Determination of Methotrexate in Human Plasma by High Performance Liquid Chromatography
OBJECTIVE To establish an automatic,rapid and accurate method for the determination of methotrexate concentration in human blood.METHODS A double-temary liquid chromatography system with ultraviolet detector in series was used.Athena C18-WP(4 mm×20 mm,5 μm)column was used as the on-line SPE column,and Athena C18-WP(4.6 mm×150 mm,5 μm)column was used as the analysis column.The mobile phase was 10 mmol·L-1 ammonium acetate,the stationary phase was acetonitrile,and the flow rate was 1 mL·min-1.The detection wavelength was 306 nm.The column temperature was 40 C.The injection volume was 100 μL.Serum samples were injected after protein precipitation with a precipitating reagent(5% trichloroacetic acid+10%zinc sulfate).The specificity,standard curve and lower limit of quantitation,precision and accuracy,recovery rate and stability of the method were investigated.RESULTS Methotrexate had good linearity in the range of 0.078-8.000 μmol·L-1(R2=0.999 4).The recoveries of methotrexate were 86.41%to 87.09%,RSD of intra-day and intra-day were lower than 7%.CONCLUSION This method is accurate,reproducible,simplified the steps of sample pretreatment and improved the analysis efficiency.It is suitable for the detection of blood drug concentration in high dose methotrexate treatment.