ANALYSIS OF SINGLE RAINDROPS IN THE NL RANGE BY CAPILLARY ELECTROPHORESIS

The analysis of single and size-classified rain- (volume: 10 mu l/3 nl ), cloud- or fogdrops (volume: pl-fl) is expected to give new and inte resting information about anthropogenic air pollution and drop formati on processes in the atmosphere. This paper presents microanalytical in vestigations for the analysis of single rain- and fogdrops. Specially developed sampling procedures and methods to store and to handle singl e rain- and fogdrops are shown. The analysis is carried out by capilla ry zone electrophoresis (CZE). Sample injection is made using a new de veloped microinjection system. Raindrops are injected directly into th e CZE capillary by applying a vacuum at the opposite end of the capill ary. The main inorganic cations and anions (NH4+, K+, Na+, Ca2+, Mg2+, Zn2+, Cl-, NO3-, NO2-, SO32-, SO42-), aldehydes, mono-and dicarboxyli c acids occurring in rain are analysed using different detection metho ds like laser-induced fluorescence (LIF), amperometry, UV and fluoresc ence detection. The absolute limits of detection are in the fmol range .