RESUMEN
OBJECTIVE:A sensitive spectrophotometric method is developed for determination of content of lidocaine hydrochloride in different medium. METHODS:Lidocaine hydrochloride reacts with bromocresol purple to form an ion-association complex, the colors of solutions change obviously, the absorption wavelength at 588 nm and at 426nm were determined by spectrophotometric method for the content of lidocaine hydrochloride.. RESULTS:At wavelength 588 and 426nm, the concentration of lidocaine hydrochloride in the range of 2.76?10-6～2.83?10-5 and 5.64?10-6～2.48?10-5 mol?L-1 respectively follows obeys Beer's law, the apparent molar absorptivity are 1.45?104 and 7.11?103 L?mol-1?cm-1, the detection limit are 8.37?10-7 and 1.71?10-6 mol?L-1 . CONCLUSION:The method has high sensitivity and fairly good selectivity, applied to the determination of lidocaine hydrochloride in medicine samples and human serum and human urine.