A rapid method for determination of hydrogen peroxide based on a non‐enzymatic amperometric sensor with an online dialysis unit was developed for analysis of sample with complicated matrices. A porous gold modified gold screen‐printed electrode was prepared by a simple method using 9 V‐battery electrodeposition. Based on data from amperometry, a linear dynamic range can be obtained in the range of 10 to 1000 μmol L−1, with a limit of detection of 0.37 μmol L−1. The proposed system was successfully applied to determine H2O2 in various milk samples with rapid analysis, high electrode stability, and excellent repeatability (1.95 % RSD with 100 replications).