Use of Open Tubular Capillary Column (Guard Column)

Introduction

In Application News G230, we discussed the optimum initial column temperature in splitless injection analysis using various solvents, using an analytical column of 0.25mm I.D. × 30m long and df = 0.25μm. In pesticide analysis, a deactivated open tubular capillary column (guard column) is sometimes connected before the analytical column to help protect the analytical column from contamination. This Application News investigates the differences in peak shape and separation obtained at different initial column temperatures in splitless analysis using the solvents acetone, hexane, acetonitrile and toluene when a guard column is connected to the analytical column. We connected a deactivated 0.53mm × 50cm guard column before the analytical column using a press- tight connector. An organophosphorus standard mixture source solution (10mg/L each acetone solution) was diluted by a factor of 100 with each of acetone, hexane, acetonitrile and toluene, and the resultant solutions were used as the sample solutions (each constituent 0.1mg/L). The sample solutions were subjected to splitless analysis at different initial column temperatures to evaluate the peak shapes etc. The other conditions were same for all the samples.

July 12, 2005 GMT