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KIRTLAND AIR FORCE BASE ALBUQUERQUE, NEW MEXICO ...

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APPENDIX B<br />

Calibration<br />

The GC should be calibrated according to manufacturers‘ instructions relative to the COCs upon<br />

consultation with the project chemist or designee.<br />

The GC will be calibrated daily prior to commencing fieldwork and that calibration will be verified<br />

throughout the day. An aliquot of vapor from the working standard will be injected into the GC. The<br />

GCs computer will be programmed to quantitatively recognize the chromatographic peaks of each soil<br />

gas target compound. Nontarget volatile organic compounds present in soil gas samples will be reported<br />

as unknowns.<br />

Sample Collection<br />

Active soil gas samples will be collected in the following manner:<br />

Quality Control<br />

A 5/8-inch diameter, solid steel probe, will be driven into the ground and withdrawn. The<br />

depth to which the steel probe is driven, typically 3 to 4 ft, will vary based on site conditions<br />

and as specified in the project addenda.<br />

A hollow sampling probe will be inserted approximately 2 ft into the hole. The sampling<br />

probe will have an outside diameter slightly larger than 5/8 inch to provide a seal preventing<br />

ambient air from entering the sample hole.<br />

A hand-operated vacuum pump will be attached to the sample probe using a<br />

Teflon ® /stainless steel fitting. Approximately 10 probe volumes of air will be purged from<br />

the sample probe to ensure the soil gas sample is not diluted by the air in the sample probe.<br />

A 1.0 mL aliquot of soil gas will be collected using a Hamilton Gas-Tight syringe. The<br />

syringe will be inserted through a septum on the Teflon ® sample tube, upstream of the<br />

vacuum pump.<br />

The 1.0 mL soil gas aliquot sample will be immediately injected into the GC for analysis.<br />

QC samples will be run throughout the field investigation to ensure the integrity and reproducibility of<br />

the data. A minimum of 20 percent of the samples analyzed will be for QC purposes or as indicated in<br />

the project-specific addenda. QC samples will be analyzed randomly or in response to suspected<br />

interferences. QC samples will include field duplicates, calibration standards, equipment and instrument<br />

blanks, and method blanks (background). Field duplicates involve analysis of 2 or more samples from<br />

the same hole and are used to check the reproducibility of the sampling and analysis procedures.<br />

Calibration standards involve re-analysis of the standard over the course of the day and are used to<br />

confirm the calibration of the GC. Equipment blanks involved analysis of ambient air drawn through the<br />

decontaminated sample probe when it is not in a sample hole (probe blanks), or analysis of an aliquot of<br />

hydrogen-free air in the sample syringe (syringe blanks); these blanks are used to verify adequate<br />

decontamination of the sample probe and syringe, respectively. Instrument blanks involve analysis with<br />

no injection (no injection blanks) and are used to determine if there is any carryover contamination in the<br />

GC. Method blanks involve analysis of ambient air and are used to assess the presence of background<br />

contamination.<br />

Kirtland AFB<br />

SOPs for Field Investigations B-62 April 2004

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