Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031, China.
Environ Sci Technol. 2012 Jan 3;46(1):367-73. doi: 10.1021/es202137c. Epub 2011 Dec 12.
1,4-Dihydroxyanthraquinone (1,4-DHAQ, a fluorophore) doped cellulose (CL) (denoted as 1,4-DHAQ@CL) microporous nanofiber film has been achieved via simple electrospinning and subsequent deacetylating, and used for highly sensitive and selective fluorescence detection of Cu(2+) in aqueous solution. As the resultant byproduct of Cu(2+)-contaminated 1,4-DHAQ@CL nanofiber film showed recovered fluorescence by extra addition of Cr(3+) nitrate solution, 1,4-DHAQ and Cu(2+) codoped CL (denoted as (1,4-DHAQ)-Cu(2+)@CL)) microporous nanofiber film has been further fabricated for the detection of Cr(3+) in aqueous solution. It was found that the fluorescence intensity of the 1,4-DHAQ@CL microporous nanofiber film linearly decreases with Cu(2+) concentration ranging from 2.5 × 10(-9) to 3.75 × 10(-8) M, while that of the codoped (1,4-DHAQ)-Cu(2+)@CL nanofiber film linearly increases with Cr(3+) concentration from 2.5 × 10(-9) to 2.5 × 10(-8) M, both with high selectivity over many other common heavy metal ions. The sensing mechanism for Cu(2+) is ascribed to the formation of phenolate between 1,4-DHAQ and Cu(2+), while that for Cr(3+) is attributed to the reversing reaction from Cu(2+)-based phenolate to Cu(2+) and Cr(3+)-based excited complex with recovered fluorescence. The sensitive and selective detection of Cu(2+) and Cr(3+) by using the 1,4-DHAQ@CL and the (1,4-DHAQ)-Cu(2+)@CL nanofiber films was further demonstrated in polluted lake waters, thus indicating their potential applications in environmental monitoring of Cu(2+) and Cr(3+) in polluted water. Additionally, both the 1,4-DHAQ@CL and (1,4-DHAQ)-Cu(2+)@CL microporous nanofiber films are reusable for the detection of Cu(2+) and Cr(3+), respectively, after simple treatment. The design concept in this work might also open a door to the design of effective fluorescence probes for other heavy metal ions.
1,4-二羟基蒽醌（1,4-DHAQ，荧光团）掺杂纤维素（CL）（表示为 1,4-DHAQ@CL）微孔纳米纤维膜已通过简单的静电纺丝和随后的去乙酰化实现，并用于水溶液中 Cu(2+)的高灵敏度和选择性荧光检测。由于受 Cu(2+)污染的 1,4-DHAQ@CL 纳米纤维膜的副产物通过额外添加硝酸铬溶液显示出恢复的荧光，因此进一步制备了 1,4-DHAQ 和 Cu(2+)共掺杂的 CL（表示为（1,4-DHAQ）-Cu(2+)@CL）微孔纳米纤维膜，用于检测水溶液中的 Cr(3+)。结果发现，1,4-DHAQ@CL 微孔纳米纤维膜的荧光强度随 Cu(2+)浓度的线性降低范围从 2.5×10(-9)到 3.75×10(-8)M，而共掺杂的（1,4-DHAQ）-Cu(2+)@CL 纳米纤维膜的荧光强度随 Cr(3+)浓度的线性增加从 2.5×10(-9)到 2.5×10(-8)M，两者对许多其他常见重金属离子均具有高选择性。Cu(2+)的传感机制归因于 1,4-DHAQ 和 Cu(2+)之间形成的酚盐，而 Cr(3+)则归因于基于 Cu(2+)的酚盐到 Cu(2+)和 Cr(3+)的基于激发态络合物的逆反应，从而恢复了荧光。在受污染的湖水中进一步证明了 1,4-DHAQ@CL 和（1,4-DHAQ）-Cu(2+)@CL 纳米纤维膜对 Cu(2+)和 Cr(3+)的灵敏和选择性检测，从而表明它们在受污染水中 Cu(2+)和 Cr(3+)的环境监测中的潜在应用。此外，1,4-DHAQ@CL 和（1,4-DHAQ）-Cu(2+)@CL 微孔纳米纤维膜在简单处理后分别可重复用于 Cu(2+)和 Cr(3+)的检测。这项工作的设计理念也可能为其他重金属离子的有效荧光探针的设计开辟了道路。
