中文摘要：

研究了流动注射在线置换吸附预富集-火焰原子吸收（FAAS）联用技术测定复杂样品中痕量铅的方法。首先使Zn（Ⅱ）与二乙基二硫代氨基甲酸钠（DDTC）在线配合形成Zn-DDTC并预先吸附在香烟过滤嘴填充柱上，然后使含Pb（Ⅱ）的标准溶液或样品溶液流经填充柱与Zn-DDTC发生置换反应而被填充柱富集。被吸附的分析物用乙醇定量洗脱至FAAS进行在线检测。此在线置换吸附预富集过程有效地消除了与DDTC的配合物稳定性较Zn-DDTC弱的共存金属离子的干扰。在样品流速为5．0mL/min和置换吸附预富集90s的条件下，得到铅的吸收信号的增感因子为33，检出限为2．0μg/L。浓度为100μg/L的铅标准溶液11次平行测定的精密度（RSD）为1．2％。本方法已应用于生物样品的分析。

英文摘要：

A flow injection （FI） on-line displacement sorption preconcentration coupled with flame atomic absorption spectrometry （FAAS） for selective preconcentration and separation of trace lead in biological samples was developed. The method involved on-line formation of the Zn-sodium diethylammonium diethyldithiocarbanate （ DDTC ） complex and its presorption onto the microcolumn packed with cigarette filter, retention of the analyte Pb（Ⅱ） onto the cigarette filter through a displacement reaction between the Pb（Ⅱ） and the pre-sorbed Zn-DDTC, elution of the retained analyte with ethanol, and on-line detection by FAAS. Interferences from coexisting ions with lower stability of their DDTC complexes relative to Zn-DDTC were eliminated because they could not displace the Zn（Ⅱ） from the presorbed Zn-DDTC. With a 90-s displacement sorption at a flow rate of 5.0 mL/min, an enhancement factor of 33 with a detection limit （ 3s ） of 2.0 μg/L was obtained. The precision （ RSD, n = 11 ） was 1.2% at the level of 100 μg/L. The developed method was successfully applied to selective determination of trace lead in biological materials.