A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment （SPEn） has been developed and evaluated to determ...A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment （SPEn） has been developed and evaluated to determine trace levels of methotrexate （MTX）. The method was based on injection of MTX into a flowing stream of phosphate buffer （0.04 M, ptt 3.4）, carried through the packed oxidant reactor of Cerium （IV） trihydroxyhydroperoxide for oxidative cleavage of the drug into highly fluorescent product, 2,4-diaminopteridine- 6-carboxylic acid, followed by SPEn on a head of short ODS column （10mm x 4.6 mm i.d., 5 I＋tm particle size）. The flow rate was 0.25 mL/min and packed reactor temperaturc was 40 ~C. The trapped product was back-flush eluted from the ODS column to the detector by column-switching with an environmentally friendly mobile phase consisting of ethanol and phosphate buffer （0.04 M, pH 3.4） in the ratio of 5：95 （v/v）. The eluent was monitored at emission and excitation wavelengths of 460 and was linear over the concentration range of 1.25-50 360 nm, respectively. The calibration curve ng/mL with a detection limit of 0.08 ug/ml..The method was successfully applied to determine MTX in pharmaceutical formulations with mean percentage recovery ranging from 99.48 to 99.60.展开更多
文摘A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment （SPEn） has been developed and evaluated to determine trace levels of methotrexate （MTX）. The method was based on injection of MTX into a flowing stream of phosphate buffer （0.04 M, ptt 3.4）, carried through the packed oxidant reactor of Cerium （IV） trihydroxyhydroperoxide for oxidative cleavage of the drug into highly fluorescent product, 2,4-diaminopteridine- 6-carboxylic acid, followed by SPEn on a head of short ODS column （10mm x 4.6 mm i.d., 5 I＋tm particle size）. The flow rate was 0.25 mL/min and packed reactor temperaturc was 40 ~C. The trapped product was back-flush eluted from the ODS column to the detector by column-switching with an environmentally friendly mobile phase consisting of ethanol and phosphate buffer （0.04 M, pH 3.4） in the ratio of 5：95 （v/v）. The eluent was monitored at emission and excitation wavelengths of 460 and was linear over the concentration range of 1.25-50 360 nm, respectively. The calibration curve ng/mL with a detection limit of 0.08 ug/ml..The method was successfully applied to determine MTX in pharmaceutical formulations with mean percentage recovery ranging from 99.48 to 99.60.
