Research on advanced methods of electrochemiluminescence detection combined with optical imaging analysis for the detection of sulfonamides.

In this study, a novel method that combines electrochemiluminescence (ECL) analysis and digital image processing was developed for the detection of sulfonamides. This method is based on the ECL system of ruthenium terpyridine, with 1 mM tripropylamine as a co-reactant to enhance the performance. Under the optimal conditions comprising a solution of pH 7 and a scanning rate of 0.08 V s-1, the Pt electrode has an excellent linear detection range from 5 µM to 5 mM, with a detection limit of 0.85 µM (S/N = 3). A wireless camera is used to record the light-emitting process. The recordings are processed, and the digital images are extracted using image-processing algorithms implemented in Python to calculate the brightness value of the image, which has a linear relationship with the logarithm of the sulfonamide concentration. Image analysis simplifies and improves the stability of the ECL analysis process, while also increasing the speed of analysis. The results indicate that the method can successfully detect a sulfonamide concentration of 5 µM. Thus, the analysis method of ECL combined with image processing is feasible for the detection of sulfonamides, thereby displaying its potential applicability as a novel method in drug and food safety, for instance, for sulfonamide detection in antibiotics.

Influence of ghost coupling points on distributed polarization crosstalk measurements in high birefringence fiber and its solution.

Ghost coupling points in distributed polarization crosstalk measurements adopting a white light interferometric method are analyzed under the circumstances of anisotropy perturbation induced polarization crosstalk and principal axis misalignment induced polarization crosstalk in polarization-maintaining fiber. The relationship between the intensities of the ghost coupling points and the real crosstalk points, as well as the relationship between their positions, are theoretically analyzed and proved by experiment. A simple method has been developed to identify the ghost coupling points by using a rotatable half-wave plate to adjust the angle between the principal axis of the analyzer and the exciting mode propagating in the polarization-maintaining fiber. The experimental results have a good agreement with the theoretical results.