FRTR Field Sampling and Analysis Technologies Reference Guide

6 SAMPLE ANALYSIS TOOLS for VOCs, SVOCS, and PESTICIDES

6.2 EX-SITU ANALYSIS

6.2.8 GC/MS

Use:

GC/MS is a hybrid technique that combines the separation capability of the gas chromatograph (GC) (see 6.2.4), the analytical capability of the mass spectrometer (MS) (see 6.2.7), and the capability to provide real-time, on-site data. GC/MS is the preferred technology for analysis of complex mixtures.

See 9.1.2 for use with explosives.

Description:

GC/MS systems allow better resolution of components in complex mixtures than mass spectrometry alone and are most commonly used for unequivocal identification of hazardous compounds. A GC is essentially a highly efficient device for separating a complex mixture into individual components. When a mixture of components is injected into a GC equipped with an appropriate column and carrier gas, the components travel through the column at different rates. A mass spectrometer (MS) located at the end of the column can then analyze each component separately as it leaves the column. In essence, the GC allows the mass spectrometer to analyze a complex mixture as a series of pure components.

Analytes:

1. Non-Halogenated VOCs	2. Non-Halogenated SVOCs	3. Halogenated VOCs
4. Halogenated SVOCs	5. PAHs	6. Pesticides/Herbicides

Media:

Soil/Sediment	Water	Gas/Air
Requires extraction to liquid or gas phase	Requires extraction to liquid or gas phase	BETTER

Selectivity:	Technique measures the specific contaminant directly.
Susceptibility to Interference:	Low.
Detection Limits :	100-100 ppb (soil); 1-50 ppb (water).
Turnaround Time per Sample:	More than a day (due to calibration requirements).

Applicable To:

Screen/Identify	Characterize Concentration/Extent	Cleanup Performance	Long-Term Monitoring
BETTER	BETTER	BETTER	ADEQUATE

Quantitative Data Capability:	Produces quantitative data.
Technology Status:	Commercially available and routinely used field technology.
Certification/Verification:	Technology has participated in CalEPA certification and/or CSCT verification program.
Relative Cost per Analysis:	Most expensive.

Limitations:

Calibration of portable GC/MS systems can be time consuming.
GC portion of the system requires a library of retention times to identify compounds, and non-target compounds could be difficult to identify if detected analytes are not in the library or the quality of the library match is too low to make positive identification.
MS portion of the system requires a library of spectra.
See limitations in 6.2.4 and 6.2.7.

ASTM Standards:

D 5790 - 95

Measurement of Purgeable Organic Compounds in Water by Capillary Column GC/MS.

(Multiple ASTM Standards exist for specific contaminants in a variety of matrices).

EPA Methods:

Series 8200	5 Methods for Specific Analytes and Equipment Capabilities.
Series 520	3 Methods for Purgeable Organic Compounds in Water (drinking water).

Sample Access/Collection Matrix

Sample Analysis Matrix

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