The CDIATM Microcystins Colloidal Gold Test Strip (Source Drinking Water) is an immunochromatographic test for the detection of Microcystins and Nodularins in source drinking water at 1 ppb.
The test is based on the recognition of Microcystins, Nodularins, and their congeners by specific antibodies. The toxin conjugate competes for antibody binding sites with Microcystins/Nodularins that may be present in the water sample. The test device consists of a vial containing specific antibodies for Microcystins and Nodularins 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 Microcystins 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 Microcystins 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 Microcystins are present in the water sample, they compete 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, Microcystins are present at a level of concern (1 ppb). Semi-quantitative results in the range of 0-5 ppb can be obtained by comparing the sample test strip appearance to the appearance of test strips from solutions of known Microcystins concentrations (control solutions).
Most of the world’s population relies on surface freshwaters as its primary source for drinking water. The drinking water industry is constantly challenged with surface water contaminants that must be removed to protect human health. Toxic cyanobacterial blooms are an emerging issue worldwide due to increased source water nutrientpollution caused by eutrophication. Microcystins and Nodularins are cyclic toxin peptides. Microcystins (of which there are many structural variants, or congeners) have been found in fresh water throughout the world. To date, approximately 80 variants of Microcystin have been isolated. The most common variant is Microcystin-LR. Other common Microcystin variants include YR, RR, and LW. These toxins are produced by many types of cyanobacteria (blue-green algae), including Microcystis, Anabaena, Oscillatoria, Nostoc, Anabaenopsis, and terrestrial Hapalosiphon. Nodularins are produced by the genus Nodularia and they are found in marine and brackish water.Acute poisoning of humans and animals constitutes the most obvious problem from toxic cyanobacterial blooms, and in several cases has led to death. Human and animal exposure to these toxins occurs most frequently through the ingestion of water, through drinking or during recreational activities in which water is swallowed. These toxins mediate their toxicity by inhibiting liver function and are potent inhibitors of the serine/threonine protein phosphatases, and therefore they may act as tumor promoters.To protect consumers from adverse health effects caused by these toxins, the World Health Organization (WHO) has proposed a provisional upper limit for Microcystin-LR of 1.0 ppb (µg/L) in drinking water. For recreational bathing waters, the WHO has established the following guidelines: (1) Relatively low risk of exposure effect at 4 ng/mL (ppb). (2) Moderate probability of exposure effect at 20 ng/mL. (3) High probability of exposure effect- scums. The U.S. Environmental Protection Agency (EPA) has also established guidelines for Microcystins in drinking water: (1) For children below school age, 0.3 µg/L (ppb). (2) For all other age groups, 1.6 µg/L (ppb).The CDIATM Microcystins Colloidal Gold Test Strip (Source Drinking Water) for source drinking water is a rapid immunochromatographic test, designed solely for the use in the qualitative screening of Microcystins and Nodularins in source drinking water. A rapid cell lysis step performed prior to testing is required to measure total Microcystins (dissolved, or free, plus cell-bound). The CDIATM Microcystins Colloidal Gold Test Strip (Source Drinking Water) provides only preliminary qualitative test results. If necessary, positive samples can be confirmed by ELISA, HPLC or other conventional methods.