74 Evaluation of the Performance of a Robotic System for Spiking Thermal Desorption Sorbent Tubes with Defined Masses of Organic Compounds

Abstract

Abstract Thermal desorption (TD) gas chromatography is a widely used analytical method for measuring airborne concentrations of (semi) volatile organic compounds ((S)VOCs) collected using sorbent tube samplers and is now widely used in the ambient, fence line, indoor and workplace air monitoring environments. Calibration and internal quality control check samples are prepared in end user laboratories by spiking individual TD sorbent tubes with microliter quantities of (S)VOCs in a carrier solvent such as methanol but this can be a laborious and error-prone step. Historically spiked sorbent certified reference materials were available from IRMM for confirmatory purposes but these stocks are now virtually exhausted. Hence new spiked tubes would be useful for quality control/assurance purposes. Previously HSE developed a system for the simultaneously spiking of 60 TD sorbent tubes with defined mases of VOCs from the gas-phase based upon requirements set out in ISO 6145 part 4[1]. With less volatile (S)VOCs however, spiking from the gas-phase presents challenges and hence an alternative spiking approach using liquid standards is proposed. The performance of a newly acquired automated robotic spiking system will be described. Reference [1] ISO 6145-4:2004. Gas Analysis-Preparation of calibration gas mixtures using dynamic volumetric methods-Part4: Continuous syringe injection method.