We later did some study on antibody capture (Deng et al. 1994 ) and on immunomagnetic concentration of hepatitis A virus (HAV) López-Sabater et al. 1997 ) and were able to show that the urea-argininephosphate buffer that had been used successfully to elute human viruses adsorbed to filters was also applicable to phages (Jothikumar and Cliver 1997) .