Detection of Three Common Organic Explosives Using Capillary Electrophoresis

In this article, a detection method for organic explosives by capillary electrophoresis (CE) is developed based on previous detection techniques. Firstly, a buffer solution consisting of 50 mmol·L-1 sodium dodecyl sulfate (SDS), 20 mmol·L-1 sodium tetraborate and 5% methanol was prepared and the UV detection in this buffer solution was conducted for three common organic explosives, including TNT, DNT and PETN. Then, the capillary UV detection method was investigated in terms of the transition time repeatability, the linear relationship between mass concentration and peak area and the limit of detection. The results revealed good reliability and stability of this method. In addition, these samples were characterized by photodiode array detector (PDA) to verify the qualitative results of UV detection.

The Transfer and Change of Paints in a Hit-and-run Motor Vehicle Accident

This work investigated transfer and change of paint evidences in a case of hit-and-run.Two kinds of attachments were found on the clothes of the victim and they were initially considered paint fragments from the vehicle causing the accident.Infrared spectroscopy(IR),scanning electron microscope-energy dispersive spectrometer,and Microspectrophotometry were applied for examination of paints and clothing fibers.Polyester was detected in one of the attachments and in the clothing fibers of the victim by IR.A traffic accident simulation experiment was designed and conducted to research whether the polyester attachments come from suspected vehicle paints or victim’s clothing fibers.The results showed that a melt mixture of transferred paints and clothing fiber was formed after a violent collision.Because the amount of transferred paints was too low to be detectable in the mixture,the components detected by IR were mainly from clothing fibers.Thereby,we inferred that only one kind of attachment and paint fragments existed on the clothes of the victim,and the polyester attachments cannot be used to indicate the composition of suspected vehicle paint.Clothing fibers and paints are both common trace evidence in traffic accident cases,and more attention should be paid to the examination of transferred paints on clothing fibers.

Application of Spectra Accuracy for Analysis of Organic Explosive: 2,4,6‑trinitrotoluene by AccuTOF‑DART

This paper,through mass spectrometric(MS)analysis for nitro compound explosives on a direct analysis in a real‑time time‑of‑flight MS,indicates that even on a high‑resolution MS with accurate mass measurement capabilities,there is no guarantee to obtain the unique molecular formula of a compound.By calculating spectra accuracy,highly accurate isotope pattern matching can be conducted to significantly improve performance of compound confirmation or identification.

Determination of Diphenylamine in Gunshot Residue by HPLC‑MS/MS

A high performance liquid chromatography tandem mass spectrometry/mass spectrometry(HPLC-MS/MS)protocol was developed for the determination of diphenylamine(DPA).Four productions of DPA were selected for qualitative assay and the peak area of the main product ion for quantitation.By means of separation using an Agilent Extend-C18 column(CA,USA)(150 mm×4.6 mm,5μm)with methanol‑water(90:10)as the mobile phase,DPA was detected by electrospray ionization(ESI)tandem mass spectrometry in positive mode.The linearity of the peak area versus concentration ranged 5‑500 ng/mL,r^(2)=0.9978.The limit of detection(S/N=3)of this method was 0.3 ng/mL.This method is applicable for the determination of DPA in gunshot residue.