An online derivatization strategy targeting carbon-carbon double bonds by laser-ablation carbon fiber ionization mass spectrometry imaging: Unraveling the spatial characteristic in mountain-cultivated ginseng and garden-cultivated ginseng with different ages.

Serving as a world-renowned tonic, ginseng contains various types of bioactive metabolites. The comprehensive profiling of these metabolites may help explore the nutritional value of ginseng. Due to high variety in chemical structures, simultaneous monitoring of these metabolites remains a challenge. Herein, a high-throughput and high-selectivity online derivatization mass spectrometry imaging strategy targeting CC was developed. As a widely existed chemical group, CC acts like a bridge connecting different kinds of metabolites. [d0]/[d10]-Bis(pyridine) iodine tetrafluoroboride reagent was chosen for the derivatization of CC, the detection sensitivity of which increased about 3 magnitudes after derivatization. Assisted by laser ablation carbon fiber ionization mass spectrometry, the spatial distribution of bioactive metabolites in mountain-cultivated and garden-cultivated ginseng were visualized. The correlation heatmap results revealed that metabolites in mountain-cultivated ginseng hold higher correlation than those in garden-cultivated ginseng. The proposed method showed potential in providing comprehensive information on the nutrient content of foods.

Ultrasonic extraction and nebulization in real-time coupled with carbon fiber ionization mass spectrometry for rapid screening of the synthetic drugs adulterated into herbal products.

Ultrasonic extraction and nebulization in real-time/carbon fiber ionization mass spectrometry (UEN/CFI-MS) was developed to screen the synthetic drugs adulterated into herbal products such as antidiabetic drug, antihypertensive drug, and hypolipidemic drug. Recently, ambient ionization MS techniques have achieved great advance for rapid analysis of sample surface. However, direct analysis of the analytes inside samples remains a challenge due to a lack of effective online sample extraction procedures. Owing to disappointing desorption efficiency, analytes inside the sample suffer from low detecting sensitivity when applying ambient ionization MS techniques. In this study, online ultrasonic extraction combined with carbon fiber ionization was used for real-time extraction, nebulization and detection of the analytes inside samples. The ultrasonic atomizer could produce a high-frequency vibration to realize online extraction and nebulization of sample. Then, the produced sample droplets could be immediately ionized by the carbon fiber ionization mass spectrometry. UEN/CFI-MS has shown great compatibility to solvents and compounds with a wide range of polarity and has few limitations for the shape of sample. UEN/CFI-MS was successfully applied for the rapid screening of synthetic drugs adulterated into herbal products. Among 37 batches of herbal products, 1 batch of Chinese patent medicine and 6 batches of dietary supplements were detected to be adulterated with the synthetic chemicals without labeling.