Department of Chemistry and Biochemistry and International Forensic Research Institute, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA.
Anal Chem. 2012 Mar 6;84(5):2239-44. doi: 10.1021/ac202834j. Epub 2012 Feb 10.
Laser induced breakdown spectroscopy (LIBS) is shown to be capable of low volume (90 pL) quantitative elemental analysis of picogram amounts of dissolved metals in solutions. Single-pulse and collinear double-pulse LIBS were investigated using a 532 nm dual head laser coupled to a spectrometer with an intensified charge coupled device (CCD) detector. Aerosols were produced using a micronebulizer, conditioned inside a concentric spray chamber, and released through an injector tube with a diameter of 1 mm such that a LIBS plasma could be formed ~2 mm from the exit of the tube. The emissions from both the aerosols and a single microdrop were then collected with a broadband high resolution spectrometer. Multielement calibration solutions were prepared, and continuing calibration verification (CCV) standards were analyzed for both aerosol and microdrop systems to calculate the precision, accuracy, and limits of detection for each system. The calibration curves produced correlation coefficients with R(2) values > 0.99 for both systems. The precision, accuracy, and limit of detection (LOD) determined for aerosol LIBS were averaged and determined for the emission lines of Sr II (421.55 nm), Mg II (279.80 nm), Ba II (493.41 nm), and Ca II (396.84 nm) to be ~3.8% RSD, 3.1% bias, 0.7 μg/mL, respectively. A microdrop dispenser was used to deliver single drops containing 90 pL into the space where a LIBS plasma was generated with a focused laser pulse. In the single drop microdrop LIBS experiment, the analysis of a single drop, containing a total mass of 45 pg, resulted in a precision of 13% RSD and a bias of 1% for the Al I (394.40 nm) emission line. The absolute limits of detection of single drop microdrop LIBS for the emission lines Al I (394.40 nm) and Sr II (421.5 nm) were approximately 1 pg, and Ba II (493.41 nm) produced an absolute detection limit of approximately 3 pg. Overall, the precision, accuracy, and absolute LOD determined for single microdrop LIBS resulted in a typical performance of ~14% RSD, 6% bias, and 1 pg for the elements Sr II (421.55 nm), Al I(394.40 nm), Mg II (279.80), and Ba II(493.41 nm).
激光诱导击穿光谱（LIBS）被证明能够对溶解在溶液中的纳克级微量金属进行低体积（90 微升）定量元素分析。使用耦合到带有增强电荷耦合器件（CCD）检测器的光谱仪的 532nm 双头激光器研究了单脉冲和共线双脉冲 LIBS。气溶胶是通过微喷射器产生的，在同心喷雾室中进行调节，并通过直径为 1mm 的注射器管释放，以便在管出口处形成 LIBS 等离子体2mm。然后，使用宽带高分辨率光谱仪收集气溶胶和单个微滴的发射。制备多元素校准溶液，并对气溶胶和微滴系统进行持续校准验证（CCV）标准分析，以计算每个系统的精密度、准确度和检测限。为气溶胶 LIBS 生成的校准曲线的相关系数 R²值均大于 0.99。气溶胶 LIBS 的精密度、准确度和检测限（LOD）平均值分别为 Sr II（421.55nm）、Mg II（279.80nm）、Ba II（493.41nm）和 Ca II（396.84nm）发射线的 3.8%RSD、3.1%偏差和 0.7μg/mL。使用微滴分配器将含有 90 微升的单个液滴滴入聚焦激光脉冲产生 LIBS 等离子体的空间。在单滴微滴 LIBS 实验中，分析单个液滴，其中总质量为 45pg，得到 Al I（394.40nm）发射线的精密度为 13%RSD 和 1%偏差。单滴微滴 LIBS 的单滴 Al I（394.40nm）和 Sr II（421.5nm）发射线的绝对检测限约为 1pg，而 Ba II（493.41nm）的绝对检测限约为 3pg。总体而言，单微滴 LIBS 确定的精密度、准确度和绝对 LOD 导致 Sr II（421.55nm）、Al I（394.40nm）、Mg II（279.80nm）和 Ba II（493.41nm）等元素的典型性能为14%RSD、6%偏差和 1pg。
