Study On The Interference And Correction Methods Of (LA)ICP-MS/AES In Trace Elements Analysis

With the development of the electronics industry and the pharmaceutical industry,higher requirements are proposed on impurities in high-purity materials,especially ultra-clean high purity reagents and active pharmaceutical ingredients.However,there is a lack of method for the determination of impurities in different types of samples.Inductively coupled plasma mass spectrometry(ICP-MS)and inductively coupled plasma atomic emission spectrometry(ICP-AES)are the most commonly methods for elemental analysis,but the interference effects are different among samples.Laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)has been rapidly developed due to the advantages of simple preparation and fast handling.In this paper,the applications of ICP-MS,ICP-AES and LA-ICP-MS in the analyses of impurities in high purity materials and interference and correction methods were studied.(1)The method of ICP-AES and ICP-MS for the elemental impurities analysis in high purity materials was established.The interference and correction methods in the determination were studied.A pre-digestion step was established to increase the capacity of microwave digestion to maximize the processing of samples by 8 times,and 39 elements in three kinds of high-purity organic compounds,such as oxalic acid,were successfully determined.During ICP-AES analysis,the interference of Fe on Al and Mn was studied,the interference equation was established to calculate the background equivalent concentration and interference factor.And the result of Al and Mn in high-content iron samples was successfully corrected.The interference of Na on As,Pb,Cu,Cd,Fe in high-purity organic sodium compounds determination was evaluated.The result could be accurately corrected by matching a certain amount of sodium.(2)A method for the determination of Al,Mg,Zn,Ni,Ba and Pb in oxalic acid by LA-ICP-MS was established.Laser ablation mode,energy,spot size,frequency and flow rate were optimized.Due to the matrix effect,the results of the commercial glass standard correction were too high.Self-made matrix matching standard could obtain an accurate results.(3)The determination of bromine in serum by ICP-MS with aqueous solution standard using methanol extraction was proposed.The bromine and proteins in the serum were separated to avoid the influence of protein.The interference of methanol in the process was evaluated,the methanol volatilization step could reduce the methanol effect.The results were compared with those by synthetic serum matrix reported in the literature,which showed a good accuracy.At the same time,a method for determination bromine and iodine in serum by LA-ICP-MS with aqueous solution standard was established.The appropriate color indicator,Alizarin Red,was chosen.Different serum pretreatment methods were evaluated,and serum dilution 10 times was selected as pretreatment method Then the main parameters of laser ablation such as energy,scan speed,spot size,frequency and carrier gas flow rate were optimized to obtain a sensitive and relatively stable signal.The results of LA were compared with the results of ICP-MS,which showed a better accuracy.