原子发射光谱Atomic emission spectroscopy

每种元素有一组特征谱线，谱线波长用于定性，谱线强度与浓度成正比（罗马金-赛伯公式 I = a·cᵇ）用于定量。激发源包括火焰（火焰光度法，用于 Na、K、Li、Ca 等易激发碱金属和碱土金属）、电弧和电火花（金属和合金直读光谱）以及电感耦合等离子体（ICP）。ICP 炬管中的氩等离子体温度可达 6000–10000 K，原子化和激发完全、基体效应小、线性范围宽（4–6 个数量级），可同时测定 70 余种元素。

Each element has a set of characteristic lines; wavelengths identify it and intensities, proportional to concentration by the Lomakin–Scheibe equation I = a·cᵇ, quantify it. Sources include flames (flame photometry, for easily excited alkali and alkaline-earth metals such as Na, K, Li and Ca), arcs and sparks (direct-reading spectrometry of metals and alloys) and the inductively coupled plasma. The argon plasma in an ICP torch reaches 6000–10,000 K, atomising and exciting thoroughly with small matrix effects and a linear range of four to six orders of magnitude, so more than 70 elements can be measured at once.

1860 年本生和基尔霍夫发明光谱分析，发现了铯和铷。此后用光谱法发现了铊（1861）、铟（1863）、镓（1875）以及氦（1868 年在太阳光谱中发现）和多种稀有气体。1960 年代格林菲尔德和法赛尔分别把电感耦合等离子体用作原子发射光谱的激发源，1974 年 ICP 光谱仪商品化。

Bunsen and Kirchhoff invented spectral analysis in 1860 and discovered caesium and rubidium. Spectroscopy then revealed thallium (1861), indium (1863), gallium (1875), helium (in the solar spectrum, 1868) and several noble gases. In the 1960s Greenfield and Fassel independently adopted the inductively coupled plasma as an excitation source, and ICP spectrometers were commercialised in 1974.

ICP-OES 广泛用于环境水样、土壤、食品、地质矿样、稀土、贵金属、石油、电子材料和医药中多元素的快速同时测定；火花直读光谱用于钢铁冶炼现场炉前快速分析；火焰光度法用于临床血清钠钾测定。天文学通过恒星发射和吸收谱线确定其化学组成。

ICP-OES rapidly measures many elements at once in environmental waters, soils, foods, geological samples, rare earths, precious metals, petroleum, electronic materials and pharmaceuticals; spark direct-reading spectrometers analyse steel at the furnace; and flame photometry measures serum sodium and potassium clinically. Astronomers determine stars' composition from their emission and absorption lines.