水样以3 000 r·min^-1速率离心10 min后取上清液，依次用0.45，0.22 μm滤膜过滤。加入KH₂PO₄调节滤液酸度至pH 4.5后，采用中空纤维膜液相微萃取-毛细管电泳法测定其中的4种磺胺类药物。最佳萃取条件为：萃取剂为正辛醇，接受相为24 μL的150 mmol·L^-1 NaOH溶液，给出相为18 mL的样品溶液（pH 4.5），搅拌速率为300 r·min^-1，萃取时间为60 min。毛细管电泳运行电压为20 kV；在3.447 kPa压力下进样5 s；负极端检测，检测波长为254 nm；温度为25℃；缓冲溶液为30 mmol·L^-1四硼酸钠溶液（pH 7.60）。4种磺胺类药物的质量浓度均在5.0~1 000 μg·L^-1内与对应的峰面积呈线性关系，磺胺二甲基嘧啶、磺胺甲基嘧啶、磺胺嘧啶和磺胺甲恶唑的检出限（3S/N）依次为1.17，0.84，0.73，1.27 μg·L^-1，富集倍数在105~393之间。方法用于环境水样中4种磺胺类药物的测定，水产养殖用水和生活污水中分别检出了2，1种磺胺。加标回收率在82.3%~99.4%，测定值的相对标准偏差（n=5）为0.39%~6.6%。

Water sample was centrifuged for 10 min at a rate of 3 000 r·min^-1, and the supernatant was taken and filtered surcessively through filters of 0.45 and 0.22 μm. Acidity of the filtrate was adjusted to pH 4.5 by addition of KH₂PO₄. The 4 sulfonamides in the filtrate were separated by hollow fiber membrane liquid phase microextraction under the following conditions:① extractant:n-octanol; ②acceptor phase:24 μL of 150 mmol·L^-1 NaOH solution; ③ donor phase:18 mL of pH 4.5 sample solution; ④ time of extraction:60 min; ⑤ stirring rate during extraction:300 r·min^-1, and determined by capillary electrophoresis under the following conditions:① operating voltage:20 kV; ② time and pressure of sample introduction:5 s, 3.447 kPa; ③ detection on cathodic side at the wavelength of 254 nm and temperature of 25℃; ④ buffer solution:30 mmol·L^-1 borax solution of pH 7.60. Linear relationships between values of peak area and mass concentration of the 4 sulfonamides were found in the same range of 5.0 to 1 000 μg·L^-1, with detection limits (3S/N) of 1.17 (SM₂), 0.84 (SM₁), 0.73 (SD) and 1.27 μg·L^-1 (SMZ), and enrichment factors between 105 and 393. In analysis of substantial samples by the proposed method, 2 sulfonamides were detected in aquaculture water and 1 sulfonamide was detected in domestic sewage. Values of recovery obtained by standard addition method were in the range of 82.3% to 99.4%, and RSDs (n=5) were in the range of 0.39%-6.6%.