The Research On Matrix Effect Of High Salt Samples And The Establishment Of Analysis Method Using Solid Phase Extraction-Inductively Coupled Plasma Mass Spectrometry

With the continuous development of science and technology,trace elements gradually show its importance in all kinds of research areas.Inductively coupled plasma mass spectrometry(ICP-MS)is the most rapid and accurate method for the detection of trace elements.It has the advantages of multi-element simultaneous detection,wide dynamic linear range,high sensitivity and good precision.But there are still some interferences with this technology,such as mass spectral interference and non-mass spectral interference(matrix effect).At present,there are a variety of effective techniques to eliminate mass spectrometry interference,but there is no systematic elimination method for the matrix effect.High salt samples are common samples in ICP-MS analysis.When ICP-MS is used to analyze high-salt samples,the easyionization elements such as alkali metal and alkaline earth metals would change the state of the plasma and affect the sensitivities of elements and the accuracy of test results.The significance of our subject was to study the matrix effect of ICP-MS in the analysis of high salt samples systematically,and use solid phase extraction-inductively coupled plasma mass spectrometry(SPE-ICP-MS)technology to detect six elements in high salt samples.The relationship between the matrix effect correction factors of elements and their physical and chemical properties at different matrix concentrations was analyzed by multiple linear regression,using sodium chloride as the representative of high salt matrix.In order to explain the influence of high salt matrix on the sensitivity of elements,we investigated the factors of ICP-MS such as sample transfer efficiency,plasma temperature,sampling depth,radial position of the torch and nebulizer gas flow rate.We also summed up the optimization direction of the instrument conditions,including increasing the sampling depth,changing the radial position of the torch and reducing nebulizer gas flow rate.At this conclusion,the elimination consequent of high salt matrix effect was evaluated through the combination of optimized nebulizer gas flow rate and the internal standard method.In order to eliminate the matrix effect of high salt samples more better,sample pretreatment technology was also studied.3-aminoethylaminopropyltrimethoxysilane modified silica nanoparticles with high adsorption capacity and high adsorption efficiency were synthesized in this work.The experimental results showed that this material hardly adsorbed alkali metal,alkaline earth metal ions and anions,and had a good removal effect of high salt matrix.In order to establish the analytical method of SPE-ICP-MS for high salt samples,the experimental conditions such as pH,sample volume,eluent type and concentration,sample solution and eluent flow rate were optimized.Then,the detection limit and precision of the method were studied,and the quantitative analysis ability of this method about nickel,copper,gallium,cadmium,lead and bismuth elements in seawater and milk powder samples was proved by spike recovery experinment.