Fast GC Using Minibore Fused Silica Capillary Columns Introduction ...

Sampling Rate and Signal to Noise RatioSince peak widths are approximately half compared toconventional columns (< 1 second), fast integrator and detectorelectrometers must be used. Integrator sampling rates must beincreased over rates used for 0.25mm ID columns since the peaksare much narrower with minibores. If the sampling rate is tooslow, then poor integration and non-reproducible peak areas willresult. Check with your instrument company and data system manufacturer to be sure your systemis capable of handling minibore sampling rates.FootnoteSRI GCs PeakSimple Data System #203 has a maximum samplung rate of 50 HZfor quantitation an A/D sampling rate should be fast enough to scan 12 times across the peakFor HIGH SPEED GC using this system at 50Hz the chromatography should limit peak widths toapprox 0.25sec ( minmum )Suggestion - probably a practical limit for such a system combined with fast temperatureprogramming limited to 10m 0.18mmID columns programmed at up to 250 deg-C/min ( ezFLASHGC ) over a 2 to 3 min analysis periodNOTE Information from OEMs regarding FID electrometer time constants and A/D Data Systemspeeds is rareShimadzu with their 2002 Model #2010 GC offer 250 deg-C temp programming and Detector A/Dsampling rates of 250Hz for HIGH SPEED GCSummary• Benefits• Shorter analysis times• Similar resolution• Lower cost• Considerations• Capacity• Injector• Detector• SamplesMinibore columns can produce shorter analysis times, equivalent resolution, and provide costsavings. But remember, converting your conventional system to a minibore system isn't as easy aschanging columns. Column capacity, sample purity, and injector and detector conditions must beconsidered and optimized for a successful analysis. Keep in mind that when switching fromconventional capillaries to minibore columns, there may be the need to optimize inlet temperatures,liners, and GC run conditions.