The Swift satellite has observed more than a thousand γ‐ray bursts (GRBs) with X‐ray data. Almost a third of them have redshift measurement, too. Here we start to investigate the X‐ray spectral fitting of the data considering the low‐energy part where the N(H) absorption takes place. Based on the available more accurate input data, we examine the robustness of previous fittings and test how sensitive the changes of the starting parameters are. We study the change of the intrinsic hydrogen column density during the outburst for a few events. No significant variability of the N(H) column density is identified.