead, Jason Thomas, Gary Stidsen, and Frank Dorman

Old Technology? Gas Chromatography is 50 years old! Like wine and cheese it seems to keep getting better!! Packed columns (over 100 different phases) Capillary debut commercially in 1970’s Phase development parallels some packed column phases

Phase Development – Early Phases

Capillary Phase Technology Pendant siloxanes do not show large viscosity changes with temperature (from -40 to 400oC) High polarity applications require a wax phase which has a high temperature limit of 260 Deactivation technology varies from manufacturer and can be a limiting factor on what is possible Pendant phases are fairly similar from manufacturer to manufacturer

What Does the Industry Need? Low Bleed? What is bleed? Can it be stopped? “MS” Phases? Application of low-bleed technology? Reproducible columns? Why do our manufacturing profiles matter to you? Inertness Professor Walt Jennings, Riva 2004 Selectivity-specific applications PCB’s, Dioxins, PBDPE’s, pesticides

What is Bleed? Common bleed ions associated with phases that contain PDMS LaChatlier’s principle works against us due to the volatility of the products.

Slowing Down Decomposition “G” groups spreads Si-O groups out so that they cannot “back-bite” each other and form small cyclic rings.

Bleed Mass Spectrum Pentamethylcyclotrisiloxane+ 50 100 150 200 250 300 350 400 450 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 m/z--> Abundance Scan 3634 (24.939 min): C0830013.D 207 Pentamethylcyclotrisiloxane+ Heptamethylcyclotetrasiloxane+ Trimethylsilyl+ 73 281 44 96 133 177 253 156 230 327 355 384 407 430 455 475

Backbone modified phases slow down the back-biting mechanism

Low-Bleed – 1st Generation (90’s) What drives innovation? Introduction of “ms” phases! As GC manufacturers make more sensitive detectors demands from the phases increase. 1st generation was a “5” in the backbone, first produced by Sveda (1951!)…did not appear in GC phases until early 1990’s. Thermal decomposition decreased due to “stiffining” of the backbone chain.

Low Bleed Next Generation 21st Century “Next” Generation was application of “other” backbone modified groups, and “new” pendant groups Selectivity can vary dramatically if the pendant groups are very different from one another, and the backbone Group “G” is significantly different than “phenyl”.

What “G” groups have been used? Literature reports the following groups:

Deactivations – A new problem? Bench-top mass spectrometers in the early 90’s had sensitivity similar to the standard FID Today, sensitivity of bench-top mass spectrometers are better than the standard FID, and the column can interfere with detection . Inertness is a more serious issue now with detection below nanogram levels on MS.

What else can we do? As the mechanism on the previous slide implies, chemically inert polymers demand the most stringent synthetic conditions We have devised “systems” that limit the polymers ability to “find” proton sources during phase procurement through deactivation techniques and through new, proprietary syntheses.

Restek’s Exceptionally Inert GC Columns (Rxi) New column technology developed by Chemists at Restek and new research lab, Restek West Rxi-1ms, Rxi-5ms New deactivation chemistry, new polymer chemistry, new manufacturing process Results in columns that are: Highly Inert Reproducible Low bleed

Reproducibility = Reliablity for the user! In-house QC results Comparison between manufacturers What do you need?

Bleed of Manufactured Columns Mean = 1.9pA SD = 0.65

Rxi-5ms Bleed Study (30m x 0.25mm, 0.25um film) Reference Peak 1ng tridecane Columns include: 5% diphenyl 95% dimethyl & Silarylene based phases (30m x 0.25mm, 0.25um) Detector: FID 350oC 6 4 330oC 2 Rxi-5ms

Retention Time “Windows” Ultimate Reproducibility Column-to-Column Exact Length Is this important? Isothermal testing Comparison of batch to batch reproducibility In-house QC results Film thickness Coating efficiency Selectivity

Rxi-5ms Column Reproducibility

Film Thickness

Coating Efficiency

Selectivity

Selectivity

Inertness 0.5ng on-column concentration Basic compound Acidic compound 2ng on-column comparison between manufacturers Chromatographic peaks of pyridine Response factor This is the area that is a “WIP”….we have come a long way…..can it get better? We’ll show Rxi as an example of what all columns should be like!

Rxi-5ms Column Inertness (30m x 0.25mm, 0.25um) Acidic Compounds m/z 79 m/z 74 m/z 184 Basic Compounds

2ng Pyridine Rxi-5ms (30m x 0.25mm, 0.25um)

Rxi-5ms Column Inertness (30m x 0.25mm, 0.25um)

Rxi-5ms Column Inertness (30m x 0.25mm, 0.25um)

Inertness Probes

Applications Environmental Clinical Semivolatile analysis Acidic and basic drugs

Rxi-5ms Semivolatiles (5ng on-column)

Rxi-5ms Semivolatiles (5ng on-column)

Rxi-5ms Analysis of Drug Compounds

Rxi-5ms Analysis of Drug Compounds

Summary of Rxi Columns Unsurpassed inertness for active compounds Low bleed Excellent column to column manufacturing Excellent overall performance due to combination of inertness, low bleed, and reproducible manufacturing process

Special Selectivity? Application specific – not everyone is doing congener specific PCB analysis Utilizes low-bleed technology, and incorporates many manufacturing techniques as our Rxi process These polymers are Restek specific; cannot be found from other manufacturers

Rtx-440 Fused Silica Column “Special Selectivity” Very good selectivity for chlorinated pesticides Low bleed column Good for GC/MS No equivalent phases on the market

Rtx-440 Fused Silica Column

Rtx-Dioxin2 New phase that is specially “tuned” for dioxin analysis

Rtx-Dioxin 2

Rtx-PCB Congener Specific Analysis Resolves most PCB’s into absolute separation or “MS-resolvable” separations (differing Cl numbers). A low bleed phase – will allow for high temperature applications for “dirty” samples.

Rtx-PCB place picture here

Rtx-5SilMs – Shape selectivity

Rtx-17 Fused Silica Column Rtx-50 vs Rtx-17 Both 50% phenyl / 50% methyl Selectivity between Rtx-50 and Rtx-17 is different GCxGC separations coupled to a 5 or 1 Equivalent selectivity to DB-17 Rtx-50 Rtx-17

Acknowledgements Chris English and innovations group for applications Roy Lautamo for suggestions on how to proceed Shimadzu for kind invitation and providing support for this trip!!