中文摘要：

本研究基于微芯片设计了一个纳流动注射系统。将样品装载到芯片的采样通道,通过八通阀的阀位切换实现纳升试样带注射到等离子体质谱。注射体积取决于采样通道的尺寸,5～25 mm长的采样通道引入试样体积为40～200 nL。此纳流动注射系统具有试样消耗低、进样精度高（优于3.0%）、进样死体积极低（接近零）和加工简便等优点。芯片纳流动注射系统的进样量和载流流速分别为200 nL和20!L/min,可获得峰高最强、峰宽较窄的瞬时信号峰。最佳条件下纳流动注射系统的绝对检出限为2.54 fg,比常规进样系统改善了3244倍,样品通量48 h＂1。10次测定20!g/L Pt标准溶液和血浆样品S1的精密度分别为1.5%和2.7%。采用纳流动注射系统和常规进样系统测定的6个血浆中Pt含量一致,加标回收率为94.3%～103.0%,表明前者具有很好的准确性。

英文摘要：

A microfluidic chip-based nanoflow injection system was designed for inductively coupled plasma mass spectrometry （ICP-MS）. The sample plug loaded into the sampling channel in the microehip was driven into ICP-MS as soon as the multi-functionM valve was changed from the load position to the inject position. The sample plug depends on the sampling channel. 40-200 nL sample was introduced into ICP-MS with the sampling channel length of 5-25 ram. The proposed microchip-based nanoflow injection system offers many advantages including low sample consumption, satisfactory precisions （ less than 3.0% ） , low sampling dead volume （ nearly zero） and easy fabrication. With 200 nL sampling volume and a flow rate of 20 ~tL/min for the carrier, a peak profile with the highest peak height within the shortest time was obtained. The absolute detec- tion limit of the chip-based nanoflow injection system for 195pt was 2.54 fg under optimized conditions, which was improved by a factor of 3244 in comparison with the conventional sampling system. A sample throughput of 48 h-1 was obtained with the nanoflow injection system. Relative standard deviations of peak heights of 10 replicate trims of 10 ~tg/L standard solution and the human plasma sample $1 were 1.5% and 2.7% , respec- tively. Contents of platinum in six human plasma samples by the proposed method agreed well with those by the conventional sampling system, and the recoveries of six plasma samples ranged between 94. 3% and 103.0%. These results indicate the accuracy of the present method.