I have a problem with developing a new method for determination of tulathromycin by HPLC
Am using ODS 150*4.6 5µ column with a mixture of phosphate buffer pH6.5, methanol and Acetonitrile to obtain a peak with a good symmetry 'about 0.9', but while performing linearity for the method all low concentration solutions have low symmetry 'about 0.5'
can any one please advice