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Figure 2 Low column bleed results in long column lifetimes,
saving labs replacement costs.
Column bleed over 400 injections of HFBA derivatization reagent.
Figure 3 Active probes show consistent, symmetric peak shape,
demonstrating the inertness needed for accurate quantification.
Test probe symmetry over 400 injections of HFBA derivatization reagent.
Symmetry values <1 indicate peak tailing and values >1 indicate fronting.
Figure 4 Peak symmetry for underivatized amphetamine is sig-
nificantly better on an Rxi®-5Sil MS than on a competitor column,
even after 400 injections of HFBA derivatization reagent.
Symmetry values <1 indicate peak tailing and values >1 indicate fronting.
Phase Stability Extends Column Lifetime
In order to demonstrate the ruggedness of the Rxi®-5Sil MS column, 400
injections of heptafluorobutyric acid anhydride (HFBA) in butyl chloride
were performed. HFBA is a very harshderivatization reagent, and the con-
centrationof reagent in the solvent was equivalent to that of a derivatized
sample. Throughout the course of 400 injections, bleed, retention, and
peak shape for active compounds were monitored by periodically inject-
ing a column test mix containing active compounds (1,6-hexanediol, 4-
chlorophenol, and dicyclohexylamine). Chromatographic results were
remarkably consistent, even after 400 injections (Figure 1). Column bleed
was monitored over the course of the experiment and remained below 5
pA (Figure 2). The consistency of retention time data and low bleed levels
demonstrate phase stability, which results in longer column lifetimes and
reduced maintenance and replacement costs.
ID df (µm) temp. limits length qty. cat. #
0.10mm 0.10µm -60 to 330/350°C 10m ea. 43601
0.18mm 0.18µm -60 to 330/350°C 20m ea. 43602
0.18mm 0.36µm -60 to 330/350°C 20m ea. 43604
0.25mm 0.10µm -60 to 330/350°C 15m ea. 13605
0.25mm 0.10µm -60 to 330/350°C 30m ea. 13608
0.25mm 0.25µm -60 to 330/350°C 15m ea. 13620
0.25mm 0.25µm -60 to 330/350°C 15m ea. 13620-127
0.25mm 0.25µm -60 to 330/350°C 30m ea. 13623
0.25mm 0.25µm -60 to 330/350°C 30m 6-pk. 13623-600
0.25mm 0.25µm -60 to 330/350°C 30m ea. 13623-124
0.25mm 0.25µm -60 to 330/350°C 30m ea. 13623-127
0.25mm 0.25µm -60 to 330/350°C 60m ea. 13626
0.25mm 0.50µm -60 to 330/350°C 15m ea. 13635
0.25mm 0.50µm -60 to 330/350°C 15m ea. 13635-124
0.25mm 0.50µm -60 to 330/350°C 30m ea. 13638
0.25mm 0.50µm -60 to 330/350°C 30m ea. 13638-124
0.25mm 0.50µm -60 to 330/350°C 30m ea. 13638-127
0.25mm 1.00µm -60 to 325/350°C 15m ea. 13650
0.25mm 1.00µm -60 to 325/350°C 30m ea. 13653
0.25mm 1.00µm -60 to 330/350°C 60m ea. 13697
0.32mm 0.25µm -60 to 330/350°C 15m ea. 13621
0.32mm 0.25µm -60 to 330/350°C 30m ea. 13624
0.32mm 0.50µm -60 to 330/350°C 30m ea. 13639
0.32mm 0.50µm -60 to 330/350°C 30m ea. 13639-125
0.32mm 1.00µm -60 to 325/350°C 30m ea. 13654
0.32mm 1.00µm -60 to 325/350°C 30m ea. 13654-125
0.53mm 1.50µm -60 to 310/330°C 30m ea. 13670
Rxi®-5Sil MS Columns (fused silica)
(low polarity Crossbond® silarylene phase; selectivity close to 5%
diphenyl/95% dimethyl polysiloxane)
17
Symmetric Peaks for More Accurate Results
Peak shape was also monitored to ensure column inertness was stable
over time—an important factor in maintaining accuracy. Peaks for the
active test probes were symmetric even after 400 injections, allowing
easy identification and consistent integration (Figure 3). In a second
experiment to complement the test probe results, underivatized amphet-
amine was injected onto a new Rxi®-5Sil MS column, an Rxi®-5Sil MS col-
umn after 400 injections of derivatization reagent, and a new competitor
column of equivalent phase chemistry. Even though underivatized
amphetamine is highly active, peak symmetry on the Rxi®-5Sil MS column
was consistent and unaffected by exposure of the column to derivatiza-
tion reagent. Additionally, peak shape on both the exposed and unex-
posed Rxi®-5Sil MS column was better than that on the new competitor
column (Figure 4).
Conclusion
The rugged arylene phase of the Rxi®-5Sil MS column results in highly
stable performance, even under the most demanding of analytical
conditions, and its exceptional inertness ensures good peak shape for
reproducible quantitation. The stability of the Rxi®-5Sil MS column
results in longer column lifetimes, reducing both downtime and replace-
ment costs.
For an online version of this article, visit
Rxi-5Sil MS after
400 injections
Unused Rxi-5Sil MS
Unused DB-5MS
Website : E-mail : TelNo : 03 9762 2034 . . . in AUSTRALIA