[Effects of substituted functional groups of cations on retention performance of ionic liquid stationary phases in gas chromatography].

Thirteen stationary phases comprising a polyvinyl imidazolium ionic liquid (IL) in which cations containing propyl, butyl, nonyl, ethyl-phenyl, or cyan methyl functional groups are paired with bis(trifluoromethanesulfonyl) imide ([NTf2]-), trifluoromethanesulfonate ([TFO]-), and hexafluorophosphate ([PF6]-) were synthesized and directly coated inside capillary fused silica tubing for use in gas chromatography. The relationship between the structure of the ILs and the McReynolds constant, thermal stability, and retention behavior of the test compound on the prepared fused silica columns was examined and discussed. The influence of the cationic substituents on retention performance of stationary phases was also studied. The variation in the retention index of the test compound with temperature was also investigated. The results indicated that the synthesized ILs have strong polarity, and that their retention performance is closely related to not only the properties of the cationic substituent but also the structure of the substituted groups and the anion. In the temperature range investigated, the variation in the retention index of the tested compounds was the same as that of conventional chromatographic stationary phases.

Oxidized multiwalled carbon nanotubes coated fibers for headspace solid-phase microextraction of amphetamine-type stimulants in human urine.

Carbon nanotubes (CNTs) have attracted a lot of attention as effective sorbents due to their strong sorption properties and several potential applications in many fields. In this work, the acid oxidized multiwalled carbon nanotubes (MWCNTs-COOH) was coated onto a stainless steel wire by a simple physical adhesion approach to develop solid-phase microextraction (SPME) fibers. By combination of the MWCNTs-COOH coated fiber-based headspace SPME and gas chromatography-mass spectrometry (GC-MS), the developed method demonstrates a good enhancement factor (288-651), low limits of detection (LODs, 0.2-1.3µg/L) for determination of amphetamine-type stimulant drugs (ATSs) in urine samples. The recoveries of the spiked ATSs (5, 50 and 500µg/L) were in the range of 88-107%, the calibration curve was linear for concentrations of analytes in the range from 0.5 to 1000µg/L (R=0.963-0.999). Furthermore, single fiber repeatability and fiber-to-fiber reproducibility were in the range of 2.3%-6.2% (n=6) and 5.7%-9.8% (n=3), respectively. The MWCNTs-COOH coated fiber is highly thermally stable and can be used over 150 times. The method was successfully applied to the forensic determination of amphetamine (AMP) and methamphetamine (MAMP) in human urine samples and satisfactory results were achieved.

[Analysis on 55 cases of traumatic cerebral infarction in forensic identification].

55 cases of traumatic cerebral infarction collected from these 5 years were respectively studied to analyze its clinical manifestation, the characteristic of CT and MRI scan, the mechanism of illness, the degrees of injury, and to explore the relation of craniocerebral trauma and cerebral infarction.