VOCs Services
Method brief: The default method for environmental water samples involves extraction/preconcentration using a purge and trap unit. For gas phase VOCs, the lab accepts TO-15 or TO-17-type samples, analyzed using a thermal desorption unit. Typical procedures are summarized here and here.
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Common target compounds:
Chlorinated ethenes (PCE, TCE, DCEs, VC): C, Cl, H*
BTEX, naphthalene: C, H
MtBE: C, H
1,2-dichloroethane (DCA): C, Cl
1,2-dibromoethane (EDB): C, Br*
chlorobenzenes (mono- and di-): C, Cl*
chloroform and carbon tetrachloride: C, Cl*
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* Reference standards calibrated to international halogen and hydrogen isotope scales are not available for certain compounds. Results are reported relatively to an arbitrary reference point, typically, the isotope composition of the working standard for that compound. Such results permit sample to sample comparison within the data sets anchored to the same reference standard, but do not permit inter-laboratory comparison without more advanced calibration.
Other VOCs can be potentially analyzed. Method setup fees may apply. Typically, KEI can determine C isotope ratios for any compound compatible with gas chromatography separation. Feasibility of hydrogen and chlorine CSIA varies. If your target compound is not listed, contact the lab for availability of service.
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Advanced analytical methods are required for difficult samples, to assure the completeness of the results. Methods are available for samples with exceedingly low concentrations of the targets, and for samples with complex organic mixtures, not resolvable by standard gas chromatography. These capabilities are unique to this laboratory.
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Water samples should be collected and preserved with HCl following the approach of VOCs concentration analysis (USEPA 5030 or similar).
MtBE and several less common compounds are susceptible to acid hydrolysis. Such samples should be preserved by increasing pH above 12, using Trisodium phosphate (TSP).
Other preservatives must be approved by the lab on case-specific basis.