Detection Of Methamphetamine In Hair By Microfluidic Chip And Fabrication Of A Wet TEM Cell

Microfluidic chip is a technology that can manipulate microfluidics on a few square centimeters in size.It can be used to integrate the typical steps of pretreatment into the chip,such as chemical reaction,separation,detection and analysis of biological samples.The advantages of low sample consumption,rapid analysis,low cost,high throughput,easy integration and automatic detection make microfluidic chip widely used in biochemical analysis field,which represents the forward direction of detection devices towards the continuous miniaturization in future.Based on the technology of microfluidic chip,our research is aimed to detect the methamphetamine in hair and develop the wet cell for in situ transmission electron microscopy(TEM).The main contents of this paper are as follows.1.It is well-known that methamphetamine poses a serious threat to public safety and health.Therefore,it is quite urgent to establish a facile method for the rapid detection of methamphetamine.In this paper,we present a method based on the microfluidic device for detecting trace concentration of methamphetamine in hair through using surface-enhanced Raman spectroscopy(SERS).In detail,we optimized the way of hair degradation,designed the glass chip,and synthesized and modified Au as well as Fe3O4 nanoparticles.In addition,we also detected the methamphetamine concentration by optimizing laser wavelength,detection time and other conditions.This method allows us to detect methamphetamine with a lower limit of detection(ca.10 fg-mL-1)including the linear correlation coefficient R2= 0.99423.Furthermore,the actual samples were tested.Compared with the traditional multi-reaction monitoring(MRM)method,our method presented here shows the same order of magnitude in the detection of methamphetamine concentration.2.The in situ wet cell TEM is capable of studying structures and processes in liquid environment with high temporal and spatial resolutions.Herein,we present a new method for fabricating the wet cell based on the bonding of SiO2-SiO2.By exploring and optimizing the bonding process,including the ratio of silicon to oxide in silicon oxide,silicon valence state,surface roughness,surface treatment,temperature and pressure,the SiO2 chips direct bonding was successfully achieved.In addition,to verify the feasibility of the wet cell in TEM,we optimized a full range of the processes of the wet cell.