Research On Detection In The Column Chromatography Separation Based On Optical Fiber Surface Plasmon Resonance Sensor

Optical fiber SPR sensing technology can detect the minute changes on the surface of the metal layer,and has the advantages of high sensitivity,no labeling,and real-time online monitoring,with the principle of the surface plasmon polaritons resonance with the evanescent wave leaked from the optical fiber.This means that the optical fiber SPR sensing technology has a very important research value in the fields of environmental monitoring,biochemistry and medicine and pharmacy.As a conventional component separation method in the field of biochemistry,column chromatography(CC)has the advantages of low energy consumption,easy recovery and reuse of eluent,and high purity of the obtained product.Among them,classical column chromatography is an important method in the fields of organic synthesis product separation,protein separation,and extraction of active ingredients of traditional Chinese medicine in scientific research.However,manual column chromatography has complicated detection processes,such as spotting,expansion,color development,or UV absorption measurement of each collection liquid to draw the elution curve,which is tedious and time-consuming.The innovative application of fiber optic SPR sensors to column chromatography systems can effectively make up for the shortcomings of classical column chromatography.During column chromatography,the components of the mixed sample pass through the SPR probe.The change in sample concentration causes the refractive index of the gel around the probe to change dynamically.The SPR characteristic resonance spectrum shows a reversible shift in the wavelength range,which enables the monitoring of the number of components,concentration and separation state when samples flowing through the probe.The main research content of this article is mainly divided into the following sections:(1)The SPR coupling structure,resonance principle and modulation method are studied,and the theoretical models of online transmission and U-shaped SPR sensors are analyzed.The purpose is to guide the design of high performance,stable and reliable optical fiber SPR sensors.(2)An online transmission SPR sensor based on high polymer cladding fiber(HPCF)and a U-shaped SPR sensor based on ordinary multimode fiber and HPCF are proposed.The effects of parameters such as coating position,length,and bending diameter on the sensor's resonance curve and sensitivity are explored.On-line transmission SPR sensors have an average sensitivity of 2100 nm / RIU,a multimode U-shape of 4500 nm / RIU,and an HPCF U-shape of 2500 nm / RIU at a refractive index range of 1.33?1.37.(3)FMN-NA and BSA are mixed as a separation sample,and a HPCF U-shaped SPR sensor is embedded in a Sephadex gel column to monitor the separation process online.The resonance spectrum measured by SPR sensing shows that the entire separation process lasts about 57 minutes.The elution time of the separated BSA is 8 minutes,which causes a resonance wavelength shift of 15.5 nm,while the elution time of FMN-Na is 27 minutes,which causes the resonance wavelength to shift by 8.4 nm.Both the first-flowing macromolecular impurities or BSA and FMN-NA alter the resonance spectrum significantly.The comparison with traditional collection liquid absorption measurements also prove the feasibility of on-line detection by fiber optic SPR sensing.