The comparison of flow rate calibration methods for high performance liquid chromatography (HPLC) pump

High performance liquid chromatography (HPLC) pump has a main function to deliver a mobile phase which need accuracy and stable flow rate. Recently, three flow rate calibration methods are used to test the HPLC pump performance such as using standard flow meter, gravimetric method, and volumetric method. These calibration methods have not been clearly described. Therefore, this study aimed to investigate and compare the flow rate calibration by the using of standard flow meter, gravimetric method, and volumetric method. The flow rate was calibrated at 0.5 and 5 mL/min with 3 replications. The stability between day of each method was observed for 3 days. The calibration procedure, traceability chart, and uncertainty budget of each method had been described. The flow rate results were analyzed by using the En ratio. The results showed that the stability of all methods had no statistically significant difference between day when compared to the first day of itself. The measurement flow rates by the using standard flow meter, gravimetric method, and volumetric method at 0.5 mL/min were 0.5062, 0.4992, and 0.5012 mL/min, respectively and at 5 mL/min were 4.9172, 4.8272, and 4.8394 mL/min, respectively. These flow rates showed consistent results between each other as confirmed with the En ratio ≤ 1. The precision of the three methods was 0.01–0.08%RSD. This study concluded that the flow rate results of three calibration methods had consistent with each other. All methods had a good stability and precision for the flow rate calibration of the HPLC pump.