FLAME-BASED THERMIONIC DETECTION COUPLED ONLINE WITH MICROCOLUMN LIQUID-CHROMATOGRAPHY .2. CHARACTERIZATION OF THE SYSTEM

Flame length and temperature measurements were used to study the influence of various parameter settings in thermionic detection coupled on-line with microcolumn liquid chromatography (micro-LC). In the present system both the rubidium source temperature and the interface performance depend strongly on the flame dimensions and gas flow-rates. When optimizing signal-to-noise ratios, the influences of the flame length, the rubidium source-burner rim distance and the hydrogen and air flow-rates are mutually dependent. When changing the micro-LC eluent composition from pure water to pure methanol, the noise and background are increasingly determined by chemi-ionization reactions.