da Silva Edson Luiz, Martins Amarildo Otavio, Valentini Antoninho, de Fávere Valfredo Tadeu, Carasek Eduardo
Departamento de Quimica, Universidade Federal de Santa Catarina, Florianópolis SC 88040-900, Brazil.
Talanta. 2004 Sep 8;64(1):181-9. doi: 10.1016/j.talanta.2004.02.003.
This study presents a new procedure for the determination of trace levels of copper(II) in an aqueous matrix, through flow injection (FI) on-line preconcentration with a minicolumn packed with silica gel modified with 3(1-imidazolyl)propyl groups. After the preconcentration stage, the analyte was eluted with a HNO(3) solution and determined by flame atomic absorption spectrometry (FAAS). The measurements of the analytical signals were carried out as peak area and peak height with the objective of evaluating the most appropriate absorption measurement for the proposed method. Four procedures to calculate the experimental enrichment factor (EF) were also studied. For a preconcentration time of 90s the enrichment factors found in this study varied between 19.5-25.8 and 36.2-42.2 for peak area and peak height, respectively. The precision of the proposed method was calculated for a solution containing 20mugl(-1) of Cu(II), when 11.2ml of solution was preconcentrated (n=7), and their respective relative standard deviation (R.S.D.) values were 1.2 and 1.4% for peak area and peak height, respectively. The detection limits obtained were 0.4 and 0.2mugl(-1) of Cu(II) for peak area and peak height, respectively, with a preconcentration time of 90s. The on-line preconcentration system accuracy was evaluated through a recovery test on the aqueous samples and analysis of a certified material.
本研究提出了一种用于测定水相中痕量铜（II）的新方法，该方法通过流动注射（FI）在线预富集，使用填充有经3-(1-咪唑基)丙基修饰硅胶的微型柱。在预富集阶段之后，用硝酸溶液洗脱分析物，并通过火焰原子吸收光谱法（FAAS）进行测定。以评估该方法最合适的吸收测量方式为目的，对分析信号进行了峰面积和峰高的测量。还研究了四种计算实验富集因子（EF）的方法。对于90秒的预富集时间，本研究中峰面积和峰高的富集因子分别在19.5 - 25.8和36.2 - 42.2之间变化。当预富集11.2毫升含有20μg l⁻¹ Cu（II）的溶液时（n = 7），计算了该方法的精密度，峰面积和峰高各自的相对标准偏差（R.S.D.）值分别为1.2%和1.4%。对于90秒的预富集时间，峰面积和峰高获得的检测限分别为0.4和0.2μg l⁻¹ Cu（II）。通过对水样的回收率测试和对有证标准物质的分析评估了在线预富集系统的准确性。
