my research is analysis formaldehyde in fish using HPLC method, so i have to use reversed phase in HPLC, why we have to use that? what happen if we use normal phase to analysis formaldehyde? please answer my question.
Because most molecules are polar and soluble in reverse phase solvents like water, methanol, acetonitrile, IPA (all have a very low UV cutoff). Normal phase HPLC is limited to mobile phase solvents like Hexane, methylene chloride.
Formaldehyde is very reactive but soluble in water not hexane!
Because most molecules are polar and soluble in reverse phase solvents like water, methanol, acetonitrile, IPA (all have a very low UV cutoff). Normal phase HPLC is limited to mobile phase solvents like Hexane, methylene chloride.
Formaldehyde is very reactive but soluble in water not hexane!
Normal phase was used first to separate organic dyes by organic solvent and polar stationery phase (silica gel or alumina). However enormous amount of compounds are relatively polar it's eluting with non polar solvent will not be sufficient. Reverse phase use polar solvent so the most polar compounds will gained first. Formaldehyde is polar compound using reverse phase is necessary to get good results. Normal phase Will be a mistake in this case.
in case of RP-HPLC mobile phase i.e. eluent is polar (say Water:Acetonitrile, 30:70) and stationary phase is non polar (e.g. C18 column) so when you have a polar organic compound its better to use reverse phase chromatography. in normal phase chromatography mobile phase is non polar (say Hexane:2-Propanol, 90:10). Since your compound of interest is formaldehyde so you can use RP-HPLC, also a number of methods can be found in literature related with that.