Immunoaffinity purification method for detection and quantification of microcystins in lake water

We have developed a new clean-up method, which consisted of solid-phase ext raction on a Sep-Pak PS-2 (styrene-divinylbenzene copolymer) or Excelpak SP E-GLF (polymethacrylate) cartridge instead of conventional ODS silica gel a nd silica gel together with following immunoaffinity purification using ant i-microcystin-LR monoclonal antibodies. This newly developed method was dem onstrated to eliminate co-existing substances and to concentrate microcysti ns in the lake water. The recoveries from lake water (1 liter) spiked with 100 ng each of microcystins-RR, -YR and -LR were 85.5, 89.2 and 92.2%, resp ectively, with coefficients of variation of 3.37.6%. Only 3 h were required to complete the total procedures starting from the microcystin extraction, the immunoaffinity purification, and the quantification using HPLC. The de tection limits for all of the 3 microcystins in lake water were 0.005 mu g/ l. Applicability of this method has been demonstrated by measuring the conc entrations of microcystins in water samples collected from lakes where wate r blooms occurred, which turned out to be 0.012-0.177 mu g/l of total micro cystins. (C) 2000 Elsevier Science Ltd. All rights reserved.