Solid-phase extraction using hierarchical organosilicates for enhanced detection of nitroenergetic targets

Abstract

A novel porous organosilicate material was evaluated for application as a solid phase extraction sorbent for preconcentration of nitroenergetic targets from aqueous solution prior to HPLC analysis. The performance of the sorbent in spiked deionized water, groundwater, and surface water was evaluated. Targets considered included 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, RDX, HMX, and nitroglycerin. The sorbent was shown to provide improved performance over Sep-Pak RDX. The impact of complex matrices on target preconcentration by the sorbent was also found to be less dramatic than that observed for LiChrolut EN. The impact of changes in pH on target preconcentration was considered. Aqueous soil extracts generated from samples collected at sites of ordnance testing were also used to evaluate the materials. The results presented here demonstrate the potential of this novel sorbent for application as a solid phase extraction material for the preconcentration of nitroenergetic targets from aqueous solutions.

Toward In Situ Monitoring of Water Contamination by Nitroenergetic Compounds

“…Further improvement was achieved through replacement of the column housing with one of a larger diameter (10 mm) allowing for an increase in the sorbent mass utilized (200 mg; Figure 4). The results achived with the prototype system were comparable to those observed for the sorbents when used in an offline configuration [23,25]. …”

“…An Omnifit borosilicate column housing (6.6 × 50 mm, Diba Industries, Mahopak, NY, USA) was selected, and a 75 mg sorbent column (MM1) was packed. The experiments described above were repeated using this sorbent column in the prototype system with somewhat improved results; however, the performance still fell short of what was expected based on previous experiments [23,25]. Both the increased pressure and tunneling effect observed for the HPLC column housing were observed for this housing as well.…”

“…More recently, we presented proof of concept data demonstrating the function of those materials in relevant matrices [25]. Since completion of those studies, we have attempted to improve the performance of the sorbents through further alteration of chemical group content and morphological characteristics [24].…”

“…Advances in the synthesis of these materials provided the potential for improving both morphological and binding characteristics. The materials were shown to provide preconcentration of nitroenergetic targets from a range of matrices including soil extracts [25]. The organosilicate sorbents were also found to recover a greater percentage of targets than commercially available materials intended for these applications and were less sensitive to variations in matrix composition.…”

Extraction of Perchlorate Using Porous Organosilicate Materials

“…We have previously described our efforts focused on the development of organosilicate materials for preconcentration of nitroenergetic compounds [9,10,11,12]. Sorbents have also been developed for the capture of organophosphate and solvent targets [13,14,15].…”