Frequently Asked Questions

Liquid Chromatography

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HPLC Knowledge Base

 

 

 

Switching the mobile phase from acetonitrile to other (methanol, etc.)

Q: I am thinking of replacing the column cleaning liquid (and mobile phase) with methanol. What proportion should I use and what flow rate should I set?
Q: According to documentation, methanol has a higher elution capacity than acetonitrile. Are there cases where this is not true?
Q: To what extent is sensitivity affected if I switch to methanol? Do I have to remake the calibration curve?
Q: If I switch to methanol, do the retention times change? Also, is it possible to continue using the same column?
Q: If acetonitrile is replaced with methanol, the pressure applied to the column increases. Is there any influence on the UV detector cell?
Q: I am using acetonitrile for solid-phase extraction in pretreatment. Can I change to methanol without any problems?
Q: Is methanol the only solvent that can be used instead of acetonitrile as the mobile phase in reversed-phase LC?
Q: What points need to be considered when replacing acetonitrile with methanol?

Use of a semi-micro column, Higher speed

Q: I am thinking of using a column shorter than the one I am currently using. Can I continue using the same gradient program without changing it?
Q: How fast should I set the mobile phase flow rate when using a high-speed analysis column?
Q: Regarding the issue of reducing the mixer capacity in accordance with a reduction in column size, is it not sufficient to just reduce the capacity of a standard mixer (minimum capacity: 0.5 mL)?
Q: I am thinking of switching to a column with a smaller inner diameter. In addition to changing the column, is there anything else that I need to consider?
Q: I currently have a standard SPD-20A temperature-controlled cell. If I replace the parts with those for a semi-micro cell, can I use this cell as a semi-micro cell?

Solvent recycling, etc.

Q: When using a solvent recycle valve, is it necessary to also purchase specialized software?
Q: At our company, we recover all of the eluate ejected from the detector in the reservoir.
Q: Is it possible to purify and reuse low-purity acetonitrile (or used mobile phase)?