A Study On Application Of Liquid Chromatography-inductively Coupled Plasma Mass Spectrometry And Standardization Of Detection Methods

Currently,liquid chromatography inductively coupled plasma mass spectrometry(LC-ICP-MS)has been widely used in the analysis of various elements in biomedical,environmental,food risk assessment,materials and other fields.However,compared with the common liquid chromatography-mass spectrometry(LC-MS)and gas chromatography-mass spectrometry(GC-MS),the application scope and popularity of LC-ICP-MS need to be improved,and also some problems,needed to be solved,exsist in some subdivision fields.In this thesis,based on innovation and optimization on LC-ICP-MS,we successful analyzed analytes which can not be easily handeled by using conventional detection method.The national standard methods are indispensable for the country and society development,and as guidelines are important for production,evaluation and goverment supervision.Since,results and identification conclusions obtained by standard methods have clear legal significance.Therefore,it is of great practical significance to develop standard methods.In this these,a national standard method for the detection of iodoacetic acid in drinking water and a national standard method for the detection of asbestos in drinking water were developed based on using LC-ICP-MS and scanning electron microscope energy dispersive spectrometry(SEM-EDS)respectively.Both of these two standard methods are new and fill up the blank of the country.Main study content has been summarized as follows:(1)We employed LC-ICP-MS to explore bromine bioforms in human serum.Three bromine species were found by size exclusion chromatography-inductively coupled plasma mass spectrometry(SEC-ICP-MS),and one of the most abundant species was identified as Br^-by anion exchange chromatography-inductively coupled plasma mass spectrometry(IC-ICP-MS).Results for the determination of Br^-and total bromine in human serum revealed that Br^-is the major form of bromine in human serum,with a ratio ranging from 57%to 69%.Furthermore,we developed a method for the determination of ambroxol based on reversed phase high-performance liquid chromatography-inductively coupled plasma mass spectrometry(RP-HPLC-ICP-MS)and then applied it in rat plasma analysis.After optimization of the PR-HPLC-ICP-MS parameters and pre-treatment procedures,the retention time of ambroxol was4.6 min and the detection limit was 7.0?g L^-1.The average recoveries were 85%,with relative standard deviations(RSD)of 8%.These data met the requirements of GBZ/T295-2017"General principles of biological monitoring method in occupational population".The above results showed that the RP-HPLC-ICP-MS method possessed the advantages of low matrix interference and time efficiency,which were better than those reported for traditional RP-HPLC methods.Therefore,this new method for the detection of ambroxol based on RP-HPLC-ICP-MS was certainly a good tool for ambroxol analysis and had promotion values.Additionally,the quantitative data of Br^-and total bromine in human serum provided clues for further study on the distribution and physiological function of endogenous bromine.(2)A method for the determination of trace inorganic antimony in PET-bottled soy sauce by IC-ICP-MS was developed.Trace inorganic Sb(III)has been discovered in PET-bottled soy sauce but has been difficult to directly quantify by using IC-ICP-MS.To determine trace inorganic Sb(III)in soy sauce,the sample was first filtered through a solid-phase extraction(SPE)column and then subsequently washed with L-ascorbic acid and methanol.Finally,the SPE column was eluted with 1.0 m L of 0.1%Na OH+2%H₂O₂.Under such conditions,the enriched inorganic Sb(III)in the SPE column converted into inorganic Sb(V)and was successfully eluted.Finally,the amount of inorganic Sb(V)in the eluate,equal to the amount of inorganic Sb(III)in the sample,was quantitatively analyzed by IC-ICP-MS.Thus,inorganic Sb(III)in soy sauce was detected.In the above method,the limit of detection(LOD)of inorganic Sb(III)was0.1?g L^-1.The RSD(n=6)was 9%,and the average recoveries(n=6)were 94%.These data met the requirements of GB/T 27404-2008"Criterion on quality control of laboratories".Comparing the amount of inorganic Sb(III)with the total antimony,we found that 26%to 50%of the total antimony in soy sauce was inorganic Sb(III).So,it is proved that trace inorganic Sb(III)exists in PET bottled soy sauce,which will bring food safety risk.The pretreatment method developed can be used not only for the determination of trace inorganic Sb(III)in soy sauce,but also for the determination of trace inorganic Sb(III)in other types of samples.Hence,it has strong promotion values and could be used as a standard method.(3)We have developed a method to directly detect monoiodoacetic acid(MIAA) and diiodoacetic acid(DIAA)in drinking water using LC-ICP-MS.MIAA and DIAA were qualitatively analyzed based on the retention time and quantitatively measured using the peak area integral.Compared with conventional GC,GC-MS and LC-MS methods,this method is of low matrix effect,interference free and strong adaptability.The method needs neither pretreatment step nor organic reagents,so it is environmentally-friendly.The figures of merit from five independent labs revealed that the LODs of the method were 0.06?0.22?g/L for MIAA and 0.04?0.18?g/L for DIAA.The spiking recoveries at high,medium,and low concentrations from five labs were 97%?101%,94%?103%,95%?107%respectively(MIAA)and 97%?102%,96%?100%,94%?103%respectively,with RSDs all below 6%.These data met the requirements of GB/T 5750.3-2006"Standard examination methods for dringking water analysis quality control".Additionally,the results for the quality control samples from five labs were consistent with one another.All the clues proved that the method is accurate and adaptable.Hence,the method used to detect MIAA and DIAA in drinking water is qualified as a standard method for wide application.Furthermore,the generation study of iodoacetic acids(IAAs)in ultraviolet-chlorine(UV₂₇₅-Cl₂)and Cl₂disinfection systems was conducted.The results showed that the amount of IAAs was significantly higher when UV₂₇₅-Cl₂ was used to disinfect the high-iodium water than when only Cl₂ was applied,especially in weak acid conditions.This conclusion is of great importance in suggesting how to reduce the potential risk of IAAs when producing drinking water when chlorine or a UV₂₇₅-Cl₂disinfection process is applied.The results also revealed that the risk of iodoacetic acid in drinking water by chlorine disinfection is not high.(4)A method for qualitative and quantitative determination of asbestos in drinking water by SEM-EDS had been established.Asbestos fibers with widths greater than0.050?0.124?m could be measured by SEM-EDS qualitatively and quantitatively.The organic interference in water samples could be eliminated by using UV-potassium persulfate digestion.The method was validated by six independent laboratories through dectecting simulated asbestos suspensions at high,medium and low concentrations.The results of spiking experiment at high,medium and low concentrations showed that the intra-lab RSDs were 10%,17%,37%respectively,and inter-lab RSDs were 10%,19%,39%respectively,and the average recovery of blue-green algae interference experiment was 98%with RSD 11%.The LODs were5.0×10⁴?11.6×10⁴ f/L in six labs,which were much lower than the limit in GB 5749.Compared with the transmission electron microscopy-energy dispersive spectrometry(TEM-EDS)method used by USEPA,our method has the advantages of simple and low cost.The method will be used as a national standard method in the new edition of GB/T 5750.