Initially experiment was started on HPLC connected with photo diode array detector at different detection wavelength. But sensitivity of analyte was very low as no detection happened at ng/ml level.
Then analyte was scanned on spectroflourimeter, and the compound was identified as florescence sensitive at excitation 274 and emission 340 wavelengths.
The robustness test showed that to create a chromatogram with a minimal variation in separation, one should strictly control the fraction of organic modifier and the pH of the mobile phase.
Buffers (disodium monohydrogen phosphate, Potassium dihydrogen orthophosphate) at different pH with varying concentrations of organic phases (methanol, acetonitrile) were tried.
Optimum resolution and appropriate retention times of analyte was obtained with potassium dihydrogen orthophosphate buffer and acetonitrile as an organic modifier.
So the experiment started by utilizing isocratic flow condition by 20 mM potassium dihydrogen orthophosphate and acetonitrile at different concentration ratio and different pH range
between (2.5 to 6.5) by orthophosphoric acid.
Adjusting the pH to 2.9 of 20-mM KH2 PO4 buffer and its flow with acetonitrile at a ratio of 60:40 associated with better resolution of analyte.