Chromatographic Methods for Environmental Analysis - Fundamentals of Environmental Sampling and Analysis - page 277

Table 10.8 GC-based US EPA Methods

Matrix Method series Method number

Air TO series 13 TO series methods (TO-1 to TO-4; TO-7; TO-9; TO-10;

TO-12 to TO-17).

Water/ EPA 500 12 EPA 500 series methods (502-508; 515; 524; 525).

Wastewater EPA 600 17 EPA 600 series methods (601-604; 606-615; 619;

624; 625)

Waste SW-846 27 EPA 8000 series methods (8000 to 8430)

The second group of GC-based methods was developed by the US EPA for
water and wastewater, including 500 and 600 series methods. The 500 series
methods were published in 1988 to support the Safe Drinking Water Act of 1974 and
focus on determining low concentrations of contaminants in drinking waters. These
methods underwent a major revision in 1991, although specific methods have been
updated since then. There are 12 GC-based analytical methods in 500 series. Six of
the methods are for VOCs and certain disinfection by-products, and the other six are
designed for the determination of a variety of synthetic organic compounds and
pesticides. Five of the methods utilize the purge-and-trap extraction, six methods
employ a liquid-liquid extraction, and one method uses a new liquid-solid phase
extraction.
The 600 series methods were published as a result of the Clean Water Act and its
amendment for use with the National Pollutant Discharge Elimination System
(NPDES) permitting process and enforcement. These methods were last updated in
1984 and still reference packed column methods. The two most important methods
in the EPA 600 series are methods 624 and 625. Method 624 is a GC/MS method for
purgeable organic compounds that includes compounds also determined by GC
methods 601, 602, 603, and 612. Method 625 measures semivolatile organics that
includes compounds also detected by GC methods 604, 606, 607, 609, 610, 611, and
612. Because of the larger number of target compounds, methods 624 and 625 are
usually specified for organic analysis of contaminated water. These are
supplemented by method 608 for pesticides and polychlorinated biphenols and
method 613 for 2,3,7,8-TCDD (dioxin). If certain compounds are detected by
method 625, they should then be confirmed with a GC method specific to that
compound.
The third group is approximately 27 GC-based methods, known as the 8000
series methods published in SW-846. As noted, various GC detectors are used
including FID, ECD, NPD, PID, ELCD, FTIR, low and high resolution MS. In
reviewing the above-mentioned GC methods, the reader should realize that
improvements of these methods have constantly been made over a period of time.
But mostly, the process is slow, such as the case for the change from packed to
capillary columns. This is partially because of the bureaucracy and fears of
adversely affecting the method performance.