Nitrobenzene is sparingly soluble in water. I tried plotting its standard curve with various dilutions ranging from 0.1mM - 1mM, using HPLC with the method given in papers (Mobile phase: Methanol and water, 50:50 v/v at 254 nm). The area obtained for all the concentrations was same. I am unable to understand this event.
Please look at the following below links which may help you in your analysis:
https://patents.google.com/patent/CN103901133B/en
http://html.rhhz.net/zghxkb/20141110.htm
Thanks
If the solubility of nitrobenzene is below the concentration in your standard solutions, precipitation and adsorption of the nitrobenzene out of your standard solutions can occur, resulting in the introduction of only the residual material in solution. If you are above the solubility threshold, then you will be out of the range of the soluble quantity of nitrobenzene in your samples, and see the same issues.
Try dropping the concentration in your standard solutions by 10, 100 and 1000 times, which should provide a sufficiently wide concentration range to help maintain the nitrobenzene fraction in solution.
Alternatively, add a solvent or perhaps a surfactant to the standards which will increase the solubility of the nitrobenzene.
why are you trying to run it by HPLC. A quick check of the literature seems to indicate GC would be a better means of analysis.
- Badges
- Science method