建立了燃煤电厂烟气脱硫海水中亚硫酸根(SO32-)的离子色谱-脉冲安培检测方法。色谱柱为IOnPAC AS14A阴离子交换柱,流动相为14MMOl/l nAOH-12MMOl/l nA2CO3溶液(PH11.7),流速1.2Ml/MIn,脉冲安培法检测。因SO23-易被氧化,故在采样时加入甲醛作为保护剂,使之稳定存在。在测定海水样品前,用nAOH溶液(PH12.0)沉淀海水中的Mg2+,以避免其在PH较高的流动相中生成沉淀堵塞色谱柱。采用该方法检测SO23-的线性范围为0~100Mg/l,平均回收率为116.8%,检出限为0.05Mg/l;对7.5,25.0和75.0Mg/l的海水基底加标溶液分别进行9次平行测定,其相对标准偏差(rSd)分别为2.1%,3.1%和4.0%。该方法具有快速、灵敏、选择性好等特点,用于烟气脱硫的海水中SO32-的检测,可得到令人满意的结果。The technology for flue gas desulfurization(FGD) with seawater is widely adopted by coal-fired power plants in coastal areas.SO2 in the flue gas is absorbed by alkaline seawater and transfered in aqueous phase as sulfite(SO2-3),and most SO2-3 is transformed to sulfate(SO2-4) after an aeration process.The remaining SO2-3 in the seawater discharged to sea area may be harmful to marine organism because of its biological toxicity,thus it is necessary to determine the concentration of SO2-3 in the seawater for desulfurization.In this study,the method of determination of SO2-3 in the seawater by ion chromatography was investigated.The separation was achieved on an IonPac AS14A column with 14 mmol/L NaOH-12 mmol/L Na2CO3 solution as the mobile phase at a flow rate of 1.2 mL/min,and the detection was performed by a pulsed amperometric detector.Formaldehyde was added as a protective agent when sampling because the SO2-3 is easy to be oxidized.To avoid the formation of Mg(OH)2 in the mobile phase with high pH value which might block the column,the Mg2+ in seawater was precipitated by NaOH solution(pH 12.0) before sample determination.The method showed good linearity within the range of 0-100 mg/L with an average recovery of 116.8%.The method detection limit(MDL) reached as low as 0.05 mg/L.The relative standard deviations(RSD) for seawater matrix samples spiked at levels of 7.5,25.0 and 75.0 mg/L were 2.1%,3.1% and 4.0%(n=9),respectively.The method has been applied for the determination of SO2-3 in flue gas desulfurization seawater with the advantages of being fast,sensitive and selective
