A green analytical method for the determination of Cu and Zn in rice samples was developed. This method was based on an ozone-assisted extraction (OAE) in diluted acid media. A novel closed system was designed for this purpose that allowed four simultaneous sample treatments being safe for the laboratory environment. The method consisted in 0.5 g of the sample, 15 minutes of ozonation, and 3 minutes of centrifugation. The obtained supernatant was ready for Cu and Zn determinations by flame atomic absorption spectrometry. Detection limits were 0.20 and 0.08 mg kg⁻¹ for Cu and Zn, respectively, with a precision (RSD) better than 5% for both elements. A certified reference material of rice flour was analyzed for trueness evaluation, and the mean recoveries (%) were 100.4 (Cu) and 95.9 (Zn). Several commercial rice samples were analyzed using this method, and the results were compared with those obtained using traditional microwave-assisted digestion (MAE). Both methods yielded comparable results. Cu and Zn levels were in accordance with reported values in other regions. The OAE resulted to be simple and economical and with results equivalent with those obtained using traditional sample preparation procedures as MAE with the advantage of being in good agreement with the principles of green analytical chemistry.

中文翻译：

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臭氧辅助样品制备方法的开发，用于测定大米样品中的铜和锌

开发了一种测定大米样品中铜和锌的绿色分析方法。该方法基于在稀酸介质中的臭氧辅助萃取 (OAE)。为此设计了一种新型封闭系统，允许同时进行四个样品处理，对实验室环境是安全的。该方法包括 0.5 g 样品、15 分钟的臭氧化和 3 分钟的离心。所得上清液可用于通过火焰原子吸收光谱法测定 Cu 和 Zn。检测限分别为 0.20 和 0.08 mg kg ^-1分别为 Cu 和 Zn，两种元素的精度 (RSD) 均优于 5%。分析了米粉的有证标准物质以进行正确度评估，平均回收率 (%) 为 100.4 (Cu) 和 95.9 (Zn)。使用这种方法分析了几个商业大米样品，并将结果与​​使用传统微波辅助消解 (MAE) 获得的结果进行了比较。两种方法都产生了可比较的结果。铜和锌的含量与其他地区的报道值一致。OAE 结果简单、经济，结果与使用传统样品制备程序获得的结果相同，作为 MAE，其优点是与绿色分析化学原理非常一致。