9- Mobile Phases for HPLC Analysis A-51 （1）-2 Miscibility 1 Acetic acid 2 Acetone ■Non-miscible of solvents 3 Acetonitrile □Miscible For preparation of HPLC 4 Benzene 5 Butanol system, column and mobile 6 Carbon tetrachloride phase, the miscibility of each 7 Chloroform 8 Cyclohexane solvent is critical. If non- 9 Cyclopentane miscible solvents are used, 10 Dichloroethane 11 Dichloromethane the column may be 12 Dimethylformamide deteriorated, and the data 13 Dimethyl sulfoxide 14 Dioxane reproducibility and system 15 Ethyl acetate performance may be 16 Ethanol 17 Diethyl ether degraded. If the mobile 18 Heptane phases to be replaced with 19 Hexane 20 Methanol each other are not miscible, 21 Methyl ethyl ketone replace the solvent with a 22 Octane 23 Pentane miscible solvent successively 24 Propanol from the HPLC system to the 25 Dipropyl ether 26 Tetrachloroethane column. 27 Tetrahydrofuran 28 Toluene 29 Trichloroethane 30 Water 31 Xylene 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Acetic acid Acetone Acetonitrile Benzene Butanol Carbon tetrachloride Chloroform Cyclohexane Cyclopentane Dichloroethane Dichloromethane Dimethylformamide Dimethyl sulfoxide Dioxane Ethyl acetate Ethanol Diethyl ether Heptane Hexane Methanol Methyl ethyl ketone Octane Pentane Propanol Dipropyl ether Tetrachloroethane Tetrahydrofuran Toluene Trichloroethane Water Xylene （1）-3 Table of solubility characteristics of solvents δ：A solubility parameter calculated based on the boiling Solvent δ δd δo δa δh ε° η point indicating the polarity or strength of the solvent. 2,2,4-trimethyl-pentane 7.0 7.0 0 0 0 0.01 0.50 Solvents with high δ can dissolve well polar samples, n-hexane 7.3 7.3 0 0 0 0.01 0.32 and solvents with low δ can solve well non-polar n-heptane 7.4 7.4 0 0 0 0.01 0.41 samples. Cyclohexane 8.2 8.2 0 0 0 0.04 1.00 δd：A dispersion solubility parameter indicating the degree Carbon tetrachloride 8.6 8.6 0 0.5 0 0.18 0.97 of selective dissolution of aromatic compounds with -S-, Ethyl acetate 8.6 7.0 3 2 0 0.58 0.45 -Cl and -I groups (naphthalene, DDT, Toluene 8.9 8.9 0 0.5 0 0.29 0.59 hexachlorobenzene, etc.). Solvents with higher δd can Chloroform 9.1 8.1 3 0.5 0 0.40 0.57 dissolve compounds better. Tetrahydrofuran (THF) 9.1 7.6 4 3 0 0.45 − δo：An orientation (polarity) solubility parameter indicating Benzene 9.2 9.2 0 0.5 0 0.32 0.65 the degree of selective dissolution of compounds with Acetone 9.4 6.8 5 2.5 0 0.56 0.65 large dipole moment (nitro compounds, nitriles, ketones, etc.). Dichloromethane 9.6 6.4 5.5 0.5 0 0.42 0.44 δa：A solubility parameter of proton acceptor indicating the Chlorobenzene 9.6 9.2 2 0.5 0 0.30 0.80 degree of selective dissolution of alcohols, phenols and 1,2-dichloroethane 9.7 8.2 4 0 0 0.49 0.79 carboxylic acids 1,4-dioxane 9.8 7.8 4 3 0 0.56 1.54 δh：A solubility parameter of proton donor indicating the 1-propanol 10.2 7.2 2.5 4 4 0.82 2.3 degree of selective dissolution of basic compounds Ethanol 11.2 6.8 4.0 5 5 0.88 1.20 (amines, ethers, SO compounds, etc.) N,N-dimethylformamide 11.5 7.9 − − − − − ε°：Solvent strength in adsorption chromatography with Acetonitrile 11.8 6.5 8 2.5 0 0.65 0.37 alumina Methanol 12.9 6.2 5 7.5 7.5 0.95 0.60 η：Viscosity (mPa.s, 20°C) Water 21 6.3 High High High − − Wako Product Information － Chromatography － 9th Edition Appendix 〈 8th A-50〉 For other products, please visit the Wako Online Catalog: http://www.e-reagent.com/.