A novel analysis technique of elements at ambient conditions has been developed. The technique is based on microwave-assisted laser-induced breakdown spectroscopy (MW-LIBS) applied to acoustically levitated samples. The technique has been demonstrated using three solid samples with different properties and compositions. These are ore containing multiple elements (OREAS 520), aluminium oxide (Al₃O₂) and gypsum (CaSO₄·2H₂O). The mass of samples was 21 mg, 23 mg, and 55 mg for gypsum, mineral ore, and Al₃O₂, respectively. Significant signal enhancements were recorded for a variety of elements, using microwave-assisted laser-induced breakdown spectroscopy and levitation (MW-LIBS–Levitation). The signal enhancement for Mn I (403.07 nm), Al I (396.13 nm) and Ca II (393.85 nm) was determined as 123, 46, and 63 times, respectively. Moreover, it was found that MW-LIBS–Levitation minimises the self-absorption of the Ca I (422.67 nm) and Na I (588.99 nm and 589.59 nm) spectral lines. In addition to the signal enhancements, the levitation process produces a spinning motion in the solids with an angular frequency of 7 Hz. This feature benefits laser-based analysis as a fresh sample is introduced at each laser pulse, eliminating the need for the usual mechanical devices. Based on the single-shot analysis, it was found that ∼80% of the laser pulses produced successful MW-LIBS–Levitation detection, confirming an impressive repeatability of the process. This contactless analytical technique can be applied in ambient pressure and temperature conditions with high sensitivity, which can benefit disciplines such as forensics science, isotope analysis, and medical analysis, where the sample availability is often diminutive.

中文翻译：

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利用微波辅助激光诱导击穿光谱法对悬浮固体样品进行元素分析

已经开发出一种在环境条件下进行元素分析的新颖技术。该技术基于应用于声悬浮样品的微波辅助激光诱导击穿光谱 (MW-LIBS)。该技术已使用具有不同特性和成分的三种固体样品进行了演示。这些是含有多种元素的矿石(OREAS 520)、氧化铝(Al ₃ O ₂ )和石膏(CaSO ₄ ·2H ₂ O)。石膏、矿石和Al ₃ O ₂的样品质量分别为21 mg、23 mg和55 mg。使用微波辅助激光诱导击穿光谱和悬浮（MW-LIBS-Levitation）记录了多种元素的显着信号增强。 Mn I (403.07 nm)、Al I (396.13 nm) 和 Ca II (393.85 nm) 的信号增强分别为 123、46 和 63 倍。此外，我们发现MW-LIBS-悬浮最大限度地减少了Ca I（422.67 nm）和Na I（588.99 nm和589.59 nm）谱线的自吸收。除了信号增强之外，悬浮过程还会在固体中产生角频率为 7 Hz 的旋转运动。此功能有利于基于激光的分析，因为每个激光脉冲都会引入新鲜样品，从而无需通常的机械设备。基于单次分析，发现约 80% 的激光脉冲产生了成功的 MW-LIBS-悬浮检测，证实了该过程具有令人印象深刻的可重复性。这种非接触式分析技术可以在环境压力和温度条件下以高灵敏度应用，这有利于法证科学、同位素分析和医学分析等学科，这些领域的样品可用性通常很小。