Facilitating Absorption Spectroscopy of Strongly Absorbing Fluids: A High-Throughput Approach

Measuring absorption spectra of strongly absorbing solutions is usually only possible by diluting the solution. However, the absorption spectra can be heavily influenced by concentration-dependent interactions, so dilution leads to misleading results. To enable reliable absorption measurements of concentrated solutions, we introduce in this work thinning fluid film spectroscopy (TFFS), a simple and highly automatable method. We present three exemplary measurement modes of TFFS suitable for many different applications and validate the TFFS measurements with control data obtained in specialized, low optical path length cuvettes. Additionally, we compare the suitability of the different measurement modes over a broad concentration range and demonstrate the automation possibilities with a spectroscopy robot. Beyond this automated approach for highly efficient and high-throughput lab work, we also show the possibility of direct integration into production systems with an in-line setup, which can be incorporated into a variety of pipe systems. The TFFS method is not limited to samples from material science but can be transferred to a broad variety of research and industry fields, including proteins, food, and pharmaceuticals or also agriculture and forensics.对于强吸收溶液的吸收光谱测量，常规手段通常仅能通过稀释溶液实现。然而，吸收光谱极易受到浓度依赖相互作用的影响，稀释操作会得到误导性结果。为实现浓溶液的可靠吸收光谱测量，本研究提出了薄层液膜光谱法（thinning fluid film spectroscopy, TFFS），这是一种简便且高度自动化的检测方法。本研究展示了三种适用于多类应用场景的TFFS典型测量模式，并通过专用极短光程比色皿获取的对照数据，对TFFS的测量结果进行了验证。此外，本研究在宽浓度范围内对比了不同测量模式的适用性，并借助光谱机器人展示了该方法的自动化实现潜力。除可支撑高效、高通量的实验室自动化工作外，本研究还展示了通过在线装置将该方法直接集成至生产系统的可能性，该装置可适配多种管道系统。TFFS方法不仅局限于材料科学领域的样品检测，还可推广至众多研究与工业场景，涵盖蛋白质、食品、制药、农业及法医学领域。