Standard Test Method for Determination of Volatile Organic Compounds in Atmospheres (Canister Sampling, Mass Spectrometry Analysis Methodology)

Importancia y uso:

5.1 VOCs are emitted into ambient, indoor, and workplace air from many different sources. These VOCs are of interest for a variety of reasons including participation in atmospheric chemistry and contributing to air toxics with their associated acute or chronic health impacts.

5.2 Canisters are particularly well suited for the collection and analysis of very volatile and volatile organic compounds because they collect whole gas samples.

5.3 Chemically stable selected VOCs have been successfully collected in passivated stainless steel canisters. Collection of atmospheric samples in canisters provides for: (1) convenient integration of air samples over a specific time period (for example, 8 to 24 h), (2) remote sampling and central laboratory analysis, (3) ease of storing and shipping samples, (4) unattended sample collection, (5) analysis of samples from multiple sites with one analytical system, (6) dilution or additional sample concentration to keep the sample size introduced into the analytical instrument within the calibration range, (7) collection of sufficient sample volume to allow assessment of measurement precision through replicate analyses of the same sample by one or several analytical systems, (8) sample collection using a vacuum regulator flow controller if electricity is not available, and (9) grab sample collection for survey or screening purposes.

5.4 Interior surfaces of the canisters may be treated by any of several proprietary passivation processes including an electropolishing process to remove or cover reactive metal sites on the interior surface of the vessel and a fused silica coating process.

5.5 For this test method, VOCs are defined as organic compounds that can be quantitatively recovered from the canisters having a vapor pressure greater than 10^-2 kPa at 25ºC (see Table 1 for examples).

5.6 Target compound polarity is also a factor in compound recovery. Aliphatic and aromatic hydrocarbons from C1 to C13 have been successfully measured with this test method but are not listed in Table 1 (21). Higher polarity target compounds may interact with the canister surface or humidity on the canister surface causing their apparent vapor pressure to decrease. Polar VOCs such as ethers and esters have been successfully measured by this test method and are listed in Table 1.

5.7 Recovery studies shall be conducted on VOCs not listed in Table 1 before expanding the use of this test method to include these additional compounds. Recovery from humidified spiked canisters shall agree with the spiked amount by ±30 %. The laboratory shall be responsible for verifying the relevant method performance characteristics for each compound added to the analyte list as agreed with their customer(s). The laboratory shall retain records of verification and make them available to customers upon request. Added VOCs (that is, those not listed in Table 1) shall be clearly identified in customer reports

Subcomité:

D22.05

Referida por:

D1356-20A, D8283-19, D1356-20A, D7911-19, D1356-20A, D6177-19R24, D5953M-23, D7297-21, E0800-20, D6670-18, D5953M-23, D6803-19, D6399-18, D7663-12R24, D6196-23

Volúmen:

11.07

Número ICS:

13.040.01 (Air quality in general)

Palabras clave:

ambient atmospheres; air analysis; canister analysis; canister sampling; gas chromatography–mass spectrometry; indoor atmospheres; volatile organic compounds; workplace atmospheres;