Study on the Antibacterial Effect of Cerium Nitrate Hand Sanitiser with Rare Earth Compounds Against Common Hand Bacteria

This study determined the optimal concentration of cerium nitrate through preliminary experiments and formulated an antibacterial hand sanitizer containing 3 mg/mL of cerium nitrate. The antibacterial efficacy of the developed hand sanitizer against common hand-surface bacteria was assessed using both the Kirby-Bauer disc diffusion method and colony counting techniques. The results of the study demonstrate that the cerium nitrate-based hand sanitizer exhibited inhibition zone diameters of （25.67 ± 0.58） mm against <italic>Staphylococcus aureus</italic>, （23.67±1.15） mm against <italic>Escherichia coli</italic>, and （18.67±0.58） mm against Pseudomonas aeruginosa, as determined by the disk diffusion method. Compared to the respective control groups, the cerium nitrate-based hand sanitizer demonstrated significantly greater antibacterial efficacy (<italic>p</italic>&lt;0.05). The colony count assay revealed that the cerium nitrate-based hand sanitizer resulted in a significantly lower bacterial count of （0.37±0.07） CFU/cm² compared to the control group, indicating substantial antimicrobial efficacy (<italic>p</italic>&lt;0.05). These findings suggest that cerium nitrate at a concentration of 3 mg/mL exerts significant inhibitory effects against <italic>Staphylococcus aureus</italic>, <italic>Escherichia coli</italic>, and <italic>Pseudomonas aeruginosa</italic>, demonstrating markedly enhanced antimicrobial activity against common hand microbiota relative to the control.