Eiceman G A, Krylov E V, Tadjikov B, Ewing R G, Nazarov E G, Miller R A
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, USA.
Analyst. 2004 Apr;129(4):297-304. doi: 10.1039/b316326a. Epub 2004 Feb 20.
Chlorocarbons were ionized through gas phase chemistry at ambient pressure in air and resultant ions were characterized using a micro-fabricated drift tube with differential mobility spectrometry (DMS). Positive and negative product ions were characterized simultaneously in a single drift tube equipped with a 3 mCi (63)Ni ion source at 50 degrees C and drift gas of air with 1 ppm moisture. Scans of compensation voltage for most chlorocarbons produced differential mobility spectra with Cl(-) as the sole product ion and a few chlorocarbons produced adduct ions, M (.-) Cl(-). Detection limits were approximately 20-80 pg for gas chromatography-DMS measurements. Chlorocarbons also yielded positive ions through chemical ionization in air and differential mobility spectra showed peaks with characteristic compensation voltages for each substance. Field dependence of mobility was determined for positive and negative ions of each substance and confirmed characteristic behavior for each ion. A DMS analyzer with a membrane inlet was used to continuously monitor effluent from columns of bentonite or synthetic silica beads to determine breakthrough volumes of individual chlorocarbons. These findings suggest a potential of DMS for monitoring subsurface environments either on site or perhaps in situ.
在常压下的空气中，通过气相化学方法使氯代烃离子化，并使用配备差分迁移谱（DMS）的微型漂移管对产生的离子进行表征。在一个配备了3毫居里（63）镍离子源、温度为50摄氏度且漂移气体为含1 ppm水分的空气的单个漂移管中，同时对正、负离子产物进行表征。对大多数氯代烃的补偿电压扫描产生了以Cl(-)作为唯一产物离子的差分迁移谱，少数氯代烃产生了加合离子M(.-)Cl(-)。气相色谱 - DMS测量的检测限约为20 - 80皮克。氯代烃在空气中通过化学电离也产生正离子，差分迁移谱显示了每种物质具有特征补偿电压的峰。测定了每种物质的正、负离子迁移率的场依赖性，并确认了每种离子的特征行为。使用带有膜进样口的DMS分析仪连续监测膨润土柱或合成硅珠柱的流出物，以确定各个氯代烃的穿透体积。这些发现表明DMS在现场或可能原位监测地下环境方面具有潜力。
