What is the role of acetic acid and triethylamine in the mobile phase?
2.2. Acetic acid and triethylamine, as two traditional mobile phase additives in reverse phase HPLC, were employed to establish acidic or alkaline conditions, respectively. Chlorogenic acid and caffeic acid are organic acids which contain hydroxyl and carboxyl groups.
Which mobile phase used in HPLC analysis is?
NP-HPLC uses a non-polar, non-aqueous mobile phase (e.g., Chloroform), and works effectively for separating analytes readily soluble in non-polar solvents. The analyte associates with and is retained by the polar stationary phase.
Can be used as a mobile phase in HPLC?
Let’s consider each of these components. A solute’s retention time in HPLC is determined by its interaction with the stationary phase and the mobile phase….Choosing a Mobile Phase–Using the Polarity Index.
| mobile phase | polarity index (P′) | UV cutoff (nm) |
|---|---|---|
| dioxane | 4.8 | 215 |
| methanol | 5.1 | 210 |
| acetonitrile | 5.8 | 190 |
| water | 10.2 | — |
How do you choose mobile phase?
Whenever acidic or basic samples are separated, it is strongly advisable to control mobile phase pH by adding a buffer. Several considerations should be kept in mind in selecting a particular buffer e.g. buffer capacity, solubility, interaction with sample or column, corrosion of HPLC system etc.
What are the most commonly used mobile phase solvents in HPLC?
The organic solvents most commonly used for mobile phases in reverse chromatography are probably acetonitrile and methanol.
Is triethylamine a strong or weak base?
The highest pKaH value here is 10.8 for triethylamine. That makes triethylamine the strongest base out of all of those listed.
Why do you add formic acid to mobile phase?
When liquid chromatography-mass spectrometry techniques are used, formic acid is also a common component of the reversed-phase mobile phases because it provides protons for the LC-MS analysis in positive ionization mode, by producing [M+H]+ ions.
What is the role of triethylamine?
Triethylamine is mainly used in the production of quaternary ammonium compounds for textile auxiliaries and quaternary ammonium salts of dyes. It is also a catalyst and acid neutralizer for condensation reactions and is useful as an intermediate for manufacturing medicines, pesticides and other chemicals.
What is the role of pH in mobile phase?
The pH of the mobile phase can affect chromatography in a number of ways. Depending on the compound being analyzed, pH can impact selectivity, peak shape, and retention. With a fairly nonpolar or neutral compound, the effect of pH will typically be insignificant for resolution and retention.