Trace detection of styphnate from pre- and post-blast samples by hydrophilic interaction chromatography with tandem mass spectrometry

Rationale

Although ubiquitous in explosives and ammunition, few trace methods for detection of heavy metal-containing primary explosives from forensic samples are currently in practice.

Methods

Extracts of cotton swabs or direct sampling of items were cleaned up using solid-phase extraction to remove heavy metal contaminants (i.e., lead) while retaining the organic styphnate component. The styphnate was chromatographically separated using hydrophilic interaction chromatography (HILIC) and detected via high-resolution tandem mass spectrometry (MS/MS) using a sensitive, targeted approach in five minutes or less.

Results

A mass spectrometric method for the detection of styphnate, including limit of detection (LOD), sample stability, and interferences was developed. We present a validated method for the extraction, separation, and detection of styphnate from lead(II) styphnate with an estimated LOD of 257 ppt (pg/mL).

Conclusions

We detail an improved LOD relative to previous reports for trace detection of styphnate and, for the first time to our knowledge, the post-blast analysis of styphnate.