In this work, the metalloporphyrin film of PtOEP/Poly (St-co-TFEMA) modified by nano Al 2 O 3 powder was prepared, and the enhancement performance of oxygen sensing was studied in detail. It was verified that the modified film extended the residence time of oxygen through the characterization of SEM. The phosphorescence intensity changes with the content of Al 2 O 3 and PtOEP were studied. The Stern-Volmer equations before and after modification of Al 2 O 3 powder was compared. It was found that the linearity of the calibration curve was still high, but the oxygen sensitivity value of K SV was significantly improved due to the increase of quenching probability between indicator and oxygen. Finally, the stability test shows that the Al 2 O 3 @PtOEP/Poly (St-co-TFEMA) oxygen sensing film presents a strong anti-photo-bleaching ability, and the response time is shortened.
Jianhua Liu,Hui Chang,Xiangyu Zhang,Shimeng Chen,Yongxin Song,Dongqing Li
Building an optical filtration function into a microfluidic chip is a promising way of simplifying the optical detection system of a microfluidic device. In this paper, a PDMS microfluidic chip filter that is capable of transmitting chlorophyll fluorescence and blocking interfering light in the visible wavelength range was developed for living algae detection with a smartphone. The chip was fabricated by sealing a layer of crystal violet solution in a PDMS layer on the top of the Sudan II-doped PDMS slab, which has a straight microchannel. Optimum dye concentrations and thicknesses for the crystal violet solution layer and Sudan II-doped PDMS slab were investigated and determined by spectrum measurements. It was found that the cut-on range of this integrated microfluidic chip is extended to about 625 nm and the transmittance in the chlorophyll fluorescence range (650 nm to 710 nm) is as high as 95%, when 25 mg L−1 Sudan II-doped PDMS slab (with a 3 mm thickness) and 2 mg L−1 crystal violet solution (with a 0.3 mm thickness) were used. Living algae detection using this chlorophyll-fluorescence-filtering PDMS microfluidic chip and a smartphone-based imaging platform was achieved, and the results compared favorably with those using a commercial filter.