Department of Applied Chemistry, Faculty of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan.
Anal Chem. 2013 Oct 1;85(19):8973-8. doi: 10.1021/ac402070z. Epub 2013 Sep 17.
This paper describes a colorimetric sensor array for the discrimination of volatile amines. Analyte discrimination is achieved by combining two functional elements: (1) a "chemical class-selective" single chromogenic sensing dye with selectivity for amines in general, encapsulated into (2) polymer nanoparticles with different polarities. The resulting array has the ability to distinguish one closely related amine from another, relying on a polarity-based approach. In order to achieve reproducible, cost efficient, and flexible sensor array fabrication with the potential for mass production, inkjet-printing technology combined with standard copy paper as a sensor substrate is applied. Printing of 6 types of inks, which are prepared by mixing two dye encapsulating nanoparticles of different polarity in different mixture ratios, results in a colorimetric sensor array with a polarity gradient. Seven primary amines with increasing alkyl chain lengths have been selected to demonstrate the performance of the sensor array. The RGB color differences (ΔR, ΔG, ΔB) of the sensor array spots before and after gas exposure were analyzed by principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) analysis. Under the selected measurement conditions, results of PCA and AHC analysis indicated high discrimination ability with high reproducibility of the sensor array down to amine concentrations of 50 ppm. The discrimination ability was maintained at relative humidities between 10% and 80%. Furthermore, the sensor array showed no significant response to common volatile organic compounds, confirming the high selectivity toward amines. This is, to the best of our knowledge, the first report of a colorimetric sensor array with selectivity for a specific chemical class of analytes and the ability to discriminate compounds of the same class, which is obtained by simply mixing two types of single dye-encapsulating polymer nanoparticles.
本文介绍了一种用于区分挥发性胺的比色传感器阵列。通过结合两种功能元件实现分析物的区分：（1）对胺类具有普遍选择性的“化学类选择性”单显色传感染料，封装在（2）具有不同极性的聚合物纳米粒子中。所得阵列具有基于极性的区分一种密切相关的胺与另一种胺的能力。为了实现具有批量生产潜力的可重复、经济高效且灵活的传感器阵列制造，采用喷墨打印技术结合标准复印纸作为传感器基底。通过混合两种具有不同极性的染料包封纳米粒子以不同混合比制备 6 种油墨进行打印，从而得到具有极性梯度的比色传感器阵列。选择了 7 种具有递增烷基链长度的伯胺来演示传感器阵列的性能。通过主成分分析（PCA）和凝聚层次聚类（AHC）分析，对传感器阵列斑点在气体暴露前后的 RGB 颜色差异（ΔR、ΔG、ΔB）进行了分析。在选定的测量条件下，PCA 和 AHC 分析结果表明，该传感器阵列具有很高的区分能力，并且在低至 50ppm 的胺浓度下具有很高的重现性。在 10%至 80%的相对湿度范围内，该区分能力得以保持。此外，该传感器阵列对常见的挥发性有机化合物没有明显的响应，证实了其对胺类的高选择性。据我们所知，这是第一个报道的具有对特定化学类分析物的选择性和区分同类化合物的能力的比色传感器阵列，这种能力是通过简单地混合两种类型的单染料包封聚合物纳米粒子获得的。
