采用超高效液相色谱-串联质谱法测定水中戊基黄原酸的含量。水样（pH 9~10）采用聚四氟乙烯材质的一次性针式过滤器过滤，滤液以ACQUITY UPLC BEH C₁₈色谱柱为分离柱，以不同体积比的水（用氨水调节pH至10）和甲醇混合液为流动相进行梯度洗脱，采用电喷雾负离子源多反应监测模式检测。戊基黄原酸的线性范围为0.500~15.0 μg·L^-1，检出限为0.114 μg·L^-1。对1.00，8.00，14.0 μg·L^-1的戊基黄原酸标准溶液连续测定6次，测定值的相对标准偏差为2.7%~3.9%。以空白样品为基体进行加标回收试验，所得回收率为95.9%~102%。

UHPLC-MS/MS was applied to the determination of amyl xanthic acid in water. The water sample (pH 9-10) was filtered with disposable needle filter of PTFE material. ACQUITY UPLC BEH C₁₈ chromatographic column was used as stationary phase, and the mixture of water(pH was adjusted to 10 with ammonia)and methanol mixed in different ratios was used as mobile phase in gradient elution. ESI^- and multi-reactions monitor mode were adopted in MS/MS. Linearity range of amyl xanthic acid was found between 0.500 μg·L^-1 and 15.0 μg·L^-1 with detection limit of 0.114 μg·L^-1. Precision of the method was tested at the concentration levels of 1.00, 8.00, 14.0μg·L^-1 amyl xanthic acid standard solutions for 6 determinations, values of RSD's found were in the range of 2.7%-3.9%. On the base of blank sample, test for recovery was made by standard addition method and values of recovery found were in the range of 95.9%-102%.