A Toolbox for the Determination of Nitroaromatic Explosives in Marine Water, Sediment, and Biota Samples on Femtogram Levels by GC-MS/MS

Abstract

To determine the amount of the explosives 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,4,6-trinitrotoluene, and its metabolites in marine samples, a toolbox of methods was developed to enhance sample preparation and analysis of various types of marine samples, such as water, sediment, and different kinds of biota. To achieve this, established methods were adapted, improved, and combined. As a result, if explosive concentrations in sediment or mussel samples are greater than 10 ng per g, direct extraction allows for time-saving sample preparation; if concentrations are below 10 ng per g, techniques such as freeze-drying, ultrasonic, and solid-phase extraction can help to detect even picogram amounts. Two different GC-MS/MS methods were developed to enable the detection of these explosives in femtogram per microliter. With a splitless injector, limits of detection (LODs) between 77 and 333 fg/µL could be achieved in only 6.25 min. With the 5 µL programmable temperature vaporization—large volume method (PTV-LVI), LODs between 8 and 47 fg/µL could be achieved in less than 7 min. The detection limits achieved by these methods are among the lowest published to date. Their reliability has been tested and confirmed by measuring large and diverse sample sets.

Warship wrecks and their munition cargos as a threat to the marine environment and humans: The V 1302 “JOHN MAHN” from World War II

“…This wreck was first surveyed using a multibeam echosounder to verify the condition of the wreck and assess the chance of finding any remaining munitions. After visual inspection by scientific divers, water and sediment samples (collected from the wreck site) were analyzed for the presence of energetic chemicals such as TNT and derivatives thereof, using sensitive GC-MS/MS technology (Bünning et al, 2021). According to our results, the sediment values are not distributed in a logical manner, since amidships the two most distant positions (S4 and S7) are higher than those amidships closer to the wreck (S1-S3 and S5-S6), while the bow (S9-S10) and stern (S11-S12) sediment samples show intermediate values.…”

“…Sediment samples were extracted as described in Bünning et al (2021). In brief, 100 g wet sediment was mixed with 250 mL ultrapure water, spiked with 25 ng 13 C 15 N-TNT, shaken for 80 min and sonicated for 15 min.…”

“…Blue mussels were processed as described in Bünning et al (2021). The method for fish filet was adjusted accordingly.…”

“…Method-specific detection limits (LODs, Table 3) were determined as described in Bünning et al (2021) using solvent standards according to the EUR 28099 EN calibration standard method. The limit of quantification (LOQ) was set at 3.3 times the detection limit.…”

“…Quantitative (Q) and qualitative (q) secondary reaction monitoring transitions (m/z) of explosives and internal standard 13 C 15 N-TNT are given. Method-specific detection limits (LODs) were determined as described by Bünning et al (2021), using solvent standards according to the EUR 28099 EN calibration standard method. Volumes applied to columns are 1 μL and 5 μL for the splitless and the PTV large volume methods, respectively.…”