Development of new calibration procedures in Micro X-Ray Fluorescence (MXRF) using Thermal Inkjet Picofluidic System (TIPS) delivering droplets of picoliter volume, and their application for the characterization of aerosol particulate matter

全反射x射线荧光（TXRF）是测定样品材料有限的痕量和超痕量元素的一种有效方法。该方法的一个主要缺点是分析对样品形态特别敏感。这阻碍了对复杂基质样品（如尿液、血液）的直接分析。通常微升体积用于存放液体样品材料。由于对干燥过程的控制有限，这些样品通常受到标准物和分析物分布不均匀的影响，并且很容易超过用TXRF进行精确分析所需的临界厚度（约4 μm）。因此，在本研究中，我们评估了具有复杂基质样品的样品制备（例如，与马里兰州Gaithersburg国家标准与技术研究所合作的尿液），使用原型热喷墨Picofluidic系统（TIPS）提供皮升体积（1-200 pL）进行直接TXRF分析。TIPS仅在洛斯阿拉莫斯国家实验室提供，并已在本研究停留的第一部分中用于制备微x射线荧光（MXRF）参考文献。将使用原子力显微镜（AFM）和MXRF（焦斑10 μm）研究样品形貌和化学均匀性等基本参数。由于新的样品制备工艺证明了它的价值，TIPS将被集成到一个原型掠入射单色微XRF （GI-MMXRF）仪器中。然后将对该原型进行评估，以便对各种样品进行快速可靠的分析。

Total Reflection X-Ray Fluorescence (TXRF) is a powerful method for determination of traces and ultra traces of elements where sample material is limited. One major drawback of the method is that the analysis is especially sensitive for the sample morphology. This hampers the direct analysis of samples with a complex matrix (e.g. urine, blood). Commonly microliter volumes are used to deposit liquid sample material. As the control on the drying process is limited these specimens often suffer from inhomogeneous distribution of standard and analyte and easily exceed the critical thickness required for a precise analysis with TXRF (ca. 4 μm).Therefore in this study we evaluate specimen preparation of samples having a complex matrix (e.g. As in urine in a cooperation with the National Institute of Standards and Technology Gaithersburg, MD) using a prototype Thermal Inkjet Picofluidic System (TIPS) delivering picoliter volumes (1-200 pL) for direct TXRF analysis. The TIPS is exclusively available at the Los Alamos National Laboratory and has been introduced for the preparation of references in Micro X-Ray Fluorescence (MXRF) in the first part of this research stay.Essential parameters like sample morphology and chemical homogeneity, will be studied using Atomic Force Microscopy (AFM) and MXRF (focal spot 10 μm). Since the new sample preparation procedure proved its value, the TIPS will be integrated into a prototype grazing-incidence monochromatic micro XRF (GI-MMXRF) instrument. This prototype will then be evaluated for rapid and reliable analysis of various samples.