Methodology and Quality Assurance/Quality Control of Environmental Analysis - Fundamentals of Environmental Sampling and Analysis - page 111

EPA 5000 Series: Headspace or Purge-and-Trap for Volatile
Compounds

Extraction methods shown in Table 5.3 cannot be used for volatile organics because
open containers are involved in the extraction procedure. Sample preparation
methods for volatile organic compounds are described in SW-846's series 5000
methods (Table 5.4). Headspace analysis and purge-and-trap (P & T) are probably
the most commonly used methods. Separation in P & T is carried out by purging the
sample (sometimes while heating) with an inert gas (N 2 ) and then trapping the
volatile materials. The trap is designed for rapid heating so that it can be desorbed
directly into GC.

Table 5.4 Sample preparation methods for volatile organic compounds

Method
series

Matrix Extraction type Analytes

5021 Solids Automated headspace Volatile organics

5030 Aqueous Purge-and-trap Volatile organics

5031 Aqueous Azeotropic distillation Polar volatile organics

5032 Aqueous and solids Vacuum distillation Nonpolar and polar

volatile organics

5035 Solids, organic Closed system purge- Volatile organics

solvents, oily waste and-trap

5041 Air sampled by VOST Purge-and-trap Volatile POHCs

from VOST

*Refer Chapter 7 for details. VOST¼Volatile organic sampling train; POHCs¼Principal organic
hazardous constituents. They are specific hazardous waste compounds identified by the EPA,
which are selected for monitoring during trial burn of a hazardous waste incinerator.

5.2.2 Methods for Physical, Biological, and General
Chemical Parameters

EPA 100 and 300 Series: Physical Properties, Inorganic,
and Nonmetallics

Common physical properties include conductance, pH, solids (SS, TDS, TS, VS),
temperature, and turbidity. Inorganic and nonmetallic constituents refer to anions of
various elements (Br, Cl, CN, F, I, N, P, S), total N and P, acidity, alkalinity, and
dissolved oxygen (DO). Measurement methods include potentiometric (pH),
gravimetric (solids), thermometric (temperature), titrimetric (alkalinity, acidity),
membrane electrode (dissolved oxygen), or iodometric (Winkler method for
dissolved oxygen). Analytical methods of these parameters are well established and
can be found mostly in the EPA 100 and 300 series. Additional methods, in the order
of importance, can also be located in APHA method 2000 and 4000 series, USGS,
ASTM, and AOAC.