College of Chemical and Environmental Engineering, Wuhan Polytechnic University, 68 Xuefu South Road, Changqing Garden, Wuhan 430023, PR China.
College of Chemical and Environmental Engineering, Wuhan Polytechnic University, 68 Xuefu South Road, Changqing Garden, Wuhan 430023, PR China.
Food Chem. 2014 May 1;150:254-9. doi: 10.1016/j.foodchem.2013.10.150. Epub 2013 Nov 4.
Titanium dioxide nanotubes (TDNTs) were used as a solid phase extraction adsorbent for chromium species by a packed microcolumn coupled with inductively coupled plasma mass spectrometry (ICP-MS), including total, suspended and soluble chromium as well as Cr(III) and Cr(VI) in tea leaves and tea infusion. The experimental results indicated that Cr(III) was quantitatively retained on TDNTs in the pH range of 5.0-8.0, while Cr(VI) remained in the solution. The total chromium was determined after reducing Cr(VI) to Cr(III). The concentration of Cr(VI) is calculated by the difference between total chromium and Cr(III). Under optimal conditions, the detection limits of this method were 0.0075ngmL(-1) for Cr(III). The relative standard deviation was 3.8% (n=9, c=1.0ngmL(-1)). This method was applied for the analysis of the speciation of chromium and its distribution and content in tea leaves, tea infusion and a certified reference material of tea leaves with satisfactory results.
钛纳米管（TDNTs）被用作一种固相萃取吸附剂，通过填充微柱与电感耦合等离子体质谱（ICP-MS）联用，用于茶叶和茶浸提液中铬形态的分析，包括总铬、悬浮铬和可溶铬以及 Cr(III) 和 Cr(VI)。实验结果表明，在 pH 值为 5.0-8.0 的范围内，Cr(III)可以定量保留在 TDNTs 上，而 Cr(VI)则留在溶液中。Cr(VI)被还原为 Cr(III)后，即可测定总铬。Cr(VI)的浓度通过总铬与 Cr(III)的差值计算得出。在最佳条件下，该方法对 Cr(III)的检测限为 0.0075ngmL(-1)。相对标准偏差为 3.8%（n=9，c=1.0ngmL(-1)）。该方法用于茶叶、茶浸提液和茶叶标准物质中铬的形态分析及其分布和含量的测定，结果令人满意。
