基于交流耦合方式的双模式离子迁移谱仪

Dual ion mobility spectrometer based on AC coupling

为了快速检测并区分未知大分子(如毒品、爆炸物、化学战剂、DNA残片、酶等),并解决在高压电路中提取极弱电信号时,使用变压器导致的电路系统设计复杂、体积庞大的问题,设计了结构紧凑、装配简便、操作简便的双模式离子迁移谱仪。谱仪的正负迁移管能够检测具备正、负离子亲和力的大分子。采用了交流耦合的方式来提取Faraday盘上的10-13 C弱电信号。谱仪仅需要12V直流电源及标准的TLL脉冲便可以被驱动且易于控制。实验表明:该谱仪能够长时间稳定地工作,能够检测到多种复杂分子。以国际上常用的参考分子三硝基甲苯(TNT)来衡量,则仪器的检测灵敏度好于1ng TNT。当单侧迁移区长度为50mm时,其TNT的分辨率可达到21,当单侧迁移区长度为90mm时,其TNT的分辨率为32。

A dual ion mobility spectrometer is developed to quickly detect and analyze complex molecules （such as explosives, drugs, DNA compounds and enzymes）, which simplifies the large, complex circuit required when using transformers to measure a weak signal in a high voltage. The spectrometer has an integrated structure, is simple to manufacture and is easily operated. Positive and negative drift tubes in the spectrometer can detect both positive and negative ion affinity molecules. The weak signal of 10-3 C on the Faraday plate is driven by an AC coupling circuit. The spectrometer is driven by a 12 V DC, TTL pulse and can be easily controlled. The spectrometer can work continuously with many complex molecules detected by the system. The sensitivity when used to detect TNT （a reference molecular used world wide） is better than 1 ng and the relative resolution for TNT can reach 21 when the drift tube is 50 mm long and 32 when the drift tube is 90 mm long.