In this work, a novel solid sampling method of Cd in grain samples was established based on electrothermal vaporization atomic absorption spectrometry (ETV-AAS). The solid sampling system was mainly composed of a quartz ETV tube, a pyrolysis furnace with a kaolin filler, an integrated outlet tube (IOT), an AAS detector and a gas generation system. The gas system generated oxidizing (containing O₂) and reducing (containing H₂ and N₂) atmospheres, in that order, from only air and water to ash the sample and vaporize and transport Cd, respectively. After drying at 350 °C for 20 s and ashing at 350–725 °C for 55 s under a 300 mL min⁻¹ air atmosphere, ∼4.5% Cd was pre-vaporized and then captured by the kaolin filler at 700–850 °C; when H₂ was introduced at 350 mL min⁻¹ to react with O₂ in the air to yield a N₂/H₂ atmosphere, Cd in the sample residue and that captured on the filler were completely vaporized from 725 °C to 800 °C (50 s ETV) and then detected by N₂/H₂ flame AAS. Under optimum conditions, the detection limit (LOD) was 0.03 ng with <10% relative standard deviation (RSD), namely 0.15 ng g⁻¹ for a 200 mg sample. The method was validated using certified reference materials (CRMs) and the Cd concentrations that were measured agreed with the certified values, and these were consistent with those obtained by microwave digestion graphite furnace AAS; furthermore, the recoveries were 95–103% for a series of real grain samples. The instrumental analytical time could be controlled within 3 min and the overall analysis time, including sample preparation time, within 10 min without the acid digestion process. The proposed solid sampling Cd analysis is thus suitable for fast detection of Cd in grain samples.

中文翻译：

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新型固体样品电热汽化原子吸收光谱法可快速检测谷物样品中的镉

在这项工作中，建立了一种基于电热汽化原子吸收光谱法（ETV-AAS）的谷物样品中镉的固体采样新方法。固体采样系统主要由石英ETV管，带高岭土填料的热解炉，集成出口管（IOT），AAS检测器和气体生成系统组成。气体系统仅从空气和水中依次产生氧化（含O ₂）和还原（含H ₂和N ₂）气氛，以灰化样品并汽化和运输Cd。在350°C下干燥20 s，并在300 mL min ^-1空气气氛下于350–725°C灰化55 s后，将约4.5％的Cd预蒸发，然后在700–850°C被高岭土填料捕获C; 当H₂在350毫升min导入^-1带O反应₂在空气中，以产生A N ₂ / H ₂在样品残留气氛，Cd和其上的填料捕获完全从725℃蒸发至800℃（ 50秒ETV），然后通过N ₂ / H ₂火焰原子吸收光谱法检测。在最佳条件下，检出限（LOD）为0.03 ng，相对标准偏差（RSD）<10％，即0.15 ng g ^-1200毫克样品 该方法已通过认证的参考物质（CRM）进行了验证，所测Cd浓度与认证值相符，并且与通过微波消解石墨炉AAS获得的浓度一致。此外，一系列真实谷物样品的回收率为95–103％。仪器的分析时间可以控制在3分钟以内，总分析时间（包括样品制备时间）可以控制在10分钟以内，而无需进行酸消化过程。因此，建议的固体采样Cd分析适用于谷物样品中Cd的快速检测。