微波消化-固相萃取光度法测定烟草中的铁

Microwave Digestion and Solid Phase Extraction Spectrophotometric Determination of Iron in Tobacco

研究了用微波消化 ,α ,α’ 连吡啶固相萃取光度法测定烟草中的铁 ,烟草样品用微波消化后 ,消化液中的铁可在pH为 4.0的HAc NaAc缓冲介质中与α ,α’ 连吡啶反应生成 3∶1稳定络合物 ,该络合物可被C1 8固相萃取小柱萃取 ,小柱上富集的络合物用乙醇洗脱后用光度法测定 ,体系λmax =5 15nm ,ε =8.2 3× 10 3L·mol- 1 ·cm- 1 。铁含量在 0～ 5 μg/mL内符合比尔定律 。

The color reaction of iron with dipyridyl was studied. In the presence of pH 4.0 buffer solutions, dipyridyl can react with iron(II) to form a stable 3:1 complex. This complex was enriched by solid phase extraction with C18 cartridge and eluted the retained chelate from cartridge by ethanol. The molar absorptivity is 8.23(103 L.mol-1.cm-1 at 515 nm. Beer's law is obeyed in range of 0-5 (g/mL. This method can be applied to the determination of iron in tobacco with satisfactory results.