原子荧光光谱法测定萤石中的微量铅

以铁氰化钾–盐酸羟胺体系代替铁氰化钾–草酸体系,建立原子荧光法测定萤石中铅含量的方法。对实验条件进行了优化,在负高压280 V,灯电流65 m A,原子化高度8 mm,还原剂3%硼氢化钾溶液(含0.5%Na OH),载流4%盐酸的工作条件下,铁氰化钾–盐酸羟胺体系有明显的增感作用。样品中Ca~(2+)含量在4 g/L之内不影响铅的测定,溶解阶段通过高氯酸冒烟赶尽HF排除氟离子的干扰,并加入硫氰酸钠–邻菲罗啉消除铁和铜等离子的干扰。测定铅的线性范围为0~80 ng/L,相关系数r=0.999 6,方法检出限为0.187μg/L,测定结果的相对标准偏差为0.25%~1.40%(n=12),加标回收率为97.8%~104.5%。该方法测定结果与电感耦合等离子体原子发射光谱法测定结果相符。原子荧光光谱法快速准确,基体干扰少,灵敏度高。

Determination of Trace Lead in Fluorite by Atomic Fluorescence Spectrometry

Lead in in fluorite was determined by atomic fluorescence method with potassium ferricyanide -hydroxylamine hydrochloride system instead of potassium ferricyanide-oxalic acid.The experiment conditions were optimized.Potassium ferricyanide-hydroxylamine hydrochloride had sensitization significantly under the working conditions with negative high voltagewhich of 280 V,lamp current of 65 mA,the atomic height of 8 mm,3％ potassium borohydride reducing agent solution (containing 0.5％ NaOH),carrying 4％ hydrochloric acid.Ca2+ which content within 4 g / L did not affect the determination of lead.During the dissolution stage fluoride ions interference was eliminated by adding perchloric acid to drive HF,and the interference of iron and copper were eliminated by adding sodium thiocyanate phenanthroline.The linear range of lead detection was 0-80 ng/L,linear correlation coefficient was 0.999 6.The detection limit was 0.187 μμ g/L,the relative deviation of detection results was 0.25％-1.40％ (n=12),the recovery rate was 97.8％-104.5％.The results detected by the method were consistent with those detected by inductively coupled plasma atomic emission spectrometry (ICP-AES).The atomic fluorescence method is fast and accurate,has low interference and high sensitivity.