Brief Introduction of EPA Method TO-1/-2 Combination

Use for volatile organics such as vinyl chloride, benzene, methylene chloride, PCE, etc.


Samples are collected by drawing a measured volume of air through a two-stage cartridge containing both Tenax and CMS. Other types of cartridges, bags or canisters may be used. If they are, however, the method would best be described by a different number (see Alternatives).


Analyzed by heating the cartridge, separating the sample components from one another by GC and identifying by selective detector (if not likely to misidentify) or by GC/MS (preferred, best for legal defensibility).


Cartridge plus one for QC, small pump, flow controller/flow meter.

Detection Limits

Detection limits - 0.2 ppbv


Convenient, cartridges and samples easy to ship, and low detection limits available.


This is a "one shot" analysis. True analytical duplicates, internal standards & surrogates are not possible. Sampler must estimate how much air to sample. Cartridge must be placed in sampling line so air flows through Tenax first, CMS second (large arrow on outside helps). Desorbing must be carried out with flow in the opposite direction.


TO-1, TO-2, TO-3, TO-14, some NIOSH methods

Representatives Uses

Ambient air surveys, fence line monitoring, impacted neighborhoods, some odor problems, indoor air, risk assessment, TPH in air, etc.

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