Muller Edson I, Souza Juliana P, Muller Cristiano C, Muller Aline L H, Mello Paola A, Bizzi Cezar A
Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
Talanta. 2016 Aug 15;156-157:232-238. doi: 10.1016/j.talanta.2016.05.019. Epub 2016 May 10.
In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL(-1) of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation.
在本研究中，一种绿色消解方法被应用于后续基于电感耦合等离子体技术的元素测定。该方法仅使用过氧化氢作为氧化剂，并在单反应腔系统（SRC-UltraWave™）中采用高温高压。选用奶粉来证明该方法的可行性和优势。高达500mg的样品质量能够被有效消解，通过电感耦合等离子体发射光谱法（ICP-OES）测定钙、铁、钾、镁和钠，而微量元素（硼、钡、镉、铜、锰、钼、铅、锶和锌）则通过电感耦合等离子体质谱法（ICP-MS）测定。消解后的残余碳（RC）低于918mgL(-1)的碳，这有助于最大限度地减少ICP-OES和ICP-MS测定中的干扰。使用标准参考物质NIST 1549（脱脂奶粉标准参考物质）和NIST 8435（全脂奶粉参考物质）评估准确性。所提方法获得的结果与认证参考值一致（t检验，95%置信水平）。此外，所提方法与使用浓硝酸的传统湿法消解所获结果之间未观察到显著差异。由于消解过程未使用任何种类的酸，与使用浓硝酸的传统湿法消解获得的消解物相比，最终消解物的特性符合绿色化学原则。此外，由于水是有机基质氧化的主要产物，过氧化氢消解物更适合后续基于ICP的技术分析。所提方法适用于奶粉中主要成分和微量元素的质量控制，符合绿色样品制备要求。
