Tea ash is the inorganic residue of tea after a series of chemical and physical reactions under high temperature environment. The compositions of tea and ash are very different. In addition, the compositions of ash are closely related to the quality of tea. In this work, the compositions of Tieguanyin tea and ash were analyzed by laser-induced breakdown spectroscopy (LIBS), and the differences of elements in tea and ash were analyzed qualitatively. Tea contains the main elements, such as Ca, Na, Mg, and K, trace elements Fe, Cu, Zn, Mn and Sr, and other metallic elements Al, Li and Ba. Comparing the atomic and ionic lines in LIBS spectra of tea and ash, it was found that the spectral line intensities of metallic elements, i.e. Ca, Al, Mn, Mg, K, Na, Li, in the ash were significantly enhanced. In addition, there were CN, C₂ and CaO molecular lines in the LIBS spectra of tea, but only CaO free radical was detected in the LIBS spectra of ash. The reason of the differences between the molecular lines of LIBS spectra of tea and ash was analyzed. This work is to determine the material compositions of tea and ash, which provides a basic foundation for the quality judgment of tea and a new idea for the enrichment detection of metallic elements.

中文翻译：

---

激光诱导击穿光谱法研究铁观音茶和灰分的光谱

茶灰是茶叶在高温环境下经过一系列化学和物理反应后的无机残留物。茶和灰的成分有很大不同。此外，灰分的成分与茶叶的品质密切相关。本工作采用激光诱导击穿光谱法（LIBS）对铁观音茶和灰分的成分进行了分析，定性分析了茶和灰分中元素的差异。茶叶中含有主要元素Ca、Na、Mg、K，微量元素Fe、Cu、Zn、Mn、Sr，以及其他金属元素Al、Li、Ba。比较茶叶和灰分的LIBS光谱中的原子线和离子线，发现灰分中金属元素Ca、Al、Mn、Mg、K、Na、Li的谱线强度显着增强。另外，茶叶的LIBS光谱中存在CN、C ₂和CaO分子线，而灰分的LIBS光谱中仅检测到CaO自由基。分析了茶和灰的LIBS光谱分子谱线差异的原因。本工作测定了茶叶和灰分的物质成分，为茶叶的品质判断提供了基础依据，也为金属元素的富集检测提供了新思路。