共沉淀法辅助分离-离子色谱与电感耦合等离子体质谱联用测定玩具材料中三价铬及超痕量六价铬

Determination of Cr( Ⅲ) and Ultratrace Cr( Ⅵ) in Toy Materials by Co-precipitation Assisted Separation-Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry

采用0.07 mol/L盐酸萃取样品,取一部分萃取液用电感耦合等离子体质谱法（ICP-MS）测定可迁移总铬含量,另一部分萃取液通过Al（NO3）3共沉淀法去除高含量干扰阳离子后用离子色谱-电感耦合等离子体质谱联用法（IC-ICP-MS）测定六价铬（Cr（Ⅵ））含量,用可迁移总铬量减去Cr（Ⅵ）含量求得Cr（Ⅲ）含量,可迁移总铭及Cr（Ⅵ）的方法定量下限分别达0.01 mg/kg和0.003 mg/kg。选取2009/48/EC玩具新指令涉及的玩具材料进行加标及阳性样品验证,可迁移总铭及Cr（Ⅵ）的加标回收率分别为90.2%～101.5%和96.7%～106.7%,实验室间相对标准偏差分别不高于7.4%和7.9%。方法准确可靠,可实现玩具新指令所涉及的3类玩具材料中Cr（Ⅲ）及Cr（Ⅵ）的检测。

The sample was extracted with 0. 07 mol / L hydrochloric acid. Migratable chromium in the extract was determined by inductively coupled plasma mass spectrometry（ ICP- MS）. Some other extract was taken and the high content of interferential positive ions was removed by co-precipitation method with aluminium nitrate. Then Cr（ Ⅵ） in the extract was determined by ion chromatography-inductively coupled plasma mass spectrometry（ IC- ICP- MS）. Cr（ Ⅲ） content was obtained by minusing Cr（ Ⅵ） content from the total migratable chromium content（ Cr（ Total））. The method quantitation limit for Cr（ Total） and Cr（ Ⅵ） reached to 0. 01 mg / kg and 0. 003 mg / kg,respectively. The method was then validated by conducting standard- addition experiments to the difference categories of toy materials according to Toy Safety Directive 2009 /48 / EC. The recoveries of Cr（ Total） and Cr（ Ⅵ） from the standard- addition experiments were in the ranges of 90. 2%- 101. 5% and 96. 7%-106. 7%,respectively,and the inter-laboratory relative standard deviations were less than 7. 4% and7. 9%,respectively. Therefore, the method was concluded to be accurate and reliable, which could satisfy the requirements of Cr（ Ⅲ） and Cr（ Ⅵ） in 3 categories of toy materials of Toy Safety Directive.