Journal of Separation Science
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Online ISSN: 1615-9314
Associated Title(s): ELECTROPHORESIS
July 31, 2007
An advanced solventless column test for capillary GC columnsManufacturing skills for capillary GC columns have improved to a point where the commonly used tests no longer distinguish between ôadequateö and ôexcellentö columns. A more stringent test mixture, coupled with a more exacting procedure, was proposed for testing capillary columns in 2004. The solutes were less sterically hindered and less retained, permitting the test to be run isothermally at lower temperatures where sorptive forces are stronger. This test mixture, used under the prescribed conditions, differentiated ôadequateö from ôexcellentö columns, but removal of the late eluting solvent prolonged run times to as long as one hour.
Therefore a more exacting QC test for capillary gas chromatographic columns has been developed by Jim Luong, Ronda Gras, and Walt Jennings. It uses the same probes proposed in 2004, but entirely eliminates the solvent. Injections utilize a plunger-in-needle micro-volume syringe, and the ôgas saverö feature of a contemporary gas chromatograph. The latter serves as a dynamic diluter to deliver nanogram quantities of undiluted solutes to the column. The test can be conducted isothermally at a lower temperature in less than fifteen minutes for most columns. Comparisons of the results generated by a conventional test and the new test were conducted on a variety of capillary columns from several reputable manufacturers. The results clearly demonstrate that the new test, used in the manner described, is capable of revealing column deficiencies that can affect qualitative and quantitative validities that were not detected by a conventional QC test, typical of those in current use. The test is suitable for essentially all common columns, from polydimethylsiloxanes to polyethylene glycols, making it unnecessary to employ different tests for polar and apolar columns.
Jim Luong, Ronda Gras, and Walt Jennings, J. Sep. Sci. 2007, 30 (15).
Full article online, DOI: 10.1002/jssc.20070131