Gonzalez Jhanis J, Liu Chunyi, Wen Sy-Bor, Mao Xianglei, Russo Richard E
Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Talanta. 2007 Sep 30;73(3):567-76. doi: 10.1016/j.talanta.2007.04.029. Epub 2007 May 4.
Pulsed laser ablation (266nm) was used to generate metal particles of Zn and Al alloys using femtosecond (150fs) and nanosecond (4ns) laser pulses with identical fluences of 50Jcm(-2). Characterization of particles and correlation with inductively coupled plasma mass spectrometer (ICP-MS) performance was investigated. Particles produced by nanosecond laser ablation were mainly primary particles with irregular shape and hard agglomerates (without internal voids). Particles produced by femtosecond laser ablation consisted of spherical primary particles and soft agglomerates formed from numerous small particles. Examination of the craters by white light interferometric microscopy showed that there is a rim of material surrounding the craters formed after nanosecond laser ablation. The determination of the crater volume by white light interferometric microscopy, considering the rim of material surrounding ablation craters, revealed that the volume ratio (fs/ns) of the craters on the selected samples was approximately 9 (Zn), 7 (NIST627 alloy) and 5 (NIST1711 alloy) times more ablated mass with femtosecond pulsed ablation compared to nanosecond pulsed ablation. In addition, an increase of Al concentration from 0 to 5% in Zn base alloys caused a large increase in the diameter of the particles, up to 65% while using nanosecond laser pulses. When the ablated particles were carried in argon into an ICP-MS, the Zn and Al signals intensities were greater by factors of approximately 50 and approximately 12 for fs versus ns ablation. Femtosecond pulsed ablation also reduced temporal fluctuations in the (66)Zn transient signal by a factor of 10 compared to nanosecond laser pulses.
使用脉冲激光烧蚀（266nm），利用飞秒（150fs）和纳秒（4ns）激光脉冲，在相同能量密度50Jcm⁻²的条件下生成锌铝合金的金属颗粒。研究了颗粒的表征及其与电感耦合等离子体质谱仪（ICP-MS）性能的相关性。纳秒激光烧蚀产生的颗粒主要是形状不规则的初级颗粒和硬团聚体（内部无空隙）。飞秒激光烧蚀产生的颗粒由球形初级颗粒和由许多小颗粒形成的软团聚体组成。通过白光干涉显微镜对坑洼进行检查表明，纳秒激光烧蚀后形成的坑洼周围有一圈物质边缘。考虑到烧蚀坑洼周围的物质边缘，通过白光干涉显微镜测定坑洼体积，结果显示，与纳秒脉冲烧蚀相比，选定样品上飞秒脉冲烧蚀的坑洼体积比（fs/ns）分别约为锌的9倍、NIST627合金的7倍和NIST1711合金的5倍，即飞秒脉冲烧蚀的烧蚀质量更大。此外，在锌基合金中，铝浓度从0%增加到5%会导致颗粒直径大幅增加，使用纳秒激光脉冲时直径增加高达65%。当烧蚀颗粒被氩气携带进入ICP-MS时，与纳秒烧蚀相比，飞秒烧蚀的锌和铝信号强度分别大约高50倍和大约12倍。与纳秒激光脉冲相比，飞秒脉冲烧蚀还将⁶⁶Zn瞬态信号的时间波动降低了10倍。
