Development and Validation of an HPLC Method for Simultaneous Assay of Potassium Guaiacolsulfonate and Sodium Benzoate in Pediatric Oral Powder
Table 2
Results of preliminary optimization.
Column
Mobile phase
Elution mode
Flow rate
Observation
Result
Luna C8
Methanol-0.002 M solution of tetrabutylammonium sulfate (20 : 80, v/v)
Isocratic
1.0 mL/min
Elution force was too weak for sodium benzoate (retention time of sodium benzoate was more than 30 minutes)
Rejected
Luna C8
Acetonitrile-0.002 M solution of tetrabutylammonium sulfate (20 : 80, v/v)
Isocratic
1.0 mL/min
The two peaks of potassium guaiacolsulfonate were not completely resolute; retention time too long for sodium benzoate (more than 20 minutes)
Rejected
Luna C8
Methanol-0.002 M solution of tetrabutylammonium sulfate (50 : 50, v/v)
Isocratic
1.0 mL/min
Unable to distinguish the two components of potassium guaiacolsulfonate
Rejected
Luna C8
Methanol-0.005 M solution of tetrabutylammonium hydrogen sulfate (20 : 80, v/v)
Isocratic
1.0 mL/min
Poor and unstable peak shape for both analytes
Rejected
Luna C8
Methanol-0.002 M solution of tetrabutylammonium sulfate (20 : 80, v/v)
Gradient (the gradient program was presented in Table 1)
1.0 mL/min
Good resolution and peak shape for components of potassium guaiacolsulfonate; good resolution between potassium guaiacolsulfonate and sodium benzoate; acceptable analysis time (15 minutes)