Optimization of accelerated solvent extraction for the analysis of munitions residues in sediment samples

Abstract

Accelerated solvent extraction (ASE) has been compared with a Soxhlet extraction for extracting and estimating the concentration of hexahydro-1,3,5-trinitro-s-triazine (RDX) and octahydro-1,3,5,7-tetrazocine (HMX) in sediment samples. Extraction of RDX and HMX was studied in terms of process kinetics and recovery. A three factor, 16 run triplicate experimental design was used to generate data on each of two extraction solvents, acetonitrile and a mixture of acetone–methanol (1:1). Response surface methods were used to model the dependence of the concentration on the experimental conditions and to establish the optimum extraction conditions. The results were complex in that several interactions were found among analyte, method, and solvent. Acetonitrile was superior to acetone–methanol for RDX and HMX from the perspectives of kinetics and recovery, due in part to a much higher solubility. The accelerated solvent extraction generally recovered more than the Soxhlet. In terms of sample throughput, the accelerated solvent extraction offers advantages over the Soxhlet. A spike recovery study using fortified sediment yielded complete recoveries of HMX and RDX. © 2001 John Wiley & Sons, Inc. J Micro Sep 13: 54–61, 2001