The SRI Model 8610C gas chromatograph (GC) is a transportable instrument that can provide on-site
analysis of soils for explosives. Coupling this transportable gas chromatograph with a thermionic
ionization detector (TID) allows for the determination of explosives in soil matrices following
simple sample preparation procedures. Samples are extracted in acetone, diluted, and injected
directly onto the GC column within a heated injection port. The high temperature of the injection
port instantaneously vaporizes the solvent extract and explosives, allowing them to travel as a vapor
through the GC column in the presence of the nitrogen carrier gas. The stationary phase of the GC
column and the programmable oven temperature separate the components present in sample extracts
based on their relative affinities and vapor pressures. Upon elution from the column's end, compounds
containing nitro groups are ionized on the surface of the thermionic bead, and the increased
conductivity of atmosphere within the heated detector is measured with a collector electrode. In this
verification test, the instrument was verified for its ability to detect and quantify 2,4-dinitrotoluene
(2,4-DNT), RDX, and TNT. For this verification test, analytical run times were typically less than
7min and reporting limits were typically 0.5 mg/kg.
For more information: SRI Instruments, contact Hugh Goldsmith,
hagoldsmith@earthlink.net, 310-214-5092