Talio María Carolina, Alesso Magdalena, Acosta María Gimena, Acosta Mariano, Fernández Liliana P
Instituto de Química de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, 5700 San Luis, Argentina.
Área de Química Analítica, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
Talanta. 2014 Sep;127:244-9. doi: 10.1016/j.talanta.2014.04.020. Epub 2014 Apr 24.
In this work, a new procedure was developed for the separation and preconcentration of lead(II) and cobalt(II) in several water and foods samples. Complexes of metal ions with 8-hydroxyquinolein (8-HQ) were formed in aqueous solution. The proposed methodology is based on the preconcentration/separation of Pb(II) by solid-phase extraction using paper filter, followed by spectrofluorimetric determination of both metals, on the solid support and the filtered aqueous solution, respectively. The solid surface fluorescence determination was carried out at λem=455 nm (λex=385 nm) for Pb(II)-8-HQ complex and the fluorescence of Co(II)-8-HQ was determined in aqueous solution using λem=355 nm (λex=225 nm). The calibration graphs are linear in the range 0.14-8.03×10(4) μg L(-1) and 7.3×10(-2)-4.12×10(3) μg L(-1), for Pb(II) and Co(II), respectively, with a detection limit of 4.3×10(-2) and 2.19×10(-2) μg L(-1) (S/N=3). The developed methodology showed good sensitivity and adequate selectivity and it was successfully applied to the determination of trace amounts of lead and cobalt in tap waters belonging of different regions of Argentina and foods samples (milk powder, express coffee, cocoa powder) with satisfactory results. The new methodology was validated by electrothermal atomic absorption spectroscopy with adequate agreement. The proposed methodology represents a novel application of fluorescence to Pb(II) and Co(II) quantification with sensitivity and accuracy similar to atomic spectroscopies.
在本研究中，开发了一种新方法用于分离和预富集多种水和食品样品中的铅（II）和钴（II）。金属离子与8 - 羟基喹啉（8 - HQ）在水溶液中形成配合物。所提出的方法基于使用纸质过滤器通过固相萃取预富集/分离铅（II），随后分别在固体载体和过滤后的水溶液中通过荧光光谱法测定这两种金属。对于Pb（II） - 8 - HQ配合物，在λem = 455 nm（λex = 385 nm）处进行固体表面荧光测定，而Co（II） - 8 - HQ的荧光则在水溶液中使用λem = 355 nm（λex = 225 nm）进行测定。铅（II）和钴（II）的校准曲线分别在0.14 - 8.03×10⁴ μg L⁻¹和7.3×10⁻² - 4.12×10³ μg L⁻¹范围内呈线性，检测限分别为4.3×10⁻²和2.19×10⁻² μg L⁻¹（S/N = 3）。所开发的方法具有良好的灵敏度和足够的选择性，并成功应用于测定阿根廷不同地区的自来水中以及食品样品（奶粉、速溶咖啡、可可粉）中的痕量铅和钴，结果令人满意。通过电热原子吸收光谱法对新方法进行了验证，结果吻合良好。所提出的方法代表了荧光在铅（II）和钴（II）定量分析中的一种新应用，其灵敏度和准确度与原子光谱法相似。
