“…The following were compared in controlled trials: (1) the microbatch (Chayen et al, 1992) and vapor diffusion methods (Ducruix & GiegC, 1992); (2) temperatures of 4" and 23°C; (3) PEG molecular weights of 3,000 to 12,000 D; (4) Monomethyl ether substituted PEGS (Brzozowski & Tolley, 1994;Patel et al, 1995) and unsubstituted PEGS; (5) salt additives at 50, 100, and 200 mMNaCl, MgCl2, Na3C6H507, Li2SO4, Mg(C2H302h (NHd2S04, NH4Cl, (NH4)3C6Hs07r all adjusted to pH 7.5 with isomolar solutions of the conjugate acid/base; (6) sample filtration-none compared to use of 0.22 p m and 300 kDa membrane filters (Blow et al, 1994); (7) detergent additives (McPherson et al, 1986): up to 0.1 % w/v P-octyl glucoside, nonyl-P-glucopyranoside or decyl maltoside; (8) organic co-solvents: 5% ethanol, isopropanol, or hydroxyacetone.…”