Comparison of absorbance and pressure between acetonitrile and methanol

Acetonitrile HPLC grade small. In the commercial HPLC and superior absorption spectra of acetonitrile and methanol, the absorption Z of acetonitrile HPLC is small (especially in the short wavelength). The so-called HPLC level is to remove impurities with UV absorption, and the absorbance is limited to the specification value at the specified wavelength. In UV detection, the noise is small, so acetonitrile HPLC grade Z is suitable for high sensitivity analysis on UV short wavelength. In addition, in the gradient baseline of UV detection, acetonitrile HPLC level produces few ghost peaks. Although there are various other organic solvents with high water solubility, it is difficult to find one with smaller absorption than acetonitrile HPLC level. In addition, although the spectrum obtained by HPLC and superior grade of methanol is not much different, superior grade cannot guarantee the absorbance, which may cause deviation, and the price is not much different, so try to use HPLC grade.

Pressure comparison between acetonitrile and methanol.

The manufacturer of acetonitrile is low, and the pressure in the column varies according to the type of organic solvent or mixing ratio. In the relationship between the ratio of water / acetonitrile, water / methanol mixture and infusion pressure, methanol is mixed with water, and the pressure increases, while acetonitrile is also mixed with water, which is not the case. Therefore, acetonitrile does not add excess pressure to the column at the same flow rate.