A SIMPLE ELUTION AND RECONCENTRATION TECHNIQUE FOR VIRUSES CONCENTRATED ON MEMBRANE FILTERS FROM DRINKING-WATER SAMPLES

An optimum concentration of urea (1.5 M)-arginine phosphate (0.2:0.008 M) buffer (U-APB) has been designed in this research as an eluent at pH 9.0 for effective desorption and elution of viruses from negatively charged membrane filters. The primary eluate is further reconcentrated by the precipitation of MgHPO4(s) on addition of MgCl2. The flocs are centrifuged, the pellet is dissolved in McIlvaines buffer (pH 5) and neutralized with sodium bicarbonate (8.8%) prior to assay on cell culture. The efficacy of the method has been tested at different inoculum levels and also for different volumes of water samples seeded with viruses. U-APB gives 92-100 and 88-93% recovery for Poliovirus 1 and bacteriophage, respectively, as against a 30-40% recovery of Poliovirus 1 and bacteriophage, respectively, and a meagre 30-40% recovery of Poliovirus 1 in the organic flocculation of beef extract method presently in use. Further, the eluent (U-APB) is easy to constitute and it performs elution and reconcentration of viruses without any pH adjustment. © 1990.