Octane five solvents

In all blend/solvent systems, a variation of X231 with the low molecular weight probe used was observed. In Table I, a representative example of the probe dependence is given. X23 varies in a 50 wt-% blend of PS and PPE at 220°C between -0.77 and -2.05. The most negative X23 was obtained from benzene, which is the best solvent for both polymers, whereas the non-solvent n-octane yielded a less negative X23 Despite, this should not be a significant effect because all five selected probes are thermodynamically symmetric with regard to the pure polymers. Thus,... 

Twenty-five ecdysteroids, derived irom 20-hydroxyecdysone, were studied in both normal-phase (silica column) and reversed-phase (Cig column) modes. IPA/dichloromethane/water (30/125/2), IPA/cyclohexane/water (40/400/3), or IPA/iso-octane/water (30/100/2) was selected as NP mobile phase. Here is an instance where the water concentration in a immiscible matrix (e.g., iso-octane) is increased due to the presence of a mutually miscible solvent, IPA. Methanol/water (50/50), ethanol/water (30/70), or IPA/water (18/72), all containing 0.1% TEA, were studied as reversed-phase mobile phases [423]. Methanol proved particularly effective in the RP separation of analytes that varied by the degree of unsaturation (i.e., number of double bonds). IPA, as a RP solvent, was superior in resolving 5a-5jS pairs. IPA was extremely effective in the separation of 20-hydroxyecdysone and polypodine B mixtures. These results are not surprising since ecdysones are polyhydroxylated. 

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