采用离子色谱法测定珠江口半咸水中5种阴离子F-、Cl-、NO2-、NO3-、SO42-的含量。以AS 23型阴离子分离柱为分离柱,以6.0 mmol·L-1碳酸钠和1.2 mmol·L-1碳酸氢钠的混合溶液为淋洗液,采用抑制电导器检测。F-、Cl-、NO2-、NO3-、SO42-等5种阴离子的质量浓度分别在0.108 2~1.536 mg·L-1、200.1~3 029 mg·L-1、0.044 2~0.602 4 mg·L-1、0.527 4~7.569 mg·L-1、10.84~151.4 mg·L-1范围内呈线性,检出限(3S/N)分别为0.02,0.05,0.003,0.03,0.10 μg·L-1。方法用于模拟海水试样中5种阴离子的测定,回收率在80.5%~115.1%之间;重复性试验测得相对标准偏差(n=7)均小于5%。

The contents of F-, Cl-, NO2-, NO3- and SO42- in semi-seawater from the Pearl River estuary were determined by ion chromatography. The AS 23 anion-exchange column was used for separation, and a mixture of 6.0 mmol·L-1 Na2CO3 and 1.2 mmol·L-1 NaHCO3 was used as eluent. Inhibitory conductivity detection was adopted in the determination. Linearity ranges of F-, Cl-, NO2-, NO3- and SO42- were found between 0.108 2-1.536 mg·L-1, 200.1-3 029 mg·L-1, 0.044 2-0.602 4 mg·L-1, 0.527 4-7.569 mg·L-1 and 10.84-151.4 mg·L-1, with detection limit (3S/N) of 0.02, 0.05, 0.003, 0.03 and 0.10 μg·L-1 respectively. The proposed method was applied to the determination of the 5 anions in simulated seawater samples, values of recovery found were in the range of 80.5%-115.1% and values of RSD′s (n=7) found were less than 5%.