三乙烯四胺修饰β-环糊精交联树脂分离富集/原子吸收法测定大米中的铅、镉

Determination of Lead and Cadmium in Rice by Flame Atomic Absorption Spectroscopy after Separation and Preconcentration Using Crosslinked β-Cyclodextrin Modified with TETA

该文制备了一种新型吸附材料三乙烯四胺修饰β-环糊精交联树脂（TETA-β-CDP）,并对其进行红外光谱表征,优化了该吸附材料对痕量铅、镉的吸附和解析条件,建立了动态条件下同时分离富集/原子吸收光谱测定大米中铅和镉的新方法。在p H 5.5时,样品溶液以1.0 m L/min流速过柱,试液中的Pb2＋和Cd2＋可被该树脂定量富集,其动态饱和吸附容量分别为22.8,31.3 mg/g,吸附在TETA-β-CDP上的Pb2＋和Cd2＋可用0.1 mol/L HCl以0.8 m L/min流速完全洗脱。该方法对铅、镉的检出限（3σ,n=11）分别为0.038 mg/L和0.016 mg/L;线性范围分别为0.2~20 mg/L和0.05~2.5 mg/L;相对标准偏差（RSD）分别为2.8%和1.7%;加标回收率分别为97.5%~101.0%和95.0%~102.5%。该方法用于大米样品中痕量铅、镉的测定,结果满意。

A novel adsorbent material,triethylenetetramine modified β-cyclodextrin crosslinked resins（ TETA-β-CDP） was synthesized,and the synthesized material was characterized by Fourier transform infrared spectrometry（ FT- IR）. The conditions of adsorption and desorption of the adsorbent material for Pb2 ＋and Cd2 ＋were optimized,and a new method was developed for the determination of trace lead and cadmium in rice by atomic absorption spectroscopy. It was found that,in the conditions of p H 5. 5 and flow rate of sample solution of 1. 0 m L / min,the lead and cadmium could be quantitatively preconcentrated on TETA-β-CDP separation resin with adsorption capacities of 22. 8mg / g and 31. 3 mg / g,respectively. The adsorbed lead and cadmium could be eluted with 0. 1 mol / L HCl at a flow rate of 0. 8 m L / min. Under the optimum conditions,the calibration curves were linear over Pb2 ＋and Cd2 ＋concentrations in the ranges of 0. 2- 20 mg / L and 0. 05- 2. 5 mg / L,with detection limits（ 3σ,n = 11） of 0. 038 mg / L and 0. 016 mg / L,respectively. The relative standard deviations（ RSDs） for the determination of 0. 5 mg / L Cd2 ＋and 5 mg / L Pb2 ＋were 1. 7% and 2. 8%,respectively. The spiked recoveries of lead and cadmium were in the ranges of 97. 5%- 101. 0% and95. 0%- 102. 5%,respectively. The method was applied in the determination of trace lead and cadmium in rice samples with satisfactory results.