More about chromatography

Rtx-1 PONA

(Crossbond® 100% dimethyl polysiloxane - optimized for hydrocarbon analysis)

• Application-specific columns meet ASTM and CGSB requirements for detailed hydrocarbon analysis .

The Rtx®-1PONA polymer was designed to offer the exact polarity necessary to resolve hydrocarbons in the specific order requested by petrochemical companies. In order to meet the demanding resolution and retention criteria of the American Society for Testing and Materials (ASTM) and the Canadian General Standards Board (CGSB), Restek has developed unique quality control tests and specifications for the Rtx®-1PONA column. The measured values for retention (k), efficiency (n), and stationary phase selectivity (RI) are controlled so that each column exceeds the requirements of the ASTM and CGSB methods.

Applications

• Detailed hydrocarbon analysis

FAMEWAX

(Crossbond® polyethylene glycol )

• Application-specific columns for FAME.

The elution order of polyunsaturated FAMEs on FAMEWAX™ columns is comparable to that on other Carbowax® columns, but baseline resolution is achieved in significantly less time.

Applications

• FAME

Stabilwax-DA

(Crossbond® Carbowax® polyethylene glycol for acidic compounds)

• Application-specific columns for free (underivatized) acids, some inorganic acids.
• Resistant to oxidative damage.
• Equivalent to USP G25, G35 phases.

Stabilwax®-DA bonded polyethylene glycol has an acidic functionality incorporated into the polymer structure. This permits analysis of acidic compounds without derivatization, significantly reduces adsorption of acids, and increases sample capacity for volatile free acids. Stabilwax®-DA columns last longer and give better peak shapes for high molecular weight acids. Some inorganic acids also chromatograph well on a Stabilwax®-DA column; the limitation is the volatility of the acidic compound.

Applications

• Free fatty acids

Rtx-225

(Crossbond® 50% cyanopropylmethyl/50% phenylmethyl polysiloxane)

• Polar phase.
• Equivalent to USP G7, G19 phase.

The cyanopropyl-containing Rtx®-225 phase is slightly less polar than bonded polyethylene glycol (PEG) phases, but it can be used for many of the same applications. Some popular applications for the Rtx®-225 column are analyses of fatty acid methyl esters (FAMES), sugar derivatives, and food and flavor compounds.

Improvements to the Rtx®-225 polymer have increased thermal stability, reduced bleed, and improved inertness. The Rtx®-225 column provides a 20°C thermal stability advantage over other “225” columns because of an unique polymer synthesis technology and proprietary siloxane deactivation. In most similar columns, the Carbowax® deactivation layer is not fully compatible with the cyanopropyl siloxane polymer, which can cause adsorption, tailing of active compounds, and lower efficiency.

Applications

• FAMEs
• Carbohydrates derivetes
• Sterols
• Flavor compounds

Rtx-1 F&F

(Crossbond® 100% dimethyl polysiloxane)

• Application-specific columns for flavor and fragrance compounds.

Retention index libraries in the flavor and fragrance industry have been compiled from years of data and thousands of compounds. Any slight variation in column selectivity could render the column useless. Rtx®-1 F&F columns are tailored to match the selectivity required in the industry, while offering excellent thermal stability. Our stringent quality testing ensures column-to-column reproducibility and extended column lifetimes over conventional 100% dimethyl polysiloxane columns.

Applications

• Flavor and fragrance compounds

Rtx-65TG

(Crossbond® 65% diphenyl/35% dimethyl polysiloxane)

• Application-specific columns, specially tested for triglycerides.

The Rtx®-65TG phase resolves triglycerides by degree of unsaturation as well as by carbon number. Because of the chemistry required to achieve 370°C thermal stability, an Rtx®-65TG column should not be used for analyses of polar compounds.

Applications

• Triglycerides

Rtx-VMS

(proprietary Crossbond® phase )

• Application-specific columns for volatile organic pollutants by GC/MS.
• Complete separation of US EPA Method 8260 compounds in less than 18 minutes.
• Restek Exclusive.

Rtx®-VMS columns offer lower bleed, better selectivity, and overall faster analysis for separating volatile organic compounds, such as those listed in US EPA Method 8260. The Rtx®-VMS stationary phase is a highly stable polymer that provides outstanding analysis of volatile compounds, in combination with sensitive ion traps and mass spectrometers. 0.18 and 0.25 mm ID columns allow sample splitting at the injection port, eliminating the added expense and maintenance of a jet separator. A 0.45 mm or 0.53 mm ID column can be directly connected to the purge & trap transfer line in a system equipped with a jet separator.

Applications

• Volatile organic pollutants

Rt-2560

(Biscyanopropyl polysiloxane - non bonded)

• Highly polar phase.
• Aplication Specific Phase for cis/trans FAMEs.

Because the Rt™-2560 phase is not nonded, It should not be solvent rised.

Applications

• cis/trans FAMEs

Rt-2330

(90% biscyanopropyl/10% phenylcyanopropyl polysiloxane - not bonded)

• Highly polar phase.
• Equivalent to USP G48 phase.

Rt™-2330 is one of the most polar capillary column stationary phases. Cyano groups on both sides of the polymer backbone give the phase a strong dipole moment and high selectivity for cis/trans compounds or compounds with conjugated double bonds. Highly polar columns typically exhibit poor column efficiencies, high bleed, and short column lifetimes when thermally cycled. To overcome some of these problems, Restek developed a surface treatment that is more compatible with the Rt™-2330 phase. In addition, improved polymer produces columns with improved column efficiency and lower bleed. Because the Rt™-2330 stationary phase is not bonded, it should not be solvent rinsed.

Applications

• cis/trans FAMEs
• Dioxin isomers

Stabilwax-DB

(Crossbond® Carbowax® polyethylene glycol for amines and basic compounds)

• Application-specific columns for underivatized amines and other basic compounds.
• No need for column priming.

Stabilwax®-DB columns reduce adsorption and improve responses for many basic compounds, without analyte derivatization or column priming. For different selectivity of basic compounds, or higher oven temperatures, use an Rtx®-5 Amine or Rtx®-35 Amine column.Stabilwax®-DB is a bonded stationary phase, but avoid rinsing these columns with water or alcohols.

Applications

• Alkylamines
• Diamines
• Triamines
• Nitrogen-containing heterocyclics