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3.3.1.2 Analysis Procedure for TCE
Concentrations of TCE were measured using a Varian 3600 gas
chromatograph (GC) equipped with an 01 analytical discrete purging
multisampler (DPM-1 6), an 01 analytical multiple heater controller (MHC-16), and
a Model 4560 purge-and-trap sample concentrator. A Supelcowax-10 megabore
column (60 m x 0.25 mm inside diameter) and flame-ionization detector (FID)
were installed on the GC.
Standards for calibration of the GC were prepared gravimetrically from
TCE stock solution. Primary stock solutions were prepared by adding TCE in a
10 mL volumetric flask containing purge-trap grade methanol. Secondary stock
solutions were prepared by diluting the primary stock solutions with purge-trap
grade methanol. Type I DI water was added to the sampling tubes using a 5-mL
glass syringe. A 100-[L aliquot of secondary stock solution containing an
appropriate concentration of the calibration standard was then collected with a
gas-tight syringe and directly injected into the sampling tubes. Similarly, a 10-[L
internal standard was injected into the sampling tubes. For TCE analyses,
toluene was used as an internal standard. All calibration curves were based on
three standards prepared over the range of expected concentrations.
Concentrations of 1, 5, 10, and 40 mg/L were used.
Supernatant liquid from the batch tests was sampled using a 100-%-L gas-
tight syringe and then directly injected into the multisampler tubes. To ensure