Determination of Primary Explosive Azides in Environmental Samples by Sequential Injection Amperometry

Abstract

The application of flow injection methodology to the determination of trace concentrations of primary explosives is presented. The approach is demonstrated with a sequential injection amperometric method for the determination of the azide ion (N 3 2 ). The proposed method can be applied to the determination of sodium azide or lead azide, a primary explosive, without regard to other sources of lead in environmental samples. The sequential injection system used for the analysis forms the basis for a proposed field-portable instrument for the analysis of primary explosives. A microporous gas permeable membrane in a gas diffusion unit (GDU) is used to separate the analyte from other anions that can also be oxidized at the amperometric cell. The behaviour of the GDU was optimized with respect to the pH of the donor stream and the timing of the preconcentration step. A study of anions that are commonly found in environmental samples showed that the species that will interfere with the analytical signal can be removed by the GDU. Results from three water samples that were spiked with 0.40 ppm of azide are presented. RSDs in the range 3-5% were typically obtained using the method. The useful working range of the method was linear up to 0.5 ppm and non-linear up to 20 ppm (second-order model). The limit of detection was 24.6 ppb.

Application of sequential-injection analysis as process analyzers

“…Application of the SIA technique to anodic stripping voltammetry (ASV) allowed the on-line plating of the mercury film and therefore substantially reduced the generation of mercury waste [44]. Primary explosive azides in environmental samples were determined amperometrically using an SIA system [45].…”

Greening Electroanalytical Methods

“…Among others, several methods for the analysis of environmental samples have been described. For instance, amperometric detection was employed for the determination of primary explosive azides in ground and lake waters [90]. Also, SIA-anodic stripping voltammetric methods (SIA-ASV) for the determination of trace metals were reported.…”

New potentiometric transducer based on a Mn(II) [2-formylquinoline thiosemicarbazone] complex for static and hydrodynamic assessment of azides

“…Among these approaches are: redox titrimetry [5], electron paramagnetic resonance [6], gasometry [7], spectrometry [8,9], cyclic voltammetry [10], amperometry [11], polarography [12] and chromatography [13][14][15]. Most of these methods require expensive instrumentation, rather complicated techniques, and/or sample pretreatments.…”