Potassium guaiacolsulfonate

[syx]

Dear members,
We develop determination method for potassium guaiacolsulfonate and prometazine syrup. The problem is potassium guaiacolsulfonate in syrup has 2 peaks. The raw material had been tested using spectrophotometric method as in USP. When we used HPLC method we found 2 peaks, though the reference standard is in single peak. Does anyone know what is the second peak that may occured in potassium guaiacolsulfonate? Both peaks have similar spectra.

Thanks and regards,
Siswanto

[Mark Tracy]

Most likely isomers. 3-hydroxy-4-methoxy-benzenesulfonate and 3-methoxy-4-hydroxy-benzensulfonate should be formed in similar amounts when one sulfonates 2-methoxy-phenol (guiacol).