For many years, the use of guard columns has been advocated by column manufacturers and other experts to protect and extend column lifetime and performance of analytical columns from potential damage caused by the presence of chemical contaminants and microparticulates in the sample and mobile phase.
Philip J. Koerner, J.T. Presley, Tom Cleveland, and Jason A. Anspach, Phenomenex, Inc.
For many years, the use of guard columns has been advocated by column manufacturers and other experts to protect and extend column lifetime and performance of analytical columns from potential damage caused by the presence of chemical contaminants and microparticulates in the sample and mobile phase. The introduction and adoption of smaller particle size (< 3 µm) and narrow ID columns (≤ 2 mm) columns for ultra-high performance liquid chromatography (UHPLC) presents additional challenges. Specifically, these ultra-high performance columns are very sensitive even to small increases in dead volume and the use of traditional guard columns or guard cartridge systems will show a marked decrease in column performance (efficiency and resolution). However, small particle columns are even more susceptible to contamination and blockage from microparticulates that may be present in both the sample and mobile phases as they can occlude the smaller porosity column frits and dramatically shorten column lifetime.
KrudKatcher Ultra in-line filters are specifically designed for use with ultra-high performance columns from 1.0 to 4.6 mm ID and are pressure rated to 20,000 psi (1,375 bar). The filter body houses an integrated 0.5 µm 316 stainless steel depth filter that efficiently removes microparticulates from the flow stream without contributing to system backpressure or dead volume (<0.2 µL).
To illustrate the benefit of using the KrudKatcher Ultra in-line filter for extending column lifetime, a chromatographic separation of a ketone mixture on a Kinetex® 2.6 µm PFP 50 x 2.1 mm column was set up on a UHPLC system (Figure 1). The initial injection shows excellent peak shape and was maintained for over 1,100 injections (1a). However, after 1,175 injections the chromatographic performance has noticeably degraded resulting in split peaks with some peak broadening and tailing evident (1b). Simply replacing the KrudKatcher Ultra and re-injecting the sample returns the original chromatographic performance (1c). The KrudKatcher Ultra in-line filter successfully protected the ultra-high performance Kinetex column from damaging microparticulates in the mobile phase flow path and sample that would have dramatically shortened the column lifetime.
Figure 1a: Initially, both the KrudKatcher Ultra in-line filter and UHPLC column show excellent performance. Figure 1b: After extended use the chromatography starts to degrade producing split peaks. Figure 1c: Replacing the KrudKatcher Ultra in-line filter extends the lifetime of the column.
The regular use of KrudKatcher™ Ultra in-line filters with ultra-high performance UHPLC columns protects and extends the lifetime by protecting them from damaging microparticulates that may be present in the sample and mobile phase. Additionally, the KrudKatcher Ultra does not have a detrimental effect on chromatographic performance (retention time, peak width, resolution, or efficiency). For additional information, please request technote TN-1063.
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