Stability And Application Of Nano Silver SERS Substrate On Microfluidic Paper Chip

Surface enhanced Raman scattering(SERS)detection of nanomaterials has become a hot research field at home and abroad,and significant progress has been made in SERS technology based on nanomaterials of different sizes.Microfluidic paper chip technology has the advantages of low cost,simple manufacture,portability,high sensitivity and multiplex detection,so it has been widely used.In this paper,Microfluidic technology and SERS technology are combined to enhance the Raman signal by using the specific size of precious metal nanoparticles.Considering that a large number of amino groups on the surface of paper chip are conducive to the deposition of precious metal particles,so using nano silver particles as the base of Raman detection.The SERS signal can be clear and obvious,thus realizing the high sensitivity of the samples to be tested Testing.The main research conclusions are as follows:1.Nano silver based paper chip prepared by brushing method has strong Raman signal and good reproducibility.However,the stability of R6G(10~-33 M)as Raman reporter molecule was investigated.It was found that the Raman signal decreased with the increase of time in 0~48 h,and almost no Raman signal was detected after 48h,indicating that nano silver is easy to be oxidized when exposed to air directly overcome.2.The stability and sensitivity of the Raman signal of the paper chip coated with silver nanoparticles by polyurethane acrylate were investigated by using the"long-range"effect of SERS,and selected R6G as the Raman reporting molecule.It was found that there is still a strong Raman signal after 20 days storage in room temperature air,which indicates that this method can effectively avoid the agglomeration and oxidation of silver nanoparticles.The recovery rate of MG is 104.5%~125.2%,RSD is 0.74%~5.84%,the overall recovery rate and RSD are kept in a good range,and the detection effect is good.3.In order to further improve the performance of paper chips,an attempt was made to prepare polyurethane acrylate coated nano silver paper chips with more uniform Raman signals by spray deposition.It was found that the reproducibility of the prepared SERS based paper chip was good,with RSD=10.2%,which was far less than 12.6%of the brushing method.When R6G concentration is 10 nM,it still has obvious Raman signal.After 96 hours storage in room temperature,the paper chip still has strong Raman signal,which shows that its stability and sensitivity are improved.In the actual spiked recovery experiment of water samples,the recovery rate of R6G is 71.1%to 83.0%,and the RSD is 0.59%to 3.13%.The overall recovery rate and RSD are kept in a relatively ideal range,which shows that the detection effect is better.This shows that the spray method for the preparation of polyurethane acrylatecoated silver nanoparticle SERS based paper chips can detect R6G in section of environmental water samples.