| Due to the large amount of matrix and endogenous substances existing in biological samples,so the samples’ pretreatment is very important for accurate analysing.For example there are cells,carbohydrates,proteins and other biological macromolecules in plasma samples which can interfere the target component.Therefore the biological samples need to be generally isolated and purified before analysisor be chemically modified so that the samples can be tested easily.In this paper,a new kind of solid-phase extraction cartridge is prepared and the optimal filler which is screened from 25 kinds of fillers that its filling method is deeply studied.The new solid-phase extraction cartridge can be applied to samples pretreatment and the result is evaluated using methodology.The main experiment result are as follws:A new type of solid phase extraction cartridge was prepared and the filling method,eluent composition and elution method were discussed.Under the optimal filling way,No.22 filling was chosen as owning the best permeability performance from 25 types of fillers.Choosing methanol and acetonitrile as eluent and comparing the elution rate so that the best eluent and elution mode were confirmed.Finally,the best elution mode was 100 μL methanol plus 20 μL blood sample and plus 100 μL methanol.The solid phase cartridges was evaluated in four aspects:Firstly,the excluding method of distractions was studied by comparing the quality of distractions attained by the precipitation method and the new solid phase extraction method.The result shows that the quality of distracions got by the precipitation method is 41 times greater than attained by the new solid phase extraction method which indicates that the new solid phase extraction method can effectively eliminate interferences.Secondly,the effect of blank interference on the experimental results was discussed using the ratio of the peak areas of the reference and standard products at different levels of addition.The experimental results show that the ratio of all the samples’ peak area were between 0.94 and 1.04 which indicated that the influence of the new solid phase extraction column on the determination of the sample composition was negligible.Thirdly,the recoveries and matrix effects of the novel solid phase extraction and precipitation methods for three different dosages’ drugs were investigated.The experimental results show that the recovery rate from the precipitation method was between 81%and 86%,RSD was less than 4.9%(n=6),the recovery rate from the new solid phase extraction method was between 89%and 92%and the RSD was less than or equal to 3.3%(n=6).Therefore,compared with the precipitation method,the new solid phase extraction method could more accurately detect the target in the sample.Fourthly,under different amounts of three drugs,the peak area had different RSD value,and this method was reproducible.The result shows that the RSD value of six groups of peak area were all less than 7.7%(n=6)that proved that this method had the good reproducibility.In combination with LC-MS,a novel SPE pretreatment method is applied to the analysis of 20 components in plasma,and its linear correlation,accuracy,precision,added recovery,and stability are caculated and assessed.The result showed that the linear correlation coefficient of all drugs were greater than 0.9990,the average recovery was between 82%-113%and RSD was less than or equal to 17.9%,they were all within the allowable error of drug analysis.Therefore,the establishment of this method can provide a reliable basis for the analysis and determination of drugs in plasma. |
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