Lower Detection Limits with Ground-Breaking Column Technology


Courtesy of Restek Corporation

Rxi technology unifies outstanding inertness, low bleed, and high reproducibility into a single high performance column line. Take variation out of the equation and get the most consistent results for trace-level analysis with Rxi columns.

phases available

  • Rxi-1ms
  • Rxi-1HT
  • Rxi-5ms
  • Rxi-5Sil MS
  • Rxi-5HT
  • Rxi-XLB
  • Rxi-624Sil MS
  • Rxi-35Sil MS
  • Rxi-17
  • Rxi-17Sil MS
  • Rxi guard/retention gap columns

Lower Detection Limits with Ground-Breaking Column Technology
Rxi columns deliver more accurate, reliable trace-level results than any other fused silica column on the market. To ensure the highest level of performance, all Rxi capillary columns are manufactured and individually tested to meet stringent requirements for exceptional inertness, low bleed, and unsurpassed column-to-column reproducibility.

Highest Inertness
Inertness is one of the most difficult attributes to achieve in an analytical column, but it is one of the most critical as it improves peak shape, response, and retention time stability. Rxi technology produces the most inert columns available, providing:

  • Increased signal-to-noise ratios to improve low-level detection.
  • Reproducible retention times for positive identifications.
  • Improved response for polar, acidic, and basic compounds.

Increased Signal and Reproducible Retention Times
When capillaries are not sufficiently deactivated, peaks become asymmetric, resulting in reduced signal and unpredictable retention times.As column activity increases, peak tailing becomes more pronounced, reducing peak height and causing retention time to drift (Figure 1). In practice, this means that sensitivity is lost and trace-level analytes cannot be reliably determined. In addition, even compounds at higher concentrations may be misidentified, due to retention time shifting.

A more significant problem for sample analysis is that retention time can vary with analyte concentration if the column is not highly inert. Since the amount of target analyte in samples is unknown, retention times on a poorly deactivated column can easily vary enough to move compounds outside the retention time window (Figure 2). This can result in inaccurate identifications, the need for manual integration, and additional review or analysis before results can be reported. Using inert Rxi columns ensures that compounds elute with good signal-to-noise ratios at expected retention times, regardless of analyte concentration.

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