The Malaysian Journal of Analytical Sciences Vol 12 No 2 (2008): 367 – 374
FORENSIC ANALYSIS OF HIGH EXPLOSIVES
RESIDUES IN
POST-BLAST WATER SAMPLES EMPLOYING SOLID PHASE EXTRACTION FOR ANALYTE
PRO-CONCENTRATION
2PDRM Forensic
Laboratory, 8 1/2 Mile Jalan Cheras, 43200 Cheras, Selangor, Malaysia
*Corresponding author: umi@kimia.fs.utm.my
Nitroaromatic,
nitramine and nitrate ester compounds are a major group of high order explosive
or better known as military explosives.
Octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,3,5-hexahydro
-1,3,5-trinitrotriazine (RDX), 2,4,6-trinitro-toluene (TNT), pentaerythritol
tetranitrate (PETN) and 2,4-dinitrotoluene (2,4-DNT) are secondary high
explosives classified as most commonly used explosives components. There is an
increasing demand for pre-concentration of these compounds in water samples as
the sensitivity achieved by instrumental analytical methods for these high
explosives residues are the main drawback in the application at trace levels
for forensic analysis. Hence, a simple cartridge solid phase extraction (SPE) procedure
was optimized as the off-line extraction and pre-concentration method to
enhance the detection limit of high explosive residues using micellar
electrokinetic chromatography (MEKC) and gas chromatography with
electron-capture detection (GC-ECD) methods. The SPE cartridges utilized
LiChrolut EN as the SPE adsorbent. By employing pre-concentration using SPE,
the detection limits of the target analytes in water sample were lowered by
more than 1000 times with good percentage recovery (> 87%) for MEKC method
and lowered by 120 times with more than 2 % percentage recovery for GC-ECD
methods. In order to test the feasibility of the developed method to real
cases, post-blast water samples were analyzed. The post-blast water samples
which were collected from Baling Bom training range, Ulu Kinta, Perak contained
RDX and PETN in the range of 0.05 – 0.17 ppm and 0.0124 – 0.0390 ppm respectively.
Keywords: Solid phase extraction, high explosives, post-blast
water samples, MEKC, GC-ECD, SPME.
References
1. Ahmad, U.K., and Rajendran, S. 2007. E-proceeding in Regional Annual
Fundamental Science Symposium (RAFSS). Skudai, Malaysia. 28-29 May 2007.
2. Barshick, S.A, and Griest, W.H. 1998. Anal. Chem. 70. 3015-3020
3. Calderara, S., Gardebas, D., and Martinez, F. 2003. Forensic Science International. 137.
6-12
4. Groom, C.A., Beaubet, S., Halasz, A., Paquet, L., and
Hawari, J. 2001. J. Chromatogr. A. 909. 53-60
5. Haderlein, S.B., Weissmahr, K.W., and Schwarzenbach,
R.P. 1996. Environ. Sci. Technol. 30.
612-622
6. Jackson, A.R.W. and Jackson, J.M. 2004. Forensic
Science. UK: Prentice Hall
7. Jenkins, T.F., Miyares, P.H., Myers, K.F., McCormick,
E.F. and Strong, A.B. 1994. Anal. Chim.
Acta. 289. 69-78
8. Kleiböhmer, W., Cammann, K., Robert, J. and
Mussenbrock, E. 1993. J. Chromatogr.
638. 349-356
9. Lewin, U., Weerich, L., Efer, R. and Engewald, W. 1997.
Chromatographia.
45. 91-98
10. Liska, I. 2000. Review Paper. J. Chromatogr. A. 885. 3-16
11. Lu, Q., Collins, G.E., Smith, M. and Wang, J. 2002. Anal.
Chim. Acta. 469. 253-260
12. Northrop, D.M., Martire, D.E. and MacCrehan, W.A. 1991. Anal. Chem. 63. 1038-1042
13. Song, L., Xu, Z., Kang, J., and Cheng, J. 1997. J. Chromatogr. A. 780. 297-328
14. Tagliaro, F. and Bortolotti, F. 2006. Electrophoresis.
27. 231-243
15. Yinon, J., and Zitrin, S. 1993. “Modern
Methods and Application in Analysis of Explosives”. England: John Wiley and
Sons