Column flushing

Column flushed with separation buffer between... 

Contamination of column. —> Flush column with strong solvent. 

If you have to install a new reversed-phase column, flush it with methanol or acetonitrile before the first run. Take care to keep your equipment free of buffers. Even better, flush your equipment first with an isopropanol/water mixture and then with methanol. Use the same procedure if you wish to go back to your original conditions. 

The signal generated by the camera when a sapphire column flushed with nitrogen is placed in between the IR source and the camera, is indicated with DLq. When CO2 is fed into the column, it absorbs part of the radiation and the remaining signal transmitted to the camera is denoted with DL. From these two signals, the transmittance and absorbance can be defined as follows ... 

Flush the microlitre syringe several times with the sample prior to analysis. If bubbles are present in the liquid column, flush the syringe and withdraw a new sample. 

A new method is described for the quantitative determination of some sulphur-containing antioxidants in PE. The polymer matrix is dissolved in hot n-heptane/ isopropyl alcohol, 97/3 v/v at 160 deg.C under elevated pressure (0.33 MPa) and precipitated by cooling. The solution is injected directly into a normal-phase silica gel column flushed with the same solvent as used for the dissolution of the polymer. This method gives high recovery of the antioxidants, good repeatability of the analysis and a low detection limit of 0.011 mg 4,4 -thiobis(3-methyl-6-tert-butylphenol) (Santonox R) /I g PE 0.074 mg ditetradecyl-beta,beta -thiodipropionate (Chimox 14) / 1... 

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