Determination of Low Concentrated Small-Sized Colloids by Laser Induced Breakdown Detection

Colloids of some nanometers in size are interesting for the transport of contaminants in natural waters because of their high specific surface. Optical and acoustic detection of plasmas induced by laser pulses on individual particles allows determining of size and concentration of smallest colloids in the ppt-range. The apparatus for laser induced breakdown detection established in the Institute of Radiochemistry at FZR is described. First results of measurements on particle standards, de-ionized waters and nearly colloid-free environmental samples are presented.