Standard Operating Procedures (SOPs) for Cosolvent Flooding Technology
ANALYSIS OF SELECTED TARGET COMPOUNDS (OU1-LNAPL) IN
AQUEOUS ALCOHOL MATRIX AND GROUNDWATER
1.0 PURPOSE
The purpose of this SOP is to ensure reliable and reproducible analytical results of specific compounds selected as target analytes in OU1-LNAPL in water samples for laboratory-based or on-site (field-based) GC-FID analyses, and to permit traceability of possible causes of error in analytical results.
2.0 SCOPE
This SOP describes the analytical procedures used by Clemson University (CU) for analysis of target analytes, in both laboratory and field studies, which were selected as surrogates for the OU1-LNAPL, a complex mixture of weathered JP-4 fuel and other unidentified and unquantified organic compounds. This SOP may not be specifically applicable to the activities of other organizations.
This SOP was written by John Coates, Patrick Haskell, and Cindy Lee at Clemson University.
The target analytes selected for use in the CU laboratory and field studies are trichloroethene, toluene, o-xylene, 1,2-dichlorobenzene, naphthalene, decane, and undecane.
The method involves gas chromatography (GC) techniques for estimation of concentrations of target analytes in water samples; a flame-ionization detector (FID) is used to quantify the analyte concentrations in the sample. The method has been found to provide reliable and reproducible quantitation of target compounds for concentrations>1-2 mg/ml; this value is then considered to be the Method Detection Level (MDL). The standards calibration curve for FID response was found to be linear even beyond this value for specific target analytes.
Samples selected for GC-FID analysis may be chosen on the basis of preliminary screening to determine approximate concentration ranges, and select appropriate GC parameters (e.g., sample injection volumes; concentration range for standard curves, etc.) However, strategies for sample screening themselves are outside the scope of this SOP.
Aqueous samples from laboratory and field experiments may be sub-sampled into 2-ml GC vials for analysis. Dilution of Aqueous samples containing high concentrations of tert-butanol may be necessary to quantify within the calibration range.
3.0 RESPONSIBILITIES
All NAPL project staff, faculty, and students are responsible for knowing the procedures outlined below for analysis of target analytes selected for the Clemson test.
4.0 PROCEDURES
4.1 Sample Containers, Collection, Transportation and Storage
Sample Containers. Aqueous samples are contained in 4-ml glass sample vials (Fisher Catalog # 03-393G or equivalent) with open caps and Teflon-faced septa. The glass vials and the caps are not reused.
Sample Collection. Each sample vial is completely filled with aqueous samples, such that no head space of air exists, and capped. The vials are not opened until the time of sub-sampling or analysis.
Transportation and Storage. For field studies, the samples are stored in coolers containing "blue ice," and later stored in refrigerators in a trailer located on the site. Samples may be subjected to on-site GC analysis, and/or shipped back to CU laboratories; samples are packed in coolers with blue ice and shipped via overnight air express (e.g., FedEx). The samples are stored in a refrigerator at 4C, until they are ready for GC analysis. After sub-sampling, the samples are returned to cold storage. For laboratory studies, the samples are stored in a refrigerator if the period prior to analysis is expected to exceed eight hours.
4.2 Apparatus and Materials
Glassware. Disposable micro-pipettes (10, 100 ml; Fisher Catalog # 21-175B; 21-175F) and Class A volumetric pipettes are required for sample dilution. Drummond Dialamatic microdispensers (Fisher Catalog # 21-170-15A and # 21-170-15D or equivalent) may be used with the disposable micropipetter. Disposable Pasteur glass pipettes (Baxter Catalog # 13-678-20B or equivalent) are required for sub-sampling. GC vials (2 ml) with Teflon-faced caps (Baxter Catalog # C4901-230 and # C4901-238 or equivalent) are required for GC analysis. Class A volumetric pipettes are required for the calibration standards.
Gas Chromatograph System. An analytical GC system is required, complete with a temperature-programmable oven, and either an integrator or a PC-based data acquisition/analysis software. Also required are other accessories, including analytical columns and the gases required for GC-FID operation.
Two GC systems are used at CU; a Hewlett Packard (HP) 5880 equipped with a FID and a HP 6890 equipped with an autosampler and FID. The HP 5880 is interfaced with a HP 5880A Level Four GC Terminal integrator and the HP 6890 is interfaced with a IBM-compatible PC loaded with HP ChemStation software.
Reagents. Reagent water is defined here as the water in which an interferant is not observed
at the MDL of the parameters of interest. Laboratory reagent water is distilled, deionized tap water in the laboratory studies and reagent grade water (Baxter Catalog # C4351 or equivalent) in the field studies.
Tert-butanol used for preparation of all standards is a Baker Analyzed ACS reagent grade solvent (Baxter Catalog # 9056-05BC).
Standard Solutions. Analytical standard solutions are prepared from pure materials in the laboratory. Stock standard solutions, at 1,000 mg/ml of each analyte, are prepared in 95% tert-butanol and kept in 12 ml glass vials (Baxter Catalog # 4802-12 or equivalent) with Teflon-lined caps; minimal head space minimizes volatile losses. These stock solutions are stored at 4C.
Old stock solutions are discarded and a fresh batch prepared every month. Any time a comparison with the check standards indicates a problem, a new batch of standards must be prepared.