室温离子液体萃取-石墨炉原子吸收光谱法测定超痕量钼

Room temperature ionic liquid extraction combined with graphite furnace atomic absorption spectrometry for determination of ultra trace molybdenum

合成一种室温离子液体1-辛基-3-甲基咪唑六氟磷酸盐（[C8mim][PF6]），替代挥发性有机溶剂用于金属离子的液／液萃取。在阳离子表面活性剂CTMAB存在下，钼（Ⅵ）与新合成的试剂5-对甲氧基苯基偶氮水杨基荧光酮（P—MOPASF）反应形成稳定的红色络合物。在显色后的溶液中，加入室温离子液体1-辛基-3-甲基咪唑六氟磷酸盐后，钼络合物被迅速萃入离子液体相。然后，用4．0mol／LNaOH溶液将钼（Ⅵ）从离子液体相反萃取至水中，此反萃液直接应用于石墨炉原子吸收光谱法测定钼。钼一次萃取率接近100％，富集倍数达100倍以上。室温离子液体萃取-石墨炉原子吸收光谱法成功地应用于环境水样中超痕量钼的测定，平均回收率为95．0％～105．5％。

1-octyl-3-methylimidazolium hexafluorophosphate （[C8 mim] [PF6 ]） was synthesized as a room temperature ionic liquid in this study. It can be applied to liquid/liquid extraction of metal ions as a substitute of traditional volatile organic solvent. In the presence of cationic surfactant CTMAB, molybdenum（VD reacted with a new synthetic reagent 5-p-methoxyphenylazosalicylfluorone （p-MOPASF） sensitively to form a stable red molybdenum complex. After the reaction completed, the complex was extracted into ionic liquid phase rapidly from aqueous phase after room temperature ionic liquid （[C8mim][PF6]） was added. Molybdenum（VD was then back-extracted into aqueousphase with 4.0 mol/L sodium hydroxide,and the aqueous phase was directly applied to determine the amounts of molybdenum by graphite furnace atomic absorption spectrometry. The extraction efficiency of molybdenum in one step extraction is about 100% and its enrichment factor is more than 100 times. The extraction combined with graphite furnace atomic absorption spectrometry has been applied to determine ultra trace amounts of molybdenum in environmental water with the average recovery of 95. 0- 105.5 %.