Method 625

Base/Neutral and Acid Organics by GC/MS

This method covers the determination of a number of organic compounds that are partitioned into an organic solvent and are amenable to gas chromatography. The parameters may be qualitatively and quantitatively determined using this method. A measured volume of sample, approximately 1 L, is serially extracted with methylene chloride at a pH greater than 11 and again at a pH less than 2 using a separatory funnel or a continuous extractor. The methylene chloride extract is dried, concentrated to a volume of 1 mL, and analyzed by GC/MS. Qualitative identification of the parameters in the extract is performed using the retention time and the relative abundance of three characteristic masses (m/z). Quantitative analysis is performed using internal standard techniques with a single characteristic m/z.

Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:	All samples must be extracted within seven days of collection and completely analyzed within 40 days of extraction.
Preservatives:	All sampling must be iced or refrigerated at 4EC from the time of collection until extraction.
Required Preps:	1 L or 1 qt, amber glass, fitted with a screw cap lined with Teflon
Collection Method:	Grab sampling
Analytical Methodology:	GC/MS
Documentation:	625

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.