An Exposure System for the Calibration of Passive Samplers to Volatile Organic Compounds at Low (ppbv) Concentrations

Abstract

A recycling exposure system, which has characteristics of dynamic and static systems, has been designed and constructed for calibrating passive sampling tubes. This system is very easy to set up and maintain. Organic vapors inside the system are generated by syringe injection, and homogeneous vapors are circulated by a metal-bellows pump. The concentrations of light hydrocarbons (e.g., isoprene) may decrease slightly after circulating for longer than 10 hours; however, this system is very stable for C5-C8 hydrocarbons for at least eight hours. The system has been used successfully to calibrate Perkin-Elmer diffusion tubes packed with Chromosorb 106 for collecting benzene vapor at low exposure doses (< 70 ppmv x min). The entire system can be easily and effectively cleaned by circulating through a U-tube packed with activated carbon.

Enrichment/separation of cadmium(II) and lead(II) in environmental samples by solid phase extraction

“…are synthetic polymeric materials [35,36] and have been used for gas chromatography as stationary phases, because they have good physical and chemical properties such as porosity, high surface area, durability and purity and are resistant in concentrated mineral acid, concentrated bases and organic solvents for a long time. Chromosorb-106 is a member of the chromosorb resin family.…”

“…It is a cross-linked polystyrene resin. It has been used on the gas chromatographic analysis of various organic compounds as stationary phase [35][36][37][38][39].…”

Evaluation of a Passive Sampler for Volatile Organic Compounds at ppb Concentrations, Varying Temperatures, and Humidities with 24-h Exposures. 1. Description and Characterization of Exposure Chamber System

“…VOC generation methods have included diffusion tubes and vials (25), saturation bubblers (17), counter-current volatilizers (20), syringe injection (23), permeation tubes (11)(12)(13), sintered spheres of glass beads coated with organic solvents (25), a capillary-effect generation system (26), and dilution of compressed gases (22). Given the ease of use and commercial availability, we selected permeation tubes as the VOC generation devices.…”