44 CHROMATOGRAPHY
Environment Canada, En14-33/2010E-PDF, Reference method for the analysis of 2-butoxyethanol (2-BE) and other glycol ethers (GEs) in selected products (automotive and household cleaners, paints, paint strippers and solvents), 2010
REFERENCE: 1
Fig. 2. Analysis of glycol ethers on a conventional 624-type (30m x 0.25mm x 1.4 µm) column showing the longer analysis time required and coelution of DEGEE with a DPGME isomer
Faster run times can also
be achieved using narrow-bore 624-type columns with the same phase ratio (e.g. 30m x 0.25mm x 1.4 µm). However, as shown in Fig. 2, chromatographic resolution is reduced in exchange for speed in this situation, and coelution of the DPGME III isomer with DEGEE occurs. Poor resolution of the TPGME isomer group is also apparent. In contrast to 624-type columns, the Rxi-1301Sil MS column provides better resolution of critical compounds for glycol ether analysis in a much faster analysis time.
Although column bleed
can be a concern with some stationary phases, the Rxi- 1301Sil MS column can be used with confidence. At 300°C (the maximum temperature used in the EC method) column bleed is minimal and does not interfere with mass spectral compound identification. Low column bleed is critical to the operation of sensitive mass selective detectors and allows full scan spectra to be collected without interference from bleed ions.
Summarising the merits of this approach Te new Rxi-1301Sil MS column from Restek provides a significant
opportunity to improve glycol ether analysis. Although 624- type columns are often used for this work, the Rxi-1301Sil MS column allows separations to be achieved in much faster analysis times and with very low bleed. As shown here, glycol ethers of regulatory concern can be analysed in just eight minutes while still achieving good separations of the key isomers. Labs interested in reducing analysis times for current methods based on 624-type columns should consider adoption of the Rxi-1301Sil MS column into their testing programmes.
For more information ✔ at
www.scientistlive.com/eurolab
Rebecca Stevens is product development chemist & Chris English is applications manager at Restek.
www.restek.com
Series of packed columns launched C
hromatography expert Shimadzu recently announced the release of its Shim-pack UC-X series. When conducting analysis with
the Nexera UC supercritical fluid chromatography system, because diffusion of the sample band in the mobile phase is high compared with liquid chromatography, separation behaviour changes significantly depending on the types of columns used. Shim-pack UC-X series was designed
with a variety of stationary phases, making it suitable for analysis of various compounds.
www.scientistlive.com
The series offers various stationary phases suitable for the mobile phase of high diffusion and low-viscosity liquid carbon dioxide.
Analysis time can be reduced at a
high flow rate without impairing the separation performance. In addition, analysis speed, which is limited in HPLC, can be increased. Shim-pack UC-X series was designed with eight types of stationary phases and sizes to meet diverse research and development needs. The series achieves high inertness for improved analysis precision and
increased column durability. Its uniform silica surface and stable chemical modification also ensure high analysis reproducibility. Nexera UC and Shim-pack UC-X series
are ideal for analysing complex samples. Isomers and structurally similar compounds that are difficult to separate can be analysed by Nexera UC and Shim- pack UC-X series at high speed. And simultaneous analysis of multiple pesticides with a wide polarity range from hydrophobic to hydrophilic ones has also been achieved using the Nexera UC using Shim-pack UC-X RP.
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