Determination Of Alkaloids And Their Metabolites Bv LC-MS/MS

For thousands of years,large quantities of secret recipes,prescriptions,recipe books about the three herbs mentioned above spread abroad in our country folk which brings about severe food poisoning constantly because of improperly processed before use.Hence,accurate and efficient analytical method to determine the concentrations of alkaloids in cooked food samples is imperative for the food safety.The main research contains four chapters as follows.In chapter 1,the main properties of three kinds of alkaloid including geographical distribution,physical and chemical properties,biological activity and toxicity,were introduced.And the conventional detection methods of alkaloids were described,including thin layer chromatography(TLC),gas chromatography(GC),capillary electrophoresis(CE)and liquid chromatography(HPLC).Furthermore,the common pretreatment methods of the toxic alkaloid were introduced,including liquid-liquid extraction(LLE),solid phase extraction(SPE)and magnetic solid phase extraction(MSPE).At last,the significance and methods of the study on drug metabolism were introduced.In chapter 2,the mass spectrometry conditions of alkaloid were optimized.The tandem multistage mass spectrometry analysis of alkaloids was carried out under the optimal conditions.The fragmentation patterns of alkaloids were studied according to the informations obtained from the mass spectrogram.In chapter 3,an ultra-fast liquid chromatography-tandem quadrupole mass spectrometry(UFLC-MS/MS)coupled with solid phase extraction method had been developed to determine 15 alkaloids in cooked food samples.Solid phase extraction was used in the pretreatment of samples.Solid phase extraction columns and the sample extraction solvent were optimized.Under the optimal conditions,satisfactory recoveries,i.e.,67.2-135%for meat dishes and 71.3-133%for vegetable dishes were obtained.At the same time,low limits of detection(0.018-0.305 ng/g)and low limits of quantification(0.059-0.971 ng/g)for vegetable dishes were obtained;low limits of detection(0.022-0.368 ng/g)amd low limits of quantification(0.080-0.982 ng/g)for meat dishes were obtained.In chapter 4,an ultra-fast liquid chromatography-tandem quadrupole mass spectrometry(UFLC-MS/MS)coupled with magnetic solid phase extraction method had been developed to determine 15 alkaloids in cooked food samples.The novel PAMAM@Mag-CNTs was prepared and then applied to an efficient and simple DPT-MSPE method for extraction fifteen alkaloids in meat dishes and vegetable dishes.Under the optimal conditions,satisfactory recoveries,i.e.,82.4-125%for meat dishes and 84.2-122%for vegetable dishes were obtained.At the same time,low limits of detection(0.016-0.317 ng/g)and low limits of quantification(0.054-1.058 ng/g)for vegetable dishes were obtained;low limits of detection(0.011-0.329 ng/g)and low limits of quantification(0.035-0.870 ng/g)for meat dishes were obtained.The recoveries of targets were better than that of solid phase extraction method in chapter 3.In chapter 5,in vitro metabolic simulation experiments of six alkaloids were carried out in the solution containing biological buffer and human cytochrome P450 enzyme.A high resolution mass spectrometer was used to detect the reaction fluid.The results showed that the original medicines and the same metabolites of every alkaloid under different enzyme reaction conditions were found which indicated six enzymes were synergistic to the metabolic reaction of aconitum alkaloids.