A simple purification technique using an anion-exchange monolithic spin tip was described for the elimination of molybdenum oxyanion interfering with precise determination of cadmium in human urine samples by ICP-MS. The tip device named “anion-exchange tip-in monolith (AXTip)” was laboratory-prepared within the confines of a commercially available syringe filter tip by a two-step process: (1) in situ copolymerization of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) and (2) its subsequent modification with trimethylamine (TMA), as a strong anion-exchange functional group, via ring-opening reaction of epoxide. The adsorption capacity of the AXTip was > 3.2 μmol/tip for molybdenum oxyanion. The performance of the AXTip was evaluated through an adsorption/non-adsorption experiment for molybdenum, cadmium and other metal and metalloid species, using a model solution and human urine samples to optimize the sample solution's pH and dilution factor for the AXTip treatment. In the case of urine sample analysis, 8 times dilution and pH adjustment to 4.0 prior to AXTip treatment were found to allow > 98% elimination of interfering molybdenum oxyanions and quantitative recovery (103 ± 7%) of cadmium. At the optimized conditions, the AXTip treatment reduces Mo/Cd ratio from ~400 in human urines to < 10, which is sufficient for conducting ICP-MS measurement of cadmium in no-gas mode (without collision/reaction cell technique). The proposed purification technique was validated through the analysis of an accuracy control material of human urine (Seronorm™ Trace Elements Urine L-1). Good agreement of the observed values with the reference values indicates that the proposed technique is practically applicable.

描述了一种使用阴离子交换整体旋转尖头的简单纯化技术，该技术可消除ICP-MS干扰人尿样中的镉，从而消除了氧氧钼离子的干扰。在实验室中，通过两步过程，在市场上可买到的针筒式过滤器吸头的范围内，准备了名为“阴离子交换吸头整体式（AXTip）”的吸头装置：（1）原位共聚甲基丙烯酸缩水甘油酯（GMA）和乙烯二甲基丙烯酸酯（EDMA）和（2）它的后续修改与三甲胺（TMA），作为强阴离子交换官能团，通过环氧的开环反应。AXTip对钼氧阴离子的吸附容量> 3.2μmol/ tip。AXTip的性能通过对钼，镉以及其他金属和准金属物种的吸附/非吸附实验进行了评估，使用模型溶液和人尿液样品来优化AXTip处理的样品溶液的pH和稀释系数。在尿液样品分析的情况下，发现在AXTip处理之前进行8倍稀释并将pH值调节至4.0，可以消除> 98％的干扰性钼氧阴离子，并定量回收（103±7％）镉。在最佳条件下，AXTip处理可使人尿中的Mo / Cd比从约400降低到<10，在无气体模式下（无需碰撞/反应池技术）足以进行ICP-MS测定镉。通过对人类尿液的精确控制材料（Seronorm™微量元素尿液）进行分析，验证了所提出的纯化技术L -1）。观察值与参考值的良好吻合表明所提出的技术是实际可应用的。