We have followed a literature method for NaHSO3 and NaHSO4 Detection by HPLC (Literature attached) in suspension formulation. Though we are receiving the peak of NaHSO3, unfortunately no peak of NaHSO4 observed while injecting the standard of NaHSO4.
We are unable to make a mobile phase, as mentioned in the literature, of pH 6 as 0.03 M tetrabutylammonium hydrogen sulfate (TBAS) and 0.01 M potassium dihydrogen orthophosphate in Milli-Q water is giving pH of 2.