Use of solid-phase microextraction/gas chromatography-electron capture detection for the determination of energetic chemicals in marine samples.
Gas chromatography with electron capture detection (GC-ECD) is a highly explosive-sensitive analytical technique. However, its application to the analysis of sediment extracts is hampered by the presence of numerous endogenous interferences. In the present study, solid-phase microextraction (SPME) was used both as a purification technique for sediment extracts and as an extraction technique for water samples prior to analysis by GC-ECD. SPME/GC-ECD coupling was optimized and applied to the trace analysis of nine explosives including nitroaromatics and RDX in real seawater and marine sediment samples. Addition of a high concentration of salt (30%, w/v) in the aqueous medium and use of a carbowax/divinylbenzene (CW/DVB) coating led to optimal extraction efficiencies. Method detection limits (MDLs) ranged from 0.05 to 0.81 microg/L in water and from 1 to 9 microg/kg in dry sediment. Except for RDX, spike recoveries in seawater were satisfactory (89-147%) when samples were fortified at 2 microg/L of each analyte. Spike recoveries from dry sediment fortified at 10 microg/kg of each analyte gave lower recoveries but these could also be due to degradation in the matrix. With a smaller volume of aqueous sample required compared to solid-phase extraction (SPE), SPME is an attractive method for the analysis of limited volumes of sediment pore-water. Moreover, the use of SPME eliminated interferences present in sediment extracts thus allowing the detection of the target analytes that were otherwise difficult to detect by direct injection.
Monteil-Rivera
Fanny
F
Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Que., Canada H4P 2R2.
Beaulieu
Chantale
C
Hawari
Jalal
J
D000097:Acetonitriles; D000327:Adsorption; D002619:Chemical Warfare Agents / Q000737:chemistry; D002849:Chromatography, Gas / Q000379:methods*; D005107:Explosions; D019015:Geologic Sediments / Q000737:chemistry*; D015203:Reproducibility of Results; D012623:Seawater / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000032:analysis; D012995:Solubility
D000097:Acetonitriles; D002619:Chemical Warfare Agents; D012965:Sodium Chloride; C032159:acetonitrile