大体积直接进样-离子色谱法测定火电机组饱和蒸汽中痕量铁和铜

IC Determination of Traces of Iron and Copper in Saturated Steam of Thermal Power Generating Unit with Direct Sample Introduction in Large Volume

提出了大体积直接进样-离子色谱法测定火电机组饱和蒸汽中铁(Ⅲ)、铜(Ⅱ)含量的方法。移取样品100.00mL,加入盐酸(1+9)溶液1mL和10g·L-1过硫酸铵溶液1mL进行消解。所得消解液经IonPac CS5A分离柱分离,配制每升体积中含2,6-吡啶二羟酸3.5mmol、氢氧化钾66mmol、甲酸83mmol及硫酸钠5.6mmol的混合液(调节酸度为pH 3.7)作为流动相进行淋洗。采用可变波长分光光度计检测器在505nm处进行检测。铁(Ⅲ)、铜(Ⅱ)的质量浓度分别在15μg·L-1和50μg·L-1以内与峰高呈线性关系,检出限(3S/N)分别为0.058,0.073μg·L-1。方法用于火电机组饱和蒸汽中铁(Ⅲ)、铜(Ⅱ)含量的测定,回收率分别为100%和90.5%,测定值的相对标准偏差(n=8)分别为1.3%和1.8%。

Contents of Fe （ Ⅲ） and Cu （Ⅱ ） in saturated steam of thermal power generating unit were determined by 1C with direct sample introduction in large volume. The sample （100. 00 mL） was digested with 1 mL of HCI （1＋9） and 1 mL of 10 g . L-1 ammonium persulfate solution. The IonPac CS5A column was used for separation, and a mixed solution containing 3.5 mmol of 2,6 pyridyldicarboxylic acid, 66 mmol of KOH, 83 mmol of formic acid and 5.6 mmol of sodium sulfate in a total volume of 1 liter was prepared （adjust its acidity to pH 3.7） and used as mobile phase for elution. VIS-spectrophotometric detector at 505 nm was used in the determination. Linear relationships between values of peak height and mass concentration of Fe（Ⅲ） and Cu（ Ⅱ ） were kept in the range within 15 μg .L-1 and 50 μg . L-1, with detection limits of 0. 058 and 0. 073 μg.L-1 respectively. The proposed method was applied to the determination of Fe（ Ⅲ） and Cu（ Ⅱ ） in sample of saturated steam; values of recovery and RSD＇s （n=8） found were 100%, 1.3% for Fe（Ⅲ ） and 90. 5%, 1.8% for Cu（ Ⅱ ）, respectively.