Download - Solvent UV Cutoffs

Transcript
  • Solvent Cut-off wavelengths

    Solvents L0/nm L1/nm

    1,2,4-trichlorobenzene 350

    1,2-dichlorobenzene 350 295

    1,2-dichloroethane 250 230

    1,2-dimethoxyethane 300 220

    2,2,4-trimethylpentane 230 210

    2-ethoxyethanol 280 210

    2-methoxyethanol 270 200

    2-propanol 240 205

    4-methylpentanone 375 335

    5-methylhexanone 350 330

    acetone 340 330

    acetonitrile 200 190

    benzene 295 280

    butan-2-one 345 330

    chlorobenzene 310 285

    chloroform 260 240

    cyclohexane 235 200

    cyclopentane 220 195

    decalin 250 230

    dichloromethane 245 230

    diethyl ether 255 220

    dimethylsulphoxide 330 285

    ethanol 240 205

    ethyl acetate 280 260

    heptane 230 200

    hexane 225 195

    isobutanol 250 200

  • methanol 240 205

    n-butanol 245 215

    n-butyl acetate 275 255

    nitromethane >400 380

    NN-dimethylformamide 300 270

    n-propanol 250 210

    o-xylene 325 290

    p-dioxane 290 220

    pentane 230 200

    Pyridine 345 325

    s-butanol 285 260

    tetrachloroethylene 320 290

    tetrahydrofuran 280 220

    toluene 315 285

    trichloroethylene >400

    water 190 185

    In this table, approximate wavelengths (nm) are specified below which the solvent absorbance may be unacceptable. For quantitative work, the cut-off may be set at a wavelength (L0) where the absorbance for 10 nm pathlength of the solvent exceeds 0.05 absorbance units (relative to water), i.e. A1cm>0.05.

    For qualitative work, it may still be feasible to work at significantly lower wavelengths and most analysts accept a cut-off based on the wavelength (L1) for A1cm > 1.0.