Goswami Anupama, Singh Ajai K, Venkataramani B
Department of Chemistry, Indian Institute of Technology, New Delhi, India.
Talanta. 2003 Aug 29;60(6):1141-54. doi: 10.1016/S0039-9140(03)00218-2.
The silica gel modified with (3-aminopropyl-triethoxysilane) was reacted with 5-formyl-8-hydroxyquinoline (FHOQ(x)) to anchor 8-quinolinol ligand on the silica gel. It was characterised with cross polarisation magic angle spinning (CPMAS) NMR and diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy and used for the preconcentration of Cu(II), Pb(II), Ni(II), Fe(III), Cd(II), Zn(II) and Co(II) prior to their determination by flame atomic absorption spectrometry. The surface area of the modified silica gel has been found to be 227 m(2) g(-1) and the two pKa values as 3.8 and 8.0. The optimum pH ranges for quantitative sorption are 4.0-7.0, 4.5-7.0, 3.0-6.0, 5.0-8.0, 5.0-8.0, 5.0-8.0 and 4.0-7.0 for Cu, Pb, Fe, Zn, Co, Ni and Cd, respectively. All the metals can be desorbed with 2.5 mol l(-1) HCl or HNO(3). The sorption capacity for these metal ions is in range of 92-448.0 micromol g(-1) and follows the order Cd<Pb<Zn<Co<Ni<Fe<Cu. Tolerance limits for electrolytes NaNO(3,) NaCl, NaBr, Na(2)SO(4) and Na(3)PO(4), glycine, sodium citrate, EDTA, humic acid and cations Ca(II), Mg(II), Mn(II) and Cr(III) in the sorption of all the seven metal ions are reported. The preconcentration factors are 150, 250, 200, 300, 250, 300 and 200 for Cd, Co, Zn, Cu, Pb, Fe and Ni, respectively and t(1/2) values <1 min except for Ni. The 95% extraction by batch method takes < or =25 min. The simultaneous enrichment and determination of all the metals are possible if the total load of the metal ions is less than sorption capacity. In river water samples all these metal ions were enriched with the present ligand anchored silica gel and determined with flame atomic absorption spectrometer (R.S.D.< or =6.4%). Cobalt contents of pharmaceutical samples (vitamin tablet) were preconcentrated with the present chelating silica gel and estimated by flame AAS, with R.S.D. approximately 1.4%. The results are in the good agreement with the certified value, 1.99 microg g(-1) of the tablets. Iron and copper in certified reference materials (synthetic) SLRS-4 and SLEW-3 have been enriched with the modified silica gel and estimated with R.S.D.<5%.
用（3-氨丙基-三乙氧基硅烷）改性的硅胶与5-甲酰基-8-羟基喹啉（FHOQ(x)）反应，将8-喹啉醇配体锚定在硅胶上。通过交叉极化魔角旋转（CPMAS）核磁共振和漫反射红外傅里叶变换（DRIFT）光谱对其进行了表征，并用于在火焰原子吸收光谱法测定之前对Cu(II)、Pb(II)、Ni(II)、Fe(III)、Cd(II)、Zn(II)和Co(II)进行预富集。已发现改性硅胶的表面积为227 m² g⁻¹，两个pKa值分别为3.8和8.0。Cu、Pb、Fe、Zn、Co、Ni和Cd定量吸附的最佳pH范围分别为4.0 - 7.0、4.5 - 7.0、3.0 - 6.0、5.0 - 8.0、5.0 - 8.0、5.0 - 8.0和4.0 - 7.0。所有金属都可用2.5 mol l⁻¹ HCl或HNO₃解吸。这些金属离子的吸附容量在92 - 448.0 μmol g⁻¹范围内，顺序为Cd<Pb<Zn<Co<Ni<Fe<Cu。报道了在所有七种金属离子吸附过程中电解质NaNO₃、NaCl、NaBr、Na₂SO₄和Na₃PO₄、甘氨酸、柠檬酸钠、EDTA、腐殖酸以及阳离子Ca(II)、Mg(II)、Mn(II)和Cr(III)的耐受极限。Cd、Co、Zn、Cu、Pb、Fe和Ni的预富集因子分别为150、250、200、300、250、300和200，除Ni外t(1/2)值<1分钟。分批法95%的萃取时间<或 =25分钟。如果金属离子的总负载量小于吸附容量，则可以同时富集和测定所有金属。在河水样品中，所有这些金属离子都用本研究中配体锚定的硅胶进行了富集，并用火焰原子吸收光谱仪进行了测定（相对标准偏差<或 =6.4%）。药物样品（维生素片）中的钴含量用本研究中的螯合硅胶进行了预富集，并通过火焰原子吸收光谱法进行了估算，相对标准偏差约为1.4%。结果与片剂的认证值1.99 μg g⁻¹高度吻合。认证参考物质（合成）SLRS - 4和SLEW - 3中的铁和铜已用改性硅胶进行了富集，并以相对标准偏差<5%进行了估算。
