Rapid immunochromatographic test designed solely for use in the qualitative screening of Cylindrospermopsin in fresh water.
The Cylindrospermopsin Strip Test for Water is a rapid immunochromatographic test designed solely for use in the qualitative screening of Cylindrospermopsin in fresh water. A rapid cell lysis step (QuikLyse) performed prior to testing is required to measure total Cylindrospermopsin (dissolved, or free, plus cell-bound). The Microcystins Strip Test provides only preliminary qualitative test results. If necessary, positive samples can be confirmed by ELISA, HPLC or other conventional methods.
The test is based on the recognition of Cylindrospermopsin by specific antibodies. The toxin conjugate competes for antibody binding sites with Cylindrospermopsin that may be present in the water sample. The test device consists of a vial containing specific antibodies for Cylindrospermopsin labeled with a gold colloid and a membrane strip to which a conjugate of the toxin is attached. A control line, produced by a different antibody/antigen reaction, is also present on the membrane strip. The control line is not influenced by the presence or absence of Cylindrospermopsin in the water sample and, therefore, should be present in all reactions. In the absence of toxin in the water sample, the colloidal gold labeled antibody complex moves with the water sample by capillary action to contact the immobilized Cylindrospermopsin conjugate. An antibody-antigen reaction occurs forming a visible line in the ‘test’ area. The formation of two visible lines of similar intensity indicates a negative test result, meaning the test did not detect the toxin at or above the cut-off point established for the toxin. If Cylindrospermopsin is present in the water sample, it competes with the immobilized toxin conjugate in the test area for the antibody binding sites on the colloidal gold labeled complex. If a sufficient amount of toxin is present, it will fill all of the available binding sites, thus preventing attachment of the labeled antibody to the toxin conjugate, therefore preventing the development of a colored line. If a colored line is not visible in the test line region, or if the test line is lighter than the control line, Cylindrospermopsin is present at a level of concern. Semi-quantitative results in the range of 0-10 ppb can be obtained by comparing the sample test strip appearance to the appearance of test strips from solutions of known Cylindrospermopsin concentrations (control solutions). Concentrated Cylindrospermopsin standards which can be used to prepare Cylindrospermopsin controls are available through Eurofins Abraxis (PN 300626).