A new analytical method of measuring absolute concentration profiles inside microstructures called SLCP is presented. The combination of chronoamperometry at microelectrodes of 15-20 mu m with scanning and positioning techniques (precision in x,y,z : 1 mu m) sets up this SXM/SXP dagger-type method. The SLCP method is capable of ion selective and localized absolute concentration measurement. It is applicable to microstructures with high aspect ratios. The measured parameter is the diffusion limited current I-lim which is directly proportional to concentration. It is recorded at a substance specific potential. The principle works with all metal ions and electroactive substances that can be deposited or consumed almost quantitatively and under diffusional control. By using potential/time programs with two deposition potentials, the simultaneous concentration measurement of two ion species is possible. The multiple pulse sequence is successfully applied to alloy deposition. Three experimental modes have been developed, in addition to local concentration measurement, local cyclic voltammograms can be measured as well. Local resolution is 10-20 mu m. Very thin microdisk analysis electrodes of 15-20 mu m tip diameter have been developed.