Abstract

CRYOGENIC MEASUREMENT OF VOLATILE ORGANIC COMPOUNDS BY GAS CHROMATOGRAPHY

*Yash Gandhi, Hiral Panchal

ABSTRACT

Cryogenic measurement of gas chromatography was easily adapted by cryogenic trap or sorbent trap for preconcentrating ambient level of volatile organic compounds which include automated GC FID system. In second GC system porous layer open tubular column of Al2O3/ KCl is used. In valve system 3-, 4- & 6-port valve & pneumatic bellows valve are used. In cryogenic free concentration system for VOC’s (volatile organic compounds) a Kleemenko cooler is used to create liquid nitrogen trapping conditions & to eliminate the use of the solid absorbents, potential source of artifacts. Concentrator system has 8 port stream select valve, 8 port switching valve, one two way & two three way valves, instrumental control & splitter box. In cryogenic preconcentration system FID (flame ionization detector) Tenax adsorption & GC/MS is used for determination of volatile organic compounds. In FID (flame ionization detector) the sample is injected into hydrogen rich flame & resulting ion fragments are detected. In cryogenic trapping of carbonyl sulfide moderate trapping temperatures down to about -60°C can be achieved using relatively simple electronic devices or mixtures of ice and various salts. Most trapping techniques for which lower temperatures are required make use liquified inert gases, such as argon and nitrogen. Here Cold trap interface, Cryotiger refrigerator & analytical system is used.

Keywords: Cryogenic measurement; Volatile organic compounds; Non methane organic compounds; FID (flame ionization detector)