| Ion mobility spectrometry (IMS) device acted as a kind of explosives, illicit drugs and chemical warfare agent trace detectors had many developments since it was born in 1970s. Many teams have interests in this technique. According to its bad resolution, the ion mobility spectrometry can not give an accurate qualitative data and always have false respons. So many groups combine the ion mobility spectrometry device to another analytical equipment to get a great result. Although many groups had achieved fruitful results in their field, less attention was force on the issues in practical explosives and illicit drugs detection. There are also a lot of strange phenomenons which was not explained before. We study nonsteroidal drugs and dissolved oxygen in drinking water as follows:1. Interfacing an ion mobility spectrometry to a mass spectrometry. An IMS-MS platform is built after combine the TR1000DB-A explosive and drug trace detector (Nuctech company limited) to a a triple quadrupole mass spectrometer (Micromass, Waters company). A hole is punched in the center of the faraday plate while a chamber shell which has the same size as the ionization chamber shell of the mass spectrometor is purchased to interface the IMS to the MS. It is because the IMS detector can be embedded in the new home-made chamber shell. Parameters such as the distance between the hole and the sampling cone, flow rate of the carrier and drift gas, intensity of electric field were optimized to introduce the ion beams into the MS. What's more, this design did not destruct the major handware of the two devices. And it results that we can use the IMS-MS, ESI-MS and APCI-MS by shift the new and original chamber shell. This design can give us more supply information and greatly broaden the application scope.2. Verifing the performance of the IMS-MS by analysing several common explosives and illicit drugs. (Positive mode:inlet temperature 210?,drift tube temperature 190?; Negtive mode:inlet temperature 190?,drift tube temperature 130?) Collecting their mass spectrum and its tandem mass spectrum in full scan mode as well as their ion mobility spectrum.These spectrums have comparison with these in library and can be a spectrum base for researching later. The results verified the reliability of the IMS-MS device and would guide the future work. And we can also sum up the ionization mechanism of the explosives and illicit drugs to explain the issures exciting in the practical detection in the future.3. Some problems exciting in the practical detection were analyzed by the IMS-MS instrument. All the reasons that these problems occurred were fully understood and several feasible suggestions and improvement were put forward.The IMS-MS instrument. The interferent that interfered the detection of cocaine was identified as the dibutyl phthalate. Ions were identified clearly and the reason why the amphetamine solution with acetone as the solvent had two peaks in the IMS is clear. Actone will acts with the amphetamine to get an azomethine and it is not suit for the detection of amphetamine as the solvent.The solvent should be chosen carefully to avoid the effects on the analysis. In addition, the heroin sample would get four ions:m/z 268,310,328,370. They contributed to the two peaks in IMS in the heroin detection. Density functional calculations were used to know well about the phenomenon that the ion mobility spectrum of different heroin sample was different. These results show that the tandem mass spectrometor give a hand to the IMS device to know more about the gas phase chemistry. |
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