Click Isotope Mass Probe for Highly Selective Determination of Trace Steroid Hormones in Food Samples

Matrix effects are a great challenge for the quantitative analysis of complex food samples by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS). Stable isotope labeling (SIL) has been widely used as an effective strategy toeliminate matrix effects. Herein, a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click-reaction-based SIL method wasproposed for a highly sensitive and selective determination of six synthetic steroid hormones in three different food samples (milk,yogurt, and eggs) by high-performance liquid chromatography (HPLC)-MS/MS. A pair of novel SIL agents,N-(2-azidyl ethyl)aniline (d0-AEA) andd5-N-(2-azidyl ethyl) aniline (d5-AEA) were synthesized to label steroid hormones in the samples and standardsolution, respectively. The reaction accomplishes in 30 min at 60 degrees C. The heavy labeled standards were used as internal standards(ISs), which experience the identical ionization processes with light labeled samples to minimize matrix effects. After derivatization,the ionization efficiencies of steroid hormones were greatly improved by 2-54-folds, and the matrix effects ranged from 88.6 to99.8%. The established method achieved satisfactory detection limits (0.1-2.5 mu gL-1) and high recoveries (85-102%). Theseresults demonstrated that the proposed method holds unique advantages for trace steroid hormones analysis in foodstuffs

Automated summary

This study proposes a SIL method based on CuAAC click-reaction for quantitative analysis of synthetic steroid hormones in complex food samples by HPLC-MS/MS. The method effectively eliminates matrix effects and improves ionization efficiency and sensitivity by labeling steroid hormones in the samples. It demonstrates unique advantages for trace analysis of steroid hormones in foodstuffs.