离子色谱法测定循环冷却水中的羟基-1,1-亚乙基二磷酸

建立了循环冷却水中羟基-1,1-亚乙基二磷酸(HEDP)的离子色谱检测方法。色谱柱为IonPac AS14A阴离子交换柱,流动相为80 mmol/L NaOH水溶液,流速1.0 mL/min,抑制型电导检测器检测。方法的线性范围为0.25～25 mg/L,平均回收率为102%,检出限为0.1 mg/L;对0.25 mg/L和0.5 mg/L的HEDP标准溶液分别进行13次平行测定,相对标准偏差(RSD)分别为4.7%和3.5%。该方法具有简单、快速、灵敏、抗干扰等优点，用于循环冷却水中HEDP的检测,结果令人满意。

Determination of 1-Hydroxyethylidene-1,1-Diphosphonic Acid in Recycle-Cooling Water by Ion Chromatography

1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP) is usually used as a scale and corrosion inhibitor in recycle-cooling water for steel industry. The quick and accurate analysis of HEDP concentration in water is of importance to control the inhibitor adding program. However, the common method for HEDP analysis, which determines the total phosphate in water samples, may suffer the serious problem of incorrectly including degraded HEDP as the active HEDP reagent. In this study, the method of the determination of HEDP in recycle-cooling water by ion chromatography was investigated. The chromatographic parameters, including elution and detection, were optimized. The separation was achieved on an IonPac AS14A column with NaOH solution of 80 mmol/L as the eluent at a flow rate of 1. 0 mL/min, and the detection was performed by a suppressed conductivity detection mode with the injection volume of 25 microL. The method showed good linearity within the range of 0. 25 and 25 mg/L with an average recovery of 102%. The detection limit of the method reached as low as 0. 1 mg/L. The relative standard deviations for 0. 25 and 0. 5 mg/L HEDP standard solutions were 4. 7% and 3. 5% (n = 13) , respectively. The method has been applied for the determination of HEDP in recycle-cooling water samples with the advantages of being simple, fast, sensitive, and interference free.