Ultra-trace determination of oxaliplatin impurities by sweeping-MEKC-ICP-MS

•The first application of sweeping-MEKC-ICP-MS to improve detection limits.•Ultra-trace determination of oxaliplatin and its impurities B and C.•Within the optimal conditions, LODs of 1 to 3 ng mL-1 were achieved.•LOD represents the detection of 227 attomol of Pt per injection.•Compared to MEKC-UV, up to 3500-fold lower detection limits were reached.•A wide dynamic range up to six orders of magnitude (R2 ≥0.9989) was achieved.