Electrolyzer-operated gas-cylinder-free GC-FID

Abstract

A new gas chromatography system, based on the use of a water electrolyzer as its only source of gases, was designed, built, and tested. An electrolyzer-powered flame ionization detector (EFID) served as the GC detector for the sensitive, carbon-selective detection of a broad range of volatile organic compounds. The concept of electrolyzer-operated GC-EFID is based on the use of the electrolyzer-produced oxygen and hydrogen gas mixture for sample desorption and sweeping in a purge-and-trap sampling system, as the analytical column carrier gas and as the only required EFID combustible gas mixture. It was found, as it has been found previously, that standard columns with dimethyl polysiloxane adsorption film could be operated with oxygen up to 200 °C. A styrene-divinylbenzene–based PoraBOND porous-layer open tubular column was used for the GC separation, and it was found that the system could be operated up to 140 °C with the electrolyzer-produced hydrogen and oxygen gas mixture. Thus, the use of a water electrolyzer enabled the creation of a gas-cylinder-free GC-FID system with enhanced transportability and ease of use and with lower cost of operation. The gas-cylinder-free system operation was demonstrated with fast chromatography separation (under 1-min total analysis time) of acetone, ethanol, benzene, toluene, and xylene with an estimated detection limit below 1 ppb. The capability of exhaled human breath analysis for industrial hygiene and medical diagnostic applications is demonstrated. An additional capability of total hydrocarbon content in air analysis is shown and the required minor modifications are discussed. © 2001 John Wiley & Sons, Inc. Field Analyt Chem Technol 5: 107–115, 2001