The molecular emission of BO and BO₂ radicals in laser-induced plasma has been investigated to analyze the boron isotopes in aqueous boric acid solution. The double-pulse laser configuration was employed to improve the detection sensitivity. The behaviors of molecular emissions were characterized depending on the interaction of sequentially configured lasers. Under the optimized conditions, the intensity of boron molecular emissions was significantly enhanced by about 10 times in comparison to that of the single-pulse configuration. The detection limit of boron in the aqueous solution was determined to be 72 ± 5 ppm. Furthermore, the isotopic shift between ¹⁰B and ¹¹B was observed at an individual rotational branch head. By utilizing these molecular emission spectra, the quantitative analysis of the isotopic ratio was conducted with partial least squares regression. In the cross-validation procedure, superior accuracy and precision were obtained. The root mean square error of prediction was 1.4% in the optimized spectral range. This study supports the understanding of molecular radical behavior according to the interaction of two sequential laser pulses and identifies the feasibility of molecular emission for real-time boron isotope detection in aqueous samples.

中文翻译：

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使用硼酸水溶液中双脉冲激光诱导等离子体的分子发射进行硼同位素分析

研究了激光诱导等离子体中BO和BO ₂自由基的分子发射，以分析硼酸水溶液中的硼同位素。采用双脉冲激光配置以提高检测灵敏度。分子发射的行为取决于顺序配置的激光器之间的相互作用。在最佳条件下，与单脉冲配置相比，硼分子发射强度显着提高了约10倍。测定水溶液中的硼的检出限为72±5ppm。此外，同位素在¹⁰ B和¹¹之间移动在单个旋转分支头处观察到B。通过利用这些分子发射光谱，利用偏最小二乘回归进行了同位素比的定量分析。在交叉验证过程中，获得了卓越的准确性和精度。在最佳光谱范围内，预测的均方根误差为1.4％。这项研究支持根据两个连续激光脉冲的相互作用来了解分子自由基的行为，并确定了用于实时检测含水样品中硼同位素的分子发射的可行性。