Automated TD Sample Preparartion of Calibration Standards

Abstract

This application note demonstrates quantitative sample preparation of calibration standards using the CDS 7550S automated thermal desorber. The internal standard loop of the 7550S is utilized here to automate the process of preparing calibration standards onto pre-conditioned thermal desorption tubes.

Introduction

Gas chromatography (GC) is an analytical technique by separating a mixture of compounds for a downstream detector to identify the chemical composition of each component. Direct liquid injection intot the GC inlet is the most common method of introducing sample onto the GC column. However, in many situations, the analyte identity, analyte concentration, or the matrix are not compatible for GC analysis. To tackle this challenge, various sample introduction techniques, including Purge and Trap, Thermal Desorption, Pyrolysis, and Solid Phase Micro Extraction were developed to introduce analyte onto the GC column to achieve the best separation result.

Here the CDS 7550S automated Thermal Desorber incorporates a sample concentration feature, which is designed to assist in sample preparation of calibration standards. Sample concentration works successively adding one more aliquots of standard gas directly from a sample loop of a known volume.