WHY EPA METHOD TO-14/TO-15 FOR AIR SAMPLING?
TO-14 is the original and most common name for
a method used to test ambient air for Toxic Organic Compounds.
An improved method is TO-14a, and the newest is TO-15.
The analytical method used at KAR Laboratories is TO-15 "Determination
of Volatile Organic Compounds (VOCs) in Air Collected In Specially-Prepared
Canisters And Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS)"
- EPA Compendium Method TO-15, Second Edition. January, 1999.
- Summa Canisters, six liter in volume, are used
most commonly for ambient air samples and for collecting samples
over time. KAR has over 75 in inventory. A Summa canister
is a stainless steel vessel in which the internal surfaces have
been specially passivated using the "Summa process". This
process uses an electro-polishing step followed by chemical deactivation
to produce a surface that is very chemically inert. A canister
will hold a high vacuum (>28" Hg) for up to 30 days. After this,
low level concentrations of VOCs may appear as contaminants.
For this reason, we store our canisters pre-cleaned using proprietary
techniques and certified using GC/MS TO-15 protocols, then stored
with pressurized ultra-clean nitrogen gas. When a canister
is ordered for use, our laboratory readies it by evacuating the
canister using the combination of a mechanical fore-pump in conjunction
with a turbomolecular vacuum pump. Sorry, but even if the
canister is returned unused, the normal per-sample charge will apply
because we must go through the entire pre-screen/analysis/cleanout/recertification
process to ensure the readiness of the container for the next use.
- Analytes. Unlike Tedlar bags or Adsorptive Tubes,
TO-14/15 covers the widest range of volatile organic compounds.
We are calibrated for and report the original 40-compound TO-14
analyte list. The newer TO-15 method mentions suitability
for a whopping 97 analytes that can be analyzed, but it is very
rare (and very expensive!) to be fully calibrated and analyze for
all 97 analytes. The most cost-effective approach for the widest
range of compounds is to request the TO-14 analyte list along with
"Tentatively Identified Compounds" (TICs) if they are detected in
the test. Click here for the TO-14 parameter
- By far the easiest sampling protocol. No stopwatches,
no evacuation chambers, no calibrated sampling pumps, no failing
pump batteries, no fragile glass tubes, no hazardous impinger solutions,
and no danger of hooking up the sampling train incorrectly.
For a grab sample, just open the valve
on the vacuum canister, let it fill up, then close valve.
- Samples can also be collected over time, from
1 hour to 7 days. We have controlled-rate orifices calibrated
for 1, 3, 8, and 24 hours. Additionally, we can supply a digital
electronic LCD timing valve with up to 20 start/stop events which
can be programmed over a one week period with a one minute sampling
- Very sensitive. Reporting limit is 0.5ppbv for
- Widest concentration range. We can inject
up to 500 mL of air sample, or we can perform static dilution techniques
for samples with high concentrations of pollutants. This eliminates
the possibility of "Out of Range" samples.
- Best accuracy and precision. Reproducibility
and accuracy is outstanding and far better than popular (and cheaper)
- Regulatory approval. Widely regarded as
the correct way to sample and analyze volatile organic
compounds in air.
- Stable. The holding time for samples in the SUMMA
canister at ambient temperature is 30 days for T014 (14 days for
TO15), not 24-48 hours as with Tedlar Bags.
- Cost will be lower if multiple samples are submitted,
or if an abbreviated analyte list is required. The canister
remains the property of KAR Laboratories - it must be returned.
Your results will be reported to you in 10 working days or less.
The cost of this test is higher because of the specialized equipment
and calibration standards consumed, multiple analysis requirements,
and prescreening/verification using an alternate technique (we use
EPA Method 0040 & 8260 for pre-screening).
If you need it done right, TO-14/TO-15 is the
method to use.