Investigation On The Metal Element Imaging Methods And Its Applications

Metals or metalloids play an indispensable role in life activities.The lack or excess of metals/metalloids can lead to serious diseases of living body.The achievement of the location and environmental information of metals/metalloids in living body is becoming more important with the developing studies on the metal elements,resulting in the urgent requirement on the methodologies developed for in situ imaging analysis of metal elements in living organism.In present study,a new isotope dilution-laser ablation inductively coupled plasma mass spectrometry(ID-LA-ICP-MS)method is firstly developed for quantitative imaging.By using the electric-filed-assisted-scanning-spraying(EFASS)device,65Cu and 67Zn isotope diluents are added onto the biological tissue samples uniformly.After the optimization of experimental conditions,a method for uniformly addition of isotope diluent is established with a-cyano-4hydroxycinnamic acid(CHCA)as the matrix and methanol as solvent.The relative standard deviation of the signal intensity for the added isotope diluent is lower than 10%(n=30).The quantitative imaging of Cu and Zn in mouse brain tissue was achieved by measuring the change of isotope ratio after isotope-diluent-addition by ICP-MS.The imaging results showed that the Zn concentration in the mouse brain was between 10-20 μg g-1 and the Cu concentration was between 8-15 μg g-1.In order to further expand the applications of metal element imaging technique,element imaging methods are used for fingerprint imaging analysis.The imaging of Ti and Zn elements in four sunscreen fingerprints are obtained by synchrotron radiation X-ray fluorescence(SRXRF),laser induced breakdown spectroscopy(LIBS)and X-ray fluorescence(XRF)imaging techniques.The results indicate that titanium oxide nanoparticles and zinc oxide nanoparticles,which are able to reflect sunlight,are found in the sunscreen samples based on the physical sunscreen principle,and the ratio of these two nanoparticles are different from each other in different brands of sunscreens.Thereafter,the imaging of fingerprints on different carriers such as copy paper,glass and ziplock bags are performed by X-ray fluorescence(XRF)imaging technique,and clear Ti and Zn elements imaging are obtained,indicating the feasibility of this established metal element imaging technique in actual fingerprint analysis.