GOT NAPHTHALENE?
Naphthalene is a difficult compound to analyze by EPA Method TO-15. Point of fact, it is not even listed in the EPA Method as a potential target compound. It is also NOT even classified as a volatile compound by the definition of the EPA TO-15 Method*. Despite being listed in EPA’s Solid Waste Method for volatiles in water and waste (EPA SW-846, Method 8260B), it is also on the target list for semivolatile compounds (EPA SW-846, Method 8270C). It thus falls on the cusp between volatile and semivolatile. Other compounds may also exist in this “gray area” (e.g., 1,2,4-Trichlorobenzene) but may be less of an issue from a regulatory standpoint because of their lower toxicity. Because of Naphthalene’s carcinogenic properties, the requirement for low detection is much greater than for other compounds, hence the need to develop accurate procedures for a difficult analyte exists.
The Problems with Naphthalene analysis
Difficulties analyzing air samples for Naphthalene stem from two sources. The first is one’s ability to obtain a proper sample. The second, assuming the sampling issues have been addressed, is the ability to analyze the sample accurately. Although not an exhaustive list of potential problems, the following are generally unique (or at least most serious) with Naphthalene and can be enumerated as follows:
- Is Naphthalene stable in the sampling container OR does the container effect the recovery of the Naphthalene?
- Can Naphthalene be efficiently removed from the sampling container OR does some major proportion remain on the container surface?
- Is Naphthalene recovered through the chemical analysis system as a volatile compound OR are there parts of the system where it acts as a semivolatile and is not recovered quantitatively.
- Do the above three “issues” also apply to sampling as well?
- Can the laboratory meet the Quality Control specified by EPA Method TO-15 for Naphthalene (i.e., is the Method valid for this target?)
Air One Labs Solution
At Air One Labs we have solved the problems associated with Naphthalene through the use of the latest technology. Our laboratory is equipped with the newest sampling and analysis equipment which maintain that all surfaces with which the target compounds come into contact are at an elevated temperature. At the elevated temperatures, naphthalene’s vapor pressure is increased and thus becomes a true“volatile compound” and the EPA Method TO-15 definition applies. There is no need for a second costly procedure to analyze for Naphthalene. EPA Method TO-15 functions perfectly well and meets all QC requirements of the Method. Our new equipment includes the following:
- Silonite--coated sampling containers-Next generation of inert treatment for air sampling apparatus (cans, valves, tubing, flow controllers, etc.). This assures that naphthalene will encounter an inert surface in the sampling can and in all locations in the instrumentation.
- ENTECH Instruments Model 7500 Robotic Autosampler with single sample flow pathway. Capable of heating cans before analysis to “volatilize” Naphthalene. The sample pathway through the instrument is heated, flushed and cleaned every analysis. There is no multiport stream selector valve to contaminate as in older systems. This allows one to be certain that the Naphthalene that is found is correctly identified as belonging to a particular sample or standard and i s not what is called a “carryover from a previous sample or standard” effect.
We at Air One Labs were fortunate and happy to make the decision to begin a new lab with all new state of the art equipment. We chose to purchase the latest equipment available to solve the problems of low level air analysis. In a nutshell, we have solved the above issues through the use of the latest technology.
* EPA Method TO-15 defines “volatile” as compounds having a vapor pressure of >0.1 torr @ 25 degrees C. Naphthalene has a vapor pressure of 0.03 torr @25 degrees C.
