目的建立同时测定制马钱子中4种生物碱士的宁、马钱子碱、士的宁氮氧化物、马钱子碱氮氧化物含量的反相离子对HPLC法。方法应用Lichrospher S C18色谱柱(4.6mm×300mm,5μm),以乙腈-水(38:62,每1000mL加入磷酸二氢钾3.4g和十二烷基硫酸钠1.7g)为流动相,流速:1.0mL.min-1,柱温:30℃,检测波长:260nm。结果4种生物碱士的宁、马钱子碱、士的宁氮氧化物和马钱子碱氮氧化物的线性范围分别为13.7～219.1,12.55～200.8,0.3743～5.988和0.6225～9.96mg.L-1(r>0.9999),平均回收率分别为98.0%,102.2%,103.3%和99.9%(RSD均小于2.5%)。结论该方法简便、准确,重复性好,适用于制马钱子中士的宁、马钱子碱、士的宁氮氧化物、马钱子碱氮氧化物的含量测定。 OBJECTIVE To establish a reverse phase ion pair HPLC method for the simultaneous determination of four alkaloids, strychnine, brucine, strychnine nitrogen oxides and strychnine nitrogen oxides in Strychnos nux vomica. Methods The mobile phase was a Lichrospher S C18 column (4.6mm × 300mm, 5μm) with acetonitrile-water (38:62, potassium dihydrogen phosphate 3.4g per 1000mL and sodium lauryl sulfate 1.7g) 1.0mL.min-1, column temperature: 30 ℃, detection wavelength: 260nm. Results The linear ranges of four alkaloids, strychnine, brucine, strychnine nitrogen oxide and strychnine nitrogen oxide were 13.7 ~ 219.1,12.55 ~ 200.8,0.3743 ~ 5.988 and 0.6225 ~ 9.96mg, respectively. L-1 (r> 0.9999). The average recoveries were 98.0%, 102.2%, 103.3% and 99.9%, respectively (RSD less than 2.5%). Conclusion The method is simple, accurate and reproducible. It is suitable for the determination of strychnine, strychnine, strychnine nitrogen and strychnine nitrogen oxides in Strychnos nux vomica.