阳离子交换色谱-抑制电导检测法测定过渡金属

Determination of transition-metal cations by suppressed conductivity detection

采用离子色谱抑制电导检测若干过渡金属离子.由于淋洗液抑制后成中性,过渡金属离子易发生水解形成氢氧化物沉淀而无法采用抑制电导检测,实验中采用在常规强酸淋洗液中加入两性离子,用于控制抑制后淋洗液的pH值.经过实验,在Waters IC-Pak C M/D柱上(150mm×3.9mm,ID)确定淋洗液条件为6.5mmol·L-1甲基磺酸(MSA)和10mmol·L-14-羟基乙基哌嗪乙磺酸(HEPES),Co2+、Ni2+、Zn2+和Cu2+等4种过渡金属离子在抑制电导检测下得到了检测信号并与碱金属、铵离子和碱土金属离子获得了较好的分离.在该实验条件下,方法具有较好的灵敏度(检测下限1.31～31.2μg·L-1)和重现性(时间RSD小于0.86%,峰面积RSD小于5.09%).

An efficient method for cation chromatography was described in which a mixture of a strong acid and a zwitterion is used as the eluent. The method can be used with suppressed conductivity detection for isocratic separation of alkali metal-, ammonium-, alkaline earth- and transition-metal cations on a Waters IC-Pak C M/D column （150 min× 3.9mm, ID）, using a mobile phase of 6.5 mmol ·L^-1MSA and 10 mmol ·L^-1 HEPES. The detection limits of Co2＋ ,Zn2＋ ,Cu2＋ and Ni2＋ were 1.31--31.2μg·L^-1 , the average recoveries were 92 %-102 %, its relative standard deviations of retention time and area were less than 0.86% and 5.09%,respectively.