RESUMEN
Objective To investigate the stability of 8 commonly used reference solutions and determine the validity period of internal control. Methods The storage solutions of reference substances were prepared and stored in the refrigerator at 2 to 10 ℃. The content of the storage solutions and the newly prepared reference solutions were determined by HPLC on days 0, 1, 4, 7, 10, 14, 21, 28 and 35, and their change values of the content were calculated. Results During the inspection period, the appearance of each reference solution was consistent with the newly prepared reference solution. There was no significant impurity peak in the chromatography. For mixed references of metronidazole, chloramphenicol and salicylic acid stored for 7 days, vitamin E, mixed references of tinidazole and chlorhexidine acetate, sulfadiazine, dexamethasone phosphate for 35 days, their contents met the requirements. Conclusion Stored in the refrigerator at 2 to 10 ℃, the effective time period of vitamin E reference solution, mixed references solution of tinidazole and chlorhexidine acetate, sulfadiazine reference, dexamethasone phosphate reference solution can be 35 days, and the mixed references solution of metronidazole, chloramphenicol and salicylic acid defined can be 7 days.