Aircraft owners rely upon many different factors to ensure safe and successful flights. Pilots concern themselves not only with their own skills, abilities, and well-being but must also be confident that their aircraft is in the best physical condition possible. It is imperative that the aircraft is airworthy. One factor that contributes to an aircraft’s airworthiness is inspection of the condition of that aircraft’s engine oil through Aviation Oil Analysis (AOA).

Aircraft owners rely upon many different factors to ensure safe and successful flights. Pilots concern themselves not only with their own skills, abilities, and wellbeing but must also be confident that their aircraft is in the best mechanical condition possible. It is imperative that the aircraft is airworthy. One factor that contributes to an aircraft’s airworthiness is the condition of that aircraft’s oil and the information oil analysis can provide on the mechanical health of the aircraft.

Three methods frequently cited for the analysis of volatile organic compounds (VOCs) in air are EPA TO-14, TO-14A and TO-15. The following traces the chronology of their publication and identifies the principal differences among them.

Compendium Method TO-14A

Determination of Volatile Organic Compounds (VOCs) in ambient air using specially prepared canisters with subsequent analysis by Gas Chromatography.

TO-14A is a slightly revised version of an earlier method, TO-14. Method TO-14 was originally published in March of 1989 in the second supplement to Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air.1

Method TO-14 was revised and updated as Method TO-14A in the Second Edition of the Compendium of Methods in January 1999.2 As such, Method TO-14 has been superseded by TO-14A.

TO-14A differs from TO-14 in these respects:3

Compendium Method TO-15

Determination of VOCs in air collected in specially prepared canisters and analyzed by Gas Chromatography Mass Spectrometry (GCMS).

TO-15 was a new method added to the Second Edition of the Compendium in January 1999. TO-15 is larger in scope and better defined for the analysis of VOCs in air and other gaseous matrices than TO-14A. The major improvements in the revised methodology include the following points:4

Summa Canisters in our ALS Laboratory

Advantages and Disadvantages

  • TO-14A is considered a very good method for the broad speciation of unknown trace volatile organics, and it has proven field and analytical technology.
  • Strictly speaking, TO-14A is limited to the analysis of non-polar compounds. In addition, the detection systems allowed may not provide the best possible identification and quantification of unknowns.
  • Due to these points, Compendium Method TO-15 is considered a more general yet better defined method for the identification and quantification of VOCs than TO-14A.

How to Select the Appropriate Method

In practice, TO-15 has supplanted TO-14A as the preferred method for the analysis of VOCs in air. Unless otherwise specified by project documentation, permit requirements or other regulation, TO-15 is the method recommended by ALS.

For additional information, the methods may be reviewed directly at the following links:

http://www.epa.gov/ttn/amtic/files/ambient/airtox/tocomp99.pdf

http://www.epa.gov/ttn/amtic/files/ambient/airtox/to-14ar.pdf

http://www.epa.gov/ttn/amtic/files/ambient/airtox/to-15r.pdf

References

  1. EPA 600/4-89-018
  2. EPA 625/R-96/010b
  3. Winberry, Jr., Jerry, Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition, Project Summary, January 1999, p.12.
  4. Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Second Edition, January 1999, p. 15-3.