Microfluidic paper chip based multicolor chemiluminescence sensing strategy for discrimination of antioxidants

The development of chemiluminescence (CL) sensing strategy with multiple-parameters for discrimination of small molecules remains a great challenge. Herein, a multicolor CL sensing strategy for the discrimination of five antioxidants, including dopamine, catechin, cysteine, glutathione, and thioctic acid was presented. Firstly, multilayer paper chips modified with luminol-Co(II), luminol-fluorescein-Co(II), and luminol-rhodamine B-Co(II) that can produce strong blue, green and purple colored light emission, respectively, via CL and CL resonance energy transfer (CRET) reactions were fabricated. The presence of antioxidants exhibits different inhibition or enhancement effect on the CL reactions, creating unique multicolor CL response pattern to each antioxidant. The red (R), green (G), and blue (B) channel split from the purple, green and blue CL image, respectively, generate cross-reactive sensing parameters for the discrimination of the five antioxidants. The distinct R, G, and B values of the CL images to each antioxidant are created as analytical fingerprints to identify five antioxidants by using principal component analysis and hierarchical cluster analysis. Satisfied results were obtained for discrimination antioxidant mixtures and spiked antioxidants in serum samples. Identification of 10 unknown samples resulted in 100% accuracy. This work presents the first example of multicolor CL sensing strategy for the discrimination of small molecules.