[Edward]

I urgently need to know the physical properties of THP including acidity, pKa, solubility, structure, polarity to start an HPLC exercise.  Is THP able to be extracted by Varian Tox A and Tox B LLE?  What is the rationale for this LLE with reference to its physico-chemical property?  Is a reversed phase C18 sufficient? I read from paper that a gradient elution generated by proportional mixing of solvent A:50mL/L acetonitrile, and solvent B 500mL/L, both in 50mL/L phosphate buffer, pH 3.0, containing 3mL/L triethylamine and 375mg/L SOS, was maintained at 12% for 3min, and returned to 12% in 3min, the waiting time between analytical runs was 7 min.  The flow rate was 1.0mL/min.  
I am new to HPLC and don't know how the author derived at this.  Could anyone pls advise how optimization can be done?
For UV detection, is it beneficial to run a UV spectrum just by scanning a diluted commercial THP?
 
Thank you very much