By Anonymous on Tuesday, June 1, 2004 - 12:25 am:
Hello
Can any body suggest an HPLC (by UV-detection) method for Methane sulfonic acid and methyl methane sulfonic acid
By Chris Pohl on Wednesday, June 2, 2004 - 01:38 pm:
Methanesulfonic acid can not be directly detected with a UV detector since it does not absorb in the UV. Your best options for detecting methanesulfonic acid are to use conductivity detection or indirect UV detection. Analysis of methanesulfonic acid via conductivity detection is straightforward and can be accomplished on any common ion chromatography anion exchange column (see, for example: http://www1.dionex.com/en-us/columns_accessories/ion_exchange/chro3609.html
). However, neither would be useful for detecting methyl methanesulfonic acid. I think you would be better off using GC for this.
By Raman.N on Thursday, June 10, 2004 - 04:28 am:
Thanks Chris.
Can you explain me what is indirect UV detection. I could not understand , recently one of the phamacopoeial method also has given an indirect UV method at 290 nm.
Thanks again.
By Anonymous on Friday, June 11, 2004 - 07:39 am:
Raman,
Indirect detection looks at the decrease in background absorption as a compound elutes from the system. You use a mobile phase which has an absorbance at some wavelength and as a compound elutes and displaces whatever is absorbing in the mobile phase and your baseline decreases. Within reason the decrease is proportional to the analyte concentration.
Regards,
Mark