Environmental Chemistry Consulting Services: Your Partner In Success

Ask the Chemist Vol. 4 - Alternative Explosives Analysis

Many of the requests we get for analysis of explosives cite EPA Method 8330. In fact, most QAPPs require Method 8330. A lesser known test is EPA Method 8095.

EPA 8330 Methods have been the standard environmental test method for nitroaromatic, nitroamine, and nitroester compounds (explosives) for many years.  The methods use HPLC separation techniques and detection by ultra-violet absorption.  EPA Method 8095 incorporating the use of GC/NPD and GC/ECD techniques overcomes disadvantages of the HPLC Methods including poor selectivity causing false positive results, multiple co-elution issues, higher detection limits, and long run times.

As written, Method 8095 employs GC/ECD techniques.  However, incorporating the use of NPD adds the advantage of superior selectivity over both HPLC and GC/ECD.  Potential interferences that could typically affect identification and quantitation of target compounds utilizing Method 8330 and to a lesser extent Method 8095 by GC/ECD, are nearly 100% eliminated with the use of NPD. The use of newer columns such as the RTX-TNT has allowed complete baseline to baseline separation of all target analytes. New generation cyclo-spliter injection port liners have essentially eliminated historically problematic injection port issues associated with analysis of these compounds. Injection cycle time is 18 minutes, far less than Method 8330. Method 8095 has multiple distinct advantages over Method 8330, yet 8330 is the preferred method.  We would like to suggest this avenue for change. 

Which method is better?

Method 8095 offers several advantages over 8330, including the following:
  • Fewer interferences due to the high selectivity of NPD
  • GC has inherently better compound identification than HPLC (RT stability)
  • All target compounds resolved, no co-elution issues, all 6 DNTs will separate
  • Shorter run time
  • Lower DLs

Some of the advantages of 8330 include: 
  • 8330 is more rugged for nitro-amines, especially HMX
  • GC techniques have slightly higher maintenance costs

Both methodologies can be performed in a mobile lab or fixed-base lab setting.

To Dry or Not To Dry?

Traditional sample prep for explosives under Method 8330 has an air drying component that leads to losses for the more volatile fractions of the explosives; namely the mono nitro-aromatics, nitroglycerin and PETN.  ECCS' sample preparation dries the sample chemically, using sodium sulfate.   This drying technique improves recovery of these compounds.


Method 8095 is a viable alternative to Method 8330 for many projects. Whenever explosives analyses are required, check with us to confirm if your project is a viable candidate for 8095 analysis.  Below are some guidelines for 8095 usage.
  • GC/NPD for manufacturing facilities
  • GC/ECD for nitroglycerine or PETN facilities or for projects with low detection limit requirements
  • RDX and Tetryl - no problem
  • HMX - maybe
© 2011 Environmental Chemistry Consulting Services, Inc. (ECCS) | All Rights Reserved | Site Credit