原子吸收光谱Atomic absorption spectroscopy

原子能级分立，吸收线极窄（约 0.002 nm），所以必须用发射同种元素锐线光谱的光源——空心阴极灯（阴极由待测元素制成）。原子化方式：火焰原子化（空气-乙炔约 2300 °C，氧化亚氮-乙炔约 2900 °C 用于难熔元素），检出限 mg/L 至 μg/L 级；石墨炉原子化（电热升温至约 2500–3000 °C，样品全部原子化），检出限可达 μg/L 至 ng/L 级；氢化物发生法用于 As、Se、Sb、Hg（冷原子吸收）。背景干扰用氘灯或塞曼效应校正。

Atomic levels are discrete and absorption lines extremely narrow (about 0.002 nm), so a source emitting the same element's sharp lines is needed: the hollow-cathode lamp, whose cathode is made of the analyte element. Atomisation is by flame (air–acetylene at about 2300 °C, or nitrous oxide–acetylene at about 2900 °C for refractory elements), with detection limits from mg/L to μg/L, or by graphite furnace (electrically heated to about 2500–3000 °C, atomising the whole sample), reaching μg/L to ng/L; hydride generation serves As, Se and Sb, and cold vapour Hg. Background is corrected with a deuterium lamp or the Zeeman effect.

1802 年沃拉斯顿、1814 年夫琅禾费观察到太阳光谱中的暗线，1859 年基尔霍夫解释为太阳大气中原子对特征光的吸收。1955 年澳大利亚联邦科学与工业研究组织（CSIRO）的物理学家艾伦·沃尔什提出原子吸收光谱分析法并研制出仪器，1962 年商品化，迅速成为测定金属元素最常用的方法。

Wollaston (1802) and Fraunhofer (1814) saw dark lines in the solar spectrum, which Kirchhoff explained in 1859 as absorption by atoms in the Sun's atmosphere. In 1955 the physicist Alan Walsh at Australia's CSIRO proposed atomic absorption analysis and built an instrument; commercialised in 1962, it rapidly became the commonest method for metals.

可测定约 70 种金属和部分非金属元素，用于饮用水和环境样品中的重金属（Pb、Cd、Hg、Cr、As）、食品和土壤中的微量元素、血液铅和尿中重金属的临床检测、合金和矿石分析、石油中的金属催化剂毒物。缺点是一般只能逐个元素测定，多元素同时分析逐渐被 ICP-OES 和 ICP-MS 取代。

AAS determines about 70 metals and some non-metals: heavy metals (Pb, Cd, Hg, Cr, As) in drinking water and environmental samples, trace elements in food and soil, blood lead and urinary heavy metals in clinical testing, alloys and ores, and metal catalyst poisons in petroleum. It generally measures one element at a time, so multi-element work is increasingly done by ICP-OES and ICP-MS.