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2.1 This method provides gas chromatographic conditions for the detection of certain nonhalogenated volatile and semivolatile organic compounds. 2.2 Depending on the analytes of interest, samples may be introduced into the GC by a variety of techniques, including: • Purge-and-trap (Methods 5030 or 5035) • Equilibrium headspace (Method 5021) • Direct injection of aqueous samples • Injection of the concentrate from azeotropic distillation (Method 5031) • Vacuum distillation (Method 5032) • Following solvent extraction (Methods 3510, 3520, 3535, 3540, 3541, 3545, 3546, 3550, 3560, or other appropriate technique) 2.3 Groundwater or surface water samples generally must be analyzed in conjunction with Methods 5021, 5030, 5031, 5032, 3510, 3520, or other appropriate preparatory methods to obtain the necessary quantitation limits. Method 3535 (solid-phase extraction) may also be applicable to some of the target analytes, but has not been validated by EPA in conjunction with this determinative method. 2.4 Samples to be analyzed for diesel range organics may be prepared by an appropriate solvent extraction method. 2.5 Gasoline range organics may be introduced into the GC/FID by purge-and-trap (Methods 5030 and 5035), automated headspace (Method 5021), vacuum distillation (Method 5032), or other appropriate technique. 2.6 Triethylamine may be analyzed by direct injection of aqueous samples. This compound has not been found to be amenable to purge-and-trap techniques. 2.7 An appropriate column and temperature program are used in the gas chromatograph to separate the organic compounds. Detection is achieved by a flame ionization detector (FID). 2.8 The method allows the use of packed or capillary columns for the analysis and confirmation of the non-halogenated individual analytes. The GC columns and conditions listed have been demonstrated to provide separation of those target analytes. Other columns and conditions may be employed, provided that the analyst demonstrates adequate performance for the intended application. 2.9 The quantitative analyses of GRO and DRO are based on the definitions provided in Sec. 1.2.2 and the procedures described in Sec. 11.11.
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