Archive for the ‘New GC Columns’ Category

GC columns – when one is not enough

Often we get asked for a column recommendation for a complex GC analysis.   This is especially true for gas analysis.  Probably the most common request is for separation of fixed (permanent) gases (like O2, N2, CO, CO2, N2O, etc…) plus separation of larger (higher-boiling point) compounds (light hydrocarbons, moisture, sulfur gases, ammonia, solvents, etc.).  Unfortunately, […]

Broken fused-silica columns – it’s rare, but it does happen.

Once in a while we get a call that one of our GC fused-silica columns has broken, and customers ask if it can be repaired and used.  The answer is “maybe”. If your column broke while at a high temperature, and the column’s phase has been exposed to oxygen (air), then probably not.  A sure […]

GC capillary columns for the European Pharmacopoeia methods

Have you ever viewed a European Pharmacopoeia method and tried to figure out which Restek GC capillary column you should use? To make the selection a little easier for our customers, I decided to match the nomenclature listed in the European Pharmacopoeia “Reagents” chapter to the appropriate Restek columns.  I hope you find the table […]

Benzo[b]fluoranthene as part of the EFSA PAH4

I’ve already had one reader of my last post, Is separation of benzo[b]fluoranthene and benzo[k]fluoranthene on 5% phenyl-type GC columns really that important for environmental analyses? ask why I had benzo[b]fluoranthene in red text on the chromatograms.  I had planned to include something about it being on the EFSA PAH4 list in that post, but […]

Is separation of benzo[b]fluoranthene and benzo[k]fluoranthene on 5% phenyl-type GC columns really that important for environmental analyses?

Some gas chromatographers might say so because of the following statement in US EPA Method 8270D (Semivolatile Organic Compounds by Gas Chromatography – Mass Spectrometry (GC-MS): “ Structural isomers that produce very similar mass spectra should be identified as individual isomers if they have sufficiently different GC retention times.  Sufficient GC resolution is achieved if […]

MXT-35 GC-FID: Medical Marijuana Cannabinoids

I’m now adding a 15m x 0.53mm x 0.50µm MXT-35 to the GC column data collection effort for cannabinoids, thanks to Ron Stricek’s help with getting that column manufactured for me. This column is made out of metal and has the features/benefits listed in this brochure.  In addition to the ruggedness of the metal column and the […]

Terpenes in Blueberry Jack Medical Cannabis – GC – More Identified

Based on acquisition of new terpene standards I was able to better profile the Blueberry Jack medical cannabis impinger sample on the beta-version 30m x 0.25mm x 1.0µm Rxi-1301Sil MS GC column.  Check it out… I’m looking for suggestions on terpene identification for the ones marked by “?” in the chromatogram below.  Help, please!

Early Eluting Terpenes – GC – Medical Cannabis

I’ve already had a request to zoom in on the early eluting part of the previously posted gas chromatogram of medical cannabis terpenes on the Rxi-1301Sil MS so the separations can be better viewed.  So here it is… More later…

Faster GC Analysis of Medical Cannabis Terpenes with Same 624Sil MS Selectivity

The chromatograms below show what happens when you translate a GC method (previously used for medical cannabis terpenes here and here) from a 30m x 0.25mm x 1.40µm Rxi-624Sil MS GC column to a 30m x 0.25mm x 1.00µm Rxi-1301Sil MS column.  Both of these columns have arylene-modified cyanopropylphenyl dimethyl polysiloxane-type stationary phases.  As should be […]

Molecular Sieve 5A & 13X packed columns – Installation / Conditioning / Helpful Hints

Molecular Sieve 5A & 13X Columns (packed) Molecular Sieve 5A & 13X (micropacked) Things to Consider Before Ordering a Packed Column . Following the steps below will ensure that your Molecular Sieve packed column is ready to use just several hours after installation.  You should only use dry (moisture-free) & hydrocarbon-free high-purity Nitrogen as the carrier gas […]