Novel teststrip with increased accuracy.
A new type of a simple and cheap teststrip for liquid samples is described. It is based on microchromatography or microtitration on a porous, capillary-active substrate (e.g., filter paper or a similar absorbent material). In case of microchromatography an analyte-selective indicator (and other auxiliary reagents) is impregnated or immobilized on the capillary-active substrate; in case of micro-titration the capillary-active substrate contains a titrant which reacts stoichiometrically with the analyte. Quantitative analysis is performed by measurement of an area (which had changed its color) rather than by evaluation of the shade or intensity of a color (like in conventional teststrips). In order to show the broad applicability of this new principle teststrips for different analytes like Quaternary Ammonium Compounds (QACs), the cation Ni2+, the anion SO4(2-) and H2O2 are described. The detection limit and working range of the novel teststrip can be adjusted by variation of its size.