Preparation And Application Of Stable Isotope Labeled Probes For Mass Spectrometry Sensitizatio

High performance liquid chromatography-tandem mass spectrometry（HPLC–MS/MS）is an effective technique for trace component analysis,but the sensitivity of the method is closely related to the ionization degree of the analytes,and the analytes with low ionization efficiency are difficult to be effectively detected by HPLC–MS/MS.Due to the difference between standards and analytes,the accuracy of the analytical results is prone to deviate from the true value due to the matrix effect.In this study,a series of stable isotope labeling probes with mass spectrum sensitization effect were designed and prepared,which were used for HPLC–MS/MS analysis of trace harmful substances in food.Quaternary amine and tertiary amine groups were introduced into the labeling probes to improve the analytical sensitivity.The matrix effect was effectively minimized by using the internal standard quantitative function of the stable isotope labeling strategy.The established method has been successfully applied to the analysis of trace components such as phenols,amines,and mercaptans,and the specific work is as follows:Chapter one:In this chapter,the methods of mass spectrometry and their classification were briefly reviewed.The common sensitizing probes of mass spectrometry were summarized,and the stable isotope labeling technology and its application were introduced in detail.The main research content and significance of this paper were expounded.Chapter two:In this chapter,a pair of novel stable isotope-labeling probes,4-（1,3-dimethyl-benzimidazole-2-yl）benzoate succinimide iodide（d₀-DPDBM）and its deuterated product（d₆-DPDBM）,were designed and prepared for HPLC–MS/MS analysis of bisphenol compounds（BPs）.Both water-soluble and lipo-soluble impurities were effectively removed by extraction and reverse extraction,and the accuracy of the analysis was improved.The proposed method was applied to the analysis of BPs in the samples of food and packaging materials.The detection limits were in the range of 1.5–6.5 ng·L^-1,and the quantification limits were in the range of4.9–21.5 ng·L^-1.The recoveries were in the range of 90.2%–96.4%,and the matrix effect ranged from–5.6%to 3.9%.Chapter three:In this chapter,a pair of cationic stable isotope labeling agents（4-carbonyl chloroyl phenyl）-N,N,N-trimethyl ammonium iodide（d₀-CCPTA）and its deuterated product d₆-CCPTA were designed and synthesized.They were used for the quantitative analysis of advanced glycation end products（AGEs）in foods.A generic multiple reaction monitoring（MRM）method was established by using N-ε-1-carboxymethyl-L-lysine,pyrraline,N-ε-（1-carboxyethyl）-L-lysine,and other standards.It was applied to the pseudo-targeted analysis of unknown AGEs in food,and 13 substances were detected.The detection limits were was in the range of 3.1–7.1 ng·kg^-1,and the limit of quantifications were in the range of 10.0–23.7 ng·kg^-1.The recoveries ranged from 90.1%to 94.3%,the matrix effect ranged from–7.1%to–2.7%.Chapter four:In this chapter,a pair of stable isotope-labeled quaternary ammonium salt probes d₀/d₃-4-（N-maleimide）phenyl-trimethylammonium iodide（d₀-MPTA/d₃-MPTA）with positive charge were designed,prepared,and confirmed.The synthesized stable isotope labeling reagent was used for the rapid HPLC–MS/MS analysis of five mercaptan compounds in rubber products,and the derivation conditions of mercaptan compounds were optimized.The detection limits ranged from 0.8 to 6.1 ng·L^-1,while the quantitation limits ranged from 2.7 to 20.2 ng·L^-1.The recoveries ranged from 90.1%to 96.7%,and the matrix effect ranged from–6.1%to 3.5%.Chapter five:In this chapter,dansyl chloride（DNS-Cl）and deuterated dansyl chloride（d₆-DNS-Cl）were selected as labeling reagents,and the stable isotope labeling strategy was applied to the quantitative detection of mycotoxins by HPLC–MS/MS,which improved the sensitivity of HPLC–MS/MS and minimized the matrix effect.The limits of detection and quantitation of mycotoxins in grain samples were in the range of 4.0–7.0μg·kg^-1 and 13.0–24.0μg·kg^-1respectively.The recoveries were in the range of 90.3%–94.3%,and the matrix effect was between–3.2%and–6.5%.