Analysis of Clodronate and related substances according to European Pharmacopoeia 9.0 method (monograph 2017:2119) using sodium hydroxide gradient 15-45 mM (0-10 min), 45-55 mM (10-22 min), 55-85 mM (22-23 min), 85 mM (23-25 min), followed by an equilibration at 15 mM during 10 min, on an IonPac AS11-HC column (250×4 mm). Eluents were stored in EQAX-B1 eluent bottles equipped with EQAX-TC1 trap cartridges for carbon dioxide removal. Background reduced by XAMS-HC high-capacity suppressor with ASUREX-A200 automatic regenerator keeping the background increase <1.7 µS/cm during the gradient. Eluent pumping by two Metrohm 818 IC Pumps controlled by 762 IC Interface, and conductivity detection by Shodex CD-200 detector at range 51.2 mS/m. An IonPac ATC-HC trap column was used to trap anionic contaminants from the eluent, wherefore gradient start and sample injection was delayed compensating for this additional 2 min dwell time. Injection of 20 µL of clodronate 1.25 g/L in water, giving signals around 300 µS/cm.