| Popis: |
This paper presents a method to predict selectivity of an ion mobility detector for capillary gas chromatography. In the process of describing this method, a term called the “reduced drift constant”, t k , is defined to be t k = t ( E / L )(760/ P )( T /273) where t is the drift time of the ion in milliseconds, E is the electric field in volts per centimetre, L is the length of the drift tube in centimetres, P is the pressure of the drift gas in torr and T is the temperature of the drift gas in degrees Kelvin. Ion mobility separation between two ions can be predicted from literature data when they satisfy the inequality t k2 - t k1 > t k2 / R where t k2 is the reduced drift constant of the ion with the lower mobility, t k1 is the reduced drift constant of the ion with the higher mobility and R is the resolution of the ion mobility spectrometer. For two ions satisfying this inequality, it can be shown that the chromatographic detector selectivity for one ion over another is greater than 100. |
