Effect of Frits on Flow Profile and Column Efficiency in Conically Shaped Preparative Liquid Chromatographic Column
筛板对台锥形制备液相色谱柱流型和柱效的影响

The inlet frit of preparative liquid chromatographic column influences the distr ibution of samples on the column header, the flow profile of sample band and col umn efficiency. By Vis-UV detector, column efficiencies of conically shaped preparative chromatographic columns with porous polytetrafluor oethylene (PTFE) frit and porous stainless steel frit were compared. The effect of the inside diameter of the frit on the column header on flow profile was stud ied by on-column visualization method. The results showed that the resulting co lumn efficiencies with the PTFE frit were lower than that of the porous stainl ess steel fri t by 40% because of the distortion of the porous PTFE frit. The distr ibution of sample on the column header was not uniform when the sample flowed th ro ugh a frit that had a smaller diameter than the column inlet inner diameter (ID) . However, the resistance force on the frit was uniform when the sample flowed t hrough a frit that had the same diameter as the column inlet ID, so the f low profile at initial moment was plug-like at the exit of the frits. Differen t flow profiles were produced by using different ID of frits. About 20% higher column efficiency could be obtained by using the same frit ID as that of the col umn inlet.