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Setting the compressibility of solvent (COMP)
Setting the compressibility of solvent (COMP)
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Answer
Although the instrument corrects the compressibility to suppress pulse increase caused by the effect of the compressibility of the solvent, setting a compressibility suitable for the solvent used enables more accurate correction.
Input the compressibility (GPa)-1 with the numeric keypad and press [Enter]. The initial value is 0.45.
Input the compressibility (GPa)-1 with the numeric keypad and press [Enter]. The initial value is 0.45.
| Mobile Phase | Compressibility (GPa)-1 |
| Water | 0.45 |
| Acetonitrile | 1.20 |
| Methanol | 1.25 |
| Ethanol | 1.20 |
| 2-propanol | 1.20 |
| Hexane | 1.60 |
| Heptane | 1.25 |
| Cyclohexane | 1.25 |
| Ethyl Acetate | 1.10 |
| Chloroform | 1.10 |
| Benzence | 1.00 |
· Single solvent
Set the compressibility according to the table.
Set the compressibility according to the table.
· Mixture of water and organic solvent
If the concentration of the organic solvent is 50% or less, "0.45" is recommended for the compressibility of water. If the concentration is more than 50%, make the value closer to the compressibility of organic solvent according to the mixture ratio.
Example) When the ratio between water and acetonitrile is 50 : 50, set "0.45". When the ratio between water and acetonitrile is 30 : 70, set "0.75".
If the concentration of the organic solvent is 50% or less, "0.45" is recommended for the compressibility of water. If the concentration is more than 50%, make the value closer to the compressibility of organic solvent according to the mixture ratio.
Example) When the ratio between water and acetonitrile is 50 : 50, set "0.45". When the ratio between water and acetonitrile is 30 : 70, set "0.75".
· In other cases or when rigorous adjustment is required
1. Connect a resistance tube (or column) that can create pressure similar to the desired delivery pressure at 1.0mL/min or less and wait until delivery becomes stable.
2. While monitoring fluctuation on the pressure monitor of the instrument, gradually increase the set value of [COMP] from 0.45 in 0.05 increments to find the COMP value with the minimum fluctuation on the pressure monitor.
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