Abstract:

A method for the determination of hydrazine ion in explosion dust of liquid explosive has been established by ion chromatography. The hydrazine ion in an explosion dust sample was extracted with deionized water by sonification and centrifugation. The large molecules and solid particles in supernatant were removed by an OnGuardⅡ RP column and a 0.22 μm filtration membrane, respectively. The filtrate was separated on an IonPac CS-12A column with isocratic elution of 5 mmol/L methanesulfonic acid (MSA). Then 0.1 mol/L NaOH solution was post-column added and the resultant solution was detected by an ampere detector with golden electrode. The results showed that, the calibration curve was linear in the range of 0.02-2.0 mg/L with a correlation coefficient (r²) of 0.9997. The limits of detection (LOD, S/N=3) and quantification (LOQ, S/N=10) of hydrazine were 5.0 μg/L and 16.6 μg/L, respectively. The recoveries ranged between 95.4% and 99.1% with the relative standard deviations (RSDs, n=5) of 2.1%-3.3%. The hydrazine content in a real explosion dust sample of liquid explosive was 10.3 mg/kg by this method. The method is simple, accurate, and suitable for the quantitative detection of hydrazine ions in explosion dust of liquid explosive, and the method can meet the needs of the criminal evidence identification work.

Key words: criminal evidence identification, explosion dust, hydrazine, ion chromatography (IC), liquid explosive, post-column alkalization